strange hit when reversing and brake

Tue Oct 05, 2010 1:45 pm

F reg E30 320 cabrio
I had some work done recently on suspension shocks, springs, mounts changed, discs changed, diff and gear box were off,after all done I "noticed a little problem"

, which definitely was not there before.

It drives lovely and brakes as it should and everything seems OK until .... I put it in reverse, and while moving back (slow or quick!) when I brake (slow or quick!) I can hear and feel hit from under the car, first time I noticed it I thought I hit something, but noooo...

went back to mechanic, sat him on passenger sit and drove forth and back and forth and back and no problems whatsoever

it seems to me that it appears only when I drive forwards for a little while, and then when I need to park or just revers, it hits again, even if I brake really gentle while moving backwards, it still hits quite hard. Sound from back underneath, may be back chassis.

Any ideas?

Tue Oct 05, 2010 2:12 pm

Hi there,
I had a similar problem on another car i had, it turned out to be the front disc pads, They were not "dealer" items and although they were correct spec for the car (Mintex), the metal part of the pad was slightly smaller than original items. This resulted in a slight radial movement of the pads within the calipers where the pads rest on the guides. (hard to explain). When going from fwd to reverse a loud clunk could be heard as soon as the brake pedal was pressed, this was the pads coming into contact with either the upper guide of the caliper or lower, depending on whether i was going forward or backwards. I was assured by the dealer technician that it was not a problem, ( It had them stumped for a while too!).
This could be what you are experiencing.... Good luck!

Tue Oct 05, 2010 2:14 pm

tangopapa wrote:Hi there,
I had a similar problem on another car i had, it turned out to be the front disc pads, They were not "dealer" items and although they were correct spec for the car (Mintex), the metal part of the pad was slightly smaller than original items. This resulted in a slight radial movement of the pads within the calipers where the pads rest on the guides. (hard to explain). When going from fwd to reverse a loud clunk could be heard as soon as the brake pedal was pressed, this was the pads coming into contact with either the upper guide of the caliper or lower, depending on whether i was going forward or backwards. I was assured by the dealer technician that it was not a problem, ( It had them stumped for a while too!).
This could be what you are experiencing.... Good luck!

Forgot to mention, this could also be the case for rear disc pads as i see you say the noise appears to come from the back

Wed Oct 06, 2010 9:34 am

tangopapa wrote: Forgot to mention, this could also be the case for rear disc pads as i see you say the noise appears to come from the back

when you say disc pads do you mean brake pads???
that must be it, I'm pretty sure it's related to the brakes
thank you very much, will check that shortly and inform

Wed Oct 06, 2010 12:34 pm

Hi again,
Yes, brake pads/disc pads is what i meant, hope you get it sorted.
Tony

Wed Oct 06, 2010 9:26 pm

You said you had the "mounts changed", what mounts ?

Thu Oct 07, 2010 9:45 am

Martinaston wrote:You said you had the "mounts changed", what mounts ?

shock mounts,
someone suggested that because they new, they move a bit until properly sit in place, it did get not that hard over some time, but did not disappear (hit sound)

I took off rear wheel yesterday, it looks like there is a little gap about 1-2 mm where the inside pad is, but the outside pad looks like just in place, so I'm not sure is that suppose to be or it's wrong?