rear brakes not working

[aquapool]

90 535ia
Have to say these cars have amazing brakes. Driven for quite some time and have never noticed my rear brakes are not working until I changed a flat the other day and noticed rotors are rusty. Go ahead crack the jokes.
So far All I have done is inspect for leaks. None found. Last night I bled out both lines and no air and fluid was clean. Fronts are fine w/no problems. Thought about frozen calipers but both just doesn't seem feasible. As a newbie I have searched archives and came up empty handed. Possibly a common problem? I was thinking could be in abs system?? Any help is appreciated.

[whiskychaser]

90 535ia
Have to say these cars have amazing brakes. Driven for quite some time and have never noticed my rear brakes are not working until I changed a flat the other day and noticed rotors are rusty. Go ahead crack the jokes.
So far All I have done is inspect for leaks. None found. Last night I bled out both lines and no air and fluid was clean. Fronts are fine w/no problems. Thought about frozen calipers but both just doesn't seem feasible. As a newbie I have searched archives and came up empty handed. Possibly a common problem? I was thinking could be in abs system?? Any help is appreciated.

If you have the back wheels up off the ground, what happens if you try to turn the back wheels while pressing the brake pedal?

[aquapool]

If you have the back wheels up off the ground, what happens if you try to turn the back wheels while pressing the brake pedal?

with it in neutral I could turn the wheel by hand while car running and someone holding down the brake. I only had the right rear off the ground.

[russiankid]

Either the caliper piston is seized(unlikely) or the guides are seized.

[aquapool]

Either the caliper piston is seized(unlikely) or the guides are seized.

If it is the guide bolt would it be visible that its binding up? Gonna pull it off tonight and check calipers and see if they are pressing out and check the guide bolts also.
Since the fluid is pressing through then it should be in the brake assembly itself correct?

[e34.535i.sport]

Is it coincidence that the advertisement in this thread is for brake related products... I'm not convinced. :D

[whiskychaser]

Is it coincidence that the advertisement in this thread is for brake related products... I'm not convinced. :D
I'm sure somebody takes points off my score when I make jokes like that:D I'd be thinking duff master cylinder, air in fluid or seized slaves. I know mine has dual circuit to the rear but not all of them do. I'd jack both sides up and remove the calipers. Put a piece of wood between the pistons and the calipers to stop the pistons coming out. Then pump the brakes and see what moves.

[e34.535i.sport]

I'm sure somebody takes points off my score when I make jokes like that:D

LOL! I learnt form the master! :D

[whiskychaser]

LOL! I learnt form the master! :D

Did I say it wasnt funny? :D

[russiankid]

You will notice that it will be hard to get the guides out if they're seized. If they are seized, I advise you to get new ones.

[Ross]

If fluid is coming out and coming out clear than I would doubt the caliper is stuck. A stuck caliper is almost always due to corrosion and clear fluid is unlikely to come from a rusted up caliper. Maybe a bad re-man unit?
If there is pressure at the caliper the master and ABS aren't suspect. The caliper slides would need to be seriously seized to prevent ANY movement(you can turn the wheel by hand with brake applied) which would usually result in a dragging brake.
Is this car new to you? The probability of what you are describing is very low unless some one has botched something or perhaps the car was unused for a long time while in a corrosive environment.
Clear fluid tells me it was recently bled though, what is the rest of the story?
Regardless, if there is adequate pressure to the caliper a fresh caliper and hardware ought to solve your troubles.

[bubba966]

How worn are the pads & rotors? Could you have possibly wore them down far enough that the caliper has doesn't have enough travel to apply pressure to the rotor anymore?

[sal_park]

You will notice that it will be hard to get the guides out if they're seized. If they are seized, I advise you to get new ones.

and they are not cheap. I replace my front ones which were quite badly pitted (nb: brakes were fine, I was replacing all the suspension and decided to the disc's and pads at the same time) and they were 15 gbp each, so 60 gbp for the front :(

One thing to be super carful of is the brake carrier (number 3 here (http://www.realoem.com/bmw/showparts.do?model=HD52&mospid=47375&btnr=34_0395&hg=34&fg=10)) that the guides screw into. It could have been I was unlucky but when I tried to put the guides back into the carrier the thread in the carrier was completely destroyed. I didn't have any trouble taking them out, and was careful handling them but this still happened. I wasn't too pissed until I saw the price at the dealer for a replacement which was far toooooo much money. Long story short, I got the carrier Heli-Coiled for about 30 gbp and it's been fine ever since.

hth

sal

[Bill R.]

If the guides were seized{not likely} then the caliper piston would still push the brake pad against one side of the rotor and wear one pad down rapidly.








Either the caliper piston is seized(unlikely) or the guides are seized.

[Bill R.]

Not possible, the caliper piston will keep on going until it comes out of the bore and fluid goes everywhere, you can't wear one down far enough that the caliper won't apply pressure to the rotor.... if that does happen as i said above the piston pops out of the bore and you suddenly lose one brake circuit completely.





How worn are the pads & rotors? Could you have possibly wore them down far enough that the caliper has doesn't have enough travel to apply pressure to the rotor anymore?

[aquapool]

Car has been daily driven for two years. I only drive 1.5miles to and from work. Not really sure how long they have not been working or if they ever have. Only time I noticed was stopping on a downhill on a gravel driveway and car would slide a little. Thought that was due to the loose control arms on front end which have since been replaced. Was not able to pull off brakes yesterday due to the snow here. Will pull off and check calipers tonight and also guide bolts. Thanks everyone for your input & help. Will post back tommorow with results.