Toyota RAV4 Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
I have a 2008 RAV4 2WD that's having an issue with the brakes. The pedal slowly oozes to the floor. I know the automatic fix is to replace the master cylinder which I did. However, the problem persists. It's not losing fluid since the reservoir level is not changing. So I'm stumped what could be causing the problem. The car is equipped with the anti-skid and VCS system, so I'm wondering if there's something funny going on there. Has anyone run across this situation?
 

·
Registered
Joined
·
7 Posts
Discussion Starter #3
Yes. I replaced the MC and bled the brakes myself. I'm going to try bleeding the brakes again. I did do one test and that was to pump the brakes with the engine off to bleed off the vacuum from the booster and then try the pedal test again. The pedal did not sink. This has me wondering about the brake booster, though I am unclear why it would sink down.
 

·
Registered
Joined
·
251 Posts
Are you vacuum bleeding or pumping the pedal? Did you bench bleed the mc first? I have had bad mc out of the box. Do the brakes work normally otherwise?
 

·
Registered
Joined
·
7 Posts
Discussion Starter #6
Yes, I bled the master cylinder. The brakes are being bled old-school by pumping. The brakes seem to be working fine otherwise. I've read on some other boards that the RAV4s tend to have this problem and it's considered normal. Apparently it has something to do with how the ABS works.
 

·
Registered
Joined
·
251 Posts
I have done my brakes and never had the problem you describe. I vacuum bleed all vehicles. Your pedal should not sink to the floor. Are you sure the new mc is good?
 

·
Registered
Joined
·
7 Posts
Discussion Starter #8
I believe so. I can pump the pedal to release the vacuum to the booster and repeat the test. The pedal does not sink if you do that, so I'll take it as a sign that the MC is not the cause in this instance.
 

·
Registered
Joined
·
251 Posts
Have you replaced your rubber lines? If the pedal only sinks with assist, then you may have a bad rubber line that is swelling under pressure. I have had that happen before.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #10
No, the hoses are original. I will inspect them when I repeat the bleeding tomorrow. I was going to do it today, but got side tracked.
 

·
Registered
Joined
·
251 Posts
Visual inspection does not usually show this problem. When it happened on my truck, I replaced the rubber line simply because it was the most likely cause, and it fixed it. The pedal was doing the same thing as yours and it was driving me nuts. Rubber lines are cheap, just do all 4 and be done with it.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #12
Re-bled the brakes and inspected all the hoses. Didn't find anything wrong. This has me stumped.
 

·
Super Moderator
Joined
·
10,776 Posts
There may be special instructions because it has ABS. Check into that or take it to a shop and get it squared away, don't screw around with this. Pay a professional before the inevitable happens.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #15
Not directly. I don't have the computer plugin to manipulate the ABS. Just for reference, the car was involved in a minor accident a few weeks before this problem appeared. It was hit on the left front wheel. When I bled the brakes the fluid was nice and clean which tells me the dealer replaced the brake fluid during repairs. I'm wondering if there's a connection.
 

·
Registered
Joined
·
2,614 Posts
Not directly. I don't have the computer plugin to manipulate the ABS. Just for reference, the car was involved in a minor accident a few weeks before this problem appeared. It was hit on the left front wheel. When I bled the brakes the fluid was nice and clean which tells me the dealer replaced the brake fluid during repairs. I'm wondering if there's a connection.
I wonder if the brake line got damaged during the accident? Perhaps there is a kink in the brake line and air is getting in. You may want to check where it got hit and inspect the brake line very thoroughly.
 

·
Registered
Joined
·
13 Posts
If you have ABS then there is a special way to bleed the system. You have to activate the ABS pump to get the air out. I have heard that you can go on a gravel road and lock the brakes up then bleed them again. Never have opened a ABS system up.
 
1 - 17 of 17 Posts
Top