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So My third Right Rear caliper in the past couple of years started binding tonight.
Its a reman installed maybe six months ago.
At that time it appeared the fluid when bleeding was not flowing at a normal volume and this possibility was raised.
So with a new hose, caliper , rotor and pads that leaves me thinking the line has some restriction.
I'll be talking to a shop on Monday and wanted to see what I may be facing if it looks like the answer is to replace that line.
So a little more thinking about this leads me to the ABS unit.
If I keep getting the same caliper the one place where the fluid gets directed to specific wheels in the ABS module.
Maybe if I take it to a shop or BMW dealership who has the equipment to operate the ABS when bleeding I might find improvement..
I had been considering a line feeding that wheel had developed some obstruction but after thinking back I don't believe I've had this 540's system bled on that equipment in the 150,000 miles I've owned it.
I did take another one to a dealership to have that unit cycled properly.
if the master cylinder was at fault why would the same caliper keep seizing?
The MC is just front and rear feeding the ABS unit where-from then each wheel gets a line
Do you have a pressure bleeder? I don't use mine much and just bleed the system the old fashion way. Only issue is you can run low and pull air into the ABS which would require the pressure bleeder to get it to pass through.
If I was you I would hook a thin plastic hose to that particular bleeder and manually bleed it and see what comes out. Make sure not to run low on fluid tho! I poked a hole in the top of a glass jar and added a little fluid into it where the end of the hose goes as to not introduce any air between pumps. Brake fluid collects moisture which could be the cause of your caliper sticking. The water in the fluid is rusting the caliper piston housing.
Bleed that one first and then continue to do the rest. This might be one of the reasons BMW maintenance includes periodically bleeding the brakes etc,
Well lets see..Quote:
Originally Posted by 632 Regal
I need to take the car to a shop as condo living dictates.
That said I expect the shop I've been visiting who knows and owns BMW's may have the means to pressure bleed the system.
We replaced all the calipers within the past year and so the system did get all four corners bled and new fluid used.
As I mentioned the right rear is on its third replacement in about three years including the original and each time they bled it did show reduced flow through. So if there has been a water incursion issue why isn't it affecting all the calipers?
I do not think my guy has the equipment to cycle the ABS as recommended so if just using a pressure bleeder can't flush that unit I'll have to try taking it where it can be done .
No problem really although I'd be surprised if that was the only step needed to properly eliminate this recurring issue.
I think I must however start with at least getting the caliper off, a new set of pads on and cleaning the piston up while its off the car.
There is so little pad left now I'd be metal on metal in no time...probably just make it to the shop 20 miles away .
I have another rotor.
Thanks for the ideas. I had considered pressure bleeding or flushing was a consideration.
Am I right in my understanding of the Master Cyl that its just front and rear and beyond that it goes right into the ABS module and from there one line to each of the wheels?
Any way to test the master for proper operation?
Correct, doubt it's the master. Has to be some issue with the ABS unit. Very strange for the same caliper to keep wigging out. Is it possible the brake line is pinched somewhere?Quote:
Originally Posted by Jehu
We put in a brand new line with the last new caliper..Quote:
Originally Posted by 632 Regal
The reduced flow was not changed after that.
Talked to the shop today.
Will have a new caliper warranty exchange tomorrow and he tells me he can address the ABS unit..
If his unit can cycle it under pressure or whatever the thing needs maybe that'll be enough...
At 307,777 miles the engine is really pinging/knocking all the time now.
Even the new knock sensors are just unable to keep it down.
Probably going to be looking for another reasonably lower mileage M60B40 donor soon..
had the caliper removed yesterday but the wrong side part had been sent.
My caliper was frozen but with no option other than leaving the car we worked on the stuck piston and got it to move. Cleaned up the pins and replaced the part. Bled ok and checking the wheel with a digital temp gun all day showed it was no longer binding.
Shop is still offering to replace this caliper at their expense since the fluid now seems ok BUT...
after an hour or so driving I suddenly developed a rather deep grinding noise and vibration when making right turns.
my first thought was the week or so driving with a sticking caliper wrecked the bearing on that wheel.
Other than some unrelated coincidental failure does this sound likely?
Will get it back on the lift tomorrow and pin it down but I had the two front hub/bearings replaced not long ago.
Shop guy thinks it could be a lose heat shield but this sounds too deep to be caused by this sheet metal.
* Eveing update.
RIP..I think I killed the engine tonight.. very deep rythic vibration when increasing RPM....
Had been knocking for a long time . Tonight I grew frustrated with this and instead of backing off as I normally do I floored it.
I felt a brief dip in output and soon began feeling a deep disturbing vibration.
Since I had this other grinding vibration I suspected was a wheel bearing it wasn't until I pulled over and reved the throttle with the car out of gear I could feel this was the engine..
drove it home mostly normal.. normal range MPG on the OBC but something happened .
Interestingly I remembered a local guy I met a few years ago I knew had an Oxford/Parchment 540/6 I think with under 150,000 miles for sale.
Called him and he asked $2,500 for it telling me he's not been with it for a few years and had a guy replacing fuel lines , hard lines with new one and wasn't sure they were all in.
How's the parking brake and caliper guide pins? I had that situation on the 535 and one of the caliper guide pins had sheared and the caliper was rubbing on the inside of the wheel. Yowza!!!
On an e30 I had the parking brake retainers rust through at the backing plate and release the shoe and cause some interesting noises as well.
They were fine.. when we removed the caliper to replace it and found we'd been sent the wrong side part we turned to the one removed and removing the guide pins , cleaned and greased them and they were fine... .Quote:
Originally Posted by ahlem
slapped on new Akebono ceramic pads and the brakes have been performing mostly normally.
Some vibration under braking but this may be rotors or even weak lower control arm ball joints..
I had shaky braking once and replaced the Lower Control arms and the braking was absolutely smooth and solid .
Its mostly moot though I will fix whatever I can even though I think the engine is compromised.
I'll keep this car which is in fine shape aside from some paint issues and if the engine stops allowing me to drive it I'll find a donor engine.. this 540 is sorted as I like them
Koni adjustable shocks and struts, moosehead engineering rear shock mounts, Powerflex Upper control arm bushings, all new Sway Bar Bushings, new rotors calipers and pads, new front wheel hub/bearings , a new left front brake dust shield, I had some new floorboards welded in repairing some holes yes holes in the floors, replaced power steering hoses, resealed upper timing chain cover , replaced knock sensors, new AC compressor, evaporator and expansion valve, receiver/dryer, new power steering pump, new alternator and engine oil hoses, recent new lower oil pan, new fuel pump. new windshield, and just after I bought it three years ago with 150,000 miles I put in a brand new metal fuel tank , had a reman driveshaft and clutch and flywheel..
so to a certain extent the car is literally almost all new. I did all this as I drove it extensively for work saying this would make it necessary when the engine died to replace it since the rest of the car is in such excellent condition.
UPDATE*
Good news. The problem was nothing more than the temp tyranny mount the shop installed. got the new part in and drove 400 miles .. engine was ok just the running vibration with basically the right mounting off balance.
Got the new caliper in and can now focus on enjoying driving again.. wow.
Glad it wasn't the engine. Have you checked the oil pump bolts?