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Sierra diff backlash adjustment in-situ
matt_gsxr - 28/5/11 at 08:15 AM

Hi there chaps,

I have a bit of backlash on the propshaft/diff about 5mm at the driveflange.

I have read up on it (on here) and it seems this can be tuned out by adjusting the massive castellated bearing housing.

So, my question is, has anyone managed to do this with the diff in the car and the driveshafts connected. I know this isn't "textbook", but if I can do it this way then its a 1 hour job, if I have to take out the diff and driveshafts then its a huge effort and I won't do it.


here is a link to a rebuild manual (very useful)
http://www.fordscorpio.co.uk/manual/rearaxle/DiffOverhaul.pdf

Matt


Steve Hignett - 28/5/11 at 08:24 AM

I've not done it and have never observed it being done, so hopefully someone else will comment about whether what I say is true or not!

But;

I was told that only one side (the Right?) is the adjustability for backlash...

ATB
Steve


matt_gsxr - 28/5/11 at 08:58 AM

The manual (link posted above) shows that you adjust both the flanges until the backlash is correct and both bearings. It might be that due to wear that only one side needs adjusting, I would assume this would be moving the crown-wheel into the pinion. So maybe the other right?


From the manual:
"
NOTE: Repeat sub-operations 1 and 2 until a
backlash of 0,01 mm is obtained. One
castellation tooth + gap = 0,04 mm change in
backlash.
62. Set the backlash to 0,01 mm.
1 Slacken the bearing housings.
2 Adjust the bearing housings until they
make contact with the taper roller bearing
"

So, basically bugger around with it until it seems to be better, which is what I was going to try. If I mark it then I can always get back to where it is, and maybe I can improve it a bit.

Just wondered if anyone had any experience of this in practice.

Matt


mistergrumpy - 28/5/11 at 09:31 AM

I know someone on here has done it because I seem to remember that they broke one of the castellations (castles?) as they were quite brittle.


sebastiaan - 28/5/11 at 10:11 AM

You need to do them both to keep (or re-set) the bearing pre-load. You also need to whip the rear cover off as the driveshaft also have (most of the total) backlash to the crown wheel. As you know I did mine this winter and it is fiddly. Very fiddly. If i'd have to do it again I'd take it out of the car for sure. Sorry....


ReMan - 28/5/11 at 10:33 AM

Without reference to any spec, but I'd have thought that 5mm (I presume this is rotational?) would be normal?

[Edited on 28/5/11 by ReMan]


sebastiaan - 28/5/11 at 10:37 AM

In mine, 90% of the backlash was NOT between the crownwheel and pinion, hence my comment on taking off the rear cover.


matt_gsxr - 28/5/11 at 11:35 AM

Not really the message I was hoping for.

But at least it may prevent me starting something that is difficult to finish.

Thanks chaps,

Matt


mark chandler - 28/5/11 at 04:39 PM

The problem is getting the castellated nuts to move, if you just whack them they snap off...