urgent brake issue

[berazafi]

The car is a td mq 7month of 83, the brakes changed this year, i just purchased a brand new master cylinder and bleed and bleed but i still get a loose peedle i can pump it up but it doesnt hold, can anyone tell me if there is anythoing (maybe spacer) in between the master cylinder and booster

Thanks in advance

[skippy's GQ]

you need two people to bleed the master cyclinder.it's completely different to bleeding the brakes.fill the master cyclinder up and get the person in the car to push the peddle to the floor get the to hold it down. then crack one of the brake lins at the master cyclinder and you should get air and fluid comming out. keep doing this on both lines till just fluid is comming out. then bleed your brakes as normal. this should get you out of trubble

[berazafi]

yeh sorry i think you may have lead you astray. The brakes blead up no air though the hose i had connected. The brakes are then ok, then i start the car and the pedel can be pushed to the floor then you pump and its ok again

[Red Rover]

your poor bastard! I know what yoyr saying. Man I had issues with the brakes. It all comes down to master cylinder or rear/front pads & shoes. They need to be bled heaps. YOu need to make sure the shoes are good, the pads are good the disks are good and all the slides are working properly on the front calipers. BE SYRE THE FRONT MASTER CYCLINDER IS STILL NOT STUFFED. Near lry all the problems were with the masrer cylinder. Was it brand new or recoed? If you push the pedel down & the fluid rises you r still getting bypass on it. It should go down when the pedel is depressed. Eventually i got mine really really good, despite every brake place telling me that all mq have spongy pedal in the diesels. what a load of crap.

hope it helps

[berazafi]

brand new prb cylinder, the old one did the same thing but i get bleeding and kept getting air in the lines(with the old one) any ideas why the brakes are ok with no booster then run booster and brakes are no good

[Red Rover]

yes it will do that with the booster, the problem is not there. Bleed the back first, then the proportioning valve then the front. What condition are the rear shoes in. They do take ages to bleed thru & get the air out. IF you want you can try one from a gq rear drum set up. THe master cyclinder will fit. It is a bigger bore and will push more fluid. What about rear wheel cylinders? What r they like. Did you have a look to c what the fluid was doing when you push the pedal down with the motor running?

[Screwy]

Mate take it into ur local brake man, he will power bleed it for $80 and ensure a good pedal.
U may have a problem with ur rear wheel cylenders, check to c they are leaking.

The other thing that i had to get fixed was the booster behind the firewall. My brake booster has been rebuilt and the reason i got it done was because when i pushed the brake i could hear air coming out the centre shaft in the front of the booster where is pushes on the master cylender. Check to see if u hear leaking air, the front seal is blown and u wont get pedal.

cheers,

Screwy

[berazafi]

I asked a friend about a power bleed it is effective and i can do it myself with a air compresspor just put air nozzel in the air opening on top of master cylinder open valves and bleed away just dont apply to much pressure, i actully think my proporting valve maby prob soory about typing i burnt the keys of my laptop accedently