Son complained about bad vibration on his f30 at about 40mph after he braked. I took his car for a drive the following day and couldn't replicate the problem. Had both front wheels balanced but this didn't cure the problem. After he has driven about 100 miles and then braked hard the vibration was severe. There are no obvious problems with the brakes. Tonight he drove 100 miles home from work and said when he got near home and braked hard the abs light and tyre pressure module errors showed. Took the car out for a drive and all seemed OK until he braked hard and the car shook badly, as if the abs was kicking in. We stopped at a junction and smoke was coming from the front off side wheel. Wheel and disc was very hot. Drove the car home gently and parked it up for a while. I went to get the error messages and note the lights on the dash and they had all cleared. When I did a check control on the car it said no fauts found. Any ideas what the problem may be? I am suspecting an abs sensor is faulty, but would this take a hundred miles to show a fault and then clear when it cooled?
If it’s slightly stuck on after 100 miles it would be a lot hotter and emphasise any warping of the disc. I’d check the wheels rotate freely and maybe get the pads out, inspect and clean them up. Could be a pad sticking in the carrier or a sticking caliper. Another thing is if the wheel is getting so hot it will affect the tyre pressure and change the circumference of the tyre which could cause an issue with the ABS.
Thanks, the pads were only changed last year by a local garage so might be the cause of the problems. Guess what my job for tomorrow is
From the sounds of it I’d be jacking the wheel up, spinning and listening to see if there is any noise. Could be a sticking pad as said.
Were they genuine BMW pads? I've had a problem in the past where aftermarket brake pads stuck in the calliper because they were slightly oversized. I should add, that was on a BMW motorcycle, not a car.
cant offer to much really other than get the car up in the air and get the nearside front wheel off for a better look the fact that you said the wheel was smoking and the disc was very hot suggests something is rubbing or binding and as the car is used things heat up and the judder becomes apparent at the moment the low ambient temperatures will be helping the discs stay cool so may take a longer journey to show the fault
I would measure the disc and pad thickness on the affected size and compare it against the good. Also the most simple thing to do is spin the wheel and see if you can feel/hear a dragging brake. My money is also on a sticky caliper. Could be as simple as the sliding pins need cleaning and copper grease being applied to them. Could be causing pad deposit because of the heat on the disc which is horrible. I had it really bad for a week on the rear of one of my old M3s after a weekend of hammering it at the Nurburgring, made braking incredibly unpleasant.
I've had similar in the past, strong vibration through the steering when braking, no lights though so I assumed it was bushes in the wishbones. Nope, my Indy told me I wasn't using my brakes enough but driving 'oldie stylee' where we anticipated road conditions and adjusted speed in advance. New discs/pads cured it. I kept the discs and had a pal machine them on his lathe [mine doesn't have enough capacity ] - still within min thickness when checked with a digital vernier , so I have a spare set of discs should the need arise again. I'm nt saying that's your son's problem, just saying.....
Have you had a chance to jack it up and spin the wheels, to see if there is drag on the side that got hot? Peter
Span the wheel and all seemed OK, no dragging and nothing obvious wrong. -2 outside yesterday so didn't want to spend too much time on it. Car is booked into an Indy on Wednesday. They said it could be a reluctor ring?
Just a thought. Could be the wheel bearing. A hearty push-pull should indicate if this is the problem.
Reluctor ring is possible (used by the ABS system to measure the rotation speed of the wheel) - my money is also on a caliper issue, will only manifest itself when the brakes get hot... Anyway you've done the right thing, needs a brake strip down to see what's causing the issue, not the weather to be messing around under cars...
Problem was a partly seized calliper, so that was replaced along with the front discs because the one that had been smoking had overheated and damaged the disc and pads and the ABS sensor. All good now, apart from my Son's wallet
