I just want to replace the oil seal on my diff and I would like to avoid the whole “pre-load” circus by replacing the crush washer with a correctly sized spacer as discussed and done in various videos online. Can this work with a Lotus diff? Where can I buy the correct spacer. Good new is, I am in the middle of a complete rebuild and the diff is out of the car after the usual couple of hours of cursing, crowbar and hammer.
If using a fixed length spacer it needs to be machined or shimmed specifically for the individual diff to get the right bearing preload. Its easily doable especially if you have easy access to a lathe to trim it down until you get the preload needed.
The collapsible spacer should be a simple one step operation to tighten it down and compress it until you get the right preload on the bearings. The problem with the current new collapsible spacers is the force necessary to collapse them is excessive and not easily achievable just by tightening the nut. I had to use a hydraulic press to collapse the last one I used to get the preload.
Another alternative is to use a thin shim on the existing spacer and just collapse it a little more to get the right preload for the new bearing assembly.
cheers
Rohan
You do not need a new crush washer or spacer just to fit a new front oil seal. If the diff was silent before attempting to replace the oil seal, it still will be if you are careful.
Make a note of where EXACTLY the pinion nut is in relation to the thread on the pinion, and how much torque you need to undo the nut. You will obviously need a tool to stop the flange from turning when you undo the nut. I made one.
Undo the nut and remove the flange. Dig out the old oil seal, trying not to turn the diff. Clean up in that area of the diff case. Fit the new oil seal. Clean and degrease the flange and the splines on the pinion. Observe where the old oil seal contacted the flange. This area can get corroded with rust, and a groove worn into that contact area. If that is the case, it is imperative that the flange is dressed in a lathe, to bring it back to bright metal with a high polish in that area. If you do not have a high polish finish on the flange, it will leak.
Put some wellseal or similar on the splines of the pinion, and on the spline grooves on the flange. Replace the flange. I then put a little silicone sealant in the well that the flange nut sits in. Replace the nut. You must use some thread lock on the nut. Retorque up the nut to exactly where it was before removal. I do that in stages, rocking the flange backwards and forwards. That seats the bearings evenly again. When you have the nut in the same place, just give it a bit more. Job done. It will be silent and leak free.
I have carried out oil seal replacements many times on diffs that were running fine but were leaking from the front using this method without issue, and so can you.
Leslie
Thank you Leslie… I was hoping that a procedure like the one you have outlined would be possible. I will follow your instructions.
Just to add further Raul, if you look at the picture I have posted, this is the finish on the flange that you should aim for, baring in mind that they are covered in grease to stop them rusting in storage. And talking of grease, when you refit the flange, grease up the seal plenty, do not oil. Oil wil run off by the time you have completed your restoration, grease will still be in place.
When it comes to tightening the pinion nut, I think the WSM states 35lb. You want to go a bit heavier than that, and as I said, rotate the flange back and forth 1/4 turn as you go up in torque, say at 5lb intervals.
You may want to consider replacing the diff output oil seals at the same time, seeing as the diff is on the bench. The ali casing will have to come off to do that, but well worth it. Polish up the shafts where the seals contact them, as per the flange. Take care that you do not take any metal off where the bearings sit. The diff output bearings are cheap as chips whilst you are at it. Buy a decent brand mind.
Good luck with it.
Leslie
Thank you Leslie… I will follow all of your advice. I did plan to replace the output seals and bearings as well since the diff is out of the car.