Braked fade when in reverse?
Asked by Thorin Feb 13, 2017 at 11:39 AM about the 2003 Jeep Grand Cherokee Laredo 4WD
Question type: Maintenance & Repair
I've had a problem with with my abs activating
when I back up, now no today when I put it in
reverse the brake pedal will go almost to the floor
but it drive there is no problem? Is my master
cylinder failing or something else?
20 Answers
It is weird that it does it in reverse. I just don't see where that would make a difference. Never the less I would suggest taking it into a shop to be inspected. You do not want brake failure.
It also does it when your first start it, if pump the pedal with it off or on it will hold pressure and be fine from there. My dad had a the same problem on one of his parents vehicles and it ended up being the check valve on the booster, is that what this could be?
Very possible, you could try changing it. It is right at the brake booster.
As a precaution I would also check the calipers and pads to see if anything looks wrong.
Do you know where I could it the part from because right now the dealer is only option that I have found to get it, all the auto parts stores around only have the whole booster assembly, I'm also going to put a new vacuum line on it too.
You know, a brake pedal should never fade, or go to the floor. You might have some air in the brake lines? Was the brake system opened up, a brake line replacement or brake fluid level gone empty in the master cylinder? I have never run across this check valve causing the brake pedal going to the floor. The brake system is a closed system. If none of the above, then I would suspect the master cylinder.
When I'm in park and mess with the brake pedal the rpms start move up and down that's why I think it is that check valve, the system has never been opened up and the fluid is full and there isn't any leaks I can find
Check the vacuum line to the check valve. look at where it is connected. It may be that the power booster is starting to go. Just have to figure this out. Booster or Master Cylinder, or Vacuum.
The dealer wants $75 to $100 to look at it but if it is a master cylinder they want around $700 to fix if it is the master cylinder
I would not go to the dealer. A master cylinder is only around $80. & 1 1/2 hr. max time to replace. Go to your local garage to have this looked at.
That's what I was thinking, ive been messing with the brakes and you can push the pedal most of the way down and the next pump will be fine
Oh, well then thats different. If there are drum brakes on there, then either the rear brakes are worn, or if the shoes are still good then they just need to be adjusted up to the drums. But probably are worn. Just need to replace the rear brakes.
It's disc all the way around and everything has around 25,000 miles on them
Well then I would just take it to your local shop to have checked out. It may be that the brake just need to be bled out. There is not much you can do for the brake pedal with disk brakes all the way around.
I can start it and pump the brakes it will be. Fine but once I put it in gear and start moving or go from reverse to drive I have to push on the brakes about as far as the pedal will go.
Well I do believe there is a problem with the Mastery Cylinder. If it were mine, I would replace it and bleed the brakes.
My friend and I are going to bleed the system out before I replaced stuff just to make sure. $700 is outrageous to replace, my friend works at shop near by and said he would do it for free if I get the parts
Yes, do not go to the dealer for something like this. There are brake shops that are much cheaper. But anyway, when bleeding the brakes, do no let the master cylinder run out of brake fluid. And you need the cover on when pumping the brakes or it spits out all over the place. I'm sure your friend knows what to do, but if for any reason you go to replace the master cylinder make sure it is bench bled before you put it on. Thanks for letting me know, let me know what the outcome is.
The problem wasn't the master cylinder, it ended being that one of my front calipers seized up and wore the pads completely away, I put more rotors, pads, and a calipers in it and now everything good.