Installing diff, large chamfered washer?

[cliffy858]

I'm am currently rebuilding my seven and installing my diff. I have purchased a new bolt pack from caterham and the build manual says that the bolts should have washer 9 which are large chamfered washers under the bolt heads. These washers were not on my car and it looks to me if they are installed they would contact the metal outer part of the bush cancelling out any benefit of having a bush there in the first place. Shall I leave them out? What's the purpose of them? Are they just to stop excessive movement should the rubber bushes fail and break up.

[Jonathan Kay]

This seems to vary between Guides. Could you copy and paste what you have?

There's a general note at the beginning of recent Guides:

Large diameter plain washer

  To prevent migration (sideways movement) of rubber bushes.

  The large plain chamfered washers are often used in conjunction with the metallistic suspension bushes. Where this is the case the chamfered edge must be fitted towards the bush to prevent contact with the outer metal part of the bush. 

But are you on diff to chassis, or A-frame to diff?

Jonathan

[cliffy858]

Hi Jonathan, 

I am referring to this part below when installing the diff into chassis.

13 Remove the upper mounting bolt (1) and refit with washer (9) under the bolt head. Centalise the differential using washers (16) and (12), as required, between the metallastic bushes and the differential. Use a further washer (9) and nyloc nut (6) on the end of the bolt. Tighten the upper mounting bolt and lower mounting bolts to 40 lbft (55 Nm). Check that the differential is central ± 2mm. Adjust if necessary. 

The chamfered washer is (9).  They wasn't fitted on my car originally and just look like they will clamp the inner and outer metal part of the bush when tightened up. 

[Jonathan Kay]

Yes, that's the bit of the Guide that has changed.

What's the diameter of the small face of the chamfered washer, and the inner and outer parts of the bush? Can you turn a washer round, hold it next to the bush and take a photo?

Jonathan

[David Belding]

I have just removed my diff after 16000 miles & there were only normal washers under the bolt heads and under the nut. Because the bushes are in pairs, even if they fail completely any 'migration will be limited by the diff itself. 

With some of the bushes elsewhere the large chamfered washers would prevent excess movement or complete disconnection in the event of bush failure.