Rear Caster bushes

Hi

Ive recently lifted my jimny 2.5" and since doing so ive noticed a knocking has developed when on slightly bumby ground. after checking everything over ive noticed my rear radius arm bushes are shot and Im assuming this is the problem. Question is should I just replace them with normal bushes or is it worth fitting caster correction ones to the rear aswell. Ive to do the job and change the bushes anyway (I'm pretty sure standard and correction bushes are the same price) so thought Id ask u guys/girls if theres any benifit in correcting the caster on the rear or is will it have no effect on anything.

Yes use castor correction bushes to the rear. To put the diff and springs at a better angle.

If you dont fit any form of correction, when the rear axle is lower, the nose of the diff is up, so if you fill the diff through the hole in the back, there is less oil in, and the pinion bearing is higher up, so it isn't getting as much oil as before.

Result: the pinion bearings wear faster. You can simply put a lot more oil in to compensate, but it may start to leak out at the axles if you over do it.

However, the propshaft is reasonably in line, and bends at the transfer end, where there is a CV joint.


dropping the nose of the diff with correction bushes fixes the oil problem, but makes the propshaft Z shaped, and will wear the UJ quickly, and produce a knocking from the rear as it trys to straighten out the shaft under load.


I guess you pays your money and takes your choice

I'd let the nose come up on standard bushes, and find a way to sort the oil level.


(It won't affect the steering or brakes anyway, which is why you fit correction at the front)

facade wrote: If you dont fit any form of correction, when the rear axle is lower, the nose of the diff is up, so if you fill the diff through the hole in the back, there is less oil in, and the pinion bearing is higher up, so it isn't getting as much oil as before.

Result: the pinion bearings wear faster. You can simply put a lot more oil in to compensate, but it may start to leak out at the axles if you over do it.

However, the propshaft is reasonably in line, and bends at the transfer end, where there is a CV joint.


dropping the nose of the diff with correction bushes fixes the oil problem, but makes the propshaft Z shaped, and will wear the UJ quickly, and produce a knocking from the rear as it trys to straighten out the shaft under load.

Thanks for the quick replies.

Ah, well going by what your sayin, in my eyes I think it might be better to use standard bushes and try overcome the oil situation rather than fitting caster correction ones and having a 'Z' shaped prop shaft.
Could maybe fill the boot of sand bags and jack the axle up in such a way to rotate the fill plug to get more oil in or at worse drill and tap a new plug nearer the top.

supergaz wrote: Yes use castor correction bushes to the rear. To put the diff and springs at a better angle.

This is what I was thinking. Never really took the prop into concideration.

I think the uj on the prop will easily handle that amount of lift. Id rather my pinion bearing get the oil.
Also I'd rather replace a uj on the prop than the diff pinion bearing.

Decision made. I'll go for the correction bushes, the more i think about it I'd have to agree with you, the prop UJ will be fine Im sure because when offroading with no lift the prop must move quite a bit anyway and Ive not lifted anything that much. plus like you say its easier to replace if I needed to.

THANKS