Knocking on brake pedal?

[SimonW88]

Hi...

I have a 1997 E280 and when i have my foot on the brake pedal I can feel this knocking.

Anyone have any ideas as to what it might be?

I have this deja vu feeling.. my previous car was a german car too (not a merc) and i think it had the same problem, so it might be a common thing?

Thanks in advance.

Simon

 

[SimonW88]

Sorry... forgot to mention.. it does have ABS.

 

[jberks]

Assuming its not the ABS kicking in, then I'd have the suspension joins and disks checked. Could be a warped disk or a failing bush somewhere.

 

[television]

If you are unlucky, an emergency stop can generate enough heat to warp the disc, other times a disc can go out of true, this is felt through the brake pedal.

Malcolm

 

[SimonW88]

Hi

I feel the knocking when i'm at a standstill, so i don't think its warped disks.

Still puzzled.

 

[Myros]

could it be

the heater duovalve resonating through the pedal. I can hear and feel mine thunking away. Test for this by turning the heater all the way off and seeing if you still get the sensation. I don't know if you have air con how this will affect it.