C5 Mk1 - How Are Rear Suspension Arm Pivot Bearings Adjusted

[aspire_helen]

Hi

I have searched various forums to find out how to properly shim the taper-roller-bearings (TRBs) when renewing the pivot bearings, but no luck.  

 

Two entries in this forum  suggest simply re-using the shim which was previously fitted (assuming it can be recovered), but this assumes that the replacement bearings and spacers supplied with the online repair kits reproduce exactly the required original dimension. Bearing "repair" kits are readily available on-line, but none come with shims.   Haynes suggest just buying the arm complete with bearings already fitted and adjusted....at £450!!  I have heard that a dealer will choose to replace the arm, at the customer's expense, rather than the potentially more expensive labour cost of removing the old bearings, making good, fitting new bearings and measuring up for the shim.  Moreover, if the dealer gets it wrong it could result in an expensive repair bill for them, so replacing the arm is their less risky option. In addition, the "complete" arm comes with extra costs ie a new hub and wheel bearing assembly; likely new ABS sensor; likely brake calliper problems etc.  So, at the end of the day, being able to replace the bearings is the far cheaper DIY option.........subject to adjusting the TRBs correctly!

 

If the shim is too thick, the TPRs will be overloaded and quickly break up; that is assuming the shim is not so thick as to prevent the pivot being fitted in between its aluminium subframe mounts in the first place. Being aluminium, there is also a risk of graunching the mounts with the pivot's hardened steel spacers during re-fitting. If the shim is too thin, or not fitted at all, the TPRs will be too slack, also resulting in shortened life.

 

Can anyone provide the procedure? For a start, it would help to know the required specified width of the assembled pivot, ie between  the outer faces of the opposing end spacers. Hope that makes sense.

 

H

[paul.h]

You are supposed to fit the bearings and use a special tool to measure for the required spacer thickness. If you message your email address I can send you a pdf of the procedure since you need the pictures as well as the wording to follow it.

[aspire_helen]

Thanks Paul, received.

 

The procedure uses precisely engineered  bushes as “tools†to calculate the thickness of shim required. Without those tools that procedure cannot be used.  However, I believe the thickness can be determined by trial and error, by partially assembling the bearings into the arm with trial shims.  The required M22x30mm shims are available on Ebay (0.1mm, 0.2mm, 0.3mm, 0.5 mm etc) for approx. £3 for 10 of each size. I measured the shim I removed from my arm as 0.018in (0.46mm), so 10 x 0.1mm should suffice. The original shim would be a good place to start.

H