Cat 815 brakes

Fritz Maurer · Jul 22, 2012

I have an 815 compactor and the major source of air leaks are the spring brakes. I rebuilt two of them, but they may not last because the chrome on the actuating rods is in such bad shape. (they're Roto-chambers). Is there any reason I can't use standard maxi chambers instead? It looks like Cat went to a lot of trouble to use the stuff they did, is why I'm asking. Possibly because they're usually submerged in dirt? Thanks, Fritz

NCWayne · Jul 22, 2012

What part of the brake chamber are you expecting to leak? I ask because I've built a couple of chambers on a CAT loader some years back and from what I remember about them the condition of the rod makes no difference because the only air pressure in the chamber is to the rear of the diaphram and not on the front side where the rod is. That being the case, the only reason air would leak around the rod would be because there is another problem internally causing the air to leak around the piston seal.

With all of that said, again based on what I remember about the chambers I rebuilt (the ones with a ring of bolts around the end of the chamber), the stoke on the chamber CAT uses is longer than the stroke on a typical chamber like your talking about using. However if you can find a chamber that will match functionality, stroke, and mounting dimensions, there is no reason that something other than the actual CAT part won't work the same as the CAT part.

Fritz Maurer · Jul 24, 2012

The stroke is one thing I never considered. You're right, I am stuck with those things. They are constructed so the air can be applied between the piston and the cylinder head, and the air is sealed in the chamber by O-ring seals around a chrome plated actuator rod (about an inch in diameter). The problem was with the rusty chrome ripping the O-rings and leaking air. The two that I did seem to be holding up OK, as long as I keep the dirt from building up and keeping them lubed so they don't rust. Thanks, Wayne, for your input.

NCWayne · Jul 26, 2012

I just looked at the Bendix site and they carry parts for the actual rotochambers. That said, I also did a search for CAT brake chambers and now I remember what your talking about. I did build a couple of them about 10 years ago. The lower part of the canister is made like a Rotochamber and the actuator rod your talking about being pitted is hollow. When you apply air to the bottom of the chamber the hollow shaft rises and releases the parking brake. Then there is another regular pancake type chamber at the top that actually applies the brake to stop. The rod it moves runs through the middle of the hollow one. One good thing about that setup is that as long as the leaks don't get so bad that they drop pressure far enough to kick the parking brake valve back out, then you can live with them and still not be worried about the actual service brakes working.
Bendix,

Cat 815 brakes

Fritz Maurer

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NCWayne

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Fritz Maurer

Well-known Member

NCWayne

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