47-55.1 Cadillac El Dorado/Seville rear calipers with parking break leaking

[NeoJuice]

After finishing up changes on the brake system on the 52 I found some break fluid dripping down onto the garage floor. I pulled off the rear drivers side caliper off the GM 10 bolt rear and found fluid leaking out around the high lighted area the attached photos. The brake fluid is not coming out from the outside piston wall, its coming out of the hole in the middle. I pulled the little rubber stopper out cleaned everything up with brake clean and rags and its still leaking out at a decent drip rate. Since the calipers are a ratchet style with the built in ebrake Im assuming a seal must be leaking on the center hense the fluid loss. There is no fluid loss on the back side of the caplier where the ebrake lever is attached. I'm trying to figure out what my options are.

1. They are only covered under 1 year warranty from Napa. They were purchased about 3 years ago and the truck has yet to be driven. Maybe they would replace it under good will?
2. Shell out $154 CAD for a new caliper and replace it.
3. See if I can find a rebuild kit? might not be worth all the hassle?

Link for reference.

https://www.speedwaymotors.com/Emerg...pers,1968.html

Any thoughts would be appreciated.

Thank you.

[mr48chev]

Looking at this kit for the 79 Seville Caliper it looks like that button is a cover for the the hole part of the park brake assembly goes though. My guess is that one or more of the small O rings you see are inside that piston and are supposed to seal against the leak you are getting.

You can probably find the kits in several brands at parts houses but I have never had one of those apart and do not have any knowledge of the what's where's and how's of doing it even with all the brakes I worked on in my life.

A search doesn't bring up any specific instructions on working on that model of caliper. They may be in the factory service manual but finding one at the local Cadillac dealer that is that old may be a challenge unless they have them on the computer and can bring up the pages and print them out for you.

[NeoJuice]

Thanks mr48chev,

I may just end up replacing it. I found this video on YouTube which shows how to take it apart but that seems like allot of work. I looked up on the Napa site and the rear caliper seal and boot kit is $35 CAD.

https://www.youtube.com/watch?v=i0fRR1kueQg

[mr48chev]

I wouldn't even be sure you could find a long time Cadillac dealer brake mechanic that can rebuild those. I've never liked to rebuild front calipers myself preferring to replace them.

I've rebuilt hundreds of wheel cylinders over the years as I used to do at least 10 brake jobs a week in the tire store I worked at in the 70's and never had a problem with wheel cylinders but calipers always tend to give me a fight.

[BBPanel]

I had those style calipers on a 10-bolt using the 79-81 Firebird backing plate/rotors. I replaced the calipers I got using them as cores, 6 months later one of them started leaking with probably less than 50 miles on it. I've been told they don't like to sit idle. I tried to find a caliper replacement w/o the e-brake built in but wasn't successful (didn't look very long though) so I replaced the entire thing - now have rotors/backing plates/calipers just sitting around gathering dust.

[mr48chev]

The Cadillac and the Firebird/Camaro calipers are different units. The Cadillac units have the same mounting as a lot of non metric GM front calipers and the 4x4 brigade that does rear disk swaps often used the front calipers on the rear so they don't have to fight the park brake issue. Around here a lot of those "Crawlers" never see the public roads nor are they driven and parked where a park brake would be needed or some are using an alternative park brake. That won't get you past any state's on the road requirements or many states state inspection.

There are park brake disks and calipers that mount on the third member for street rods but I don't know how practical they are in the real world. Plus unless you have a 9 inch Ford Rear you probably can't get a bracket that fits.

The rear brakes on my 98 BMW 528I have small brake shoes inside the rotor and those work flawlessly. i don't know why more manufactures don't use a setup like that except for the expense.

[NeoJuice]

Originally Posted by BBPanel

I had those style calipers on a 10-bolt using the 79-81 Firebird backing plate/rotors. I replaced the calipers I got using them as cores, 6 months later one of them started leaking with probably less than 50 miles on it. I've been told they don't like to sit idle. I tried to find a caliper replacement w/o the e-brake built in but wasn't successful (didn't look very long though) so I replaced the entire thing - now have rotors/backing plates/calipers just sitting around gathering dust.

what did you replace it with if you dont mind me asking?

[_Ogre]

terrible design, similar to the 86 trans am calipers i had on truk.
my parking brake never worked and when i lost the mc they were impossible to bleed
i swapped mine for the front caliper that gm used on pretty much every vehicle in the 80s & 90s
it fit the caliper mount fine with a little modification of the backing plate
i no long have a parking brake like mr48 says 2 posts up

the hole is for pushing in the ratchet pawl, to allow the piston to be pushed back
have you tried sticking a rod in there to 'free up' the seal?
not much for advice

[BBPanel]

Originally Posted by NeoJuice

what did you replace it with if you dont mind me asking?

I used a kit from https://scarebird.com/ who makes the backing plate using S10 disc brakes.

[BBPanel]

Originally Posted by mr48chev

The Cadillac and the Firebird/Camaro calipers are different units.

Yes, they are different - notice I said "those style calipers", that being integral self-adjusting parking brake. They suck!

As for pinion-mounted parking brakes TSM makes some but not for 10-12-bolts.
https://www.tsmmfg.net/the-original-...rake-6400.html

Years ago a guy on Chevelles.com made 10 and 12-bolt pinion mounted parking brakes - pictured is 10-bolt:

[mr48chev]

Several outfits sell the pinion mounted rotor and caliper for 9 inch Ford rears. About the same price as a pair of Cadillac calipers.

I'm not a big Speedway fan but here is there link https://www.speedwaymotors.com/Pinio...ake,44784.html

[NeoJuice]

Originally Posted by _Ogre

terrible design, similar to the 86 trans am calipers i had on truk.
my parking brake never worked and when i lost the mc they were impossible to bleed
i swapped mine for the front caliper that gm used on pretty much every vehicle in the 80s & 90s
it fit the caliper mount fine with a little modification of the backing plate
i no long have a parking brake like mr48 says 2 posts up

the hole is for pushing in the ratchet pawl, to allow the piston to be pushed back
have you tried sticking a rod in there to 'free up' the seal?
not much for advice

Ogre,

I'll try sticking a center punch into the hole and see what happens. If it continues to leak I'll order another caliper. Thanks for the suggestion.

[NeoJuice]

Thank you everyone for your suggestions. I'll update the thread once I have time test test the caliper or replace it.