redsp3
G'day guys,
just replaced all the brake lines front and rear. Front brakes bleed no problems, good to go. Rear does not want to bleed. ie pumping the pedal does not draw any fluid into the cylinder. I can feel pressure in the master cylinder by putting my thumb over the pressure switch/banjo bolt area, when you pump the pedal you can feel pressure in the system.
Any body got any ideas??
Cheers
Greg
stafford
If your caliper is underslung you will may have to take it off and get the bleed nipple high to for the air to bleed out. Or use a vacuum unit to draw the fluid through.
adie851
Hi ,As Stafford states....remove the underslung caliper from its mount and bleed it upright..then put it back on its mount....should sort it...
Cheers, adie851
duck2
Splash out on a cheapo vac pump from evil bay, I did after 30+ years of using the olde tried and tested method of using the m/c,s( it was to stop fluid spray when bleeding air locked m/c banjo bolts) it really is a simple clean way to get better brakes/clutch feel stress free,no cleaning up! Just pulls the fluid through the lines and dumps the trapped air in the process!
motobob1000
bleeding
sometimes, when the pedal/master cylinder are adjusted tight the piston in the master cylinder cannot retract far enough to draw fluid from the reservoir. back off on the pedal adjustment to get more throw to the master cylinder. once it is bled you can tighten up on the adjustment.
Foggy 888
Using a vacuum bleeder is a great help, especially when the system has been drained of fluid in order to replace the brake hoses. The rear master cylinder does not push a large volume of fluid when trying to refill the entire system.
I coat the threads on the bleeder screw with grease. This seals the bleeder screw when pulling a vacuum on the system, otherwise it sucks air from around the threads and is hard to see if you have all of the air out.
If it is an underslung caliper, I recommend removing and repositioning it so that the bleeder is the highest point in the system. If you are pumping the brake pedal to bleed the rear caliper with it off, you should put something ( a screwdriver or wedge) between the brake pads to keep the pistons from popping out of the caliper.
Motobob1000 suggested that the piston in the master may not be returning to its full rest position due to incorrect adjustment. This could cause the master to not draw brake fluid from the reservoir when pumping the brake pedal. It can also cause the rear brake to stick on when the system gets hot, as the compensation port in the master will not allow fluid to return to the reservoir. When the system get hot, it builds up pressure and can cause the brakes to stick on, burning them up. You should be able to have reverse flow from the outlet of the master to the inlet when the brake pedal is in the rest position.
