Rear wheel camber - MOT failure

[RogerH]

Hi Terry,

using your dimensions you have apprx 3.3 degrees negative camber on the OS and 2.3 on the NS

 

This could be reduced to 0.5 degree negative to help reduce your problem.

 

I assume the boot was more or less empty. As it loads up your camber will go more negative.

 

Regarding the 17mm difference in height - are the tyres the same height. Measure from the bottom lip of the wheel to the wheel arch to give more accurate dims.

 

Have you had a look at the Buckeye write up on this . It is very comprehensive and works.

 

Roger

[Peter Cobbold]

Terry,

Following on from Roger, you need to take 3deg camber off OS and 2 off NS. The brackets can be fitted either way up but the bolt location is not central, so by inverting and swapping you can raise or lower the angle of the trailing arm viewed from the rear. You need to raise the inner mounting relative to the outer by the required degrees. Lowering the outer might do it, or a combination of raised inner or lower outer.

Sketch the geometry and convert the degrees to mm to get the correct amount you need to raise the inner relative to outer, which we call H.

eg If the separation between brackets is ( guessing here! ) say 200mm then Tan 3deg (which is**: 0.05) = H /200. So H = 0.05 x 200 or 10mm.

Peter

 

** http://www.rapidtables.com/calc/math/Tan_Calculator.htm

Edited April 27, 2017 by Peter Cobbold

[Terry Field]

Hi Roger,

 

The boot was empty, apart from the spare tyre, and I moved the car to ensure that the wheels were properly settled.

 

I followed buckeye, up to the point where I need to start dismantling springs, bushes and brackets etc.

 

I was going to ask how to adjust the camber, but as I was typing, Peter's missive came in about bracket adjustment, so I need to get my head around that (thanks Peter!)

 

I'm just a bit perplexed as to how the car has done about 7000 miles since it was rebuilt, and the problem has just shown itself.

 

Regardless of anything else, should I be thinking about smaller tyres?

 

Thanks

 

Terry

[Peter Cobbold]

I'm just a bit perplexed as to how the car has done about 7000 miles since it was rebuilt, and the problem has just shown itself.

 

 

Thanks

 

Terry

Terry,

Yes indeed. Inspect the brackets for cracking- I had one let go- and the chassis where they bolt into. Also check the chassis for cracking below the bolts for the shocker bracket- mine went there.

Most of all I suspect the t/a rubber bushes have collapsed - it might be the time to fit PU.

If a rubber shim under the springs has disappeared that can affect ride height and alter camber a bit. There are PU shims that can be substituted. If the ground clearance is below spec then shims can help.Its tricky to visualise in 3D but camber and toe both change as the t/a moves through an arc. As the wheel rises the negative camber gets greater and the toe goes more in.

 

Try to do the toe-in at the same time, by adding or removing shims on the brackets. Part of the tyre wear may be due to too much toe-out.

 

Peter

[88V8]

Goodparts adjustable trailing arm brackets.

https://www.goodparts.com/shop/index.php?categoryID=13

 

Camber gauge

https://www.machinemart.co.uk/p/040817066/?da=1&TC=GS-040817066&gclid=CJHBsobbxdMCFQgq0wodvIkPhw

Think Moss sell them?

 

Toe in... at the rear should be slightly more than at the front.

http://www.gunson.co.uk/product/G4008

 

Relatively easy to swap rear springs by lowering the trailing arm, spring can be lifted out. You can also buy alloy spacers to go under the spring.

 

Here's my saga from 2008. I did get it sorted, and 10,000 miles later the Goodparts brackets are still good.

http://www.tr-register.co.uk/forums/index.php?/topic/14526-help-cant-get-negative-camber-at-the-rear/

Note my comments about trailing arm geometry and date. Check yours in case you have non-matching trailing arms; in 40 years, stuff happens.

 

Edit.... Tyres.... my car had 215/70. With proper camber your 195s will be fine.

 

Ivor

Edited April 27, 2017 by 88V8