Anyone Overhauled the Diff?
Discussion
Big job, in anyone's book.
Awkward enough to get the diff out of the car even before you start stripping it down.
To change that bearing and seal, the whole thing needs to come apart.
Firstly the crown wheel/LSD assembly comes out by unscrewing the two alley adjuster wheels, you can see these on either side of the diff from the outside. You need to make a special tool up to locate into the webs to undo them. Effing tight if they've never been off before. I used a length of 4 by 2 box section steel with 6 bolts drilled through it, in a circle shape to locate in the webs. Don't be tempted to use any heat as the alley expands quicker than the cast body as I found out
Once this is out you'll be able to see the pinion. Undo the nut where the prop attaches and knock the pinion shaft out through the diff. You can then knock the bearing outer race's out as per any other bearing.
Refit is certainly not as easy as 'reverse of disassembly'
You'll need to get yourself an INCH/pound torque wrench. When you refit the pinion shaft you'll need to purchase a new 'crush washer' this sits between the two taper bearings that hold the shaft in place. As you tighten the end nut you crush this washer until the correct preload is put on the two bearings. To check the preload, you attach the inch/pound wrench to the nut and try and turn the shaft. You're checking how much torque it takes to turn the shaft. If its too loose you then tighten the nut further and then retest.
Once you're happy with the pinion fit its time to re install the crown wheel assembly. This time you're be trying to get the backlash correct (how much free play between the crown wheel teeth and the pinion teeth). this is done by using a DTI looking at the free play of the crown wheel. By tightening one of the alley adjusters and loosening the other you either reduce/increase the back lash by moving the assembly slightly left/right. Although a preload also needs to be applied to these bearings before you start measuring. Only grease is used on the alley adjusters, they're eventually held in place with two stops which bolt to the rear diff case (they've got slotted holes).
Hopefully that's an overview to let you know what you'll letting yourself in for
If you're going to give it a go, I've got some literature somewhere from BTR on the preloads needed.
For all the bearings, seals and a lot more advise use John Reid from Grantura engineering. I can't recommend this guy enough, unlimited advise and everything on the shelf.
Good luck,
Rich.
Awkward enough to get the diff out of the car even before you start stripping it down.
To change that bearing and seal, the whole thing needs to come apart.
Firstly the crown wheel/LSD assembly comes out by unscrewing the two alley adjuster wheels, you can see these on either side of the diff from the outside. You need to make a special tool up to locate into the webs to undo them. Effing tight if they've never been off before. I used a length of 4 by 2 box section steel with 6 bolts drilled through it, in a circle shape to locate in the webs. Don't be tempted to use any heat as the alley expands quicker than the cast body as I found out
Once this is out you'll be able to see the pinion. Undo the nut where the prop attaches and knock the pinion shaft out through the diff. You can then knock the bearing outer race's out as per any other bearing.
Refit is certainly not as easy as 'reverse of disassembly'
You'll need to get yourself an INCH/pound torque wrench. When you refit the pinion shaft you'll need to purchase a new 'crush washer' this sits between the two taper bearings that hold the shaft in place. As you tighten the end nut you crush this washer until the correct preload is put on the two bearings. To check the preload, you attach the inch/pound wrench to the nut and try and turn the shaft. You're checking how much torque it takes to turn the shaft. If its too loose you then tighten the nut further and then retest.
Once you're happy with the pinion fit its time to re install the crown wheel assembly. This time you're be trying to get the backlash correct (how much free play between the crown wheel teeth and the pinion teeth). this is done by using a DTI looking at the free play of the crown wheel. By tightening one of the alley adjusters and loosening the other you either reduce/increase the back lash by moving the assembly slightly left/right. Although a preload also needs to be applied to these bearings before you start measuring. Only grease is used on the alley adjusters, they're eventually held in place with two stops which bolt to the rear diff case (they've got slotted holes).
Hopefully that's an overview to let you know what you'll letting yourself in for
If you're going to give it a go, I've got some literature somewhere from BTR on the preloads needed.
For all the bearings, seals and a lot more advise use John Reid from Grantura engineering. I can't recommend this guy enough, unlimited advise and everything on the shelf.
Good luck,
Rich.
Yep, been there, i have a tool i made up for undoing the side tensioners, Maaaannnn they were tight, i had to heat it up there was no other option, it worked in the end. Did not use any gauges, just did it by feel. That crush washer REALLY takes some squashing, like a big Snap on bar full wellie and full omg if this snaps the THREE of us are gonna be in trouble!!
PS got my bits from JR too, nice guy.
PS got my bits from JR too, nice guy.
Edited by Brummmie on Thursday 15th July 00:06
If it helps...and it sounds like its a good idea!...I removed and refitted my diff myself but sent it off to be refurbed by John Voight...cost just over £400.
However, add to that the new bushes you really should do when the diff is out - approx. £100 for poly ones - and new oil and any new bolts, nuts, washers, etc.
As others have said its not easy...takes a bit of time and is much easier with help from a mate or two!
Make sure you get the right oil!
Hope you get sorted one way or another.
However, add to that the new bushes you really should do when the diff is out - approx. £100 for poly ones - and new oil and any new bolts, nuts, washers, etc.
As others have said its not easy...takes a bit of time and is much easier with help from a mate or two!
Make sure you get the right oil!
Hope you get sorted one way or another.
Inspiring words one and all.
I have an uneasy feeling I will fail at the seized adjuster hurdle.
I already have the pinion bearings, washer, sela etc. Oil also. I await getting shot by you all but it is Morris Oils for LSD. Supposedly less prone to aeriate. as the last diff failed saw no reason to stick with Mobil
The diff is on my bench at the moment with Prop drive plate removed. Spare diff fitted to car. Pinion is like a chipolata in a bucket.
I also forgot to mention my old diff is a hydratrak. Words like much easier would be good.
Pre-tension data would be helpfull, if I get that far.
I have an uneasy feeling I will fail at the seized adjuster hurdle.
I already have the pinion bearings, washer, sela etc. Oil also. I await getting shot by you all but it is Morris Oils for LSD. Supposedly less prone to aeriate. as the last diff failed saw no reason to stick with Mobil
The diff is on my bench at the moment with Prop drive plate removed. Spare diff fitted to car. Pinion is like a chipolata in a bucket.
I also forgot to mention my old diff is a hydratrak. Words like much easier would be good.
Pre-tension data would be helpfull, if I get that far.
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