Hi pinion setup + solid spacer - preload ? (1 Viewer)

[Cube Dweller]

Not sure if hardcore is the place, but didn't seem like there was much experience with setting up 3rds w/ solid spacers in 80's tech.

Reusing all bearings- all looked good, very smooth, etc. Using a solid pinion spacer from Marlin with correct clearance for oil ring. Kit included spacer shims from .25-.45mm. Problem is .45mm is too tight, like 20in lbs preload and .55mm is too loose, no play in bearing but minimal preload, maybe 2-3 ft lbs. I made a coke can shim and stacked with another spacer got it to ~.50mm. Still too much preload. In SAE units that's like 0.001 difference, so the difference between too much and not enough is like 0.0005.

So with a used bearing, what's the consensus? Too little or too much pinion preload????

 

[Mickldo]

I've never measured the preload with anything before. I've rebuilt hundreds of diffs and have only ever felt the preload by hand. After you have done a few you get a feel for the correct preload.

When you rebuilt the diff did you reseat the bearings properly? I always give the outside of the housing a tap near the bearing cups while they have a bit of preload on them. This usually settles the bearings in properly and loosens the preload a bit.

If its still not right you might be able to hone the washer or shim a bit to reduce the preload to the correct specs. Use some 1200 wet & dry emery paper on a flat sheet of glass.

 

[Cube Dweller]

I know what you mean about feeling correct preload. I can nail setting the preload on wheel bearings, the one time I actually used a pull gauge I measured 8lbs, right on factory spec.

This is different, prob due to the solid spacer. I can feel with the "too thick" spacers the bearings are tight, binding. Pull out .05mm worth of shim and I can't get more that prob 2 inlbs. I can feel a very slight drag on the bearings, but it's not at least 6inlbs as per the factory manual for a new bearing. But there is no side to side or axial play.

I do have a surface plate so I could use that as a surface to hone.

 

[montocr]

seat bearings

tap end of pinion on each side to make sure pinion is seated. Also on toyota diffs the pinion bearings generally have fewer rollers, and will have more initial break away resistance than rolling risistance. Still if needed, you can file the spacer ever so slightly ( and evenly).