Diff to roll bar clearance

[Scotland North AR]

Hi, if anyone has a spare minute, could you have a look under the car and see what the clearance is between the rear anti-roll bar and the centre web of the diff please. Just taken the bar out to check the bushes (both sides goosed) and refurbish the drop links. The bar is touching the diff if not slightly bent down over, signs of the powder coating being rubbed off where it touches the diff.

The car is a 2009 Sigma 150 SV, everything standard. A couple of years ago I got an exchange diff from Road and Race. Are there slightly different casing sizes and shapes? Any other suggestion as to why it might be touching?

[Paul Deslandes]

Can't look at my car at the moment but I seem to remember that the web on the back of the diff had to be trimmed as supplied by CC.  Maybe yours wasn't ground/cut off enough. In the manual it says remove exactly 3/4" and no more but I don't know what that should leave.

Paul

[Scotland North AR]

Thanks Paul, will RTFM in the morning, maybe my original was ok but the exchange on hadn't been doctored.

[ECR]

I think that what Paul is referring to is the trimming of the boss on the REAR of the casing to avoid contact with the diff. Your anti roll bar passes over the top of the diff doesn't it?

[Englishmaninwales]

From what I recall (before I removed and dispensed with the rear arb altogether) the 'over the top' arb is close to the central rib on the diff. I filed a bit off the diff.

[Scotland North AR]

Covered in section 5, page 2 of the manual two places on the diff which should be removed. One bit at the top at the back and one bit on the central web at the front in way of the roll bar.

Thanks for the tip Paul.

[John Vine]

A couple of years ago I got an exchange diff from Road and Race. Are there slightly different casing sizes and shapes?

That may well be the reason.  The Assembly Guide that came with my 2008 kit included this diagram:

ETA AG text:

PREPARATION

1 The rear lug on the differential, Fig 1
refers, requires material to be removed in order
to give clearance for the De Dion tube. Measure
and mark 43 mm from the machined face of the
backplate and main differential casing. It is most
likely that this has been removed prior to supply
however if this is not the case it can easily be
removed using a hacksaw.

CAUTION

If less than 43 mm is measured then the
differential casing may be holed. If more than
43 mm is measured it is possible that the De
Dion tube may hit the differential.

2 Measure and mark a line on the differential
casing 38 mm from the forward face of the lower
mounting. Using a file remove material from the
differential web, 15 mm either side of this line to a
maximum depth of 5 mm.

As it happened, both areas had already been trimmed at the factory, so there was nothing extra for me do do.  However, when I came to fit the rear ARB, I found that it still touched the bottom of the diff, so I attached a length of fuel hose around the bar to act as a cushion.

JV

[Scotland North AR]

Thanks for the tip. Have just used a power sander the remove some of the web so will see how that looks tomorrow once the paint has dried on the roll bar. The sketch above does seem to suggest that the web is quite deep but it only seems to be 5 mm high. Given what it says in the text i.e. remove a maximum of 5 mm, then that would make the web flush with the rest of the casing.

Start one job, six others appear, the chassis tubes look like they need a fair bit of sanding down and repainting so that can be the job for the next few days whilst I'm in that area.

[grumpy the 7th]

I too have a bit of rubber hose tie wrapped round the roll bar where it (just) touches the diff.

I now have one spurious clunk less that took a while to diagnose where from many many years ago!

[Scotland North AR]

I'll also do that thanks:)