I am having a nightmare stopping brake fluid leaks. I have leaks from 2 places. I have leaking at the right front steel line to right hose, and at the hose to caliper mounting. I have been struggling with, off and on for a couple weeks.


A little background. I am 64 and have done dozens of brake jobs before with no problems. I used all factory parts with new steel lines, new hoses and rebuilt calipers from NAPA (Cardone). I have used new copper washers on both sides of the hose end any time I removed and reattached. I have used 2 different sets of new rubber hoses. I torqued the banjo bolt to 25, then 30, then 35 pounds numerous times and it still leaks. I did get two calipers that had the defined circles (ridges) at the mounting surface, just like the hoses.


I just bled the brakes, tightened up the bleeder screw and pushed on the brake pedal with a broom stick to put a little pressure on the lines and I get drips.


I plan to bend a new brake line and eliminate the leaking line I bought from InLine Tube. It looks fine to my eye, as do the rubber brake hoses (both sets).


This is ridiculous! Am I missing something? I am using DOT 3 fluid. Is it possible I have 2 sets of defective brake hoses and a defective steel line? How tight would you torque the banjo bolt?

 

"leaking line I bought from InLine Tube"

Ok then

 

But also at the hose to caliper banjo bolt.

 

Did you install the copper washers? If yes try tightening a bit more.

 

Well, your first problem is that Cardone parts are not "factory parts". Others here have documented problems with the seal between the copper crush washers and these calipers, often due to marks or scoring on the sealing surface. Check it carefully. Also, verify that you have the correct length banjo bolts and that the threads for these bolts are the correct depth in the calipers. Measure the thickness of the banjo fitting on the hose and compare it to the one that doesn't leak. Anything that prevents the banjo bolt from properly crushing the washers will cause a leak.

The other leak is due to either a bad flare on the hard line or a bad female fitting on the rubber line. Inspect closely, but you may not be able to see a problem. At some point you just need to replace the parts.

 

I bought 6 banjo bolts NOS from a Chevrolet Dealership that was clearing out old stock. I never considered that they might be too long...or the copper washers too thin. Do you have a better source for rebuilt calipers than NAPA (Cardone)? These are Delco calipers rebuilt by Cardone. I had a major problem with right calipers having smooth mounting surface with no circular rings. I got both NAPA and Cardone tech involved and after about a week and a half I got what appears to be a good caliper, but it still leaks...unless it is bolt length or washer thickness.


I have always used new washers, 2 per banjo bolt when reattaching. I am presently torqued 10 pounds over spec at 35 lb. ft.

 

How about the thickness of the banjo fitting on the hoses?

 

Joe, what do you mean by "the thickness of the banjo fitting"?

 

How thick is the metal fitting on the caliper end of the hose that the banjo bolt goes through? It the replacement hose uses a thinner fitting that OEM, the bolt may bottom before the washers crush all the way.

 

Check for burrs on the machined surface of the caliper where the banjo bolt/copper washers seat.
Went thru a quart of brake fluid before I found that leak on my daughter's Chevelle.
Rebuilt calipers from AutoZone. The burr kept the hose end from seating properly.

 

Funny, I had this exact same problem with my 72 when I went to bleed the brakes last year. Exact same locations of the leaks too.

1. I installed new ILT brake lines. I found the bend in the line wasn't an exact line up to the brake hose, so I had to tweak it a little to make the flared end seat properly. Before I did that I couldn't spin the flare nut by hand to the seating position. You've done this enough times to know what I mean. Anyway that solved that part I believe. Have to test it again this year when I dust it off for more work.

2. I also had to replace the RS caliper and got a reman Delco from NAPA. The caliper wasn't the problem. It was the wrong size/thickness of copper washers. Went back with one of the brake hoses and measured them on site. Reinstalled - tightened - no leaking

3. The only real difference in the hose is I had OEM replacements still in their GM wrapping. I compared one OEM to a NAPA brake hose and they're virtually the same shape and length.

EDIT: I bled the brakes after all this was done and the system was tight - no dripping anywhere even after numerous brake applications.

 

I just add an extra copper washer to the mix on the banjo bolt, doesn't matter where. A used one will work fine. Not correct but works for me. We are after all just trying to stop the leaks.
I have had other problems there, with a Chinese banjo bolt, it had a burr and cut the copper washer. But since you have new GM probably not the problem.

 

I just pulled the caliper and the bolt is no where close to bottoming out. The washers are the same diameter as the caliper seat, the banjo bolt seat and the brake hose seats. Some washers I have are 1/32 thick and some 1/24 thick. Even with two 1/24 washers I am no where close to bottoming out the banjo bolt.


Anyone know what the correct dimensions for the copper washers are? I can't find it anywhere in my Service Manual CD.

 

Okay, I think (I sure hope so) that I found the problem with the caliper leaking. At the mounting seat on the caliper, it has well defined concentric rings, but it looks like it was hit with something and there is a hard to see groove cutting through all the rings except the one against the banjo bolt. It became a bit more obvious with a magnifying glass. It must be slowly weeping out the groove through the rings. So it's back to NAPA for another return.


I also removed the RF brake line. Looking at it with a magnifying glass, it appears like most of the sealing was being done by the very end of the flare. Shouldn't it be sealing on the tapered part of the flare against the tapered part of the hose fitting and not the very end of the brake line? I am going to buy a 5 foot piece of brake liner and bend it myself.

 

Well it appears I'm in the same boat as you now...I just checked my 72 and the only place it's leaking is the RF brake connection. Still have to put it up on stands and remove the wheel, but there's a small accumulation of brake fluid on the dolly the wheel is sitting on. Very very small leak from what I can see, and I can't see right now if it's from the banjo bolt or the brake hose connection. Let us know what you find out. I'll post my results when I get the car up on jackstands.

 

I attached a picture of the "rut" through the ridges on the caliper seat at about 12:00. That must be the source of the leak. The copper washer also shows the same rut as a flat spot.

 

Interesting. The copper washer should fill in the valley there, and I see no indication that the inner ring has any issues. Maybe try a very thin crush washer against the caliper and another stock size next to it? Theory is the thinner washer should fill in those gaps and bond to the next copper one on top.

 

Is it a stainless steel line? If so, they are known for leaking due to the metal hardness. Often you have to loosen and tighten at least a couple times for the flare to seat. It's a very common prob.

 

No, it is a regular steel line, not stainless. I have tightened the caliper to hose fitting as much as 35lb ft and it still leaks. Allan, you are right, there is only one unbroken ring to seal. But that sounds pretty wimpy to me. Plus, that inner ring is right by the edge of the washer. At 35 lb ft, the copper does not fill the "valley".

 

If your having that much trouble, I would return the parts and find a different supplier.

 

This may sound strange but what about heating the copper crush washer and quickly install? That might soften the copper more and get a seal in the grooves. Is there any kind of rtv that could be used on those problem areas? IDK if it would just dissolve or not.

 

I was wondering about a thin coat of RTV, or maybe a good epoxy, like Marine-Tex. I installed a pair of self bleeders and noticed the threads appeared to have some type of sealer on them and wondered if that would help.


I am about out of options. I had both NAPA and Cardone engineers / quality control people working on this, and have been trying to get a good caliper since March 19th. I will be back on the phone with them tomorrow. My understanding is that Cardone rebuilds for most of the parts stores, so changing stores won't solve the problem.


Does anyone know of another source for a rebuilt Delco caliper that isn't Cardone?

 

I( was called by Cardone a couple times yesterday. They agree that they have a problem and that my caliper should not have the cut across the ridges, and are trying to locate and send me a good caliper. I've been down this road before, and hope this time is the last time!

 

Might be worth your while to buy a good used OEM caliper from one of the parts guys here and just rebuild it yourself?

 

I was considering trying to find a used caliper, maybe in a local wrecking yard.


Does anyone know what other cars use this caliper? I know all GM 69-72, but did they change in 73 or is the same caliper used on newer GM A bodies too?


I did speak to the Cardone rep again on Friday. They can't find another good core yet. Their "engineers" say that all they have is OEM that used the flat surface design, and not the concentric rings. HUH? Anyone ever hear of these calipers having a flat surface design? The brake hoses have the rings, but not the caliper? Sounds like they are trying to feed me a BS story.

 

73 and newer is different.
Check the boneyards and see what you can find. The hardest part of getting the caliper off will be undoing the caliper bolts. If you find one with newer brake hose, take it too. While you're there, load up on some copper washers so you know the size and thickness. Use them and see if you still have leaks.

There's a guy close to you (Jim) who may be able to help you out. He's resto modding a 70 Cutlass S and may have some parts from the front end build. Here's his contact info if you're interested. Send a PM to JCMC64

 

Thanks Alan