Brake Problem with GQ brakes

[zuffen]

I have an odd brake problem.

I've built a custom vehicle that uses a few GQ parts (transfer, diff, drive shaft, brakes) and I can't get the rear brakes to work in sync with the fronts.

The brake system is GQ master, hoses, calipers and discs.

There's no rear proportioning valve and it uses a Mitsubishi booster.

The front brakes will lock up without standing on the brakes but the rear will only warm the discs.

The front has new pads but the the rears are older.

The front calipers are re-built but not the the rears.

All hoses are new.

When I blead the brakes there's ample fluid flow from the rear brakes.

I recently fitted a new master to see if this was the problem.

I'm now thinking of re-building the rear calipers (they are moving the pads as the discs heat up a little) and fitting new pads.

The lack of proportioning valve shouldn't reduce the rear braking, in fact it should increase it and make it work harder then cause me a rear end lock up problem.

Any suggestions would be greatly appreciated.

[zuffen]

Fixed.

[JWB]

Well! what was the remedy????
cheers

[zuffen]

First I replaced the m/c to eliminate it from the potentiallist of problems. Not hard or expensive so I did it.

I removed the rear callipers and checked they were working with compressed air, then checked the calliper slides. I had one tight one so removed it and lubricated it and reassembled the rear and bled the system.

Still little or no brakes.

I then removed the brand new pads in the rear and replaced them with the pads that came with the axle when I got it. The brakes are much improved, but far from perfect.

I figure the rear pads were glazed (no idea why the they've done perhaps 3klm) and the old ones now need bedding in.

I also figured some of the problem is it happens when I drive on painted floors or carpet (yeah my garage has carpet on the floor) and the engine is cold, I figure the high idle until it warms up is engaging the torque converter and making it look/feel worse than it is.

The car stops on the road quite well and when on sttands the rear end pulls up well without undue pedal so it may be a matter of time to bed the pads (I'll put new pads in the rear) and things will be OK.