Leaking Caliper - What am I doing wrong?
Thread Starter
Racer
Joined: Aug 2015
Posts: 383
Likes: 144
From: Pine Ridge FL
Leaking Caliper - What am I doing wrong?
Within a year, I am now on to my fourth leaking reman caliper and only one of those I drove on! My passenger caliper sprung a leak so I figured I'd better do both but my driver side is now an albatross around my neck. First two re-mans were AC Delco Gold from Rock Auto. Each leaked before I even drove the car. Gave up on those and got a reman from Auto Zone. That lasted until just this weekend when I had to remove the caliper to fix something else. I was sliding the caliper on the rotor with the pads in place when I heard a squish and had brake fluid squirting out. I used Autozone's warranty and got a replacement. However, this caliper is leaking even before I had a chance to bleed it!
Could I be destroying the lip seals when I install the pads? Are they really that fragile? I even bought the special tool to hold back the pistons but I figured installing the caliper/pads together would be safer to keep the pistons from sticking at an angle. Or could it be that all the reman calipers are really that bad?
Is going o-ring the answer here? If that's the answer should I rebuild what I have or is best to just to pay the big bucks and buy new calipers?
Could I be destroying the lip seals when I install the pads? Are they really that fragile? I even bought the special tool to hold back the pistons but I figured installing the caliper/pads together would be safer to keep the pistons from sticking at an angle. Or could it be that all the reman calipers are really that bad?
Is going o-ring the answer here? If that's the answer should I rebuild what I have or is best to just to pay the big bucks and buy new calipers?
Melting Slicks
Joined: May 2021
Posts: 2,264
Likes: 1,309
From: Fleming Island, FL
I would say just bad luck. I would rebuild them yourself. Very easy to do. I recently rebuild my calipers with o ring type seals. So far so good but I've haven't had them long enough to say that o rings is better than lip seals.
Le Mans Master
Joined: Jun 2019
Posts: 7,649
Likes: 2,466
From: Indiana
I am an expert at leaky calipers 
my advice..
go oring calipers..
do you still have original delco calipers? Trade them in for same.. 1 year warranty…not fool proof but best shot..
don’t forget to measure caliper runout..
all of my lip seal calipers i rebuilt leaked, one i rebuilt o rings and pistons all good…
fronts sent in exchange rebuilt and both leaked replaced under 1 year warranty so far ok..
it sure is a great pedal feel when there are no leaks..in fact as good as any modern car minus abs.
If you have delco and good stainless liners, get the o ring kits usa made..you will do a better rebuilding job imo
my advice..
go oring calipers..
do you still have original delco calipers? Trade them in for same.. 1 year warranty…not fool proof but best shot..
don’t forget to measure caliper runout..
all of my lip seal calipers i rebuilt leaked, one i rebuilt o rings and pistons all good…
fronts sent in exchange rebuilt and both leaked replaced under 1 year warranty so far ok..
it sure is a great pedal feel when there are no leaks..in fact as good as any modern car minus abs.
If you have delco and good stainless liners, get the o ring kits usa made..you will do a better rebuilding job imo
Last edited by interpon; Dec 7, 2021 at 09:29 AM.
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,573
Likes: 7,017
From: New Or-leens Loo-z-anna
Some caliper matching faces are NOT flat...causing small o-rings to leak between caliper halves.
Lip seals can be I stalled backwards at the reman shop.
Seats that bleed screws seal against may be pitted which would prevent them from sealing g.
Find where the caliper is ACTUALLY leaking...take some pics....post 'em.
Lip seals can be I stalled backwards at the reman shop.
Seats that bleed screws seal against may be pitted which would prevent them from sealing g.
Find where the caliper is ACTUALLY leaking...take some pics....post 'em.
Racer
Joined: Apr 2008
Posts: 406
Likes: 46
From: Lebanon OH
I know you're into this for some money already, but you should consider rebuilding a set of original calipers. It's not hard to do. I use a lip seal kit. I know there are some opinions on this, but the best information I have is that O-ring kits are good for cars that spend a lot of time sitting. When I get the lip seal on the piston, I compress it until the seal touches the bore. Then I apply gentle pressure on the piston while I tuck the seal into the bore with a small screw driver or pick. If you don't tuck the lip seal in, it will leak. I've rebuilt three sets of calipers, and none have leaked. I don't think reman houses take the time to do it properly. Just my two cents. Good luck.
Last edited by MajD; Dec 6, 2021 at 10:43 PM. Reason: Added information
Thread Starter
Racer
Joined: Aug 2015
Posts: 383
Likes: 144
From: Pine Ridge FL
Some caliper matching faces are NOT flat...causing small o-rings to leak between caliper halves.
Lip seals can be I stalled backwards at the reman shop.
Seats that bleed screws seal against may be pitted which would prevent them from sealing g.
Find where the caliper is ACTUALLY leaking...take some pics....post 'em.
Lip seals can be I stalled backwards at the reman shop.
Seats that bleed screws seal against may be pitted which would prevent them from sealing g.
Find where the caliper is ACTUALLY leaking...take some pics....post 'em.
Race Director
Joined: Mar 2017
Posts: 11,927
Likes: 4,497
From: Virginia
I've had great luck with Lonestar O-ring rebuilt calipers, and also with DIY rebuilds using O-ring kits from CSSB Inc. All were original Delco cores with stainless sleeves.
There are reasons to use lip seals instead of O-rings. I've read the background, and went with O-rings on my cars. YMMV.
There are reasons to use lip seals instead of O-rings. I've read the background, and went with O-rings on my cars. YMMV.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
I've had great luck with Lonestar O-ring rebuilt calipers, and also with DIY rebuilds using O-ring kits from CSSB Inc. All were original Delco cores with stainless sleeves.
There are reasons to use lip seals instead of O-rings. I've read the background, and went with O-rings on my cars. YMMV.
There are reasons to use lip seals instead of O-rings. I've read the background, and went with O-rings on my cars. YMMV.
Jebby
Melting Slicks
Joined: May 2021
Posts: 2,264
Likes: 1,309
From: Fleming Island, FL
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
I will, lol. Anyway, you can't over pressurize the brake system. Leaking past the lip seals could be caused by pitted pistons, worn/faulty seals, bore worn, etc. I still have the lip seals on my ss sleeved rebuilt D-M's. They don't leak.
Le Mans Master
Joined: Jun 2019
Posts: 7,649
Likes: 2,466
From: Indiana
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Jebby
Thread Starter
Racer
Joined: Aug 2015
Posts: 383
Likes: 144
From: Pine Ridge FL
Le Mans Master
Joined: Jun 2019
Posts: 5,439
Likes: 2,160
From: Loveland
Maybe there is an issue with the installation. It is imperative to NOT let the pistons/seals pop out of the calipers. If there is any pressure to the caliper before it is installed over the disc they can dislodge. They can also dislodge because of the spring pressure behind the pistons. When I rebuilt original non stainless calipers I honed all the bores to a shiny surface.
Drifting
Joined: Oct 2020
Posts: 1,566
Likes: 574
From: Wisconsin
The bores have to be PRISTINE. No pits, ridges, scratches, nothing.
3 rebuilds of one caliper.
