hey guys, i will try to explain this as clearly as possible.
About two weeks ago i drove my e39 m5 on the weeknd after it had been sitting for about a week. A minute or two into the drive i felt something so subtle but i thought it was just me. Accelerating from a full stop seemed to take a little more throttle than normal, and felt the car would come to a stop quicker. Somewhat like its helping me push the brakes.
Fast forward to last night i decided to take it out again ( been sitting in the garage since last incident) fired up right away and put in reverse. trying to back out of the garage and the car does not want to go. Almost like the Ebrake was still engaged. With enough gas it will start going but the second i let go of the gas it stops itself as if i slammed the brakes.
i drove down the block thinking my brakes were sticking and thought maybe i can drive it off. Started smelling like something was burning. went back home thinking my e brake is stuck or the calipers are seized. smelled the front wheels, nothing unusual.
smelled the rear wheels and the smell was forsure coming from there.
i then jacked up the rear end only to find out that i can feely spin the rear wheels while in neutral. so its NOT the brakes?!?!
i kind of wish it was. now im thinking something transmission or differential related.
to sum it all up, it feels like im driving with the ebrake on
starts to smell after couple minutes of driving
no squeals no clunks no other noises
car starts perfectly and goes into any gear perfectly
any help would be greatly appriciated as i have done a good amount of search but no help
Does it smell like brake pads or an oil smell? Even a slightly seized caliper can allow enough "wheel spin" while burning the pads.
If you had a diff or transmission issue you would be hearing grinding or clunks
Great thought! I'll check out the routing of the cables and see if I notice anything. However I did try again after lowering it and same thing. Then again might have just stuck the cable again when lowered it back down haha
A couple thoughts...... I don't see how jacking it up would free the brake shoes.
Could the ABS be acting up, applying brake force when it shouldn't? This might explain why it spins freely with engine off. Any ABS or DSC lights?
Does the wheel spin freely in BOTH directions?
Also might be a wheel bearing although they usually make a distinct sound.
Check your CV joint boots to see if there is a tear or leak at the clamp.
You seem to have missed the first couple of tests and without them the others are pointless. Can you move the car when it is in N? If you put the car in gear but push the clutch can you push the car? Start the car and repeat. Try if the DSC button makes a difference. Next I would jack under the control arm of each wheel and spin them. That way they stay loaded. Know matter where you smell check each wheel because that is the smart way to do diag.
When the car is in N it will move but require more push than nirmal. I will try again tonight with the car on and off and see if there is a difference. I will also check if DSC makes a difference
If I am at an incline and depress the clutch it will roll but only on a extreme incline and some reward momentum. or else it feels like I'm pushing the brakes.
Do you have a Infrared Thermometer? If so, a quick thing to check is to shoot each brake caliper after driving and see if you have one that is higher temp than the others.
The center of the wheel will also be warmer if a brake is dragging so you can just use your hand and touch each wheel in succession if you don't have a IR thermometer.
I am afraid to drive the car again until the odor comes. Since I have to drive for about 8 minutes or so for the odor to appear. For now I'll do my best to diagnose in my garage.
Hopefully tonight I'll find some time to get under her again and take a closer look
When I first put the car up and turned it on in N
Tried spining the wheels by hand and I could NOT.
Turned the car on and put it into gear, and slowly let go of the clutch. The car stalled since the wheels struggled to turn not turn fast enough for the motor. Turned it back on and tried again while giving slight gas. Wheels started turning and was able to let go of clutch and watch them spin freely.
Seems almost like the brakes were literally stuck.
After that in N I was able to spin both wheels both directions by hand. I made a short video showing some tests I did. Looked at the CV boots looked perfect looked at e brake lines looked perfect . no abs or dsc lights on
One weird thing I found was when in N (car is running) with the clutch pedal DEPRESSED the wheels turn veryyy slowly. i can stop them by hand. when i PRESS the clutch they will stop
i always thought in neutral they should not spin at all but maybe its because there is no friction whatsoever when in the air?>
maybe some axle grease found itself onto the emergency brake pads causing them to swell, or the adjuster for the e-brake is somehow dysfunctional for some odd reason. Have you taken off the rear rotor and checked inside? Maybe the spring busted, maybe the adjuster is out of whack, maybe Venus was in the incorrect alignment with Mars and created some type of wave anomaly that somehow your car was the recipient of. We're just guessing. Please take of the rear and post pics of the inside because it sounds like something is going on with your e-brake that only happens under load. Please keep us posted.
haha yes this is what i will do next...... when i get back from las vegas for the weekend!!! whoo! hopefully i win some money for new e brake shoes and 6 piston brembo calipers :grin:devil
Finally got around to removing the brakes and rotors today. Nothing I can see that seems off. Here are some photos. All these photos are with the ebrake OFF and the last photo is with the ebrake ON
Also the car has been in the air since my.last post last week. Wheels still spin freely with the car in gear. Curious to see if I put it back together and drop the car if the problem disappeared
Those look like the hub may have been heated, but it is always hard to see from pics. Heat looks like it might be in the bearing. A failed bearing with no load can spin free but as soon as it gets loaded resists rotation and heats. Listen close as you spin them.
what type of noise should i be looking for. i dont remember hearing any noise when spun. i will go back tomorrow and listen more carefully
if no apparent noise is heard what else can i do to find out if i should just order a new wheel bearing. is it the bearing i would need or the hub? or both? unless the hub is warped, i dont see it really going bad so im assuming i would get away with just the wheel bearing.
Compare the two hubs. The pics you posted don't look healthy. Maybe the PO took a grinder or sander to one. I see black I see silver I just don't see normal. It will be up to you as you are the only one with the car in front of you. As far as noise any noise will not be good. The only noise that would be acceptable would be the sound of grease passing by perfectly round bearings. I don't know how to describe that.
You might force the hub one way or the other and see if it still spins free. If you feel any resistance to rotation while forcing the hub in any direction you have likely found the cause. It is unlikely you would have two failed bearings so compare the two side in feel and visually.
say the other side spins smoother/more freely/ quieter
so i go about replacing the wheel bearing or the hub. from what it looks like the bearing is what fails and not so much the hub? am i wrong. regardless, ill probably replace both but just curious
update: both rear hubs are good. they spin very quietly and freely with the car on stands and in gear. no weird noises just clean turning.
i took both rear calipers off cleaned the crap out of them. flushed the old fluid out of the entire system and put new fluid. Bled the brakes and put the car on the floor. instantly it was fixed. the car rolled out of my driveway on its own in N. I went for a 2 minute drive and the problem was gone.
HOWEVER this morning. finally wanted to take her out and its back! i drove the car down the street and back just to get the smell to appear. and it definiantly smells like a hot metal smell. and theres extreme amount of heat coming from the rear wheels whereas the fronts are cool when i put my face next to it.
UPDATE #2: unplugged the ABS module under the hood. turned the car on and the problem is gone!!!!!!! looks like ill be repairing the module for the second time. despite the problem being gone something is still funny. say im going about 40mph and push on the brakes somewhat hard the car will slow down and if i let go of the brake quickly it seems like the brakes dont immediatly disengage how they should. thinking if i have a combo package of a bad abs module and a sticking caliper
pretty much,when i got the car i had the 3 lights on brake dsc and traction light on. i got my abs module rebuilt. ever heard of them going bad without throwing any of the codes? well unplugging it did fix the problem so im not sure whats going on here
Took the brake lines out. Looks great and are clear on the inside
Took calipers out was able to push the piston by hand squirting all the fluid out the bleeder. Nothing seems seized
Problem still occurs when abs is unplugged. No lights on when abs is plugged.
Anybody?
The problem is definatley at the calipers. When I remove the calipers everything is freely spinning.
Forgot to mention. Once, when I did unplug the abs it seemed to free the calipers but then started again. Maybe it is the abs or maybe it was coincidence
The only one I unplugged was the large black connector on the abs module with the slide out type connector. There's also a small connector on the silver metal side. Is that one to disable the actual pump? I'll give it a shot after getting more brake fluid tomorrow since I ran out constantly refilling the reservoir
Are you sure those are not from when you had the plug off? Smart thing to do with DSC is read it again after you clear to make sure the codes are gone, they don't always. Just noting the front left wheel sensor is a common code when the DSC is bad.
Looked at the diagrams more closely and the precharge pump should be in the big plug, but it is hard to tell. The diagrams suck. What wire colors are going to the silver? Black and something, two wires? If yes they maybe the ones.
Have you determined if it is both rear brakes getting hot or just one? If your SAS is bad it can tell the DME you are turning while the other sensors (yaw and lateral accelerator) say you are going straight, creating a false understeer situation and the ABS will activate one of the rear brakes.
Clear your codes. You might also try disconnecting your battery to see if the SAS will reset.
But it still happens with the module unplugged? Very strange.
As I found out recently it is a tad more than just disconnect the battery to reset the steering angle. Likely the steps will happen anyway but just in case. When power to the SAS is interrupted it looses the count of where the wheel is as far as rotations but not position, you need to change the position so that it learns everything. So you need to park the car with the wheel cocked away from straight. Disconnect the battery straighten the wheel then reconnect the power. There must be a wheel speed sensor signal for this part just sitting stopped will not do it. You must also not exceed 20 MPH or then the learn procedure will stop. The steering needs to go past one lock then back to straight then past the other lock and returned to straight.
My guess is you can pass thru the straight to the other lock but since my last try failed I am holding straight for a few seconds.
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