rebuilding E-brake calipers

[bddcustoms]

Hey,

I'm swapping in rear disc brakes onto my 1969 C20 with an HO52 rear end using a kit for 14-bolts I got from DIY4X. I need to rebuild the salvaged calipers I'll be using (from a 1976 Caddy Eldo). I've heard horror stories about guys accidentally rotating the e-brake arm, forcing the caliper piston and spring out of the bore, with no hope of it going back in. Anybody here ever rebuilt one of these before? Any advice? For example, if I don't move the arm, can't I simply use compressed air to blow out the piston, and replace the seal, etc. like any other caliper?

thanks!

David

[N2TRUX]

Anyone?

[Spray-Bomb]

I need to know this also... Hope we get a good reply

[sn33kyp3t3]

I've got the same question. I can find rebuild kits-a-plenty on the net, but striking out on the rear e-brake calipers.

Words of wisdom would be appreciated.

[sn33kyp3t3]

Found a rebuild kit here, in case anybody else comes looking.

I searched for a 79 caddy El Dorado.

http://www.napaonline.com/masterpage...oot+Kit+-+Rear

[Sinister]

Hey bddcustoms, I'd love to see pics of your disc brake install.

[SoCal71K20]

I believe those caddy calipers are the ones that have a screw action to the piston movement. Meaning compressed air or a standard disc pad compression tool won't work. Auto Zone web site used to have a nice diagram and write up on working with these calipers. Not bad once you figure out that piston kinda screws back into bore once you loosen nut in back of caliper by e-brake lever.

[nu2-72]

You will want to remove the arm.
Remove the arm and be very careful to do this over a large clean surface. There is a disc under the arm.
Use air to push the assembly out of the bore. Remove the caliper seal.
The piston does have a LH or RH spiral center. You may remove it for piston and stem cleaning.
Install seals and re-assemble.
The reason for removal of complete assembly is because there is a rubber seal on the spiral post to prevent fluid leaks and the disc under the arm provides pressure against that seal. These parts will come in the new kit and should be used for a guarenteed seal job.
The arm has flats and can be repositioned after the assembly very easily.

DO NOT drive the piston out as the inner assembly is fragile. Use air only and it will pop right out.
Would pics help?

[mikeoj]

yes, pics please!

[Tigman]

Great tech article!!


http://classicbroncos.com/reardiscs.shtml

http://www.pirate4x4.com/forum/showthread.php?t=772253

[nu2-72]

I will tear one down for you in the morning.

[nu2-72]

Here we go.
Picture 1 shows the arm removed and the nut and outer seal still on the post.
Pictute 2 shows the seal and nut removed and the hex on the post. The hex is how you set the arm, in one of six positions and it will be clear when you reassemble.
Pic 3 shows the piston removed, by air, and the compressed spring inside.
Pic 4 shows the inner seal and the brass washer. The washer is used as a thrust washer on the inside of the bore so the post can rotate. The seal rides in the post bore as an inner seal. The outer seal is compressed against the housing by the arm and nut and that is what seals the outer face from dirt and leaks.

[nu2-72]

pic 5 is the seal and washer off of the post. Again the seal rides inside the small bore. The post just slips in and out and there is no alignment to worry about. The entire assembly will rotate as needed when put together so the brakes will remain functional. As the pads wear, the hydraulic pressure pushes the piston out and rotates it, this way the post never has to move and the brakes are applied with the foot brake pedal as normal. When you set the park brake, the post rotates mechanically and sets the brakes.
pic 6 more of stem and seals. The washer goes back on first and the seal last. Do not put the seal on and try to force the washer over it. It will tear.
pic7 is the bore outer seal for the piston groove and the inner seal/o-ring
pic 8 is the o-ring better view with outer seal removed

[nu2-72]

Now, a word about the calipers.
You know there are two different ones. LH and RH. In order for the manual park brakes to work one must be CCW and the other CW.
All of my research has shown O'Rielly's, Auto Zone, Parts America and more to show these calipers in their books. Most have pics and most are by A1-Cardone. The pics and refference #'s all state 224 as the casting #. They will also tell you that the pic is for show only and not the actual part.
I have ordered 3 times from different stores and all recieved were 224.
Why does anyone care? Even if they use the 224 casting and use the other caliper internals it will not work. Each casting is made so the bleeder is on top. You cannot use two of the same castings. The lever has stops also and must be oriented correctly.
Good news is that the rebuild kits are the same since they consist of seals and washers.
So be very careful before you order sets and hand over your old calipers as cores. Match them exactly.
Once they leave the parts store you are the pooch.
The casting # should be very clear in two places and they are also marked "L" and "R".
Here is a correct 223 casting and I have the correct 224's as well.

[nu2-72]

This is how I do mine.
Read the other articles and use your best judgement. There are many vehicles to choose calipers from so realize that statements are generalized and you need specifics to the ones you have.