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Unread 04-30-2009, 10:13 PM   #1
TheRobster
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Brakes broken. Master Cylinder shot?

Driving to work yesterday, and suddenly no brakes.
Brake pedal goes almost all the way to the floor.
Fortunately managed to stop in time.

Topped up the fluid and got home OK. Picked up new front brake hoses as the driver side hose was quite wet.

I replaced the driver side hose today and as I was bleeding the lines I had the cap off, and noticed that with the engine running every time I stepped on the brake pedal it would shoot brake fluid straight up. Is this normal? Is my master cylinder shot?

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Unread 04-30-2009, 10:49 PM   #2
joeyrossmiller
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iv got the same problem with my pedal. not quite as bad. i asked the same question earlier today and yeah the master cylinder is most likely shot. also, i called autozone to see how much one was and asked what else i should check before spendin some money and they said see if there's any water in the booster. just take off the covering and dump it out.
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Unread 05-01-2009, 06:40 AM   #3
zeus87gn
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If you have your pedal back after the line replacement, then no. Your master cylinder isn't dead. Sometimes they will shoot fluid out of them if you push the pedal fast enough. It can be normal. Bleed it with the cover on and see if everything comes out Ok. If it does, you're good to go.

If the other lines are original to the vehicle, you should to replace them all. If you have lost one, the others are sure to follow. They are the next weakest link.
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Unread 05-01-2009, 06:51 AM   #4
TheRobster
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Quote:
Originally Posted by zeus87gn View Post
If you have your pedal back after the line replacement, then no. Your master cylinder isn't dead. Sometimes they will shoot fluid out of them if you push the pedal fast enough. It can be normal. Bleed it with the cover on and see if everything comes out Ok. If it does, you're good to go.

If the other lines are original to the vehicle, you should to replace them all. If you have lost one, the others are sure to follow. They are the next weakest link.
Thanks. That is what I wanted to hear.
I have the other front I didn't replace it as I was a little disheartened last night. The rear line is coming, it is on order. Should be in today.
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Unread 05-01-2009, 06:54 AM   #5
zeus87gn
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So you actually have your pedal back?

It sounds like you just lost a line.
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Unread 05-01-2009, 07:16 PM   #6
TheRobster
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Quote:
Originally Posted by zeus87gn View Post
So you actually have your pedal back?

It sounds like you just lost a line.
It was great for a while. but comming home from work tonight, I got the soft pedal again. I guess I will be doing my master cylinder.

Does anyone know if there is one from a Cherokee that will fit? I am really hard up for cash and the local pick a part has a few Cherokees,and a Comanche, but no YJs.
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Unread 05-01-2009, 07:28 PM   #7
tomwhysy
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1999 f350 booster and master fits got to redrill few holes and extend a shaft a 3.75" but it even had the same brake light sensor mount NOW i got BRAKES
if You getting soft pedal and loosing fluid u need to fix leak
master cylinder brakes sometimes but thats rare I only broked one by using linelock and forgot and hit pedal for second time before disengaging. it will disquise itself by weird pedal feel (first it will act like is braking but when you apply more pressure it will skip and be very soft with only front or rear brakes depends which part of master fails from what you say it looks like you got bad line or could be overextended caliper but that would leak too.
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Unread 05-01-2009, 07:35 PM   #8
ufatbastehd
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Quote:
Originally Posted by TheRobster View Post
It was great for a while. but comming home from work tonight, I got the soft pedal again. I guess I will be doing my master cylinder.

Does anyone know if there is one from a Cherokee that will fit? I am really hard up for cash and the local pick a part has a few Cherokees,and a Comanche, but no YJs.
maybe you have some air left in the line?
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Unread 05-02-2009, 04:26 AM   #9
TheRobster
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Originally Posted by ufatbastehd View Post
maybe you have some air left in the line?
I don't think so. I bled it three times. It feels OK at first, then the pedal gets that sinking feeling.
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Unread 05-02-2009, 06:22 AM   #10
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Check and make sure you dont have a wheel cylinder leaking................
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Unread 05-02-2009, 10:04 AM   #11
TheRobster
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Quote:
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Check and make sure you dont have a wheel cylinder leaking................
No fluid leaking from any of the brakes.
All the plumbing under the master cylinder soaked with brake fluid.
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Unread 05-02-2009, 04:08 PM   #12
TheRobster
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Well $30 at the local pick a part I got the master cylinder and booster from a 94 Cherokee. The booster is a little different, but the Master is exactly the same. In the process of putting in in now.

I am sure bleeding this mess will be fun.
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Unread 05-02-2009, 08:27 PM   #13
TheRobster
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Just for the record

Replacing the master cylinder fixed the problems.
It was a pretty easy swap too.
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