3 replies to this topic

[pongle]

Hi Guys, I have just replaced the brake master cylinder on my tubby and decided to back bleed the brakes rather than force the air all the way through the system to the wheels. I figured that the two brake pipes leaving the side of the master cylinder probably operate two separate circuits, each being a diagonal from one rear to one front wheel. I managed to successfully to push fresh fluid through to the resevoir both from the front left and right rear calipers. However on testing the pedal afterwards it goes to the floor pretty much with little resistance or building pressure.

 

Have I missed something here? The master cylinder does have the end of the piston sticking up in the air towards the front of the car so I guess there could be a large bubble still caught there but beyond that I'm stumped.

 

Any suggestions?

 

Steve

[Johnboyhgt]

Bleed in the conventional way, rears first.

 

Then unbolt your front calipers and rotate them 90 degrees so the bleed nipple is uppermost and at a slight angle so as to allow the air to rise when its in the second part of the caliper.

Don't forget to place a block of wood or similar between the pads to stop the pistons falling out.

 

There's air somewhere in there. 

[siztenboots]

I just vacuum bled mine this afternoon , plus also a bit of pedal pressure bleeding

[Foxy_Jr]

Bleed in the conventional way, rears first.   Then unbolt your front calipers and rotate them 90 degrees so the bleed nipple is uppermost and at a slight angle so as to allow the air to rise when its in the second part of the caliper. Don't forget to place a block of wood or similar between the pads to stop the pistons falling out.   There's air somewhere in there. 

Second that. The air gets trapped in the inner side as the transfer pipe is on the bottom. Vac/pressure bleeding is the way to go, much easier. There also could be air trapped in the ABS pump, I changed one recently and managed to get bit of a pedal then got the pump to activate on gravel. Tech2 (if thats what its called?) I believe has a option for bleeding the system more scientifically, but the gravel did the trick for me! THT.