Oil Cooled Brakes.....

Hello All,

Sorry for the long post......Since I got back from sea I have been working a couple of projects related to steering and brakes. The steering shaft went well and for the first time ever I have no play in my steering wheel.

The brakes however is a different story and hopefully you guys and gals can help me out. My Jeep is a 75 CJ5 and I have a leaking brake cylinder on the passenger side rear. After I removed the drum I was shocked at the amount of oil that was covering everything inside. I removed the cylinder and went to the local FLAPS to pick up a new one. I ended up going to three different ones before I found what we think is the correct cylinder and I won't know for sure till it arrives tomorrow. The cylinder I took off is smaller than any of the ones that was listed for a 75, when I say smaller I mean the physical size and the bore that passes through the back plate. We ended up ordering one for a 71 commando based on the numbers stamped on the cylinder which is made by Wagner Lockheed. This also stated it was for 10.5" brakes. This got me thinking that maybe this isn't the original rear end and brake assembly for my 75 but I don't know how to tell for sure. I am pretty sure these are in fact 11" brakes and the pads are 2" wide. This is where I need the help, I have attacked some pictures that will hopefully give you a better understanding of what I have and thanks in advance.

 

Looks right for a '75. The maximum diameter (probably 11.060") will be embossed in the drum somewhere. The diameter is measured inside the drum, from inner surface to opposite inner surface.

The Jeep specialty places (Walck's, Turner, etc) should be better at getting you the right parts than your FLAPS. A 'modern' FLAPS is at the mercy of their computer or books. The old-time parts stores keep their old books and can sometimes look to these for the correct numbers, or a cross-reference to a modern number.

 

If you can measure the bore of the wheel cylinder it will get you alot closer to what you need. Sometimes the small independant parts stores
are more helpful than the chains. They might even like the challenge.

 

Looking at your tape measure, that doesn't read 11". Looks smaller. You need to measure the inside diameter to determine the size. So hold the tape end on the inside of the drum and measure to the other side. Looks like 10" to me.
Also you say it was covered in oil? or did you mean brake fluid. The gear oil will smell pretty nasty, easy to identify. If you have gear oil on your brakes your wheel seal has failed, and quite likely your wheel bearing could be bad also which causes the seal to fail! Make sure you check this also. Good luck, sound like your parts guy is hooking you up with the right parts.

 

Thanks again, I have agree with you GPin and believe these to be 10" brakes. I thought all 75 year CJ5's came with 11's so I guess the rears have been changed by the PO at some point. I am going to clean up the drum and look for a stamp like Timgr advised to be sure. Oh yeah, it's definitely brake fluid and not gear oil but thanks for the input and hopefully the new cylinders will work when they arrive. Thanks again.

 

The postals (DJ-5x) may have had 10" brakes in '75, but not the CJs. Measure from the inner surfaces - the thickness of the drum does not count.

If they are 10", I would not bother to fix them - why waste your money? Get some 11" brakes from a wreck or R&P or Herm.

What's on the front?

 

Well, I measured like you said and they are in fact 10" drums, I tried cleaning the drums to look for a stamping but its too rusted and then painted with POR 15 during the restoration. I also pulled the fronts and they are 11". I have never heard of a factory set up like this on a 75 CJ so I think it's safe to assume the rear end was probably changed out at some point and the brakes were changed over with it. Does anyone know the years that 10" brakes were used, I assume 64-74 but correct me please. As far as converting them over to 11"........I don't do much off-roading and only drive the Jeep as a weekend toy on sunny warm days, stopping was never a problem. I guess I will stick with my "unique" set up for now. Thanks again.

 

They ended in '71. '72-on civilian Jeeps had 11" all around, or disks later.

I don't think it would be wise to stick with the 10" rears. They are hard to find parts for, and you won't know if the front-rear brake balance is as the factory intended. You might be driving down an icy road some day, put on the brakes, and end up reversing directions or worse. May not be that dire, but I would not take any chances with the brakes.

Plus, if you need drums, you'll be most of the way there, cost-wise.

The axle looks right otherwise. Are there any grind marks on the axle where the spring pads were moved? There are a couple other sources for centered 44s, but I think they all have the spring pads in a different location. Have you compared the ratios front and rear? ... not that I really suspect they are different, but to make sure.