Caliper rebuild--iron single-piston

[Schurkey]

I've been on a caliper-rebuilding kick for awhile. Decided to pull the calipers apart on my '97 K2500 8,600lb (8-lug) because the fluid in the reservoir looked horrible.

Turns out, the front pads are hardly worn, and the calipers are both black-painted remans. Neither had sticking pistons, but there was plenty of sludgy crap inside. I bought the truck 2 1/2 years ago, the previous owner neglected all sorts of problems. Apparently, they threw on rebuilt calipers and fresh pads, but didn't bother to flush the brake fluid.

Left side was no real problem. Bleeder screw needed some Oxy-Acetylene encouragement, but the piston popped right out with some compressed air, and cleaned-up nicely. The slider pins and bolts moved freely. The dust boot is not easily removable without wrecking it, so I left it in place. Removed the square-cut seal and wiped it clean. I cleaned up the piston and the caliper bore with clean rags and aerosol brake cleaner. Went back together, and back on the vehicle. I even re-used the copper washers on the brake hose banjo bolt. Bleeder screw threads lightly painted with anti seize.

The right side caliper was a bugger. Somebody installed a bleeder-screw "repair kit". Of course the repair kit has a microscopic bleeder screw (5/16 wrench size instead of 10mm) which was totally seized. I broke it off. I blew the caliper piston out with compressed air as usual, cleaned up the piston and the caliper bore and seals. Then I tried drilling out the bleeder screw with a left-hand drill bit, which I hoped would back-out the screw. Nope. But that did leave me a hole in the bleeder screw to pound an Easy-Out removal tool into. Again, with some Oxy-Acetylene action warming the iron around the bleeder, I got the whole repair kit to back out. This left me with a perfectly-usable caliper minus a working bleeder screw.

NAPA lists three bleeder screw repair kits, but none of the on-line photos look like the one I removed.
UP-BF17,
UP-BF117, and
NOE-6755180

NAPA can't be bothered to list the sizes or thread pitches for any of these on their consumer web site, and that info isn't on the in-store computer either. And the local store didn't stock any of them, so I couldn't test-fit. It kinda bugs me that I managed to clean up the caliper piston, extract the broken bleeder, but can't figure out what bleeder repair kit to use.

I came home with another black-coated "Total Eclipse" reman caliper; p/n CAL-SE4848, about $40 plus more than that as a core-charge. I'll return the core later.

It'll be awhile before I get the replacement caliper bolted-on, and the fluid flushed.

Photo 1. Contaminated piston from sludge inside caliper. The black spot near the piston is a couple drops of contaminated brake fluid!

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Photo 2. Cheap, low-grade caliper mounting hardware. The OEM stuff does not allow the bolts to be removed from the sleeves, and the chrome plating is better--more rust-resistant.

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Photo 3. Broken bleeder screw. The rusty "circle" around the freshly-broken bottom part of the bleeder is the top of the outer section of the "repair kit".

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More photos coming...soon (?)

 

[454cid]

I've cleaned my master cylinder out a couple of times, and the fluid starts turning dark again in short order. It makes me wonder if a seal is breaking down. I even wiped out the reservoir with paper towel.

I'm not sure I ever saw the original pins on my truck, as I paid to have the brakes done early on, a few times. I have had the captured sleeves included with some calipers and I don't like them, or see the point. I'd rather be able to fully disassembly the pins for cleaning on a wire wheel.

I've purchased rebuilt calipers with "repaired" bleeder screws. I dont' like them.

 

[RichLo]

I seem to remember that after the core was exchanged I only paid around $15 for a rebuilt unit from the parts store. This was around 5 years ago but the prices couldnt have gone up that much have they?

 

[MrPink]

Rich,

I paid $31 ea for my new front calipers but I did not return the cores($12), I am rebuilding them to use on the rear when I do my rear disk. they are not much more than what you paid years ago. $18/ea after core.

 

[RichLo]

Yea, thats why I'm wondering what is the benefit to rebuilding them yourself when professionally rebuilt ones are only $18 with a warranty.

 

[someotherguy]

Yea, thats why I'm wondering what is the benefit to rebuilding them yourself when professionally rebuilt ones are only $18 with a warranty.

Used to rebuild calipers regularly back before super cheap rebuilts were ever a thing. It's fairly easy work as long as the parts are salvageable. It gives you a nice up-close look at whether there's any pitting on the piston or in the bore...

When you buy a super cheap rebuilt caliper, you really don't know what's in there. Think of the quality level of other rebuilt parts and how that has been trending downward the last few years.

Richard

 

[454cid]

Yea, thats why I'm wondering what is the benefit to rebuilding them yourself when professionally rebuilt ones are only $18 with a warranty.

I don't think very many people do, any more..... and likely haven't for quite some time. They're not always cheap though. This was over a decade ago, but I bought some cheap calipers at Autozone, and either one of them was bad, or they didn't have one in stock.... can't recall. They told me that the store near where I worked, had one...."Oh good, I'll pick it up on my way to work". I get there, any they want to charge me like 3x the price!!! It was a small town, and Autozone was pricing according to their only competition, NAPA!!!

Wheel cylinders are even cheaper.... unless they're for the front of my Buick. AC Delco is like $35, from Rockauto! I bought the rebuild kits. I've never rebuilt a wheel cylinder and haven't seen it done since my dad did it on his 76 Dodge D100 when I was a kid.

I wish I would have kept my trucks original calipers, to rebuild.

 

[MrPink]

i'm only rebuilding mine as I haven't done it before so it's worth a shot lol.

 

[Schurkey]

Three reasons for the higher price of my caliper:
1. NAPA. They aren't marketing themselves as a discounter.

2. Mine are the less-common size. Each of the two smaller piston sizes for GMT-400 would likely be less expensive.

3. The black-coated "Total Eclipse" line is a little upmarket. The bare-bones version was $32.



Why D-I-Y rebuild when commercially-rebuilt calipers are so cheap?

14 calipers cleaned-out, reinstalled, in-use.
17 more to go in my lil' fleet.

So far I'm into this for one $4 bleeder screw (Trailblazer)
one replacement caliper (K2500), plus a few rubber caps for the bleeder screws.

 

[94K3500PROJECT]

Yea, thats why I'm wondering what is the benefit to rebuilding them yourself when professionally rebuilt ones are only $18 with a warranty.

IMO none.
But I have rebuilt K20 calipers recently because I had them powdercoated.
Gonna pull apart my front dually calipers for the same reason.