engaging the parking brake - creak

rh71 · #1 07-28-2009, 07:24 AM

When I engage the parking brake while on an incline like a driveway, turn off the vehicle, then release the brake (or vice versa on the last two), there's a really prominent creak even from inside of the cabin. I've experienced it on other driveways of varying degrees as well - I know there's something that is engaged that locks things in place but the creak... does that bother anyone else? Doesn't happen on flat ground of course... just wondering if it should be as loud as it is and if you guys notice it. On other vehicles, once the parking brake is engaged, it's locked pretty solidly in place but not the X... there's more initial give than usual.

I want to be sure it's not a mechanical problem relating to a suspension creak of similar sound I sometimes get when going over bumps (which of course didn't happen when the service guy rode with me).

pureflames · #2 07-28-2009, 12:24 PM

Good question - I have the same symptom.

rh71 · #3 07-28-2009, 03:39 PM

are others just not parking on inclines or simply don't have this sound when they do?

Thunder22 · #4 07-28-2009, 05:26 PM

IMO it's normal.

Weasel · #5 07-28-2009, 07:59 PM

Normal, it happens on just about any BMW I ever see... (the driveway behind my stall is a decent incline)

x5mad · #6 07-28-2009, 09:23 PM

Happens with mine as well, quite annoying though that the parking brake does not take all the load to begin with. It creaks and sometimes rolls fowards and backwards slightly, letting the transmissions parking pawl (pewl?) take some of the weight.

FunfDreisig · #7 07-28-2009, 10:12 PM

I'm guessing that the creak occurs during the transition between hydraulic and mechanical control of the parking brake....

" Electromechanical Parking Brake.
Starting off on a slope, in stop-and-go traffic or whenever the engine is turned off: the Electromechanical Parking Brake ensures your BMW stays comfortably and reliably at a standstill whenever required.

Working together with Dynamic Stability Control (DSC), the Electromechanical Parking Brake controls all braking processes whenever the vehicle is not moving. If the engine is running, it operates hydraulically via the DSC brake system. If the engine is switched off, electromechanical brake cables support the function of the conventional handbrake...."

FWIW our 2001 X5 brakes would creak very loudly if I released the brake pedal very slowly and then reapplied the brake (e.g. when backing up very slowly to hook up the trailer).

Funf Dreisig

Quoted from
BMW Technology Guide : Electromechanical Parking Brake

FunfDreisig · #8 07-28-2009, 10:29 PM

Quote:

Originally Posted by rh71

....I want to be sure it's not a mechanical problem relating to a suspension creak of similar sound I sometimes get when going over bumps (which of course didn't happen when the service guy rode with me).

One of the quirks of our late lamented 2001 X5 was the loud creak/snap when going over bumps at low speed. After BMW technicians replaced nearly all of the front suspension bits in multiple failed attempts to eliminate this creak/snap, I took off the sway bar during a BMW CCA tech session at the local dealer and discovered/fixed the noise

The problem was grit build up in the rubber mount/bushing that would freeze and quickly release the energy/sound to the large aluminum 'splash pan' under the engine. This flat pan acted like a large speaker amplifying the sound.

The diagnostic clue was that the creak/snap noise only happened when the two front wheels went over a bump at different times (i.e. driving over a speed bump at an angle) at low enough speeds to get the two sides to react differently.

Funf Dreisg

rh71 · #9 07-28-2009, 11:16 PM

Quote:

Originally Posted by FunfDreisig

One of the quirks of our late lamented 2001 X5 was the loud creak/snap when going over bumps at low speed. After BMW technicians replaced nearly all of the front suspension bits in multiple failed attempts to eliminate this creak/snap, I took off the sway bar during a BMW CCA tech session at the local dealer and discovered/fixed the noise

The problem was grit build up in the rubber mount/bushing that would freeze and quickly release the energy/sound to the large aluminum 'splash pan' under the engine. This flat pan acted like a large speaker amplifying the sound.

The diagnostic clue was that the creak/snap noise only happened when the two front wheels went over a bump at different times (i.e. driving over a speed bump at an angle) at low enough speeds to get the two sides to react differently.

Funf Dreisg

That sounds pretty accurate to what I'm getting as I turn one direction coming off the driveway lip... wheels coming off at different times. I've heard it in the back wheels too. You say it's a grit build-up... is this bad for the whole system over time? You also mention it freezes but we're having summer days here. It is not happening as frequently, but it is still happening. Also wondering why there would be grit build-up in a relatively new vehicle - been happening since near the beginning. Regardless, I'm hoping that's the problem and that it is not serious.

FunfDreisig · #10 07-29-2009, 08:34 AM

Quote:

Originally Posted by rh71

That sounds pretty accurate to what I'm getting as I turn one direction coming off the driveway lip... wheels coming off at different times. I've heard it in the back wheels too. You say it's a grit build-up... is this bad for the whole system over time? You also mention it freezes but we're having summer days here. It is not happening as frequently, but it is still happening. Also wondering why there would be grit build-up in a relatively new vehicle - been happening since near the beginning. Regardless, I'm hoping that's the problem and that it is not serious.

Sorry my terms were meant to be descriptive not literal. By "freezes' I meant that the rubber mount/bushing 'sticks' to the sway bar as it twists. Then 'unsticks' letting go of the bar quickly which lets the mount relax back into its normal position with a snap. This mount is attached to the large aluminum plate under the engine. The key is the location of the mount to the aluminum plate which acts as a amplifier of relatively quite sounds.

In my case the inside of the rubber mounts/bushings for the sway bar were very dirty and had built up gritty/rusty bumps on the sway bar. I had to scrap the grit/rust off the sway bar with a utility knife. The grit stuck to the bar made it very rough. So it did not twist inside the mount smoothly. This same behavior could be caused by anything that keeps the sway bar from being able to twist smoothly inside the rubber mounts (e.g. being too dry, too tight, etc.)

Of course the dealer didn't have the new mounts in stock when I was at the tech session. So I simply scrapped the grit/rust off the bar, liberally lubed the mounts and re-installed the bar/mounts. The noise went away completely. We later had new rubber mounts installed. If you are even halfway good with a wrench, you can pull the mounts and check for grit/rust build up and spray the inside of the rubber mount with a small amount of rubber lube. You don't want too much lube because it might attract more dirt.

Funf Dreisig