Okay, my brake pedal is mush when I try to stop. If I pump it a couple of times it will stiffen up to a normal feel but if I let off again it immediately goes to mush the next time I press the pedal. If I do not let off of the pedal it stays firm. It is not leaking anywhere. Has not seemed to lost any fluid whatsoever. It has gradually gotten worse over time. The front pads are in good shape and the rears are as well.

I am lost.

Any help is much appreciated.

Thanks,
Josh

 

bleed the lines. Get a friend to tighten while u pump the pedal or there is a one ma brake bleeder at advance for like 6 bucks.

 

Might also be your master cylinder. You can get remanufactured MCs from AutoZone for $45+core. It's easy to do and should take less than two hours including a coffee break.

 

Check that $4 peice called a Check Valve located mid way on the vaccum line coming from your booster. I have the same problem, but my booster isn't retaining pressure. It has a vaccum leak.

 

That type of behavior is usually indicative of air in the lines. When was the last time you swapped your brake fluid. I tend to change out my fluid once a year.

On the s2000, I'll do it every 6 months. But that car sees much harsher braking than the Runner.

 

I'm gunna repeat the call to bleed the brakes. cheap, and easy. If proper bleeding doesen't fix the problem then you can move on to checking other items.

 

Also if your rear brake adjusters are not working you will get similar behavior. Manually turn the adjuster through the backing plate at the back drums. But bleed your braked first as stated above.

 

Even with no air in the lines, dirty, dark, old, moisture saturated fluid will do the same. Since this has happened over time, I'm gonna say that's what it is. So, yeah....bleed/flush thoroughly with new fluid. And since the pedal stays put at a stop, it's not the master cylinder.

 

Ok, I appreciate the input. This leaves me with one question. If there is air in the line, how did it get there?

 

Deteriorating wheel cylinders or caliper pistons, rusty brake lines eating through, gremlins cracking your brake line fittings overnight to play dirty mind games on you....any number of things.

 

the other thing is that water can cause the same types of issues over time, and dot3 loves water. If you completely flush the system it will work way better. Go get a couple bottles of dot 3, and just keep bleeding till you get clean brake fluid out of all 4 bleeders

 

Just out of curiosity, do you have an functional e-brake on there?

 

dont forget to bleed the lpsv......

after you bleed all 4 wheels

 

lspv?? what's that?

 

load sensitive poportioning(sp?) valve

its the little thing that hang down to your rear axle..... looks like a junction box for your rear brake lines. it has a bleeder on it

 

proper bleeding order is
Driver Rear, Pass Rear, Pass Front, Driver Front, LSPV (if equip). Use plenty of clean (new) brake fluid until the fluid comes out clear from each bleeder screw. Have a helper pump the brake pedal approx 10 times and hold it to the floor. Put a piece of clear tubing on the bleeder screw so you can see the condition of the fluid that is comming out. Make sure you only open the bleeder screw enough that the fluid/air starts to come out (opening to much gives false air bubbles). Tighten the bleeder screw before you release the brake pedal. Repeat until no air bubbles are visible in the fluid and it looks new. Do that for each wheel. Try not to lock up the brakes the first time you hit the pedal after bleeding the system.

 

Nope.

 

Does anyone have a part number for this check valve? I'm having similar problems and figure thats an easy and cheap peice to start with.

 

Actually, it should be pass rear, driver rear, pass front, driver front, lspv.

 

Update:

Replaced front pads (didn't really need it)
Replaced master cylinder
Blead everything in the correct order (10 pumps bleed 4 - 5 times each place including LSVP)

The pedal is a little better but still falls to the floor unless I pump it up.

The E-brake is worthless. I tried using it to self adjust the rears as well as reverse pedal braking. No change. The self adjustors are in fine working condition and I screwed them all the way in.

Anyone else have any insight?