Caliper halves keep leaking!

[Gary S.]

I just had an interesting ride in that I almost wrecked my 1972. After a complete rebuild of all four calipers I had difficulty getting the right front caliper halves to seal. I rebuilt them twice including using new O rings (talking about the little 1/2" O ring used to seal the halves) because the first time I couldn't get the halves to stop leaking. After successfully bleeding them and a couple of minor test drives I took the 72 out for a couple of local errands. Approaching a stop sign, the pedal went to the floor but, luckily, the rears were working fine. I limped home and brake fluid is seeping out of the bottom of the caliper at the O ring. Is there such a thing as a caliper warping such that it won't seal or is the such a thing as an over sized O ring? I am not new to rebuilding these types of calipers but this one has me stumped.

They have been previously sleeved with SS and have been working well enough before I decided to "fix" them.

[Joe L.]

Re: Caliper halves keep leaking!

I just had an interesting ride in that I almost wrecked my 1972. After a complete rebuild of all four calipers I had difficulty getting the right front caliper halves to seal. I rebuilt them twice including using new O rings (talking about the little 1/2" O ring used to seal the halves) because the first time I couldn't get the halves to stop leaking. After successfully bleeding them and a couple of minor test drives I took the 72 out for a couple of local errands. Approaching a stop sign, the pedal went to the floor but, luckily, the rears were working fine. I limped home and brake fluid is seeping out of the bottom of the caliper at the O ring. Is there such a thing as a caliper warping such that it won't seal or is the such a thing as an over sized O ring? I am not new to rebuilding these types of calipers but this one has me stumped.

They have been previously sleeved with SS and have been working well enough before I decided to "fix" them.

Gary------


I've never heard of this. I realize that you did this twice but are you sure the o-ring did not become dislodged prior to your mating of the caliper halves? I would not think that an over-sized o-ring would be a problem. An undersized one might be, though. By undersize, I'm referring to cross section and not OD/ID. As long as the o-ring fits into the machined relief in the casting half, the latter should be fine.

[Gary S.]

Re: Caliper halves keep leaking!

I, too, have never seen this nor experienced it. I am going to put a straight edge on both halves to see if there is some unseen issue with them. I am doubly certain that the O rings are still there and properly seated but I am going to take this one caliper apart AGAIN. This is driving me crazy. Perhaps the O ring was defective (both of them?) and came from a supplier with QC issues?

Do you or anyone else know if this O ring is available without going through one of the usual Corvette specialty shops. That is, is this a common size and sold at Advance Auto, Auto Zone, Kellys or somebody like that? I had hoped to be driving this car soon.

[Gary S.]

Re: Caliper halves keep leaking!

Confession time! I took the caliper off thinking, boy those halves seem to have a gap in them. Put my socket on the bolt and it spun freely in my hand!!!!! How on earth that happened I don't know but we'll chalk up one ruined set of new Delco 17D8 pads to a lesson learned. Ok, I have my flame retardant suit on - fire away!

I am humbled at making such a stupid and avoidable mistake. I even thought I went around and checked all of my work. This was the one caliper that leaked after a rebuild so I can only assume that I was in a hurry since this was the last thing to be done after its hibernation.

Sorry for the wasted time, gents.

Gary

[Leif A.]

Re: Caliper halves keep leaking!

Confession time! I took the caliper off thinking, boy those halves seem to have a gap in them. Put my socket on the bolt and it spun freely in my hand!!!!! How on earth that happened I don't know but we'll chalk up one ruined set of new Delco 17D8 pads to a lesson learned. Ok, I have my flame retardant suit on - fire away!

I am humbled at making such a stupid and avoidable mistake. I even thought I went around and checked all of my work. This was the one caliper that leaked after a rebuild so I can only assume that I was in a hurry since this was the last thing to be done after its hibernation.

Sorry for the wasted time, gents.

Gary

Yeah, because none of us have ever done anything like that Glad you found the answer and addressed before a real problem presented itself...like-an-accident!!

[Gary S.]

Re: Caliper halves keep leaking!

Leif,
When I came up to the stop sign at 35 mph and the brake pedal went to the floor I almost did. I did a quick pump (thinking maybe Master Cylinder - it couldn't be the brakes themselves) and got enough pedal to lock up the rears, with a minor fish tail. Limped home and now I am checking my work.

What amazes me is that this passed a "pump/release" two person bleed and two minor test drives with heavy braking. Not a drop anywhere until I was out in the neighborhood.

New pads on order. This is getting pricey.

Gary

[Paul Y.]

Re: Caliper halves keep leaking!

Glad you are safe Gary. Pads are cheap compared to fiberglass repair or human body damage.

[Joe L.]

Re: Caliper halves keep leaking!

Confession time! I took the caliper off thinking, boy those halves seem to have a gap in them. Put my socket on the bolt and it spun freely in my hand!!!!! How on earth that happened I don't know but we'll chalk up one ruined set of new Delco 17D8 pads to a lesson learned. Ok, I have my flame retardant suit on - fire away!

I am humbled at making such a stupid and avoidable mistake. I even thought I went around and checked all of my work. This was the one caliper that leaked after a rebuild so I can only assume that I was in a hurry since this was the last thing to be done after its hibernation.

Sorry for the wasted time, gents.

Gary

Gary------


I was going to ask you if you had the caliper half clamp bolts properly torqued but I figured no way would you have that wrong.

By the way, the front caliper half clamp bolts are torqued to 130 lb/ft. This is the highest torque spec of any fastener on a Corvette.

[Gary S.]

Re: Caliper halves keep leaking!

Joe,
of course I checked the bolts because NOBODY forgets something as simple as that. (Looking for an emoji of idiot slapping his forhead.) Huge duh on me but I serviced and I learned.

[Richard M.]

Re: Caliper halves keep leaking!

Gary, Glad you're okay. Don't beat yourself up.... things happen. We're all the same we just have different names.

BTW, I had a caliper that drove me crazy once. I too thought it was at the 2 halves joint at the bottom. Retorqued, okay and figured it'd have to come apart. It was actually a leaky bleeder port due to bad machined surface. It would slowly drain down and drip at the bottom joint.

I was going to mention it when reading your posts but you found the loose bolt.

When I do a chassis restoration or brakes, steering, or anything critical, I have a few fail-safes I use. If any fastener is not torqued, I put a piece of colored masking tape on the bolt or nut. At a glance I can see if I missed something. Comes in handy. On non-judged type car tasks, I'll use a marking crayon and put a dab on every fastener after it's torqued.

Rich

PS Joe, What about the Pitman Arm Nut to steering box shaft? Isn't that around 150 lbs/ft?

[Gary S.]

Re: Caliper halves keep leaking!

I too have methods for ensuring that bolts are checked and double checked. I certainly failed on this one. Your technique/reminder is better than my system.

[Patrick H.]

Re: Caliper halves keep leaking!

I too have methods for ensuring that bolts are checked and double checked. I certainly failed on this one. Your technique/reminder is better than my system.

Good thing you drove the planes, and didn't work on them.

[Gary S.]

Re: Caliper halves keep leaking!

Hey. Hey. That ain't fair. They never asked me to work on the airplane (well, once in Saudi Arabia in 1976 I helped change an engine - 110 degrees, no proper lift or hoist and only basic tools. Six hours but we did it and I didn't get to torque anything.)

[Terry M.]

Re: Caliper halves keep leaking!

Hey. Hey. That ain't fair. They never asked me to work on the airplane (well, once in Saudi Arabia in 1976 I helped change an engine - 110 degrees, no proper lift or hoist and only basic tools. Six hours but we did it and I didn't get to torque anything.)

We never worried about leaks on the F106. The term was: "Normal seepage." Of course I don't think Convair makes flying machines any more, at least I hope not.

[Gary S.]

Re: Caliper halves keep leaking!

While I don't know anything about its reliability or flying personalities, it is one gorgeous airplane.

Gary