280zx rear differential rebuild question

[Broken-Z]

Hey guy's, I'm hoping someone can help me with this. I'm rebuilding the R200 rear differential on my 1982 280ZX ,and I am at the point of re-installing the carrier, with new bearings. I understand that I will need to set the backlash ,and also preload the bearings upon assembly.My question is,with no shim set available from Nissan(only replacement shims),how am I going to do this? I know that I can buy replacement shims

(not an assortment) and grind them down to a specific size if needed.How can I come up with an initial number? I'm thinking using flat shim stock for trial until a number is achieved. Anyone have any experience with this? Thanks in advance!

[zcarnut]

If all you did was change the bearings then 90% of the time you can re-use your old shims. Bearings are made to very exact tolerances (at least the non-Chinese ones are). Go ahead and re-assemble the differential and then measure the backlash, pre-load and wear pattern. If one of these parameters is incorrect, then address it with different shims. If you need different thickness pinion shims then you can obtain cheap ones from http://www.phoenixspecialty.com.

 

BTW, I hope you are using the factory service manual for you re-build instructions.

[Broken-Z]

If all you did was change the bearings then 90% of the time you can re-use your old shims. Bearings are made to very exact tolerances (at least the non-Chinese ones are). Go ahead and re-assemble the differential and then measure the backlash, pre-load and wear pattern. If one of these parameters is incorrect, then address it with different shims. If you need different thickness pinion shims then you can obtain cheap ones from http://www.phoenixspecialty.com.

 

BTW, I hope you are using the factory service manual for you re-build instructions.

 

Thanks Zcarnut. I went back and re-read the FSM and it became a bit more clear. I didn't expect to have to drive the side bearing spacer with such interfearance. I didn't use a puller to remove the carrier at the initial removal. It came right out, but I dont think this will be the case now. It's going to be snug(hence the term pre-load). I am still a little confused as to where they(FSM)get thier values for a,b.c ect...in the formulas posted.I guess they are a given. I think what threw me off was some research that I did on similar diff,where you would set the back lash first, and then preload a specified value seperately.Hope this makes sence.This is my first differential rebuild so I am working through a learning curve.

[zcarnut]

…I didn't expect to have to drive the side bearing spacer with such interference…

 

That’s not unusual. All the R200 diffs I’ve re-built required some insertion force to seat the carrier side shims so that the correct pre-load is obtained. On a high mileage diff the bearings have enough wear so that the carrier usually falls out under its own weight upon disassembly.

 

…I think what threw me off was some research that I did on similar diff, where you would set the back lash first, and then preload a specified value separately…

 

There are two preload specs. The input (pinion) bearings must be preloaded as well as the side (carrier) bearings.

 

The correct assembly sequence is:

 

1. Set the pinion preload. With the carrier removed, set the pinion bearings preload with the correct sized pinion bearing spacer (shim washer). Note: use the original pinion height adjusting washer. Measure the pinion preload with an inch-pound torque wrench. Should be 10 to 15 inch-lbs.

 

2. Set the side bearings preload and ring gear backlash. Leaving the pinion gear with its pinion bearings installed in the diff case, install the assembled carrier gear into the case. Use the original side shims in their corresponding (left or right side) locations. As long as the ring gear turns freely do not be concerned with the backlash or wear pattern at this time. Measure the side preload at the pinion nut (where you measured the pinion preload). It should have increased by 5 to 10 inch-lbs.

 

The total thickness (left and right sides) of the side shims determines the side preload. How you divide them between the left and right sides determines the backlash.

 

3. Measure the ring gear wear pattern. Paint several teeth of the ring gear with the indicator paste and rotate several times. The ring gear should be “loaded†to get a more accurate pattern. This can be achieved by wedging a piece of wood between the outside of the ring gear and the diff case. If you are lucky and the wear pattern is correct, then you are done. If not then you will have to adjust the thickness of the pinion height adjusting washer. This means disassembling the diff and repeating the above steps.

 

Consult any number of the differential rebuilding sites on the web for better pictures of the correct ring gear wear pattern and how to interpret the wear pattern so you know how to proceed.

[Broken-Z]

Thanks Zcarnut, I really do appreciate your effort and the much detailed explaination. I assembled the unit this morning and it went together with no problems. The preload on the carrier side bearings went together with no glitches. A good tap fit, checking for binding inbetween taps.Ended up with .006 backlash(a little on the high side,but within tolerance) and a ring gear wear pattern that was almost perfectly centered. Seals and output shafts installed. Job should be completed in the morning.Thanks again!

[mickey_bigdaddy]

Broken-Z,

 

I hate to drag up an old thread. But, I'm getting ready to undertake a rebuild of a R200 for my first time. I know the pinion gear is bad for sure. Can you give me your take on how it went for you? Also, what special tools did you need?

 

Oh and where did you get your parts, I'm wanting to get them a cost effective as possible.

 

Thanks in advance for your help.

[Broken-Z]

I didn't replace the pinion bearing when I rebuilt mine,as it seemed to be OK. If I remember correctly I purchased the bearings from a place called import auto parts but, was a bit of a hassel. I would call Car Quest. I believe the transmission shop that pressed my bearings recomended them. My rebuild thread.http://forums.nicoclub.com/zerothread?id=388827 Make sure to mark spacers when dis-assembling, you will need to have them go back in the same position.