Still on the short end of the learning curve. Need direction

[BergerNJ]

I'm almost positive I have a semi frozen caliper and it goes away after braking but seems to come back after a bit. When driving I hear a hiss or like swipe sound thats on rhythm and as soon as I brake it goes away-then my normal breaking sound comes on....if I let off the pedal it comes back. The slower I go the slower the sound slows too. I hear it better when driving next to the median or a wall. Without pulling the calipers on my right side off to visually inspect how else can I diagnose?

Otherwise, my brakes feel fine as does the pedal, they dont pull the car to the side either. My rotors definitely need to be replaced when I do any brake work since they look like they've been turned 20 times. but my pads have plenty of life on them I think.

How should I go about replacing my rotors? oem? or can I go for a slight upgrade?(no tracking just normal dd and sometimes a hard stop here or there) If I do indeed have one or maybe two bad calipers, whats my best option for a slight upgrade. I'm confused because there's like 400 different kits and rotor/caliper options on all of the popular parts sites that float around this forum..I dont wanna rebuild I just wanna put all new parts on the car and be able to sleep at night.

sorry for the long post in advance any help/direction would be appreciated

[immajackuup]

I'm almost positive I have a semi frozen caliper and it goes away after braking but seems to come back after a bit. When driving I hear a hiss or like swipe sound thats on rhythm and as soon as I brake it goes away-then my normal breaking sound comes on....if I let off the pedal it comes back. The slower I go the slower the sound slows too. I hear it better when driving next to the median or a wall. Without pulling the calipers on my right side off to visually inspect how else can I diagnose?

Otherwise, my brakes feel fine as does the pedal, they dont pull the car to the side either. My rotors definitely need to be replaced when I do any brake work since they look like they've been turned 20 times. but my pads have plenty of life on them I think.

How should I go about replacing my rotors? oem? or can I go for a slight upgrade?(no tracking just normal dd and sometimes a hard stop here or there) If I do indeed have one or maybe two bad calipers, whats my best option for a slight upgrade. I'm confused because there's like 400 different kits and rotor/caliper options on all of the popular parts sites that float around this forum..I dont wanna rebuild I just wanna put all new parts on the car and be able to sleep at night.

sorry for the long post in advance any help/direction would be appreciated

im in the same boat

[jlevie]

With a stock power train, there is no reason to upgrade the brakes. The stock brakes on an E30, with good pads, are more than able to overwhelm R-compound race tires. The best rotors you can get are plain, not drilled or slotted. In the Spec E30 community we use the cheapest we can find. And you can be sure that if anything increased performance, we'd use it.

You can tell if a rotor is dragging by simply getting the car up in the air and spinning each wheel. This test is best done by bringing the car to a stop without using the brakes.

My guess is that you have a sticking caliper. I'd rebuild them, and replace all of the soft lines. The other option is to purchase a set of rebuilt calipers (and also replace all the soft lines).

An an FYI: BMW rotors should never be turned. They should be replaced when worn below the wear limit. The wear allowance is only 2mm and a simple check is to compare the ridge with the thickness of a dime. If the ridge is that high, or almost that high, replace the rotors.

[AndrewBird]

Severely worn brake hoses can cause the calipers to not retract as well. Basically the pressure from pushing the brakes forces fluid in, but then the hose collapses, not allowing the fluid to return to the master cylinder.

Also, disk brakes in general will drag slightly under normal conditions. Not enough to keep the wheel from turning obviously, but you probably will hear the pads dragging slightly when you spin the tire by hand.

[lateracer]

Does sound like stuck caliper. Rebuilt calipers are around $40 each. Caliper rebuild kits and a set of new guide bushings start at around $30 per wheel. I had the pleasure of rebuilding all my calipers and then discovering that I still had a dragging pad because of a worn guide bushing. Too much of a PITA to save about $40 IMHO. Additionally, if my caliper pistons would have been too rusted to reuse, the rebuild method would have actually cost more than the replace method.

Good quality E30 parts are pretty reasonable. If you don't mind paying a marginally higher price (about $50 in the case of calipers) for peace of mind in knowing everything is right, I would totally recommend just replacing the calipers, lines, and rotors. I went this route on my DD and I think the total cost was around $350. Not to mention is that since you're pulling the brake lines, you need to bleed them, so you might as well put in new brake fluid for about $10.

You can reuse old pads, but you'll need to remove them from the dirty old calipers and put them in your shiny new ones. The temptation to just put new ones in will be pretty strong...just sayin.

[BergerNJ]

thanks for the help guys...


Levie I see your posts almost every time I lurk the threads about certain repairs trying to retain information for my future use. You always give great and to the point advice. I was hoping you would post in this thread. Thanks!

Another few questions now, if memory serves correct, the only soft lines in the car are from the hard lines near the wheel wells that go to the calipers?

I inspected my brakes about 2 weeks ago and discovered two wires going to my right front and one going to my left front. I'm guessing the PO didn't replace a sensor correctly? I think I'm right because with bumps and just on random occasion my break lining light will flash or stay lit then turn off. I think the existing sensors haven't been touched in a while and the car is getting confused with different signals?

[lateracer]

In addition to the soft lines at the calipers, there are two more that link the hard lines to the rear trailing arms. Those are a little bit of a chore compared to the four at the calipers.

The wires you're seeing are more than likely the ABS and pad wear systems. ABS sensors are on every wheel, pad wear sensors are on driver front and passenger rear. The pad wear sensor is pretty basic (on or off) and there aren't any signals that get sent or interpreted. Might just be that your pads have worn out...which is how I discovered my stuck caliper.

[BergerNJ]

I haven't looked in my Bentley yet but is there a section on the soft lines?

Im aware of the rebuilt calipers rusting out quick should I just paint them with something before I put them on? What paint is good for that ?


Thanks for all the advice seriously

[jlevie]

The caliper hosings are cast iron. They will form a layer of rust pretty quickly, but the process is self limiting. Other than looking nasty the rust hurts nothing.