Cherokee Brake Problems-Brake Booster?

When i'm driving, sometimes there will be brake pressure and somtimes there won't. If i apply pressure for a few seconds, the pedal loses presure and goes to the floor. I have to pump the brakes to get the car to stop. I tried bleeding the brakes and got through the back to wheels fine, but when i tried to bleed the front right brake, air bubbles kept coming out. After refilling the resivoir for the 3rd time (it never got completly empty), i got the idea that it might be somethign more complicated. I was able to bleed the front left with no problems but the same thing kept happening when i tried to drive it. I checked all the lines and can't find any leaks, but i have an oil leak so i might be missing something thinking its just oil and not brake fluid. There is some black fluid underneath where the brake booster connects to the master cylinder but i don't konw if its coming out of there or is oil . I can also hear some air come out of the brake booster inside the car but i dont' know if that is normal. My brake fuild is also pretty dark, i know i should flush it out and replace it but could that be the problem? I don't know too much about brakes and i don't want to take apart the whole system before i know what to look for. Any ideas?

Reply to
tyytyy22
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tyytyy22 did pass the time by typing:

If your getting fluid from between the booster and master cyl or coming out the bottom of the booster (and it's not spilled or leaking from the connections) then your master cyl needs to be rebuilt/replaced. Front and rear are seperate pistons in the master cyl.

Barring that I'd be checking the proportioning valve for leaks.

Loosing pedal pressure (without seeing a massive puddle of brake fluid under the Jeep) makes me about 90% sure it's your master cyl.

Reply to
DougW

thanks for the help. if i took out the master cylinder and replaced all the parts in one of these kits:

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you think it would work? or should i just buy a new master cylinder?

Reply to
tyytyy22

If depends.... do you have the hones, etc that would be required to do it yourself?

Master Cylinders don't cost that much to buy remanufactured and if you have another vehicle you can remove your current one beforehand and avoid paying the core charge ($20-$25) They will also (usually) come with a small kit for bleeding before installation.

As a final note I would use suggest that you use the synthetic DOT 4 fluid instead of the standard DOT 3. It is less attractive to water which leads to less corrosion in the system (the black gunk), has a higher boiling point, and only costs an additional $1 per quart.

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do you think it would work? or should i just buy a new master cylinder?>

Reply to
billy ray

You have too many threads going on.

I gave up rebuilding MC's years ago. The kits just plain don't work because you have to hone out the cylinder and they 'don't' sell you oversized O-rings or cups to make up for it.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

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do you think it would work? or should i just buy a new master cylinder?

Reply to
Mike Romain

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> do you think it would work? or should i just buy a new master cylinder?>>

A big plus with the better rebuilt master cylinders is the installation of a bronze cylinder which is much less likely to corrode than the aluminum of the original bore.

Reply to
Dave in Columbus

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