KH brake help

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1938dodge

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Hello all,
I’m in the process of changing over my brakes to the KH disc brakes.
I have the completed setup but having a hard time getting the pistons out of the calipers. I tried air to no avail used grease got one piston out but can’t seem to get the other one out. I’ve tired to place a metal plate over the removed piston and the grease just keep squeezing grease out around the plate.
Also have the bleeders rusted and can’t get them to move. Don’t want to brake them off.
One more question I’m doing this on my 62 Valiant wagon what or do I need to do any changes like a portioning valve?
Any ideas or help would be greatly appreciated
 
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Uhhh, do you mean Kelsey-Hayes? As in, the factory small bolt pattern disk brakes?

If that's what you're talking about they're generally referred to as KH disks, so you may want to update your title. And if those are indeed the brakes you have, @hemi71x may have some tips for disassembly...
 
I have the official Miller Special Tool Company, special tool, from back in the dinosaur days, in getting pistons out of the Kelsey Hayes, 4 piston calipers.
So it's no big deal at all for me in getting stuck pistons out of their bores, or ones that will easily come out.

Yes i know of that "trick" method, in removing stuck, frozen, rusted, pistons out of their caliper bores.
Pumping them out hydraulically always works, in getting them out.
But for you one piston already came completely out of it's bore.
Then your screwed unless you put that piston back in the bore, and pump away until the frozen one begins to come free.
But your going to have to block the movement of the one that came out, until the frozen one begins to move.
I put the caliper body between the jaws of my bench vise, and open, little by little, until i see the pistons come out equally.
A block of wood i use on the bigger caliper halve's. A 4x4x4 has been working for me.

Then you also say the bleeder screws are also frozen in place.
Then your really screwed.
If you keep trying, and then round them off, you will have to drill them out.
No other way.

How long have these things been sitting, without being in use?
You get them from a rust bucket state?

I don't want to come across as a personal salesman here, in helping you out.
But if worse becomes worse, for you, i have a pair of rebuilt calipers advertised for sale, here on this forum.
Jim V.
hemi71x

EDIT.
Here's a photo of some caliper piston removal tools.
The tool on the right is the official Miller Special Tool Company, "special tool."

Caliper Piston Remover Tools 001 (Small).JPG


CALIPER TOOL IN PISTON 001 (Small).JPG
 
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Thanks Jim,
I picked them up a few years back and they have been sitting in the garage. I sealed them with brake fluid thinking it would help. I will give it a try one more time with the vice. I had one side start to move and I placed a clamp on it and started to pump and the other piston got away from me and popped out.
I have the the halves soaking in PB blaster hoping to free them up.
I will let you know how it all goes.
 
I did the same with grease, took a bit but it worked. Like Jim said ideally both come out at same time or you have to block/clamp the lead one in.
Pits/rust in caliper bores as long as it's not too severe. Pistons, NONE. The orings in the piston bores create the seal to the piston.
Good luck.
 
Rock auto sells Nugeon rebuilt ones with new pistons and seals etc for a descent price……. I’ve installed 2 and they are good
 
My grease gun hose screwed right into the bleeder hole same threads and grease gun pressure pushed the pistons out. But you have to use a C Clamp or something to make sure one piston does not come all the way out before the other breaks free.
 
There is a really good video on YouTube on how to remove stuck pistons. I followed his procedure earlier this year when I did mine. Yes a grease gun, wood blocks and a c clamp are required. A hammer helps when used to lightly tap on the caliber when under pressure. It was a bunch of work and a few pistons needed replacing.
 
I got all the pistons out finally and one bleeder valve out and one to go.
Thank you all for the help.
 
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