Forum:
why does my brake pedal go to the floor slowly ihave changed the master cylinder checked all callipers and seals and i have no air coming out of the system when bleeding can someone help before i pull all my hair out plus it is not losing any brake fluid it is a daihatsu fourtrak 2.8 tdx
master cylinder.
Most master cylinders are duel system ... supplies pressure to paired wheels. Last time I had the symptom it was the master cylinder leaking past one of the 'duel' seals.
brake problems
I would agree that the pressure is not being maintained either due to air trapped within the pipes or a seal allowing presure to escape.
Have you checked the servo for correct operation? These have seals withinh that can fail. They often allow brake fluid to squeeze through in to the servo but since you are not losing the fluid this seems unlikely. Test it by pumping the brake with the engine off. You will hear the hissing as the servo is exhausted. An alternative is to place your foot hard on the brake and then start the engine. You will feel the pedal rise as the servo charges. There is a one way valve in the vacuum pipe that can also fail. Test this by removing the pipe and seeing if the valve is working. You should be able to blow up the manifold side but not down from the servo end.
Endsure that you are bleeding in the correct way, some of the bends trap air and the fluid passes by. A good shove with the peadl and engine on should dislodge the air. I use an Easibleed system which also does the job effectively..
Good luck
OLDMINIMAN
M J Young
brake broblems
hi thanks for your suggestions olminiman we tried blowing the one way valve on the vacume pipe and it appears who ever had the car before had renewed the vacume valve but had put it on the wrong way around we have turned it around and the brakes are brilliant pressure and all working fine thanks again phil