Brake master cylinder problems - JeepForum.com
 
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post #1 of 5 Old 02-16-2008, 09:53 PM Thread Starter
4XGore
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Brake master cylinder problems

I wish this was a build thread but it's more mundane than that. I have had a problem with my master cylinder leaking, but only when I use my brakes. I went out on the trails in Sept. and had troubles with the brakes and a fuel issue on the way home so I parked the Jeep and didn't touch it for over 4 months. I had time for the first time since Sept. on Thursday to look at it. I expected the master cylinder to be empty, but it wasn't, it was full. I drove it around the block but had to pump the breaks once or twice for the brakes to work and they would work excellent (after the pumps). I have no leaking anywhere except in the engine compartment so my question is, well should I just remove the master cylinder and replace it or could there be more to it than that? Also if the reservoir is full but I need to pump the brakes I will need to bleed the lines correct? Is there a tool to do this by myself? I had this problem about 4 years ago and took it to a shop to get fixed. It worked great for about 3 years. So is there anything I'm missing?
Thanks in Advance!

Edit: I don't have power brakes.

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post #2 of 5 Old 02-16-2008, 11:42 PM
OldSailor
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Yes, it could be that you need to bleed the brakes. But that wouldn't cause leaking in the engine compartment.

It could also be that the pistons or piston seals in the master cylinder are worn (or the cylinder walls are scratched), causing osme of the fluid to bypass the piston instead of being pushed down the brake line to the brakes.

If your master cylinder pistons are bybassing, its going to be tough to bleed the brakes. So take the brake lines off of the master cylinder and thread plugs into the holes on the master cylinder. Make sure the reservoirs are full, put the cap on, and then get in and stand on the brakes. If the pedal slowly sinks down, you need to replace the master culinder..

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post #3 of 5 Old 02-16-2008, 11:49 PM Thread Starter
4XGore
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Quote:
Originally posted by OldSailor
So take the brake lines off of the master cylinder and thread plugs into the holes on the master cylinder. Make sure the reservoirs are full, put the cap on, and then get in and stand on the brakes. If the pedal slowly sinks down, you need to replace the master culinder..
If the peddle goes down slowly I'm assuming fluid would be leaking from somewhere correct? Maybe at the firewall?
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post #4 of 5 Old 02-17-2008, 12:08 AM
Performance
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No higher than what they are, I would just get another master cylinder. I just got a reman from O'Reilly Auto Parts for $18. Just remember to bleed the master cylinder before you install it and then bleed the brakes. Very cheap and easy fix to your problem.
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post #5 of 5 Old 02-17-2008, 06:37 AM
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You might want to read this post also, we can combine answers...

http://www.jeepforum.com/forum/f8/brake-pedal-low-521315/

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