I am nearly finished this conversion. 80 series front and rear axles, chromolly axles and cvs, twin lockers, 35in beadlocked silverstones, guard chop etc.

I have just plumbed up the brakes to the original Land Rover master cylinder and booster. Brakes worked perfectly with the Rover axles but I lose pedal once the engine is running and cannot hold the truck back with the brakes completely.

The truck is a 95 Disco 1 with ABS. I removed the ABS system completely and plumbed the Toyota brakes back to the Rover master cylinder. I have fitted new rotors, pads, calipers, flexible lines. Each axle only has a single connection to the brake system. Rear port on the master feeds the rear axle, front to front.

It's bled up perfectly and has a good hard pedal without the motor running but after starting the motor and pump once or twice the pedal drops away.

Anyone have any thoughts?

 

Did you disrupt the vac hose at all ? , V8 or TDI ?

 

Sorry it's a V8. No I haven't touched the booster line. I have checked that and it appears okay.

I am leaning towards a failed master cylinder. It has sat for a bit with no fluid in it and the pedal has been pumped a few times.

Cheers
Matt.

 

I reckon more likely a booster or vacuum problem since you said it had a hard pedal with engine not running.

 

Sounds like you skipped the proportioning valve too. Two lines to front brakes and one to the rear set. Also the master is split into two, primary and secondary. If one fails the pedal travel will increase.

If you go the Rover MC route buy a good OEM unit because aftermarket will lock up without notice which means it could get pretty squirrely at 60mph or just lock up and fail at a stop.

 

As mentioned if you have a good pedal till start up it has to with vacuum.But removing the ABS with effect the proportioning valve you may have to add an adjustable one.
Stock master may not be up to the job without the abs pumps.
Also I thought t the front feed the rear and the rear feed the front.
Also correct on the Master , I got two bad ones.

 

Thanks for all the replies.

I have left the proportioning valve out for now. Will add that once I have basic brake operation.