Strange tapping Sound when braking

Christiansen1968 · Post by **Christiansen1968** » 27 Sep 2020, 14:33

Hi
I've got a bit of a problem with my 1996 850 Estate. Its a 2,4 144 bhp automatic with 200.000 miles in the clock.
Engine is running fine and gearbox is shirting fine.
When i brake a strange tapping Sound accures. Its not when i apply the brakes but just before the car stops. Typical from 20 miles to 0. Sometimes it continues for a while after the car has stopped. As soon as i accelerate the Sound dissapears. Its hard to describe the sound. It sounds like clapping og tapping and dont follow the engine revs.
My mecanic thinks its the timing belt that has been stretched or a dead motor Mount. The timingbelt was changed at 170.000 miles .
The Sound does come not come from the driver side.
Any thoughts?

Post by **FLXC90** » 27 Sep 2020, 21:25

Doesn't follow RPM, so I would check chassis items. Does it follow vehicle speed, if you coast after it starts, does it continue, or only if you slow to a stop. I would also look at heatshields. Check the torque-strap mount under the front, and the mount at the timing belt end of the motor.

Christiansen1968 · Post by **Christiansen1968** » 28 Sep 2020, 05:01

Hi FLXC90

I cant hear anything when im coasting. Sometimes i can hear it if i lift of the accelerator. So again when the weight of the engine shifts forwards. I replaced the lower right engine mount and it was pretty rusty and warn but the sound was still there . I started to replace the upper mount yesterday - its totally perrished. Unfortunaly i wasnt able to finish the job - I couldnt get the darn thing into the socket with my homemade press...
Wandering what to do now.

Post by **Clemens** » 28 Sep 2020, 12:55

As for the upper mount: find someone with bigger arms than you have to get it in. i couldn't get mine in, but my big big neighbor could.
As for rhw sound: unfortunately no clue

Cookeh · Post by **Cookeh** » 28 Sep 2020, 13:20

Use two G-clamps to wind it in. Much easier than faffing around with home-made puller tools. Clunks when lifting off the accelerator would match up with worn torque mounts - especially the one you're in the process of replacing. The dog-mount under the car should also be checked, as FLXC90 alluded to.

Post by **kallekula** » 28 Sep 2020, 14:45

Check if u have balance weights on the inside of the wheel. I have seen examples of the weights making contact with the brake caliper upon breaking, causing
pulsating knocking sound.