You can use an adjustable bias adjuster but it needs to be locked(to the satifaction of the tester) so that it cannot be adjusted. This usually means pining the bias bar. The alternative is to fit a brake proportioning valve in the circuit for the rear brakes, the Sierra is fitted with one as is the Fiat Uno range, these reduce the pressure to the back brakes but are not adjustable. The prototype is fitted with Standard Sierra front discs and rear drums and didn't need a proportioning valve, the brakes are excellent - do you need rear discs? It's worth considering.

If you go with rear discs I'd recommend making an adjustable proportioning valve as shown on this page by Dave Andrews.

http://www.members.aol.com/dvandrews/bpvalve.htm

This would need setting up OFF ROAD by turning up the valve until the fronts lock up first in all situations. As this is adjustable, but not from the drivers seat (it's usually under the car or in the rear suspension area) it's ok for the SVA.

Cheers

Chris :)

Some options for this problem are the standard brake bias valve mounted at the correct angle as the original fitment.
A mini bias valve which fits on the master cylinder.
Or a twin cylinder bias bar system with the adjuster bar pinned.
My friends Robin Hood super spec that we took to SVA last month has Cosworth brakes all round and was suspect on the brake test but the equipment broke so a road test was done and while he passed, the rears locked up at almost the same time as the fronts.

rear hubs for disks
 

hi ,
i have bought off ebay 2 rear hubs 2 flanges and 2 rearstubs which are 108mm diameter ,im told they are off a 2.9 4x4 1989 are the rear hub all the same size? and are the drive shafts and lobro joints all standard size?
the other question is which disks can i get for this will they be solid or vented?

regards
lee

The 4 x 4 had solid discs, as far as I can remember all the Sierra hubs are the same size, with two different types of driveshafts, ones that push into the diff and the bolt on ones.

Cheers

Chris :)

There's 3 i think, 2 sizes of CV joint, standard 100mm & cosworth 108mm and the push in type.

ATB

John

rear driveshafts
 

cheer's lads,even thow the driveshafts come in various forms cv joint push in type/lobro & stub 100mm & 108mm are they all the same spline size & pattern between the hubs and differential and are the length's of the shaft's the same?

sorry if these seem to be silly question's

regards

lee:D

For those in North America. I used a common Merkur rear disk brake conversion kit, '91 Thunderbird SC calipers, and '88 Thunderbird Turbo rotors. Everything seems to fit correctly without interference.

http://usera.imagecave.com/mconley3/...prights_03.jpg
http://usera.imagecave.com/mconley3/...prights_02.jpg
http://usera.imagecave.com/mconley3/...prights_01.jpg
http://usera.imagecave.com/mconley3/Brakes/brakes01.jpg

Mark