Caliper rebuild--iron single-piston

The ones I got from Napa had new pins and hardware in them. They call that semi loaded. Also one of the bleeder screws was smaller than the other. Just an observation. About 26.00.

alpinecrick said:

454,
Most pads I have bought in recent times come with the rubber bushings. Here's the one's I have in my RA cart:
https://www.rockauto.com/en/moreinfo.php?pk=5417244&cc=1051120&jsn=1902

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That's pretty nice. I've not gotten any of the Raybestos higher end stuff.

At first blush that's what I was wondering, but I can look at the piston and could see if it was cocked, but it looks fine. If we think about it, pretty darn hard to get a piston cocked. I'm thinking it's combination of not using new pins/sleeves and maybe the mag chloride washing away my grease on the inside pad where it has to slide on the caliper.

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I wonder if it would only be crooked under pressure.

I used this Permatex grease on the slides, pins, inside pads, and where the calipers slides on the knuckle this past fall when I did the brakes on one of my vans and it seems to be working well. I'm going to use it on the rest of my vehicles and see if it continues to work well.
https://www.permatex.com/products/l...atex-ceramic-extreme-brake-parts-lubricant-2/

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Maybe I'll try that. I've got the CRC stuff and the AGS Sil-Glyde.

I get most of my parts from Rock Auto and Taiwan has become the big player in new castings with steel pistons. I have been rebuilding calipers since the 70’s. Had a hay day when Chrysler moved to “Phenolic” pistons. They swell and stick and great for business. But I would rebuild a caliper every time as long as I can get the bleeder screw loose first. Nothing replaces the hand feel on a 6 point SnapOn bleeder wrench. Torch, yes. With O rings out, I would run a “Flex Stone Hone in the bore while spraying it with solvent. Once dry, lots of high temp PTFE lube (Little packets in Delco/GM seal kit. Scotch brite the bore, clean large cut groove and had 3 boot install tools from Kent-Moore. Check piston slide with a little correct lube and pins/guides. Without pads, just make sure the frame slides. I use ACDelco ceramic pads with high temp PTFE lube on back metal contact points, install rotor, install cone adaptors & torque nuts. In stall magnetic base w/dial indicator. Lateral run out 1/4” from edge and zero. Spin slow and max is 0.002” or less. Lexas, Acura, Cadillac and dozens has “Zero” lateral run out.
Place rotor on lathe, make clean smooth cut. Mag base dial shows zero. Loosen nut, hold shaft still and rotate rotor 180 degrees & tighten. Mag base w/dial indicator reads 0.032”? File burrs from inside holder on the flat steel/table/Floor, use a stone and finish wish sandpaper (Wet-Dry 400 Grit), cut with drum cutter on outside using brake lever. Now, take a cold chisel and mark lathe nose & holder, wipe white paint in Mark. Place holder on mark each time and the tech will not cut lateral runout into rotor each time. You have just qualified the brake lathe. Do this for your local shop w/manager or tech standing there. You will be a hero!
Just don’t use vise grips on brake hose. Use a cut rubber inner tube from bicycle shop trash. Place and hold with a medium spring clamp if a banjo type to keep from leaking, before flushing. Just a thought, as we used to have raced in shop.
Drum on rear. Ever dress the 3 pads on leading and 3 on trailing side. They match the shoe dimples on each. Always use PTFE grease on each pad so the shoes engage & retract perfect. Just old school.
Rebuilt my AD244 alternator last week. Slip rings on rotor were shot. Used a cold chisel, chipped off Epoxy on soldered connections. Pulled it off using two large flat blade screwdrivers, then hooked small SnapOn bar puller. The center is keyed, so dab of dielectric grease, block of wood, tapped it home. Wires are good copper & twist together with long needle nose, cut extra off, soldered with my antique SnapOn RB450 with new 450 watt tip ($30) cooled, bent flat, covered with epoxy and works great. Note; End cover on slip ring area is plastic covered. Full fields at 238 Amps using CS/AD Field tool (Kent-Moore)
ASE Master Tech since 1978, Best of luck to all, you can do it!

Ken K said:

Had a hay day when Chrysler moved to “Phenolic” pistons. They swell and stick and great for business.

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I remember those days.

My Trailblazer front calipers appear to be Phenolic. 250K+ miles, they're still usable. The Treasure-Yard caliper I bought had a sticky one, though. But I don't think it stuck because it was phenolic. I think it stuck because of crappy, old brake fluid. It went back into the cleaned-up caliper just fine.

Ken K said:

But I would rebuild a caliper every time as long as I can get the bleeder screw loose first. Nothing replaces the hand feel on a 6 point SnapOn bleeder wrench.

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Give me a 6-point socket, and the longest 3/8 ratchet I own. A long handle gives good controlability. As evidenced by my first post...I can't save 'em all. But my track record is pretty good.

Ken K said:

Torch, yes. With O rings out, I would run a “Flex Stone Hone in the bore while spraying it with solvent.

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I quit honing the piston bore. Given the fairly enormous clearance between piston and caliper bore, I figure the piston never touches the bore in any meaningful way.

Ken K said:

install rotor, install cone adaptors & torque nuts. In stall magnetic base w/dial indicator. Lateral run out 1/4” from edge and zero. Spin slow and max is 0.002” or less. Lexas, Acura, Cadillac and dozens has “Zero” lateral run out.
Place rotor on lathe, make clean smooth cut. Mag base dial shows zero. Loosen nut, hold shaft still and rotate rotor 180 degrees & tighten. Mag base w/dial indicator reads 0.032”? File burrs from inside holder on the flat steel/table/Floor, use a stone and finish wish sandpaper (Wet-Dry 400 Grit), cut with drum cutter on outside using brake lever. Now, take a cold chisel and mark lathe nose & holder, wipe white paint in Mark. Place holder on mark each time and the tech will not cut lateral runout into rotor each time. You have just qualified the brake lathe. Do this for your local shop w/manager or tech standing there. You will be a hero!

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I guess I need to see the video. I'm not getting it.

Ken K said:

Just don’t use vise grips on brake hose. Use a cut rubber inner tube from bicycle shop trash. Place and hold with a medium spring clamp if a banjo type to keep from leaking, before flushing. Just a thought, as we used to have raced in shop.

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I haven't had an actual problem LIGHTLY clamping rubber hoses. Squeeze 'em too hard, sure, you'll damage them.

Ken K said:

Drum on rear. Ever dress the 3 pads on leading and 3 on trailing side. They match the shoe dimples on each. Always use PTFE grease on each pad so the shoes engage & retract perfect. Just old school.

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I've always been concerned that grease just catches brake dust, making a "lapping paste" that makes wear worse.

Ken K said:

soldered with my antique SnapOn RB450 with new 450 watt tip ($30)

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I think I have that same soldering gun, without the Snap-On branding.
Photo stolen from eBay. WEN 450 soldering gun with low- medium- and high-wattage tips.

This soldering gun is from decades ago when Wen made real tools. Long discontinued. When I found out, I bought a heap of replacement tips.

Hint: Works great for diagnosing HEI ignitions, too. Has enough wattage to induce AC into the pickup coil.

For anyone who may be looking for made in USA brake pad options, I have gone through 4 or maybe 5 sets of Akebono pads now with no problems at all. Excellent fit and finish, as expected of American manufacturing, and great stopping power.

I realize this is 3 years late, but what do you think about this caliper and piston? Good to roll with? Theres a little nick on the piston, think it’ll cause a leak/cut the seal?

Pull out the square-cut seal from the caliper bore, clean-up and inspect the seal, and clean-up the caliper bore and caliper groove.

Look at the dust-boot, see if it's torn.

I'm not seeing a nick in the piston. There's a tiny "dash" just above your thumb...I think it's too small to cause a problem. But you do need to clean the sludge off the top of the piston, and clean-out the dust-boot groove.





Update: I've bought my first couple of sets of Raybestos Element 3 pads. The Performance Friction Carbon Metallic pads work OK, (stop good, no brake dust) but service life has been less than ideal.

Thanks Schurkey! Oh yeah, I’ll get it clean. That spot above my thumb was what I was talking about. Your finger nail can grab it, but that’s about it. Do you have a favorite method for reinstalling the piston?

You are definitely right about cleaning up well! I should have taken a before picture but it cleans up well. It’s crazy the amount of sludge these things. I guess some people don’t believe in bleeding.


I also had the Element 3, but on my Acura. Obviously I have no empirical data, but Honda rotors are already prone to warping and it seems these pads sped it up. I also was happy with the “bite” but not worth the warped rotors. Went back to full ceramic, seems better so far.

Reega said:

That spot above my thumb was what I was talking about. Your finger nail can grab it, but that’s about it.

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Touch it with a jeweler's file, or extra-fine sandpaper/emery cloth.

Reega said:

Do you have a favorite method for reinstalling the piston?

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Poke a rubber-tipped blow-gun into the brake hose port. Reduce air pressure to ~40--50 psi instead of 90+ using a regulator. Hold the lubricated-with-brake-fluid piston with three fingers on it's inside, and inflate the boot as you push the piston down. The piston kinda flubbers on top of the dust boot. When everything aligns, the boot blows over the bottom of the piston, and you stop the air flow.

Then the piston gets shoved past the lubricated square-cut seal. Should slide past easily by hand. Once the piston is crammed to the bottom of the bore, the free-end of the dust boot pops into the groove in the piston, and you're done.

As always Schurkey, really appreciate your wisdom/experience. Thank you!