Tokez420

i installed some new rotors, pads, and flushed out the whole system with new brake fluid. but now the brake pedal is soft. any suggestions

superjoe83

did you let the master cyl. get dry? if so its common for an air bubble to get caught in it, and you may have to take it off and bench bleed it.

jimbo74

not sure how you evacuated the system of the old stuff... but sounds like you need to bleed the system

Flamedx4

I just had the same problem! After my gear install I bled the brakes and couldn't get pressure. (I forgot the rear load proportioning valve.) I did it again, and again, and although I have brakes, I still have soft pedal and it's a pain to drive. I've always found soft pedal to be air in the lines or a bad hose (had one once with a bulge in it and it gave the pedal a squishy feel.) I can't for the life of me figure it out. Can't see any reason for the change, pedal feel was fine before I r&r'd the thirds... Suggestions welcome!

mt_goat

Maybe it's your bleeding technique? It helps if you have one of these too. http://www.motiveproducts.com/

Here is some good info on bleeding brakes http://www.gadgetonline.com/BrakeFlush.htm

Flamedx4

Yep, Gadget may have the answer. I called one of my old Toyota mechanic friends and he said the same thing that Gadget said, if it was an old master cylinder I probably ruined the seal when bleeding by pushing the pedal to the floor. Since it holds pressure though (pedal doesn't ease all the way to the floor) I'm gonna bleed it one more time (4th time!) and if that doesn't fix it, a rebuilt master cylinder is in my future...

Flamedx4

Thought I'd pass along what happened with mine. I bought a Mighty Vac brake ($30 at Harbor Frieght) and rebled my system. First, I had someone step on the pedal while I cracked the lines a couple times at the master cyl. Then I used the Mighty Vac to bleed each wheel and the load compensating valve until I got clear new fluid. I used nearly a whole 28 oz can of brake fluid. It worked - fourth time apparently is the charm! Brakes are perfect now. But there are a couple of things I learned from my retired mechanic buddy:

First - ABS. Some ABS systems have very specific and peculiar bleeding needs. Especially if they traction control. Some systems are pressurized and can be damaged by traditional bleeding methods, some systems have bleeders on the ABS unit etc. Check first.
Second - the order you bleed the calipers and cylinders is important. Start nearest the master cylinder! Work away from the master cyl. In mine that was LF, RF, load valve, LR, RR. If you go the other way you pull air (if present) through the lines and it usually will end up with spongy pedal again. This is most likely why mine didn't work properly the first time. This is true of all vehicles, although ABS or other components may have special requirement. My guy said there is never any time to start farthest from the master cyl, for the above reasons.

So Tokez420, have another go at it, do it in the correct sequence, and you may be fine. I'll just put that master cylinder money in the new tires fund....

Tokez420

the pedal was soft after i took it for a test drive....but then next day it was fine
but thanx for the help guys

mt_goat

[QUOTE=Flamedx4]
Second - the order you bleed the calipers and cylinders is important. Start nearest the master cylinder! Work away from the master cyl. In mine that was LF, RF, load valve, LR, RR. If you go the other way you pull air (if present) through the lines and it usually will end up with spongy pedal again. This is most likely why mine didn't work properly the first time. This is true of all vehicles, although ABS or other components may have special requirement. My guy said there is never any time to start farthest from the master cyl, for the above reasons.
QUOTE]

That is different than everything I've heard, but it makes sense if you are bleeding out an air pocket. My BMW manual says to start the farthest away from the master cylinder but that is for replaceing all the fluid, not just bleeding out an air pocket somewhere.

Flamedx4

I agree, I've always started farthest away and always read and heard that. But once air is in the system, not just at the wheels, it makes logical sense to start closest instead. I checked some of the various manuals I have laying around, and most say start closest to the master cyl. including the toyota manual.