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 datsunparts.com 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.

Rear Axle Installation

Tonight I finished re-installing the rear axle assemblies into the differential, a job I had begun yesterday. With the rear axle bearings replaced, pressed on, and packed with grease, it was just a matter of re-inserting them into the differential, lining everything up, and tightening the bolts.

First I had to replace the inner grease seals. Removing the old seals was more difficult than I’d anticipated. I bought new seals from Carl Jaeger, a roadster parts vendor located up in Canada. The seals are NLA from Nissan but Carl sold me a pair for $15. Here are pictures of the new seals and the old seal in place on one side.

I couldn’t get the old seals out and I tried a lot of methods. Grabbing with pliers resulted in tearing off bits of rubber. So tonight on my way home from work I stopped at Autozone to see if they may have a puller for rent that would do the trick. It would need to be small and have the arms gripping outward unlike a typical pulley puller. The provided me with the hooked seal puller shown below. For $7 I decided it was worth a try. I hooked it on the edge of the seal as shown on the packaging.

I gave the tool’s handle a couple of taps with the hammer, and out popped the seal! This is a tool I highly recommend for this purpose after struggling all day Sunday with how to remove those stubborn seals.

I wiped the area behind the old seal clean in preparation for the new seal.

I pressed the new seal into place with the flat side out, same as the old one. I found a 1 1/4″ socket that was about the same circumference as the seal. After adding a short extension to the socket I had a nice little driver to seat the seal in place.

So I lined the socket up over the seal and gave it a couple of light taps with the mallet. The seal seated firmly and squarely into the axle housing.

With the new inner grease seal in place, I inserted the axle. Pictured is the installation of the left axle, which had two shims and which I marked in order to be sure I kept track of it. The right side required no shims.

About halfway in there was a bit of resistance. Then maybe 3/4 of the way the axle entered the differential. I turned it a bit to get it to start into the diff.

Then I stopped to put the two shims, where are cut so they need not go over the end, onto the axle. The shims were Nissan part #43036-04100 and cost $1.18 each.

Then I slide the axle the rest of the way in. It seated with a satisfying “thunk.”

First I turned the backer plate on the axle in order to align the holes in the grease catcher with those in the backer plate. I started the first bolt through the rubber grease catcher and the catcher packing gasket and then through the backer plate hole. I simply re-used the original bolts, which have a head that is flat on one side which rides up against a step in the grease catcher to prevent the bolt from spinning.

Then I started the second bolt. I slid the axle out a bit in order to align the holes in the shims on the inside of the backer plate with the bolts. Then I pushed the axle back in, hanging the shims on the bolts and making sure the two bolts when through the bolt holes in the axle casing.

Then I pushed the other two bolts through the assembly and casing, and started the new lock-nuts, provided as part of Pat Mahoney’s rear-end bolt pack. I used a 1/2″ socket to tightened the nuts onto the bolts, moving in a star pattern. First I tightened them all down to just touch the housing.

Finally I torqued down each bolt, moving in the same pattern around the axle, to 28 foot/pounds using my torque wrench (Spec, according to my Chilton’s manual, is 20-28 foot/pounds).

Here are some pictures of the re-assembled differential.

The final step was to replace the breather and drain plugs, and re-fill the differential with gear oil. I used one quart of 75-90 weight Mobil 1 synthetic gear oil.

Rear Wheel Bearings, Pack with Grease

In preparation to re-install the rear axles, this afternoon I packed the new rear wheel bearings with grease. I bought some Mobil 1 synthetic grease that should be high quality and happens to be a distinctive magenta color.

Since grease can be very messy, I applied some masking tape over the holes on the inner side of the backer plates to prevent any grease from smearing over to the brake-side of the plates. Then I began by applying one pump of grease on the bearing.

When cleaning some grease off the corner of the ridge of a bearing collar using a Q-Tip, I had an idea. A Q-Tip with the cotton cut-off was just about the perfect size to pack the grease down into the nooks and crannies of the wheel bearing. Small, disposable, and I have an entire box of them on-hand. I’m sure there is a more elegant way to accomplish this, but the Q-Tip method worked pretty well. After packing down the grease I added another pump in three positions around the radius of the bearing.

After adding and packing grease another three or four times, it seemed to be filling the bearing substantially.

It was easy to tell that the bearing was packed full of grease when I rotated the bearing and it had a very solid feel. So I cleaned off the excess grease from the edges of the bearing and the collar.

Then the axles were ready to install in the differential.

Rear Wheel Bearing Replacement

Tonight I cleaned up the rear axles and loosely installed the new rear wheel bearings. I will need to take the axles to a machine shop to have the bearings pressed on but for now I just re-assembled everything in the correct order so the machinist will be able to press fit everything in the proper place.

All of the parts I needed to rebuild the rear axle bearings I obtained from Nissan. Unlike with the front wheel bearings, the rear bearings are specific to this application and therefore there is no cross-reference part number, i.e. you have to order the bearings from Nissan rather than just buying the correct part from a bearing supplier.

I cleaned up the ends of the axles using a scouring pad and some Simple Green, then applied two coats of paint. The paint I used was Eastwood‘s Chassis Black in gloss, which matches the paint I’ve used on the differential and some other places on the frame that couldn’t be powdercoated. I sprayed on the first coat and then re-coated after fifteen minutes, per the instructions on the can.

Because the left side axle had two shims where it connects to the differential housing that I plan to replace when I re-assemble, I marked the left axle using a small dot of white paint so I don’t confuse it with the right side.

When the paint had dried I began re-assembling the wheel bearing parts. I ordered all of the parts I needed from Everything Nissan, two of each shown. I assembled the axles with the wheel lugs downward, which is opposite to the way I disassembled everything. Consequently I was working from the outside of the axle (closest to the wheel) inward.

The first parts I added were the new grease catchers, part #43234-18401 priced at $5.25 each. I slid them down over the axle with the flat surface upward, and then seated the part over the axle where it fit tightly in place.

Between the grease catchers and the backer plates is a small gasket-like packing material. The packing, which is Nissan part #43239-H5000 ($0.48 each) has holes that line up with those in the grease catcher, as shown below. I dropped the packing onto the axle and over the grease catchers.

Next, on went the rear brake backer plates. The “prongs” and surfaces where the rear brake cylinders and adjustors mounted where oriented upwards. The backer plates had four holes for the bolts that attach each axle to the differential case, as do the grease catchers. These four holes are useful for orienting the grease catchers with the backer plates.

The next part in the sequence was the new wheel bearing spacer, which is Nissan part #43070-01L00 and cost $1.83 each.

The spacers had a bit of a slope to them, which enabled them to seat firmly over the curved ridge of the axle surface. They went on so that their recessed outer edge was facing downward so they would lock over the ridge in the axle.

Next I added the rear wheel bearings themselves. The bearings are Nissan part #43215-08000, and cost $34.35 apiece. Expensive, but there are crucial parts. I should never have to replace them again provided I repack them with grease regularly. I just dropped the bearings into place where they go in this sandwich; the machine shop will press them down and permanently into place.

Finally I added the new collars, which will be pressed into place above the bearings. The collars, part #43084-10600, were $13.63 each. The pressing on and off of these components causes the metal to flex, so for safety I would never consider re-using the old ones.

Here is the assembly ready to go off to Bishop’s Automotive Machine Shop for the final pressing.

Rear Wheel Bearing Removal

Today I finally finished removing the rear wheel bearings from both axles, a process that has been going on over a week. Before I began, I found a very useful write-up by Tom Walter (who happens to live in the same town as me, small world!) in the roadster mailing list archives.
Below is a picture of the axle assembly from my manual and one of the axle assembly before I began.

As shown below, the wheel bearings were held in place by a collar that has a ridge around its center. The bearings and collars are pressed into place. What I took from Tom’s post was that it may be preferable to cut off the collars rather than press them off, so that the wear on the axle is kept to a minimum and the new bearings and collars, once pressed on, will be less likely to come off. That is, pressing off the collars may wear-down the axle unduly and reduce the life of the axle, which is typically good for a finite number of pressings. Rather than using a Dremmel (mine is very wimpy and didn’t cut effectively at all), I used progressively larger drill bits to work away at the collar.

The 1/8″ bit I was using worked its way through the ridge in the collar.

Then I switched to a 3/16″ and then a 1/4″ bit, enlarging the hole in the collar each time.

The drill left a groove through the collar at least as deep as the ridge. I then inserted the tip of my cold chisel into this groove and started pounding with my 3-pound sledge hammer.

After around ten to fifteen solid blows with the cold chisel, the groove in the collar was getting deeper and the inner diameter of the collar began to expand. Eventually the collar came loose around the axle and slid off.

Here is a shot of the collar after it slid off the axle.

Next, in order to remove the wheel bearings, I held the backer plate in my hands, axle-end down, and slammed the axle downward into a block of wood on the floor. The idea was to use the force of the backer plate, which has maybe a half and inch of play up and down on the bearing, to knock the bearing off the axle.

On the left axle this worked nearly immediately. On the right side it did not. After my hands got sore from the impacts, I decided to soak the bearing in Liquid Wrench, which I did each night of the last week. Then I switched over to PB Blaster which, after several days of soaking, worked the stubborn right axle bearing free.

After the bearing slid off, there was a small spacer and then the backer plate, then the grease catcher that rests against the axle hub.

Next I went to work on the backer plates themselves. On the outside of the plates reside the brake cylinder and the adjustor, opposite. On the inside of the plates the cylinder and adjustor are fastened to the plates.

First I removed the cylinder, which was covered by a rubber dust cover.

The cylinder itself was held up against the inside of the backer plate by a series of clips. On the left side there were four of these clips, on the left axle side (shown) there were only three. I pushed the clips off using a flathead screwdriver, and the occasional tap of a mallet.

Off it came, and underneath were two more interlocking clips, that appeared to be copper.

I removed these to opposing clips in the same manner.

This allowed the cylinder assembly to fall back off the backer plate.

With the cylinder removed, I began to work on the brake adjustor, onto which the opposite ends of the shoes attach.

On the opposite side the adjustor was held in place by two nuts, which I removed using a 7/16″ socket.

The adjustor didn’t come off immediately, so I tapped the ends of the bolts lightly with a hammer, and it came free.

The adjustors appear to be frozen, but I will make an attempt to get them working again. If not, I will find replacement parts.

Next I took the backer plates outside and cleaned them up.

The backer plates are the last of a lot of parts I will send off to be sandblasted and powdercoated. When I get those parts back I should be ready to re-assemble the chassis.

Rear Wheel Hub Removal, Part II

Two weeks ago I was removing the rear axles from the differential and had trouble getting the left axle free–it was stuck in place. I learned a trick from Dave Kaplan on the forums at 311s.org that solved that problem. Here is the stubborn axle in place. I tapped it with a rubber mallet to no avail. A slide-hammer should work, but I didn’t have one on hand.

So what I did was this: replace the brake drum on the hub, only put it on in reverse (inside-out if that helps). Then put the lug nuts on and tighten them down only a couple of turns.

What I don’t have a picture of, because I had to use both hands and therefore put the camera down, is what I did next: grab the drum at three and six o’clock and push it in and then pull it back out so it taps against the lugs. Repeat a few times and it is a homemade slide-hammer. After just a few pulls the stubborn axle came right out.

Here are shots of the inner axle backer plate with the wheel bearing and collar and the differential’s axle housing, which still holds the inner oil seal inside.

Rear Wheel Hub Removal, Part I

This evening I started removing the rear wheel hubs so that I can clean-up and re-build the rear brakes.

I started by simply pulling the brake drums off. With the wheels removed from the hubs, there was nothing mechanically holding the drums in place. The drums were aluminum and finned.

Here is the hub after the drum was removed. On the right I began to pull the brake shoes off. They are spring-loaded and I first tipped on shoe forward and off its mounting point.

Then I freed the other end of the shoes from its mounting point and popped the shoe assembly free.

Here is a shot of the hub after the shoes were removed.

The hubs have a backer plate that bolts directly to the rear axle. I removed the four bolts that make this connection using a 1/2″ socket.

With those bolts removed the hub came free, with the half-section of axle attached! Apparently the wheel hubs need to be backed off the inner end of the axle.

Both the hub backer plate and the end of the axle case had shim/gaskets on them. Below left the rear wheel bearings are visible up against the backer plate.

I will need to have the bearings pressed off in order to get the brake assemblies off the axle. That is something for another day.

Draining the Differential

I drained the oil from the differential in preparation for disassembling the rear wheel hubs and axle. Fist I propped the differential up on my jackstands, to provide better access to the plugs. Having spent an hour yesterday and another hour this afternoon cleaning it, the diff looked pretty nice at this point.

I started by removing the breather, using a 5/8″ socket.

On the right rear of the differential are a fill plug and a drain plug. It is always a good idea to ensure that the fill plug comes out prior to removing the drain plug and draining the differential. I used the drive of my 1/2″ drive socket to loosen the fill plug.

I removed the fill plug and then positioned my oil pan underneath the differential in preparation for draining.

Then I removed the drain plug: first using my 1/2″ drive breaker bar to gain some leverage and break it loose, then using the socket wrench with no socket, then spinning it off the last few turns so I could catch it in my hand.

Then the oil drained out of the differential. It smelled a little sour, but I suppose that is normal.

I lifted the axle up on each end in order to drain as much of the oil as possible. I will replenish the differential oil after I’ve done some work on the rear brakes. I don’t know what all the fuss is about–it is easy to change the differential gear oil, all you have to do is remove the rest of the car from the diff first!

Emergency Brake Arm Removal

This afternoon I removed the emergency brake assembly from the rear of the differential and then gave the diff a second cleaning. The e-brake assembly consisted of an arm that spanned the two rear brake drums and would apply pressure to the brakes if the lever in the car was pulled. The e-brake cable, attached to the handle in the car, attached to a bracket on the right side of the differential. I began at the wheels and worked my way in.

Starting on the right side, I unscrewed the Philips head screw that held the spring tensioner to the brake cylinder.

With the screw loose the small tab could slide outward towards the wheel hub, relieving the pressure on the spring.

On the right side the arm was attached to the brakes by a pin which had a cotter pin through its bottom. I pulled the cotter pin and then worked the retainer pin up and out of the arm.

This allowed me to disconnect the right e-brake arm from the wheel hub.

On the left side was a similar set-up. I loosened the spring screw, and removed the spring from the hub. Then I removed the cotter pin and tapped the retaining pin free using a nail-set and mallet.

That freed the left e-brake arm from that hub.

Just right of center, the two arms that activate the left and right rear brakes came together on a pivoting arm; this is where the emergency brake cable came in. I removed this mechanism next. First I pulled out the cotter pin below the mechanism and pulled off the retaining washer.

Then the piece slide of a bracket mounted onto the differential case.

In order to slide the assembly off the differential, because the left arm fed through a small loop on the diff. I had to remove the spring assembly from that end in order to pull the arm back through the loop. I removed the mounting screw and then pried the retaining bracket back to get the spring piece off the arm.

Then I removed the rubber cushion from the inside of the loop an order to slide the left arm through the loop and off the differential.

The center linkage for the e-brake mounted to a bracket on the differential. I removed this by taking out the two bolts using a 1/2″ socket.

After removing the emergency brake linkage from the rear wheel hubs and differential, I spent another hour cleaning the differential. More Simple Green and a good scrubbing with some #2 steel wool pads made it come remarkably clean.