Rear End Assembly

Today I re-assembled the rear end, which included replacing the leaf springs, re-attaching the differential, and installing the new shock absorbers.

I am going with a different rear suspension set-up than stock or what came with the car. I bought a new pair of rear leaf springs. After reading the recommendations in the Bob Sharp Competition Manual I decided to swap out the later-style leaf springs for a pair of the early roadster leaf springs that came in the pre 1967.5 1600 and 1500 cars. The early-style springs have the same dimensions as the later ones, but are a bit firmer and maybe a bit lower. The other popular option is to go with a pair of Nissan Competition leaf springs. Although these are more readily available than the early-style stock springs, they are very flat and most people say they ride pretty rough. I am looking for good handling without too much compromise in ride comfort, so the early stock springs are what I chose.

The early-style stock leaf springs are No Longer Available from Nissan in the U.S. (I checked). Using the part number I inquired of a number of custom spring manufacturers to see if I could have a set made to spec. The cheapest I found was $300 per set at an order quantity of five pairs. I figured I could find four other people looking to get these springs but actually could not find enough interest in a timely manner. Additionally, that price did not include the front eyelet bushings, which would have added to the cost somewhat. Ultimately I ended up buying a new pair of Nissan springs (with the front eyelet bushings) from Rallye, which is a roadster parts vendor in Washington state, for $342.43 plus shipping. I also wanted to upgrade my rear spring bushings and sandwich pads at the same time. I also scouted around to see if there was an application from Energy Suspension or another company that would fit the roadster. In the U.S. these companies (in my experience) are fairly reluctant to recommend parts based on dimensions if they were originally intended for a different application, probably due to legal concerns. In Australia, where there are quite a few urethane suspension bushing manufacturers willing to do just that, I did find a couple of matching applications, but they were fairly expensive even before shipping. I found that Dean at makes and sells urethane leaf spring kits specifically for the roadster. I bought a set of their urethane bushings and sandwich pads for $88.

I also went with new Gas Adjust shocks from KYB which match those I used in the front. The part number is KG5447 and I found a pair in stock at my local Van’s Auto Parts for $95.50. This part was originally for a Nissan pick-up but fits the roadster perfectly. The one exception is the lower tower bushings that come with the shocks are smaller than stock. I found a set of rubber shock tower bushings for $12 in the Help! aisle at Autozone that were nearly a perfect match to the stock ones. Below right is a picture of the new one next to the old one.

I began by lifting up the rear end of the car and supporting it with a pair of jack stands.

The first step was to mount the leaf springs in the rear, which required first bolting on the “scroll” brackets to which the back of the springs mount.

When the frame was powdercoated, some of the coating ended up inside the threaded bolt holes, so I chased them using a 3/8″-24 tap. Then I lined-up the scroll brackets on either side. The brackets are not interchangeable, but it is pretty clear which one goes on which side based on the triangular pattern of bolt holes on each.

Then I threaded on the new mounting hardware, which was part of the Frame Bolt Kit I got from Pat Mahoney. I tightened down the bolts using a 9/16″ socket and a same-sized box wrench when necessary to hold the nuts.

Here are the scrolls installed.

The brackets are oriented such that the spring eyelet floats above the scroll eyelet. The two mount together with a piece that has two threaded studs. I slipped two of the new spring bushings onto the ends of each stud. Then I inserted the studs through the scroll bracket (below) and the rear spring eye (above).

Then I slipped two more of the bushings onto the other ends of the two studs.

Then I slapped the retainer plate over the two studs and added two new nylock nuts. The bolt set actually did not provide these two nuts, but there were four leftover nuts of the correct size from the front end set, which would have been used on the upper A-arm spindle mounting bolts if I could have found a way to get them inside the housing. I couldn’t, and rather than use the old nuts here I used these new spares, which were the same size. I did the same thing on the other side.

I tightened the nuts down using a 9/16″ socket.

Next I hung the shock absorbers in place from their top mounting points. The threads on the studs on which they mount had likewise been covered in powder which made the nuts difficult to thread. I used a wire wheel to remove the coating from the threads.

That cleaned-up the threads and allowed the new shock nuts to thread.

So I pushed the upper shock eyes over the posts. In order to seat them all way down without pushing the shock off the rubber upper eye bushing, I used a 17 mm socket, which had an internal diameter just wider than the post itself, and tapped on the bushing. That moved the shock inward without coming off that bushing.

So then I threaded on the new upper shock nuts and tightened them down (not too tight, the shocks needed to rotate into their final position) using a 1″ socket.

With the leaf springs mounted in the rear and the shocks bolted on top, I rolled the differential into its position. I placed the diff on my dolly and moved it in over top of the fronts of the leaf springs and and positioned the shocks in front of the axle.

Then I raised the differential up by stacking some wood blocks underneath it in the middle. I raised it up higher than it actually sits relative to the frame so that I could attach the leaf springs in the front unencumbered and then later lower the diff down onto the springs. From this point I fully completed one side before working on the other.

In the front, the leaf springs mounted to a bracket and a bolt went through the bracket from the outside and the eyelet bushing with a nut holding everything in place on the inside edge of the frame. I lifted the spring up in the front and positioned it so it lined-up with the mounting holes. Here are some shots of the right (passenger) side.

Then I started the mounting bolt from the outside, re-using the original bolts, lock washers, and nuts. The bolt has a flat spot on its head that matches up against a tab on the frame to prevent it from rotating in place. I used a mallet to tap the bolt through the spring’s eyelet bushing.

With the bolt in place I added the lock washer and nut on the inside and tightened it down with an 11/16″ socket.

With the differential raised up artificially high, I put one of the new sandwich pads onto the spring.

Then I put on one of the retaining plates, which have straight edges in the front and back. I lowered the axle onto the plate.

On top of the axle housing I put the rear bumpstops. I re-used the old bumps, which I had cleaned up and painted. The rubber was still in pretty good condition. I oriented the bumps so that the rubber part was closer to the center of the frame than the outside of the frame, that way they line up more closely with the frame member above. Over the bumpstops and down through the holes in the plate I fed the two U-shaped spring bolts.

Below the axle is a similar set-up, where the inner sandwich pad was covered by the outer plate. I first slid the sandwich pad up onto the spring post from below.

Underneath the sandwich pad plate went the shock-mount plate. These parts are not interchangeable from side-to-side. Facing the side of the car onto which I was installing the shock plate, I knew I had the correct part when the tab that the shock tower mounted to, when facing up to the sky, was tilted towards the rear of the car. Another way to see if I had the right part for that side of the car was that, with the sandwich pad plate lined up on the shock mount plate the shock mount plate’s mounting hole would be pointing in and forward toward the center of the frame. If I tried this orientation with the shock plate from the other side of the car the holes on the two plates would not line up.

So with everything oriented correctly I slid the sandwich plate and shock plate over the spring bolt ends and threaded on the new nylock nuts to hold everything in place.

I tightened the nuts down using a 9/16″ socket.

Then I mounted the lower shock end onto the hole in the tab of the shock plate. I first added the shock washer and a new rubber bushing, then I stood over the shock and pulled the bottom of it upwards, compressing the shock, until I could drop it over the shock plate hole and have it extend down with the shaft going through the hole in the plate.

Then I added the bushing, washer, and retaining nut on the bottom of the plate.

That basically completed the installation of rear end parts. I put both sides together, and then came back to tighten and torque everything down once everything was in place. I tightened down the upper shock nuts down first.

Before tightening down the leaf spring nuts I jacked-up under the shock plate and axle in order to relieve any downward pressure so I could line the springs up under compression. I torqued down the rear mounting nuts to 50 pound-feet, again using an 11/16″ socket.

I torqued down the front leaf spring mounting nut, using an 11/16″ socket, to 50 pound-feet.

The four axle bolt nuts under the shock plate I had to tighten down quite a bit using my 9/16″ socket. Once they threaded down, pulled the sandwich together, and firmly seated the axle in place, I used my torque wrench to tighten them to 35 pound-feet.

I tightened down the lower shock tower nut using a 9/16″ box wrench. When it tightened enough to want to spin the shaft I held the shaft using my vice grips and tightened some more.

Then I added the lock nut onto the shaft. I tightened it against the first nut by holding the upper nut with a wrench and using a 9/16″ socket on the lock nut.

The final thing I did was to re-install the torque strut on the right (passenger) side of the car. It went between to mounting brackets on the frame and its role is to reduce flex in differential relative to the frame as power is sent to the wheels. I dropped the torque strut down onto its mounting brackets from above and fed the original bolts through the brackets and eyelet bushings in the strut. Although the eyelet bushings are in good shape, I would have considered replacing them if I could have found new ones anywhere (but I couldn’t).

I tightened both the front and rear bolts using a 3/4″ socket and wrench. I torqued them down to 75 pound feet.

Here is a picture of the completed right rear end, including the torque strut.

Here are the two suspension assemblies from the front and rear.

And a couple of final pictures from the front and right rear.

Front Suspension Installation

This morning I bolted the front suspension components, which I assembled yesterday, onto the frame. In the process I installed the new shocks and springs. I used all new bolts which I acquired from Pat Mahoney.

In the top of the shock housing, in the area where the spring seats at the top, originally was a rubber spring isolator that cushioned the spring against the metal frame. I obtained some new urethane spring isolators from Energy Suspension that are a close fit to the originals (pictured below left is the new one with the original one). I bought these from Suspension Restoration, part #9.6114G for $9.00 for the pair. The spring isolators went up into the housing with their raised lip facing down to ride along the inside edge of the top coil on the spring.

Before beginning I checked the upper A-arm bolts in the frame and noticed that they didn’t want to go in because some of the powdercoating must have covered the threading. I used a 7/16″-20 tap to chase the threads.

Then I put the suspension assembly on my dolly and wheeled it into its general position.

I lifted the upper A-arm up over the shock housing and slide it into place so the holes on the frame lined up with those in the upper spindle.

I started the bolts by hand, and then tightened them about halfway using a 5/8″ socket.

With the upper A-arm fastened to the frame, I removed the cart and allowed the suspension assembly to rest on the floor.

My new front coil springs were Datsunsports competition springs I bought from Mike Young for $150. These are a fairly popular spring to use in the front. Compared to the stock springs, they are more than 1 1/2″ shorter, which will lead to about an inch and a half drop in the front end and a more modern sporty stance for the car.

I also bought new KYB Gas Adjust front shocks, which were part #KG4528. I got mine from Summit Racing for $29.95 each.

What I did was to place the shock, with the inner plates and bushings installed, inside the spring with the isolator on top of the spring.

Then I fed the shock and spring up into the shock housing so that the shaft came through the hole atop the housing. I put on the upper rubber bushing, metal plate, and added the nut onto the shock shaft to hold it in place.

Then I pivoted the lower A-arm upwards so that the spring plate caught the bottom of the spring, holding both pieces in place. I rolled my floor jack underneath the lower A-arm to hold it at that height.

Using both hands, I temporarily lifted the lower A-arm up so that the lower shaft of the shock protruded through its hole in the shock plate in the middle of the arm. Quickly, I popped on the bushing and plate and threaded on the lower shock nut to hold the lower A-arm in position.

Using the jack to raise and rotate the lower arm into position, I then inserted the first of the bolts that connect the lower spindle to the frame.

Then, with a little more positioning, I was able to add the remaining bolt on that side and the two on the other side. I tightened them using an 9/16″ socket.

With everything in place, I torqued down the two upper A-arm frame bolts to 80 pound/feet and the four lower A-arm frame bolts to 50 pound/feet.

I tightened down the upper shock nut and added the lock nut on to of it, using a 9/16″ socket for each.

Then I did the same on the bottom shaft of the shock.

Here are a couple of shots of the assembled front suspension.

Here is the opposite side and a shot of the front end.

Steering, E-brake, and Frame Parts Painting

This evening I painted the components of the steering linkage and some other miscellaneous parts that where not powdercoated, but will be bolted onto the frame. This included the steering linkage (center and each side), the steering and idler boxes, the arms of the rear emergency brake linkage, the rear bumpstops, and the frame’s torque strut. Mostly these were parts that, for one reason or another, could not be powdercoated.

The first thing I had to do was repair one of the center steering rod’s ends. I had trouble removing one end from the idler box and ended up damaging the threads when I removed it. I was able to repair the threads, though, using a 7/16″-20 die.

First I lubricated the end of the threaded shaft with some leftover gear oil. Then I started the die onto the end of the shaft. It turned with a moderate amount of force at first. I followed the old rule of thumb: half a turn forward, then a half a turn back.

After getting it started the turns became more difficult. Eventually the shaft began to spin inside its pivot. I used a pair of vice grips to hold the shaft steady while I continued to work the die on the threads.

In no time the threads were repaired enough to thread on the original castle nut. I removed all of the grease zerks from the tie rod ends using a 5/16″ wrench.

Next I masked-off the surfaces of the parts that should not be painted, and gave all of the parts a quick final washing to remove any grease and dirt. I wet them down with the hose, sprayed them with Simple Green in a spray bottle, then rinsed them clean. Wearing gloves I moved them off to dry.

When the parts were dry, again wearing gloves I moved them over to the painting area.

I painted everything using Eastwood Company’s gloss Chassis Black paint. I sprayed on the first coat and then waited 20 minutes in accordance with the directions on the can. Then I did a second coat.

After allowing an hour for the first side to dry, I flipped everything over and repeated the process to paint the other side of each part.

With these parts restored I should have nearly everything ready to reassemble the structure of the frame next weekend.

Front Suspension Assembly

I spent today putting the front suspension assemblies together. The front suspension consists of a wheel spindle that has upper and lower ball joints bolted to it, which are each in-turn bolted to upper and lower A-arm assemblies. The ball joints act as pivots and the arms bolt to the front-end of the frame, with the springs and shocks, which go in between the arms, regulating the compression and rebound of the suspension.

I assembled each side basically in four steps. First, I put the spindle arm and stub axle together. Second I assembled the lower A-arm, and third I assembled the upper A-arm. Finally, I attached the arm assemblies to the spindle assembly, creating the completed front suspension assembly.

Below I document the assembly of the front left suspension. I began with the wheel spindle. On it will eventually be mounted the hubs, rotors, and wheels.

Over the spindle was mounted a caliper-adapter plate, which had two forward-facing holes onto which the brake calipers bolt. Then, over the adapter plate is a shield that acts as a backer plate for the brake rotors.

However, it was much easier to bolt the ball joints onto the backside of the spindle before bolting those components onto the front. Here is a shot of the back of the spindle, where the upper and lower ball joints mount.

I bought sets of used but excellent condition upper and lower ball joints on ebay. For the uppers I paid $140 and the lowers I paid $150. New ball joints are very expensive, and these used ones are in much better shape than my old ones. All of the new ball joints came with new rubber dust boots. Below left are the lowers and uppers.

I began by pushing the upper ball joint onto the top of the spindle. The downward-facing bolt-shaft was fastened to the spindle by the castle-nut, which I twisted on and then tightened using an 11/16″ socket.

After tightening the nut down I installed a 1/8″ x 1 1/2″ cotter pin and bent it back to prevent the nut from backing off the shaft.

The lower ball joint went on upside-down relative to the upper. I tightened down the castle nut and installed another cotter pin.

My “new” upper ball joints came with new grease zerks, but the lowers did not. I installed a new 45-degree zerk into the lower balls using a 5/16″ box wrench. I actually bought a complete set of new grease zerks for the car, also on ebay, for around $30.

As mentioned above, it is easier to install the ball joints as a first step because I could access the castle nuts for tightening much easier than I could with the other pieces mounted to the spindle.

So, with the ball joints mounted to the back of the spindle, I layered the caliper adapter and backer plate back onto the front of the spindle.

There were a total of four bolts that connected those parts to the spindle. However, the top and bottom bolts connected directly into the spindle, whereas the right and left bolts go through the spindle and bolt into another part. Consequently I installed the top and bottom-oriented bolts first, so that they would hold these three pieces together and oriented correctly. The powdercoating layer made the caliper plate a tight fit around the edge of the spindle, but the bolts pulled the two pieces together nicely.

On the back of the spindle assembly is a steering knuckle bracket, which bolted to the spindle and has a forward-facing hole through which the steering linkage rods connect. This enables the steering wheel to rotate the suspension assembly to turn the car. The knuckle brackets are not interchangeable from one side to the other. The shaft from the steering linkage rods will only fit through one end of the bracket because the hole through which is mounts on the bracket is tapered (wider at one end than the other). The knuckle bracket should be oriented in such a way that the wider end of the hole is facing downwards, because the steering linkage rods mount up through the brackets on the car. Two longer bolts fed through the right and left holes in the front of the spindle assembly and threaded directly into the knuckle.

After tightening down all four bolts that held the spindle assembly together, I torqued each of them down to 35 pound/feet.

Here are a couple of pictures of the inner and outer sides of the spindle assembly.


The second step, after putting the spindle assemblies together, was to assemble the lower A-arms. Below is a picture of the pieces that constitute one of the lower A-arms. It is important to note that not all arms are created equal. Each A assembly contains one straight arm and one angled arm. I went back to the pictures of when I took the front end apart, and realized that the straighter arm is oriented towards the front of the car with the A-arm assembly upside-down, as it is connected to the car. The straight arms also have a tab (faces downwards) and a slot (faces upwards) onto which the front anti-sway bar mounts. Keeping the arms in the appropriate positions and even matching the same spindles back to their corresponding arms made everything go together more smoothly.

The first thing I did after laying out the pieces was to install the spindle into the arm pieces. First I slipped on the new dust boots, which I bought for $1.55 apiece from Nissan (part #54539-04200).

The spindles threaded onto the arms and I tightened them down by hand.

Then I turned my attention to the spring plate, which is the triangular piece that mounts into the center of the lower A-arm. The plate has a center disk bolted into it (the shock plate) through which the shaft of the shock absorber bolts. Also, the triangular plate itself supports the bottom of the spring.

The powdercoating must have worked its way into the bolt holes, because I found it necessary to chase the threads with a 1/4″-28 tap to get the bolts to thread.

I added the new bolts through the shock plate and tightened them down very firmly using a 7/16″ socket.

The spring plate mounted to the arm pieces with four bolts; two on either side. In order to get the holes to line up and force the spring plate up into the arm, I used a large screwdriver as a lever through the upper right pair of holes. After prying downward on the screwdriver to align the holes on the opposite side, I slipped one of the bolts through to lock the plate into position. I then tightened down the nut on that bolt and worked the other bolts into place. I used a 9/16″ socket on the bolt and a 9/16″ wrench on the nut.

Finally I torqued all of the bolts down to 30 pound/feet.

I added a pair of 45-degree grease zerks at either end of the spindle, using a 5/16″ wrench to tighten them down. That completed assembly of the lower A-arms.

The third step was to assemble the upper A-arms. The upper A-arms bolt onto the upper ball joints and also connect to the frame just above and behind where the shocks and springs mount to the frame. I began by installing new dust boots (part #54541-04100 from Nissan, priced at $.59 each) on the ends of the upper A-arm spindles.

Then I put the spindle onto the stamped A-arm piece in order to thread the metal bushing pieces onto the spindle.

I started the bushings onto both ends of the spindle and hand-tightened them roughly equal amounts. When installing the bushings I was sure to replace the lock-plates that have tabs that bend down onto the bushings to prevent them from backing off the spindle. I used my impact wrench with a 1 1/8″ impact socket to alternate tightening the two end bushings down until they were tight.

The uppers were fairly simple to assemble.

I completed the assemblies by adding new grease zerks to the bushings.

The fourth step was to bolt the upper and lower A-arms onto the spindle assemblies, through the ball joints. This would complete the front suspension assembly.

I began with the lower A-arm assembly. It mounted on the lower ball joint and was held in place by four bolts. The little arms on the base of the ball joint fed into the triangle-point of the A-arm. I used a mallet to persuade the ball joint to go into place.

Once I got the first of the holes to align, I tapped a new bolt through to hold that position. Then I worked the rest of the holes into alignment by further tapping the ball joint back. I inserted the remaining three bolts from below.

Before installing the nuts on those bolts, I had to drop on the bumpstop. Because I will be installing competition front springs that will lower the front-end by an inch or so, the stock rubber bumpstops would be too large. They would come into play much more frequently at the lower ride height, each time causing a temporary but disconcerting loss of traction. The Bob Sharp Competition Manual suggests cutting down and shaping the stock bumps to about half their original height. I elected to replace the stops with new urethane bumps from Energy Suspension. I bought these, which were around 1 1/2″ tall, from Summit Racing (part #ENS-9-9103) for $8.50 for the pair. They are also available in red : ).

The new bumpstops had a threaded shaft that was a bit larger in diameter than stock bumpstops. In order to mount them on the bumpstop bracket I had to tap the hole using a 7/16″-20 tap. That enabled me to screw the new bumpstops onto the brackets.

Underneath the bracket I added the bolt onto the shaft and tightened it down using a 14 mm socket on a long extension.

The new bumpstops mounted very firmly to the old brackets.

So I dropped the bumpstop assembly over the lower ball joint/lower A-arm bolts and then put on the new nylock nuts. I torqued the bolts to 17 pound/feet using a 1/2″ socket in the torque wrench.

Here is a shot of the assembly after attaching the lower A-arm and prior to installing the upper A-arm.

The upper A-arm simply mounted over the upper ball joint, and was attached using four bolts that threaded down into the ball joint’s arms. The hole in the top of the upper A-arm enabled the ball of the upper ball joint to protrude through and allowed for access to the grease zerk in the ball joint. I torqued these bolts down using a 1/2″ socket to 17 pound/feet.

That completed the front end suspension assembly. The next step will be to bolt each side onto the frame.

Powdercoated Frame & Suspension

I picked up my frame and suspension pieces from the powdercoaters in Mexia. The name of the place that did the coating is Craftmasters Powdercoating, Inc. Overall they did an excellent job. The frame looks awesome. All of the pieces were sandblasted and coated in gloss black; they actually did two coats on the frame.

Here is a shot of all of the stray pieces that bolt to the frame, including the exhaust and bumper brackets and the front anti-sway bar and gravel shield.

Here is a shot of the rear suspension pieces. Not that on the u-bolt assemblies they masked off the threads. I’m told that powder is thick enough to impede a nut from threading on and does not simply scrape off when the bolt is spun on like paint would.

Here are some pictures of all the front suspension pieces.

You can see on the spring plates how smooth the upper surface is relative to the underside, from the sandblasting.

The frame looks tremendous. It is hardly recognizable given the dirty, grease-caked monstrosity it was when I pulled the body off.

Then VIN is now clearly visible on the frame: SRL 311-01633.

Suspension Parts

Today I didn’t get much of anything done on the car, but I did do some research into the parts I will need when I rebuild the front and rear suspensions and the steering linkage. There are several rubber bits, including bushings, grease seals, and dust boots that I will replace with new pieces. The following table shows the results of my research, including Nissan part numbers and current prices from Everything Nissan.

Part Name Part Number Price (each)
Leaf spring rear bolt bushing (8) 55046-04100 $1.36
Leaf spring pad (4) E4043-C9001 $5.99
Leaf spring front bolt bushing (2) 55045-04100 $12.29
Rear bumpstop (2) 55240-25500 $5.38
Torque rod bushing (2) 55404-25500 ?
Upper ball joint boot (2) 40142-25900 $7.24
Lower ball joint boot, inner (2) ? ?
Lower ball joint boot, outer (2) 40192-25900 $8.26
Tie rod bearing boot (4) 48522-25900 $12.94
Center rod bearing boot (2) 48522-16501 $7.90
Upper A-arm spindle boot (4) 54541-04100 $0.59
Lower A-arm spindle boot (4) 54539-04200 $1.55
Front spring isolator (2) 54036-04100 $2.28
Small upper bumpstop (2) 54053-04100 $0.80
Lock-washer clips for spindle (4) 54509-04100 $0.61
Ball joint clip (4) 40091-08000 $0.21

I’m not sure which of these parts will be available from Nissan and which are NLA. Some of the rubber bushings I may replace with eurethane where available from Energy Suspension or one of the roadster vendors, provided it doesn’t get to be too expensive.

The front bumpstops need to be modified to use competition springs that drop the front end an inch or so. Using comp springs with doing this would result in the bumps contacting the A-arms all to frequently, which can be pretty harsh and make you momentarily use traction. One option is to cut down the stock bumps to about half their intended height. Another option is to use smaller bumpstops. I plan to do the latter, and Energy Suspension part number 9.9103 ($9 per pair) fits the bill. At 1 9/16″ tall, they are just about an inch shorter than the stock bumpstops.

Also from Energy Suspension, parts 9.13105 ($6 per pair) and 9.13119 ($6 per pair) can be substituted for the upper and lower ball joint boots respectively, and are somewhat cheaper than the Nissan boots, so I will probably use them instead. I buy Energy Suspension products from Suspension Restoration in California. ES has a urethane universal spring isolator that should fit this application, but at $9 per pair they are nearly twice the cost of the Nissan parts, so if they are available from I will buy from Nissan.

ES has no urethane rear leaf spring bushing kit for the roadster, but they do have one for the early Datsun 510s (part 7.7102, $17). If the leaf springs in a 68 510 are the same as in the 68 roadster, I will buy the urethane bushings instead of rubber for the leaf spring bolts.

Leaf Spring Clean-Up

This morning I cleaned-up my rear leaf springs in order to assess their condition. I’m in the process of deciding whether to replace them or have them re-arched (or de-arched, as the case may be). The springs hold their arch well, so their is no need to add a leaf or anything like that.

Also, both springs are arched equally, so neither side is high or low, which would require correcting. Below, left is a shot of both springs lined-up; they are basically identical which makes it difficult to see the one in the rear. On the right I measured the distance from the floor up to the bottom of the spring where the mounting bolt is. The distance was 3 5/16″. I’m posting to the forums at to see what height others are running. The competition springs lower the rear of the car a bit, so I may actually want to have these de-arched an inch or so. We’ll see.

After measuring I took the springs outside to wash them. Like everything else off the underside of the car, they were pretty filthy. I wet them down and wiped on some Simple Green.

I used a wire brush to loosen up some of the dirt and then scrubbed the springs with scouring pads and more Simple Green. I’ve found it important to continually wash away the dirt as it comes off the parts.

The bottoms of the springs (which are actually mounted upward on the car) were equally dirty.

But they actually came clean enough to read the part numbers on the springs. I cleaned up the edges the same way.

I was pleased at how nicely the leaf springs cleaned-up.

Suspension Parts Washing

Today I spent some time cleaning up the suspension parts I’ve removed from the frame. They were, without exception, thoroughly covered in dirt and grease. These parts work pretty hard, so I wasn’t surprised by that.

I decided to invest in a 20-gallon capacity parts washer (on sale for $70 from Harborfreight). In the long run this will save my back and make washing parts much easier. Today it was rainy so having the new washer up and running was convenient because I could work in the garage whereas previously I did most of my clean-up out back where the hoses are.

I filled the parts washer with about ten gallons of water and a gallon of Simple Green. The re-circulating pump provides a steady stream of cleaner to continuously wash away dirt. I used scouring pads and a wire brush and a lot of elbow grease.

Below left is a picture of the rear suspension pieces dirty, just as they were when I removed them from the car. On the right is a shot of the same pieces after I washed them thoroughly using the parts washer. Pretty big difference.

Basically I just allowed the parts to soak for several minutes in the bottom of the washer, so the de-greasing detergent could go to work. Then I pulled each piece up, one at a time, and scrubbed them using scouring pads and my small wire brush.

The difference in the torque strut was significant. Underneath all of that grime the original finish was still in fairly good condition. Next I washed the front suspension components the same way.

After removing a lot of dirt from the rear pieces and a lot of grease from the front suspension components, I took the opportunity to inspect the cleaned pieces for wear. Everything seemed to be in good condition. I was worried about the shallow threads on the front upper control arm spindle bolts, but after posting my question to the forums at for opinions, I was assured that that is how those threads look even on new spindle bolts and is not evidence of wear. The inner threads on the arms (front and rear) are in very good condition, so luckily these pieces don’t need any work or replacement.

The lower ball joints I’m not so sure about. We’ll see when I clean them up and have a closer look at them.

Front Suspension Components Disassembly

Today I finished taking apart and inspecting the front suspension pieces. This is necessary to see what parts need to be replaced before I clean-up and paint the remaining parts.

Yesterday I stripped down the front of the frame. Here are a couple of pictures of it totally bare.

I used a pulley puller to remove the left steering rod from the idler box yoke. Tapping with the mallet wasn’t getting it done, but this did the trick.

First I pulled the rubber bumpstops off the metal brackets they were mounted on. I used a 1/2″ socket on the mounting nut located inside the bracket.

Then I took the lower A-arms apart. I began by removing the plate that the springs rest on. I used a 9/16″ socket and wrench to remove the bolts and nuts mounted to the inside of the bottom of the plates.

I didn’t have a socket the correct size to remove the lower spindles, so I left them attached to the arms. I next disassembled the spring plates, which have a central disk bolted onto them. I used a 7/16″ box-end wrench to loosen the bolts.

Then there was enough clearance to use a 7/16″ socket to remove the bolts entirely. The disks came off the plates with no problem.

Then I went to work on the upper A-arms. The upper spindles have a metal tab that helps prevent them from loosening. I bent this tab free using a screwdriver.

Then I removed the bolts that hold the spindles to the arms. I used a 1 1/8″ socket, first on a breaker bar and then on a socket wrench.

The spindle mounting bolts had grease zirks which allow for lubrication of the spindles.

The upper A-arms also have small rubber bumpstops that I removed by pushing them back through the mounting holes with a screwdriver.

Front End Disassembly

Today I disassembled the front end of the frame. This entailed removing the wheel assemblies, steering, and suspension components. It left the frame pretty much stripped. I want to give it one more good cleaning before painting.

Before I began I took plenty of pictures of the assembled front suspension for reference. Here are a couple from the left side:

And a couple of pictures of the right side:

And here is one picture from below:

First I broke loose the lug nuts on the front wheels using a 19 mm socket with the wheels resting on the ground and I then jacked-up the front end of the frame. I supported the frame using jackstands.

Then I removed the wheels. Here are a couple of shots of the suspension on the passenger’s side with the wheels out of the way.

My first move was to remove the gravel shield mounted at the front of the frame. It was mounted by two Philips-head bolts. One came out easily with a #2 screwdriver and the other one was rusted into place and broke off. Good start!

Then I removed the front anti-sway bar. The front tips of the bar attached to the frame via clips that were bolted into the frame by two flat-head bolts (one each side). I removed these and popped off the clips.

Then I unbolted the brackets that held the front of the bar to the frame. I used a 7/16″ socket on each of the two bolts on each bracket. With those bolts removed the brackets came free and the anti-sway bar sprung loose. The bar was wrapped in rubber bushings at its mounting points.

I haven’t decided whether I am going to use the stock anti-sway bar or acquire a thicker competition bar.

Next I went to work on the steering linkage. The steering system consists of the steering box on the driver’s side which is connected to the steering idler box on the passenger side by a cross rod. The steering and idler boxes each have mounted at their bottom a steering yoke bracket which snakes through the frame and connects to a rod (one on the right and one on the left) which connects into the wheel hub assemblies. Turning motion into the steering box move the cross rod left to right and that directs the front wheels, via the yoke and rods to either the left or right. I began by disconnecting the cross rod, which runs across the front of the frame, from the steering and idler box yokes. The pictures below illustrate that process on the steering box (driver’s) side.

This is the cross rod from the rear (picture taken prior to removing the gravel shield and sway bar).

The cross rod has a threaded, vertically-oriented bolt that mounts through a hole in the steering yoke. On the end of this bolt is a “castle” nut that is held in place by a cotter pin. I straightened the cotter pin with a screwdriver.

Then I pulled the cotter pin out using needle-nose pliers. I loosened the nut using an 11/16″ socket.

I finished removing the nut and the cross rod lifted off the yoke with a couple of taps from the mallet. On the opposite side those two pieces did not come apart nearly as easily.

The left-side rod, which connected into the rear of the yoke similarly to the way the cross rod connected to the front, terminated on the other end at the wheel hub. At the hub the connection was oriented upside-down relative to the yoke, with the threaded bolt pointing upward and the castle-nut on top. I removed the cotter pin and nut to free up the left rod from the hub.

Then I went to work removing the steering box. Here are a couple of shots of where it mounted to the frame.

The steering box was mounted to the frame by three bolts. I started with the one on the top, using a 9/16″ socket and a box wrench to hold the nut while I removed the bolt.

Then I removed the other two mounting bolts, also using a 9/16″ socket. Both bolts can be seen below on the left. Once I had the bolts undone I worked the box free from the frame and removed the left rod from its connection point on the rear of the yoke.

Next I proceeded to the idler-box side of the steering linkage, located on the passenger side of the car. I began by disconnecting the center rod from the front of the idler-box yoke.

Once the nut was off the center rod didn’t want to come free, so I moved on to removing the idler box with it still resting in place. The idler box was mounted opposite the steering box. It had a black cap covering the inner workings, which were full of grease.

I removed the mounting bolts from the top and side of the idler box using a 9/16″ socket on an extension.

With the steering linkage disassembled I then moved on to taking apart the front suspension on the passenger side. I began at the top, with the shocks and springs. The shock hardware consisted of two nuts on the end of the shock’s threaded shaft. The outside nut is meant to prevent the inside one from backing off the shock. If you remove the outer nut alone, when you go to remove the inner one it will just spin the shock and not want to come off. To get around this, the first thing I did was to align the two nuts by holding the inner one with a 9/16″ box wrench and turning the outer one with a deep 9/16″ socket.

Then, with the nuts aligned, I was able to drop the socket over both nuts and turn both simultaneously to loosen them. The two nuts provided enough friction against one another to prevent the shaft itself from turning.

Down at the bottom I removed the lower nuts from the shocks using the same technique.

Next I removed the right rod that connected the idler yoke to the wheel hub. Once again, I removed the cotter pin from the castle nut and loosened the castle nut using an 11/16″ socket.

With some taps from the mallet, the rod came free.

Next I removed the four bolts that connect the front of the lower A-arm to the lower ball joint. Those bolts, which also hold the bumpstops in place, I removed using a 1/2″ socket.

Then I was able to remove the bumpstop. The lower A-arm and ball joint stayed together because it was a tight fit.

I removed the bolts that connect the upper A-arm to the frame, through the upper spindle, using a 5/8″ socket.

After the upper bolts were removed I tapped the protruding top the shock absorber (the shaft) downwards into the A-arm. Then I pulled the upper A-arm up and outward and off the frame entirely. The result was that the suspension came “unhinged,” allowing the hub to rest on the ground, with the only remaining connection at the lower A-arm.

So next I removed the bolts that held the lower A-arms to the frame. For this I used a 9/16″ socket.

With those bolts removed I was able to pull the entire suspension/hub assembly free from the frame. I was also able to pull the shocks and springs off the assembly.

Here is the frame after I removed the passenger-side suspension and wheel hub. Note that the right steering rod is still in place because I couldn’t get it separated from the yoke right away.

Because I had already removed the bolts connecting the lower A-arm to the lower ball joint at the time I removed the bumpstop, removing the lower A-arm from the hub was simple a matter of sliding it back off the ball joint arms. I used a mallet for a bit of persuasion, but it came off without too much trouble.

Likewise the upper A-arm was mounted on the upper ball joint assembly. After bending the metal clip back, I loosened all four bolts that held it in place using an 11/16″ socket.

With those four bolts removed I pulled the upper A-arm off the upper ball joint piece.

I left the ball joint assemblies mounted on the hubs for the time being.

Enough for one day!