Wheel cylinder rebuild

I'm probably going to try to rebuild the wheel cylinders on my '62 DJ3A, rather than buy new ones - I figure I'm not out much if the rebuilds don't work, and if they do I've saved some.

Does anybody have any advice or tips for doing a wheel cylinder rebuild?

Oh, and a knowledgeable DJ guy said mine's a '62 according to the S/N, rather than a '63 like I'd been told by the seller.

Thanks.

 

Well, if they leak they contaminate the brake shoes so those will need to be replaced also. Did you make sure rebuild kits are available? Sometimes they are and sometimes not. Are the wheel cylinders pitted at all? If so they are not rebuildable unless you want to have them sleeved. If in very nice shape and rebuild kits available you will need a cylinder hone the right diameter and a drill. I like to use brake fluid as honing fluid do NOT use anything petroleum based.
You want a nice cross hatch pattern, not mirror smoothe but not rough either. Use brake assembly fluid or brake fluid as lube when assembling. Make sure ALL the contaminants are cleaned thoroughly before assembly including the inlet and bleeder passages. Before starting make sure the bleeder screws are free and clean before starting
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alex did you get my pm on the 10" drums?

 

Nickmil - Yes, the kits are available. Kaiser-Willys' catalog lists a kit for "all 3/4" bore wheel cylinders" and "all 1" bore wheel cylinders" (which is what I think mine's got on it) so I'm figuring that's what I need. I'm not sure of the condition of the wheel cylinders yet - with all this rain in MO I haven't even taken them off yet. I did take the brake lines off of them, though, and it appears that they still have fluid in them so there may be a chance they're still good. ??? I already have a drill and hone. Thanks for the tips. I'll make sure they're clean and cleaned out thoroughly.

CJ5/442 - Sorry I haven't gotten back to you! The PM's headed your way.

 

My average with rebuilding brake cylinders has been about 50%. What Nick says is right - if there are any pits in the cylinder bores after you hone them, they will leak. Water is the main culprit. Typically the pits will be at the lowest point in the cylinder, where the water collects.

Brake cylinders for popular models are not very expensive. You might check out the price and availability of the complete new cylinders before you attempt to rebuild (and risk your new brake linings).

For cleaning, I used denatured alcohol, and assembled with brake fluid. This will get everything clean-clean-clean and not introduce any oily solvents.

 

I took one of the rear cylinders apart yesterday, and I'm not sure how clean it is - there's a lot of dirt and roughness (that seems to be on the bore surface, not in it) in the bore, but there may be rust underneath it. I'll just have to hone it and find out, then go from there.

I found a replacement brake cylinder on Ebay for $21 - will this be any worse quality than the ones Kaiser-Willys has in their catalog for $32?

Thanks for the help. I'll do my best!

 

I'm with Nickmil & Tim. The only brake cylinders I will rebuild are the ones I can not get new (like the ones on the 54 FWD). It is nearly impossible to get a rebuilt to last as well as a new one and if your time is worth anything, just not a good investment of it, especially if you plan to use the Jeep for a few years and have to do them again.

 

Thanks for the input, duffer. Honestly, right now, my time is much, much more plentiful than the $$$ to buy new wheel cylinders - and it can't hurt to know how to rebuild a wheel cylinder, what will work, and what won't. Today I bored the rear cylinder I'd taken off, and it cleaned up pretty good - it's not spotlessly clean, but you can't feel any of the imperfections in the areas where the cups will run. (The only notable marks left after honing are in the very middle of the bore, on each side of the passage to the fitting for the brake line.) I'll get a rebuild kit, put it in, and see if the rebuild takes - if not, back to square one!

One thing's for sure - I'm making sure the parking brake works on this rig! (Wait - didn't they used to call them "emergency" brakes?) jeep toss

 

If you do replace the wheel cylinders remember that the metal brake lines like to twist when they are wrenched on. You may want to figure to replace them at the same time.

 

Thanks for the reminder. I'm replacing the old lines with new (or at least good, solid used) lines, so that shouldn't be a problem.

 

If you have some older shops nearby you might get lucky and find the cups and seals you need locally. My dad had a large bin of brake cups in his shop and many times we sourced parts out of there when we could.

All the FLAPS places will probably sell kits, but there's nothing special about them. If you get the right size cups and seals you're fine.

 

Thanks for the tip. I wanted to go with a whole new kit, as the old pistons didn't come out too easily and I figured they were just as well replaced. A local shop had the cups only for $0.25 each, but aside from the pistons the boots were also ripped, so I figured a kit was the way to go.

 

The kit won't give you new pistons - only the boots, cups (the rubber seals) and a spring, typically. You reuse the pistons, the cylinder itself, the bolts and the bleed screw. You can get a replacement bleed screw if you need one.

 

I was planning on trying to reuse my pistons, Tim, but this particular kit I got for the rear, 3/4" bore cylinder came with new ones. The other kit I got for one of the fronts doesn't have them.:?

 

That's odd. Very rarely have I seen a rebuild kit come with pistons. Usually only if the seal is integrated into the piston. That's a good score

 

30 years ago when I worked at NAPA we had kits both ways, with or without pistons. Those days may be gone as you can usually get cylinders pretty cheap. Like calipers. They are so cheap now no one rebuilds them themselves unless they are unavailable

 

Yep. This is Napa #610, and it's a 3/4" bore kit that came with the pistons. The other kit, 1 1/8" bore #164, didn't include the pistons.

Interesting. Yes, new cylinders are available and affordable - I guess I'm just curious to see if these work, and would like to know how to/not to do it for future referrence.

 

Correction: The #610 kit is NOT 3/4" bore as I thought, it's 13/16" bore.

I took the left-front cylinder apart today, honed it, and determined it's still too badly pitted to try to rebuild. The rear cylinder's bleeder screw hole is stripped and the bore isn't spotless, so - to eat the words I typed just earlier today...

I've decided I'm just going to buy new wheel cylinders.

This DJ3A doesn't have the (from what I can tell) usual 3/4" bore rear and 1" bore front cylinders, which would be easy to find - it's got 13/16" bore rears and 1 1/8" bore fronts. Any ideas where I can get replacements? They're both Lockheed-Wagner cylinders; the rear is FD-10029, and the front is FD-15429.

 

I'm not sure on the size but R&P stocks the ones on for their 11" brake conversions which I "think" is the 1 1/8" fronts. They can be reached at 503-557-8911. They may have the rears, not sure, but worth a call. They won't list them on their web site.

 

Thanks. Would you know what the mounting hole pattern on these is? I need them that have both holes on a horizontal line, one on each side of the bleeder valve. I know some of the later Jeep cylinders have the holes caddycornered - one on the lower left, one on the upper right, I think.