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Sierra noisy diff
axle - 19/1/17 at 09:41 AM

Hi all
Has anyone tried fitting this type of bushes to Sierra rear diff, as the noisy diff we all experience is due to fact that it is fitted directly to the chassis.
This can resonate and make the normal noise from the diff louder as explain to me differential specialist.

http://www.super7thheaven.co.uk/blog/caterham-rear-diff-cover/

If so please post some images it is not clear on the above?


CosKev3 - 19/1/17 at 05:13 PM

The diff is mounted straight to the chassis in that link?

Just has an extra mount on the rear cover,that is hard mounted too


jacko - 19/1/17 at 07:27 PM

them side mounts look like mk indy plates


mcerd1 - 20/1/17 at 09:02 AM

The old sierra based Dax rush used rubber mounts for the diff - this shows it fairly well:

http://www.alfadax.com/content/during/01/rearsuspension.htm

[Edited on 20/1/2017 by mcerd1]


CosKev3 - 20/1/17 at 11:22 AM

quote:
Originally posted by mcerd1
The old sierra based Dax rush used rubber mounts for the diff - this shows it fairly well:

http://www.alfadax.com/content/during/01/rearsuspension.htm

[Edited on 20/1/2017 by mcerd1]


That's the way they all should be mounted imo,much better job


mcerd1 - 20/1/17 at 11:39 AM

The standard dax setups can have issues if the bolts ever loosen though (at least that's the best guess anyone has had as a cause of the failures)
long bolts right through the 7" version should help too - dax didn't use the mounts on the rear cover of the diff at all though, if you've got space for either the ford or caterham style one I'm sure this would help alot.


but its critical that washers are used between the bushing and the diff with this setup - the diff case is alloy and therefore relatively soft, so when the bolts are tightened the crush tubes will dig into the diff casing effectively loosening the bolt by shortening the thickness it is clamping.


I'm sure there are better ways of doing it (the dax one is also a total PITA to get the diff in or out btw) but the dax setup is very compact and doesn't add much weight even compared to solid mounting

[Edited on 20/1/2017 by mcerd1]


Paul Turner - 20/1/17 at 06:00 PM

quote:
Originally posted by mcerd1
dax didn't use the mounts on the rear cover of the diff at all though, if you've got space for either the ford or caterham style one I'm sure this would help alot.



Caterham have never used the rear mount either. Just the long bolt at the top and a bolt either side at the bottom. The rear mount had to be cut off the diff to provide clearance for the de-dion tube to move.


40inches - 20/1/17 at 07:22 PM

The first MK chassis used rubber Diff mounts. They all failed. Including mine


andyhaase1 - 21/1/17 at 05:34 PM

I've just fitted my Sierra diff with nylon spacers. Everyone tells me they will get chewed up in no time. We will see. If they do I'll make up some ally ones.
Andy


axle - 21/1/17 at 05:40 PM

Thank you all very interesting, any chance of picture Andy if it is not too much trouble.

Cheers


mcerd1 - 21/1/17 at 06:17 PM

quote:
Originally posted by 40inches
The first MK chassis used rubber Diff mounts. They all failed. Including mine


dax ones seem ok for that - they use the same bushes as the suspension though...


axle - 21/1/17 at 06:33 PM

Dax set up is different from Mk. how are they fitted to MK fitted?

quote:
Originally posted by mcerd1
quote:
Originally posted by 40inches
The first MK chassis used rubber Diff mounts. They all failed. Including mine


dax ones seem ok for that - they use the same bushes as the suspension though...


axle - 22/1/17 at 05:42 AM

if they do it will not be a bad idea to fit the alloy one someone else who is good in matters like sound transfer was telling me it will be a good idea to have a brass sleeve tight fit (or threaded) on the alloy this take a bit more of the noise from the fitting rod and should minimize the noise more!





if

quote:
Originally posted by andyhaase1
I've just fitted my Sierra diff with nylon spacers. Everyone tells me they will get chewed up in no time. We will see. If they do I'll make up some ally ones.
Andy


Paul Turner - 22/1/17 at 08:56 AM

Caterham use metalastic type bushes to mount the diff, exactly the same bushes that are used in wishbones etc. Mine have been in since the chassis was made in 1992 and still appear to be in perfect condition. I checked them when I had the diff refurbed a couple of years ago and the rubber still looked fine with no separation. Replacement would be an absolute bugger, you would have to make a tool to wind then out/in since there is obviously no space for a press. I replaced all the suspension bushes in about 2003 and they also appear to be currently OK, the originals became very "squeeky".