Hi so I have a 1997 jeep Cherokee xj and I’m experiencing some brake problems that I’d like to avoid taking to a shop if possible. About 6 or so months ago we were driving and my brakes were fine until we went to stop for a light and the pedal just went to the floor. I have since replaced the master cylinder, brake booster, and bleed my brakes twice. I can’t seem to find any leaks and I’ve about ran out of options. My brakes are still spongy and do nothing to stop the jeep unless I put it in neutral. If anyone has any ideas or suggestions please help because I am not financially able to pay a shop to figure it out for a while.

 

Did you "bench bleed" the master cylinder? How did you bleed the brakes (vacuum, pump-and-dump)? Do you have ABS?

How old is the brake fluid? Is the color dark?

Spongy feel is typically an "air in the system" issue.

 

We are are going to try to bench bleed the master cylinder tomorrow, both times we bled the brakes we opened the valve by the tire and pumped the brakes then held them. No abs to my knowledge. Brake fluid is relatively new, we replaced it when we replaced the master cylinder

 

You need to bench bleed the MC before install- then bleed all 4 sides again (back to front, ending at the side of the brake booster is how it is usually done)

I have had spongy break pedal for years and replaced almost everything. Pedal to the floor means a leak though.

The FSM has testing procedures for the brakebooster as well.

Q: what do you mean with no braking unless put in Neutral?

 

It won’t completely stop unless in neutral. I found it easier that way because when in drive it still wants to push forward so I just bump it into neutral to stop.

 

1) Because you replaced the mc and the booster you should check the pushrod length. Look at the shop manual.
2) Make sure the bleeder screws on the calipers are on the top of the calipers ( if swapped sides they would be on the bottom and air would be trapped on top.)

 

In addition to the above, include check pushrod, and bleed Master (can be done in car, with a lot of care, plastic and towels)

The best way I have found to bleed is car nose up, slow gravity bleed

I just do the fronts first, and the fluid should literally run straight through. Front circuit should be so easy. If not something is very wrong

For rear circuits, gravity bleed is not as easy, but still should work, you can/should bleed each junction. This means you will find if there is a blockage

There is more, but that is enough to start you with

Dont allow the reservoir to run dry, as you must start all over

 

I used to do the brake press method with a catch bottle. Then I bought a cheap $15 vacuum bleeder and it was a game changer. It's much faster and you can pull lots of fluid. Smear some thick anti-seize on or around the bleeder threads so it doesn't suck air past the threads and trick you into thinking you're still getting air bubbles.