brakes

[waitey]

Mornin
just replaced the discs and pads on my kj and now the brake pedal slowly fades away under pressure when the engine is running.
i have bled and changed the fluid and still no better any sugestion?

 

[flman]

Mornin
just replaced the discs and pads on my kj and now the brake pedal slowly fades away under pressure when the engine is running.
i have bled and changed the fluid and still no better any sugestion?

Master cylinder failing? Are you losing any brake fluid?

 

[waitey]

brake fluid is ok not used a drop

 

[journeyjim]

Would that be the vacuum booster? or the vacuum pump since it's a crd or a vacuum leak in between? since you are not losing fluid.:shrug:

 

[flman]

It don't have to leak to be a master cylinder. A wheel cylinder would leak for sure of it were bad. Or maybe some air in the lines? But that would always give you a spongy pedal.

 

[waitey]

spent all day on the brakes no cylinder leak but cant bleed the front right caliper taken the bleed nipple out and no fluid to be found after some serious pedel pumping some fluid comes out but not a lot, brakes are now worse than ever

 

[Neal]

The master cylinder is bad, leaking internally. Replace master cylinder and bleed.

 

[waitey]

Mornin
Fitted new master cylinder bled brake's peddle rock solid drive down the road brake's hopeless.
when the engine is running and foot on the brake peddle it slowly goes down to the floor

 

[flman]

What year is it, does it have ABS? Not sure, but you might have to bring it to the dealer for bleeding if it does?

Here is something from the FSM:

PEDAL FALLS AWAY
A brake pedal that falls away under steady foot pressure is generally the result of a system leak. The leak point could be at a brake line, fitting, hose, or caliper. If leakage is severe, fluid will be evident at or around the leaking component.

Internal leakage (seal by-pass) in the master cylinder caused by worn or damaged piston cups, may also be the problem cause.

An internal leak in the ABS or junction block may also be the problem with no physical evidence.

 

[Auberon]

Just a suggestion a little out of left field but is there solidified muck in the bleed nipple? Have had this resistance to bleeding brake systems before. It can sometimes pack into the vents on the nipple and prevent a successful bleed of a wheel cyclinder.
Can take some cleaning for sure. Have had to hand spin twist drills of increasing sizes to clear them as it corrodes helping it cement in there as well. If you do don't forget to glove-up to prevent cutting fingers.