Hi,

We cant seem to get the brake bias setup right on our luego.

Can someone post me some pictures preferably from above showing the position of the bias bar and the placement of the master cylinders etc so we can get a good idea what to do...

Alternitivly, can someone give me a guide to setting it up....

We are running 0.705 on the rear, running to rear discs with 43mm sierra calipers. 0.625 on the front running to 60mm sierra front calipers.

please help!!!!!

Ian

Not sure about your setup because I have used the same size master cylinders front and rear, but shouldn't yours have the .7 one on the front circuit?
I think that .7 is larger volume wise.

Sounds like a similar setup to my ST, you may find that with disks on the rear, its impossible to achieve correct bias within the adjustment of the bar, because the rear is effectively over braked. I fitted a Fiat Uno adjustable proportioning valve into the rear line which cured the problem.

Al

nope, definitely have the master cylinders correct, the larger volumne creates less hydralic pressure, so it feeds the rears, the smaller moves less fluid, BUT produces more hydralic pressure to feed the fronts where you need greater pressure. You use the thread of the M/c in to the clevis pin to make sure you start pushing fluid to the front m/c first.

I might try fitting a sierra deceleration valve to the back then to reduce pressure under heavy braking.

I just failed SVA on this.

However, I have it right now.

You need the bar screwed over towards the Front master clyinder by a LOT. The nut on the rear side (of the bar is showing about 6mm of thread after the lock nut.)

I have 240mm (smallest Sierra vented) discs on front and std sierra discs on the rear.

If you fit the deceleration valve, ensure you have the angles absolutely correct as there are two types of valve that I know of, and they are mounted differently.

I dont have the valve fitted. Its larger cylinder 0.7 fro the rear and the smaller one for the front.

The front wheels must lock before the rears.

Also new std pads need to bed in 50-200 miles, and with no servo, you need to push fairly hard.
Make sure you bleed the system correctly.
My rear calipers are on upside down so you have to take them off and invert them to bleed, and then put back on. ie cant bleed the rears on the car.

I failed on Split pins and Nyloc nuts on the bar. It MUST be a Roll Pin through the bar and both sides of the nut.
I put split pins in as I thought the car would fail anyway, with the aim of replacing with rollpins if it passed the brake test. A darn sight easier to remove split pins than roll pins in that hard to get at place!. Especially if fails the test and you need to get the roll pins out again.
It failed on the other things so it was a good strategy. If the brakes had passed, then its easy to remove the split pins and knock in the roll pins. Although splits are a fail point.


[Edited on 12/5/2006 by wilkingj]

Don't use a decelleration valve aka "g" valve, if you fit a valve it has to be either a pressure limiting valve or a pressure distribution (regulating) valve.



You have the cylinders correctly plumbed small bore to the front (this gives more pressure to the front), and wind the balance bar centre bearing towards the front brake master cylinder.

If you still get the rears locking before the front just stick a pressure limmiting valve in the rear circuit. If your mastercylinder has imperial thread connections it might be best to plumb it to a Fiat valve. If you have metric master cylinders just use the Mondeo valve screwed into the cylinder outlet.


[Edited on 12/5/06 by britishtrident]