Rx300 Brake Pedal Slowly Go Down ?

[hellgrace5]

Hello. I have a 2004 Lexus RX300 with chassis JTJHF31U800020658

I notice the brake pedal is going down when i depress and hold it at certain position.

I already replace the brake cylinder pump right in front the brake booster. I did bleed the brakes with correct steps.

There were no brake fluid leaking and the fluid level is MAX.

Did i miss something ? or its another symptom causing it to fade ?

[lenore]

you bleed from the right rear first, and then moved around to the front wheels....? Sounds like you still have air in the system...if not than it is possible the master you got is bad, or the booster is leaking....

[hellgrace5]

Thanks for reply lenore.

Yes I did it from rear right, rear left, front left, front right.

I thought that booster leak would cause the pedal to go stiff ?

Can someone confirm this ?

[lenore]

Booster leak would cause it too move slowly down, if the leak was slow....than it would get stiff when just the hydralic was actuated. Is the engine running when you test it.? If not turn it on and recheck and see if the pedal drifts downward. If it does you have a leak either in a caliper or the master you put in is defective.

[lenore]

Booster leak would cause it too move slowly down, if the leak was slow....than it would get stiff when just the hydralic was actuated. Is the engine running when you test it.? If not turn it on and recheck and see if the pedal drifts downward. If it does you have a leak either in a caliper or the master you put in is defective.

[hellgrace5]

Yes the pedal goes down slightly when engine is running. Calipers have no leaks. All brake fluid linings are fine no leaks.

Can it be that unlucky i get a new master and its faulty :(

[pauljcl]

Yes the pedal goes down slightly when engine is running. Calipers have no leaks. All brake fluid linings are fine no leaks.

Can it be that unlucky i get a new master and its faulty :(

Hellgrace5 and lenore:

If the symptom is that the brake pedal is depressed to a certain level when the engine is not running, then depresses slightly more (with the same foot pressure) when the engine is turned on, then I believe this may be normal. If I remember correctly, this was the case on my 99RX300, which had no brake problems. I always thought it was simply the hydraulic power (the master cylinder/power brakes) entering into action: thus, for a same foot pressure, the pedal would depress more when hydraulic pressure was available than without the power brake active. [i explain this badly. Sorry.]. But I bow to the expertise of both of you and do not wish to muddy the thread.

[hellgrace5]

Thank you pauljcl for your information. :)

[lenore]

If the peddle stops moving after it reaches a certain point, but not to the floor you are probably fine....If it goes to the floor than the master is bad....