a few days ago i stripped a parts car recently in an accident.
the front brakes were all virtually brand new with all new parts.

the car, a 91 240 with abs had calipers on it that were specifically originally designed for a non abs vehicle. there were 2 side by side threaded holes for the brake lines and 3 holes fitted for brake bleeders.

in fact its fair to say this caliper was exactly what you buy for a non abs car.

what the rebuilder did was plug one of the side by side brake line holes with a set screw and then plug both middle of the calipers brake bleed holes with set screws leaving only the single bleeder at the inner top of the caliper.

i asked the owner how the brakes worked before the car was hit and he said they worked fine, same as always.

there is a freely flowing passage between the two pistons same on each of the caliper halves. fluid does flow from one piston to the other and to each side and back.

Hard to see, but the drilling seems adequately sized. Can you tell how they did it? Are the joining passages a V which allows drilling from the angle allowed by the depth of the pot?

Can you remove the bleeder and port plugs and see how they sealed the mating surface for the flare fitting?
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Art Benstein near Baltimore

"Wise sayings often fall on barren ground, but a kind word is never thrown away."
-Sir Arthur Helps

hi art

the initial hole between each bore hole is at a 45 a bit less than 1/2" diameter. then a smaller more like 3/16 is drilled at a shallower angle where it intersects with the one drilled from the other side.

all in all fluid deposited into one bore hole flows instantly into the other

i am reluctant to remove the set screws especially the tiny ones for fear i might ruin the threads. there does appear to be some sort of material inserted into the bleed hole then the set screws are threaded in. this might be something as simple as gasket maker in a tube.

Oh, if you are concerned about the threads then it is apparent to me you intend to use this caliper, not sacrifice it. If you split it to take those photos, you've gone beyond my daring to re-seal these Girlings. I've been hesitant thus far to split them because of flat seals not being available and not being confident about the bolts' torque to yield properties. Plainly I'm chicken.

Thanks for what you have done for my curiosity and others'.
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Art Benstein near Baltimore

Marriage is a wonderful institution, once you are ready to be nstitutionalized. - R. Cooke

i have seals to refit the halves. as for torque never had a problem rebuilding them before.

It is for the greater good.

this brings up a relevant question. are these calipers really any different in safe braking power and efficiency than their 1 bleeder 1 line cousins if interchanged in this manner?

I have no idea but in my case it was going on my daughters car and I was not willing install it.
Dan

Right. Given the earned reputation of remanufactured calipers, needing inspection on the parts counter, I'd do the same. But Ted here has an opportunity to find out if they did it right.
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Art Benstein near Baltimore

Good judgment comes from experience, and a lot of that comes from bad judgment.

Apparently it does work as stated by the PO. My daughter lives a couple of hours from me so I was in no mood to experiment with brakes and it just looks shady to me.

I had to wait an extra day to get another caliper delivered but was able to attend her M.A defense at school so it worked out well.

Dan

i am not arguing with you merely very curious to see what happens on a real car driven by someone who knows its been done and what the brakes ought to feel like versus what they do feel like with this modded caliper installed.

I guess is it works fine but it looked shady to me and the parts people didn't have a clue if it was good or even what I was talking about.

I wasn't about to put it on my daughters car.

They were more than willing to replace it, it just cost me an extra day to get the job done.

Dan

I have a hard time believing it does work fine unless they did internal modifications to the fluid passage OR I misunderstood how the 3-bleeder, 2-line calipers worked. I was under the understanding that circuit A activated (for example) the upper two pistons on the RF , lower two pistons on the LF and the whole right rear brake. If this is a separate, redundant system I cannot see how both piston sets on that caliper could be actuated unless there was a jumper line verse plugs.

So what did I miss?

Yes, they would have drilled between upper and lower pots somehow.

Look at these links if you want a refresher on how the dual diagonal system used the 4 pot Girlings one half at at time.


girling20.jpg

girling21.jpg

girling insides
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Art Benstein near Baltimore

There are three kinds of men: The ones that learn by reading. The few who learn by observation. The rest of them have to pee on the electric fence and find out for themselves.

if i were to guess it would be the rebuilder wen the quick and dirty way and simply rebuilt this non abs caliper to function on an abs car knowing that only two of the pistons on each caliper would function. the way to verify this theory is to drive the car using the softest brake pads i can find and watch of radically uneven pad wear over a period of many months of hard brake usage.

imo the cost to internally connect all the passageways into one bleeder would exceed the profit on the sold caliper.

OR remove a piston on the blocked off line circuit and see if fluid drips out or can be forced through from the working line.

if it is blocked off and no fluid comes through is that in fact a case of fraud on the part of the rebuilder? minor though it may be

These are very possibly the second most important safety item on our vehicles after the tires. How can intentionally degrading the the effectiveness of such a critical system be "minor" fraud?

This is an area very near and dear to me after spending a lot of time over the last two years working with what I consider SEVERELY under-engineered and potentially dangerous brakes. We did push them far beyond their reasonable design parameters but the failures were similar to what you would have if say, you applied an off-axis force to an elongated brake pad...which is exactly what GM did with dozens of models that share the exact same caliper design.

This same asymmetrical pressure is what you would have with only the upper or only the lower piston active. The insidious part is the brakes work very effectively even when failing...right up until they fail catastrophically.

I bookmarked this thread as "ABS Caliper Fraud" as someone will tear these apart and tell us what they did and how, if not Ted. Then the topic will pop up again, and I'll refer them to this "you saw it here first."

I'd bet a phone book full of tort lawyers the reman was done responsibly -- just news to us. And that's still not a strong enough bet for me to use one on my daughter's car without knowing what goes inside.
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Art Benstein near Baltimore

Remember what Cardinal Cooke once said:
"A man would do nothing if he waited until such time as no one would find fault with what he has done". - originally John Henry Cardinal Newman

It would seem to me that if you pushed one pad back to retract the pistons all the way--and then removed the pad so you can clearly see piston movement while an assistant pumped (carefully, one stoke at a time) the pedal you should see equal movement of top and bottom pistons if a channel has been created between them. -- Dave

I hope you are right and it does seem uselessly foolish to do otherwise if there is a reasonable way to make the brakes work as designed.

actually art i am going to install them on an abs car and experiment.i'll let you know after a few weeks of driving it around. there is nothing like real world application to find out one way or the other.

clearly they bleed properly or the parts car would not have been safely driveable.
the accident was not his fault.

Too bad.

I have no doubt the caliper will stop the car. You already know that.

My curiosity centers around the technique the rebuilder used to drill between upper and lower piston pairs in pursuit of cores for the ABS calipers. What the drill size was. Also, how are the line and bleed plugs done; is there soft material under the set screws?

You won't know this stuff unless you sacrifice one. I doubt I will ever see one, but it is an interesting comment on the reman marketplace.


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Art Benstein near Baltimore

After eating an entire bull, a mountain lion felt so good he started roaring. He kept it up until a hunter came along and shot him. The moral: When you're full of bull, keep your mouth shut.

I wonder if the rebuild was done by Cardone?

Dan

I received a similar Cardone rebuilt caliper from a national chain auto store and immediately returned it for a replacement.

Dan

This is what I posted about a year and a half ago on the subject.

"I got an early 80's non ABS caliper for the solid rotor with 3 bleeder valves sold to me as a 92 ABS caliper. One of the brake line Ports was capped off so there was only one available.

This is a first for me!"

Rebuilding non ABS calipers for use on ABS cars may be a somewhat common practice.

The rebuilt caliper I got a year and a half ago was clearly older from a car with solid rotors. There was no way it was going to be installed on a vented rotor. I suspect the rebuilder did not know there was a difference between solid and vented rotors / calipers and mistakenly rebuilt the older caliper.

ABS caliper cores must be rare.

Dan