Rear wheel camber questions

[Plan B]

Hi chaps
Putting my back end together (- ooh err)and just want to check the fixing method on the rear wheel camber adjuster i.e. upper wishbone to rear upright. There's a helluva width gap between the mounting lugs on the wishbone and the part of the upright that locates between the lugs. So - I'm assuming the arrangement is 2 x thick penny washers inside the lugs and 2 x thick penny washers outside the lugs plus the 2 x plastic washers next to the bush in the upright. Does that sound correct? See piccy to get an idea of the gap before inserting any washers - I just don't remember it being that wide a gap ........



One other question which is puzzling me. The camber is set by sliding the upright to the right spot in the elongated slot in the wishbone and then clamping it all together so it doesn't move out of position. What I don't understand is in normal daily operation the upright stays approximately upright however the wishbone is moving up and down with road conditions. In which case the wishbone is twisting by a few degrees each way against the upright. Would this not encourage the camber setting to move out of adjustment for example after hitting a pothole coinciding with a sideways jolt - i.e having a big rear suspension deflection causing the wishbone to rotate against the upright whilst giving the upright a sideways jolt. Am I just daft and missing something or is it reality that the rear camber settings easily get knocked out.

[TVR Beaver]

You are very correct in your observations … it is indeed a cr*p design… I went through this when I first got my car and was painting / re-bushing the wishbones, so if you look back on my history, it will be there….

The question is… are both sides the same?.. what I found was that the bottom wish bones, that set how the upright presents to the top nip, was not the same side to side.. resulting in the LHS one tending towards the front of the nip, where as the RHS one tended towards to back…

So first I made a jig to hold the bottom wish bones so I could true them up.. so they were both the same….

Them I put the uprights in and looked at the top gap.

I’d already re-worked the top wishbone to make the face parallel to one another as they had been pulled about by the problem you’ve seen.

Make the faces parallel by straightening up the top wishbone (yours look quite straight as they are).. then I made SS packing washers to go either side of the top nip so it positioned the nip same both sides of the car….

Don’t think it overly matters where it’s clamped so long as it’s the same and not pulling the upright one way or the other….

I still have the rig for the lower if you want to use it



Here you go... http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by TVR Beaver on Wednesday 15th October 09:42

[Plan B]

Just read your other thread and my setup also has the same symptoms. On the drivers side the front tube on the lower wishbone appears lower relative to the front. This manifests with the upright being flush with the nip at the front and having all of the gap at the rear. I'll try putting a single washer at the front and maybe two at the rear and see what loading that's going to leave on the bush.

Back to my original question - I still don't understand haw the wishbone can freely rotate against the upright when the upper wishbone is clamped rigid against the upright. Will prolonged suspension movement not eventually grind the paint off the wishbone/upright juncture thereby loosening the nip and losing the camber setting??

[TVR Beaver]

what have you fitted?.. the rubber type bush or a poly bush.. if it's the latter, the tube will be held by the washers you fit when you clamp up and the plastic washers will look after the thrust (ID of these being slightly bigger than the tub OD)...

If it's the rubber bush you've fitted, you need to nip them up with you arms at 'normal' ride level.. so take the shock off and set the bottom arm level.. then nip them up and they will twist at the rubber when they go up or down from that point...

Is this what you mean?...

[Plan B]

I've fitted Powerflex bushes. So are you saying the nip is transmitted through the central steel cylinder in the bush and not through the upright body?

[TVR Beaver]

I think I need to answer YES to the above?.. its the top PIVOT.. it does not lock out on the upright otherwise why would you have the bush in there???.. The top bolt will nip up the central tube (you are going to fit steel spacer washer here to close up the gap.. these will have a ID same as the bolts OD so the central tube end goes against them)... the poly bush and bearing when pushed into the top of the upright housing will then pivot around this?...
thrush washes (plastic) will stop any front to back movement...

this is the same as all the rest work?.. what have you got in the two bottom positions on the upright?



Does this help?

http://thumbsnap.com/sc/CbG3BTif.jpg[/img]|http://t...

Actualy.. the drawing needs to show the 'spacers you are going to make' about the same OD as the bit of tube welded onto the top of the upright.. so it will stop thrust either way....

Edited by TVR Beaver on Wednesday 15th October 17:05

[Plan B]

Thanks John that's clear. Today I've ordered a bunch of heavy thick 7/16 heavy "Table 4" washers that have an O/D of 1" which should do the job fine.
Cheers

[Plan B]

Just remembered You asked what I have at the bottom of the upright.

At the mo I've just pressed Powerflex bushes in there but haven't tried fitting into the lower wishbone - I'm assuming this should all be OK normal. Saying that have I just tempted TVR-fate??

[TVR Beaver]

No. The bottoms are fine. You may find the bushes stick out a bit on the inside faces. But from memory the thrust is done on the outside faces.

Try get those bottom arms level with eachother. Then you are not loading the top arm in opposite directions