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Diff Backlash removal
carnut - 24/2/05 at 09:23 AM

I was talking to a chap today who said he had his sierra diffs "wound up" to remove the backlash. Does anyone know exactly how this is done and if it can be done your self? If they have ust been tightened, does it mean they will wear gears and bearings a lot faster?

Carnut


clbarclay - 24/2/05 at 09:57 AM

The gears in diffs can be moved small amounts to align them up.
Done properly ther should be no binding (the gears should move freely), and almost all back lash is removed.
Around where the driveshfts come out of the casing there are rings of teeth these have a locking tab. remove the locking tab and the the rings can turn.

the rinngs are threaded so turn one out and the other in to move the diff side to side in the casting. I think that is what was ment by wound up.

At this point I strongly advise you to get expert advice in the flesh to make sure you do it properly. yes you can do this your self but knowing when you've got it right is the hard bit.

The most noticable affect (unless its realy bad) would be the diff cluncing when you start to use engine breaking when slowing down.


carnut - 24/2/05 at 10:01 AM

My diff clunks like hell at the moment and has loads of backlash in it. I think it can only be good to remove some of this.

Do we have any diff experts on the forum who have wound up diffs?


Bob C - 24/2/05 at 10:49 AM

I'm not a "diff expert" but I rebuilt my diff to put an LSD in. Here's what I found.
1)The castellated thing will just break unles you make a special tool that pushes at least 10 of them at once. I made a fairly poor special tool to do this (and broke off 3 castellations)
2)from memory each castellation is 4 thous
3)bearing preload on the castellated bearing carriers is 44ftlbs on a torque wrench
4)check for lash all the way round the crownwheel, there'll be a high spot.
5)that's all from memory so trust it at your peril!
Bob C


britishtrident - 24/2/05 at 10:57 AM

It could be also that at some point in the cars history a new pinnion oil seal has been fitted incorrectly pulling the pinnion forward out of mesh.

You are going to have to disconnect the shafts anyway it would be just as easy and might have more chance of success to fit another diff.


clbarclay - 24/2/05 at 11:59 AM

Another diff (if in good condition) will cure the problem, but if there is no internal damage then correct adjustment is all that is needed to get the diff in good order again.

Not sure about the pinion position, i'm just working from dast experiance of various diffs and a sierra haynes manual, which don't say a lot about positioning the pinion (looks like fixed position only).

Haynes manual beign as useful as normal doesn't give a figure for acceptable diff backlash. Does any bod know of a site that has backlash figures for various diffs? I've got an english escort diff i want to check.

[Edited on 24/2/05 by clbarclay]


carnut - 24/2/05 at 12:05 PM

I need to change to diff over to a LSD with a taller ratio.


mangogrooveworkshop - 24/2/05 at 01:41 PM

Snoopy mentioned that they took a standard diff and added quaif lsd internals for the red rocket. How he did it exactly I dont know. Perhaps he will be along
to tell us.


NS Dev - 24/2/05 at 02:51 PM

quote:
Originally posted by Bob C
I'm not a "diff expert" but I rebuilt my diff to put an LSD in. Here's what I found.
1)The castellated thing will just break unles you make a special tool that pushes at least 10 of them at once. I made a fairly poor special tool to do this (and broke off 3 castellations)
2)from memory each castellation is 4 thous
3)bearing preload on the castellated bearing carriers is 44ftlbs on a torque wrench
4)check for lash all the way round the crownwheel, there'll be a high spot.
5)that's all from memory so trust it at your peril!
Bob C


This advice is spot on, I have the Ford Motorsport Sierra Prep book, with full diff prep instructions. If any more setup advice is needed, request on here and I'll answer once I am at home and with the book!!!!


chriscook - 24/2/05 at 03:06 PM

Are there many pages? being cheeky again here but,, any chance of scanning the diff pages?

Cheers,
Chris


NS Dev - 25/2/05 at 12:13 PM

If I can find time over the weekend I will try and get them scanned and into my archive on here, there arent too many pages.


chriscook - 25/2/05 at 03:09 PM

That would be great if you can. I might have a go at swapping lsd internal over myself as the guy that is meant to be doing mine has had it for months!

Cheers,
Chris