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Did we rule out the emergency brake out of curiosity? I wonder if in the replacing of the caliper, especially if you got a new rotor, maybe it got adjusted improperly? Just guessing, OP. Hope you figure it out!
Good point, and similar to the other current post about overheated caliper. Easy enough to check . I'm more sensitive to the hose issue because I also have a 67 BMW, and swollen hoses are not uncommon.
 

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Did we rule out the emergency brake out of curiosity? I wonder if in the replacing of the caliper, especially if you got a new rotor, maybe it got adjusted improperly? Just guessing, OP. Hope you figure it out!
E brake cannot cause the brake pedal to feel firm under pressurized fluid.
 

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I'm wondering if the firm pedal is a red herring. Why wouldn't all the calipers be stuck if it were a central problem as opposed to one corner?
 

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I'm wondering if the firm pedal is a red herring. Why wouldn't all the calipers be stuck if it were a central problem as opposed to one corner?
+1. IF the pedal was firm under pressurized fluid then all brakes should have been dragging.
 

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Discussion Starter #25
Got an update, the brake shop tried cleaning and polishing the piston also bleeding and rechecked the hand brake, I drove about 20 min and got stuck again, I noticed the pedal kept holding pressure, even when the car moved freely. Got back to work shop they tried bleeding rear then front then rear again but no fluid passed through, he tried checking if fluid was pumping from the master cylinder and it was only pushing air, no fluid, they sent the cylinder for reconditioning. Will update you all tomorrow when I get feedback.
 

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That is very puzzling. I don't understand why, if the master is only pumping air, does the car stop and the pedal have pressure. And comments on the hose theory?
 

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Before taking the master cyl apart, can you confirm that other calipers work? Are we talking just one corner?
 

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Discussion Starter #29
Before taking the master cyl apart, can you confirm that other calipers work? Are we talking just one corner?
The other calipers worked 100%, main problem was after driving about 5km (3.1miles), the rear left caliper would squeeze and hold the piston gradually until it held full lock on the disk, after pulling over and sitting around 7 to 15min the caliper released and I can then drive another 5km.
 

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Discussion Starter #30
Wow, how did you brake and stop the car if the master cylinder only pumped out just air (or full of hot air as Trump did) and no fluid?
The brakes were sending out brake fluid properly until they bled the other working caliper, Thats when they checked the valve on the master cylinder was pushing air instead of fluid and their was a two way movement (Air in when pedal pressed and air out when pedal released)
 

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Discussion Starter #31
Hopefully this brake shop is not thumbsucking, cause at the end of the day I need to pay them for all these "problems":cautious:
 

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The other calipers worked 100%, main problem was after driving about 5km (3.1miles), the rear left caliper would squeeze and hold the piston gradually until it held full lock on the disk, after pulling over and sitting around 7 to 15min the caliper released and I can then drive another 5km.
OK, if we stop at this point, then you have a problem on one corner. You say you had the caliper replaced. Was that a rebuild with the bracket and refurbished sliders? Assuming it is working properly, and the handbrake is not dragging, then I'm back to the hose. Mike Miller of Roundel says they should be done at 15 years. On that basis, I'd say this can't be ruled out in your case.
However, your info past this point makes no sense to me. But I'm not an expert. Other than the seized caliper, did everything work before the repair? Where are they detecting this air being pumped? Is the fluid reservoir down? If they are using a 15 psi pressure bleeder, it may not be enough to push past the blocked hose. If the cylinder won't pump fluid, I don't see how it would pump air. And where is the air getting in? If the reservoir is full, not through there. How did you determine the caliper piston is not releasing?
Old hoses can swell internally: the system pressure (several hundred psi as I recall) can squeeze through when the pedal is pushed, but the residual pressure in the caliper is not enough to just flow back through as easily. That's what takes the 10 - 15 minutes for teh piston to relax.
I expect a dragging hand brake would just get worse as you drove, but would also release when it cooled down. This would be easy to check with car on a rack. Spin the wheel and check for dragging.
My concern would be them throwing parts at it. I'd be on the phone Monday morning.
 

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Given all you've said, and going back to first principles, you have one of 2 problems;

either the caliper is sticking or something is messed up in the hydraulic system.

There is an easy test to figure out which, albeit you'll have to pull the wheel.
Get it to bind, pull over, pop the offending wheel off, and open the bleeder.
A little fluid will drip out, (or maybe squirt.) Snug the bleeder again,
and if you can then spin the wheel freely, the caliper's ok
but the hydraulic system is not.
If the wheel is still bound, you have a defective caliper. Or defective installation.

Occam says this is by far the most likely scenario.

Old hoses don't hold enough pressure to lock a caliper on- they can cause caliper
drag, but they will do it from full cold the first time you apply the brake.

If it's the hydraulic system, I'm with Don on the electronic problem.
Both rear wheels share a half of the master cylinder, so if it's not releasing
(this DOES happen, and something as silly as a slightly binding pedal or misaligned
brake light switch can do it pretty easily)
both rear wheels should be dragging, and eventually locking, as the pressure in
the rear circuit should be the same.

The only hydraulic part that's unique from one rear wheel to the other will be the left and
right section of the ABS unit.

I'm not familiar with the 99's ABS, but INPA can give you the pressures on the front and
rear circuit- that might help rule out anything BEFORE the ABS.

Good luck- I'm betting on a bad caliper.

hth

t
 

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The brakes were sending out brake fluid properly until they bled the other working caliper, Thats when they checked the valve on the master cylinder was pushing air instead of fluid and their was a two way movement (Air in when pedal pressed and air out when pedal released)
Wow, this is a Reverse master cylinder. This sounds like you are talking about the master cylinder feed hose port which connected to the fluid reservoir, and not the high pressure ports which we are more interested.
 

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The other calipers worked 100%, main problem was after driving about 5km (3.1miles), the rear left caliper would squeeze and hold the piston gradually until it held full lock on the disk, after pulling over and sitting around 7 to 15min the caliper released and I can then drive another 5km.
Ok, assuming the RL caliper was dragging or somewhat seized all the time. At cold it allowed the wheel to turn with some drag but car was moving fine to you (not me for sure as I can tell a dragging caliper any time). The the constant friction heated up the pads and caliper up to the point that fluid started boiling in that caliper, causing pressurized fluid and firm pedal. (But why this pressurized fluid and gas did not release to reservoir via the master cylinder feeding port is a mystery to me.)

OP, wait until the RL caliper cool down, try to turn the wheel by hand and see how much dragging as compared to other wheels. The open the RL caliper bleeding nibble and turn the wheel again to see if the drag force decreased; if not then you have seized piston and it needs to be pushed out and cleaned.
 

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Lets not forget this was supposedly a "new" caliper, hopefully that means reman. So maybe it was bad out of the box, or not installed properly, or the sliders didn't get changed/reman too. Assuming that checks out, is the handbrake out of adjustment. Does the wheel turn freely when cool? A visual inspection with someone pressing the pedal in the car should check that. Once we get into ABS, etc., I'm out of my depth. I would want to know why they think the master cyl is the culprit.
 

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I didn’t read all the new posts but did anyone mention the ABS/DSC unit itself?

Maybe there’s a computer fault causing the one caliper to lock up. Ignore if that’s already been debunked.


Sent from my iPhone using E46Fanatics
 

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I didn’t read all the new posts but did anyone mention the ABS/DSC unit itself?

Maybe there’s a computer fault causing the one caliper to lock up. Ignore if that’s already been debunked.


Sent from my iPhone using E46Fanatics
That was raised, and OP reports abs sensor was changed. But if DSC, wouldn't the light flash? And ABS pulse? Don't know, just asking.
 

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the constant friction heated up the pads and caliper up to the point that fluid started boiling in that caliper, causing pressurized fluid and firm pedal.
It doesn't boil- that releases pressure. It just gets hot and expands, causing the caliper to lock on.
If you then hose the thing down with water or a CO2 extinguisher, it'll roll again (but you may crack the rotor).
Boiling water (in the brake fluid) is a gas, which has no real working pressure in a hydraulic system.

OP, you're going to have to do the bleeder test to know. There ARE mechanical check valves in the
ABS body, and the abovementioned release port in the master. It would be amusing if the RR caliper
was actually stuck, and the problem was in the ABS, causing the LR to lock on...

And look at pressures in INPA.

t

there's only so much you can do over the internets.
 
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