Brake caliper rebuild?

[K201979]

Has anyone here rebuilt their brake calipers? Im having trouble figureing out for sure which pistons and seals. Its a 79 k20 silverado that came with sb400/th400. Brake code says "j55 hd brakes" (see picture). Also pictures of the caliper cast numbers from the ones that came on the truck(trying to rebuild these). Cant quite make them out. Ill have to clean them better, but something like 18003332 and 18003333. And one more picture of the calipers i bought to replace the old. One of the " rebuilt" ones is dragging now so i think it was just sandblasted and sent. Anyway, i want to rebuild the old ones for the front and rebuild the one(right side) thats dragging and use the replacement on the rear down the road when i convert to disc. I think its gonna be carlson 7502 on the piston but i have no clue on the seals. Next step is to blow one apart and measure the piston but i havnt got there yet. I think its gonna be 3 5/32" but not sure. Any help is appreciated. Thanks

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[HotRodPC]

Don't be so quick to jump and say it's the caliper causing the drag. What condition is your soft rubber brake hose? When they start to collapse internally, they start to work like a 1 way check valve. They'll let fluid pass through to apply brakes, but then they don't let the fluid back off causing the caliper to drag.

 

[K201979]

I went thru everything less than a year ago fighting the dragging till i got to the calipers. Changed them and it stopped for a while. When i got the "refurbished" right caliper it actually had sand in it so i ended up not using it since i was dragging on the left. Right side stared dragging a couple months later so i cleaned out the refurb, rinsed it with fluid and put it on. Worked good for probly 6 months and truck started pulling to the right( right after a tire change). I suspected tires cause there was no excessive heat in the rotor on that side so i swapped fronts. No change. Checked bearings and ball joints which are all fairly new, but u never no. All good, found a broken swaybar mount(removed swaybar), and wore out draglink ends and replaced but still pulling. I did notice slightly more drag on the brakes on the right when they were off the ground so ive been leaning that way. Now im noticeing pulling to the left under braking and a slightly warmer wheel on the right. Time to change the "refurbished" caliper that i got ripped off on. Anyway. Thank you for the suggestion, but the rubber lines, along with everything elsefrom the m/c to the calipers, except the prop valve has recently been replaced.

 

[K201979]

Its my understanding that the piston gets corroded and doesnt let the square "o-ring" do its job to return the piston.

 

[HotRodPC]

If the calipers are that new I still find it hard to believe they're having that problem so soon. I've been wrong many times, but it just don't sound right. So you say "went thru" everything a year ago. What does that mean on the rubber brake hose? Was it replaced? I've seen them look brand new in great shape on the outside but they're torn and collapsed on the inside.

Sometimes you can get the caliper to hold the drag problem, then release the air bleeder and if it releases then you know it's the hose.

 

[bucket]

I remember about 10 years ago, it took me a few pairs of calipers to get some that didn't cause an initial pull to one side, followed by an initial pull to the other side when releasing the brakes.

 

[K201979]

I replaced the hoses when i first started to address the initial problem. I think the refurb caliper i got was a core that got cleaned up and sent, or maybe resealed with a corroded piston. Good tip on the bleeder. Hadnt thought of that. It looks like if i can find a deal its almost as cheap just to replace. Got a hard time trusting parts now tho. Mat just have to take it apart, measure and send some emails.

 

[HotRodPC]

I replaced the hoses when i first started to address the initial problem. I think the refurb caliper i got was a core that got cleaned up and sent, or maybe resealed with a corroded piston. Good tip on the bleeder. Hadnt thought of that. It looks like if i can find a deal its almost as cheap just to replace. Got a hard time trusting parts now tho. Mat just have to take it apart, measure and send some emails.

Very possible. If you still have the receipt or remember where you bought the calipers, call and find out if they're lifetime warranty. I once was going to rebuild some C10 calipers. The cost difference for the rebuild kit and reman calipers was $8 but the calipers had lifetime warranty so for $8 I opted for the lifetime warranty and bought the calipers instead or rebuilding them.