Brake master cylinder problems - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep CJ Forum > Brake master cylinder problems

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineRockridge 4WD IS Taking Zone Offroad Suspension Lift Kits Rough Country Jeep Suspension Deals at Rockridge 4WD!

Reply
Unread 02-16-2008, 09:53 PM   #1
4XGore
2 chicks at the same time
 
4XGore's Avatar
1980 CJ7 
 
Join Date: May 2003
Location: Seattle
Posts: 1,775
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.

4XGore is offline   Reply With Quote
Unread 02-16-2008, 11:42 PM   #2
OldSailor
Registered User
1977 CJ7 
 
Join Date: Sep 2007
Location: Livonia, Michigan
Posts: 858
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..
__________________
1977 CJ7, AMC360 V8 w/ headers, DUI HEI, Edelbrock intake, Holley 4150 carb, , TF999, D300, D30 front and AMC20 rear with 4.56 gears and lockers both ends, 4" susp lift, 2.5" body lift, 35" BFGs, ARG steering, 8000-lb winch, etc.
OldSailor is offline   Reply With Quote
Unread 02-16-2008, 11:49 PM   #3
4XGore
2 chicks at the same time
 
4XGore's Avatar
1980 CJ7 
 
Join Date: May 2003
Location: Seattle
Posts: 1,775
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?
4XGore is offline   Reply With Quote
Unread 02-17-2008, 12:08 AM   #4
Performance
Registered User
1988 YJ Wrangler 
 
Join Date: Nov 2007
Location: Surgoinsville, Tennessee
Posts: 166
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.
Performance is offline   Reply With Quote
Unread 02-17-2008, 06:37 AM   #5
HighCountry
Registered User
1986 CJ7 
 
Join Date: Aug 2001
Location: North East Texas, Texas
Posts: 998
You might want to read this post also, we can combine answers...

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

Bruce
HighCountry is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.