Brake Pedal Feedback..

[Ian_C]

Guys,

Quick question about the brakes. I am a new owner (well a few weeks) of the Black E55 1998.

Question is, when I put the foot on the brakes, when stationary, I can feel a small pulse through the pedal. These pulses are just over a second apart and I can certainly feel a little pulse. The car may do this too when braking but I cannot feel it.

If this the servo, is this brake assist.......More importantly is this not right or an indication as to impending brake doom.

Anyone have any idea.

Many Thanks for reading

Ian

 

[portzy]

This might sound crazy but, can you also hear it or feel it maybe through the steering wheel?. A few folks on here including myself have noticed this but it was'nt brake related though.

Portzy.

 

[Ian_C]

Good point. I cannot hear it at all and I am not aware that I can feel it through the wheel, and I am very fussy. I am sure I would have felt it through the wheel...

On another note I did think something was wrong this morning as when I braked there was this chunk sound. I was worried, but the realised it was the cigarette lighter in the ash tray Good old Merc.

Ian

 

[Dieselman]

It's the heater control valves pulsing. They are mounted next to the servo so transmit the pulse.

 

[portzy]

Good point. I cannot hear it at all and I am not aware that I can feel it through the wheel, and I am very fussy. I am sure I would have felt it through the wheel...

On another note I did think something was wrong this morning as when I braked there was this chunk sound. I was worried, but the realised it was the cigarette lighter in the ash tray Good old Merc.

Ian

Just to be absolutely certain though; park her up somewhere quiet, turn off everything like radio etc and just have the heater fan on its first setting and try to have the temp control set to what the interior actually is then listen.

As Dieselman said and I experienced also, the heater duovalves can at times sound and feel 'pulsey' when the interior temps match those set on the selector.

If that does not pinpoint this as being the culprit I'm afraid I'm not all that up to speed brake fault wise .

Regards.

Portzy.

 

[Ian_C]

Fabbo, will try that....Good old Mercs

Just off to wash wheels

Ian

 

[Ian_C]

One turns the heater off and everything is fine.

many thanks for input....

Now to find out why the brake judder when braking from high speed

Cheers

Ian

 

[Dieselman]

One turns the heater off and everything is fine.

many thanks for input....

Now to find out why the brake judder when braking from high speed

Cheers

Ian

Either warped disks or brake material incorrectly transferred onto disk from the pads.
If the car has been laid up for a while the friction material can transfer onto the disk in a patch. this patch will create higher friction than the rest of the disk and it leads to brake judder, particularly under heavy braking.

If this is down to transfer then it will only get worse.

In addition the disks can corrode behind the pad leading to a similar issue.

Check the disk run-out and the condition.

Try driving with your left foot hard on the brake and the right foot on the floor to really get some heat into the brakes. If this effects a temporary fix it's down to transfer.

The best fix is to remove the disk and scrub it with either coarse wet-n-dry paper or a sharpening stone...honestly.

My car suffered after being laid up for six weeks and was getting worse. Scrubbed the disks and no more problems for two years....I'm not a heavy braker and the EBC pads are kind to the disks..

 

[Ian_C]

As things have been busy I have not got round to cleaning the disks up (as I know as soon as I start, next think I know I will have wasted a day and will have painted the calipers too).

Anyway, about 8 stops from 100-10mph seems to have cleared up the problem, for now. Thanks.

This was quite useful from anothe thread here :
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

Nearly got a heart attack when I saw the prices of brake pads and disks for the car. Average price for pads £117.

Ian

 

[BlackC55]

As things have been busy I have not got round to cleaning the disks up (as I know as soon as I start, next think I know I will have wasted a day and will have painted the calipers too).

Anyway, about 8 stops from 100-10mph seems to have cleared up the problem, for now. Thanks.

This was quite useful from anothe thread here :
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

Nearly got a heart attack when I saw the prices of brake pads and disks for the car. Average price for pads £117.

Ian

Welcome to AMG.........

 

[Ian_C]

Well finally go the wheels off today, to give them a polish and some paint.

While checking the brake disks they were very black in colour, so I ran some wet n' dry over them.

Will try the brakes laters, after the rain stops so I can put wheel back on.

Just had to paint the calipers silver too....:bannana:

Cheers

Ian

 

[Dieselman]

Did you do the back of the disks as well.

Try THESE people for brake pads. I have no complaints with my EBC pads and will definately use them again as they appear to grab better, stop better and create much less dust which doesn't burn in to the wheel laquer.

Fit them F & R for best effect otherwise they will imart more braking onto the front end if only fitted there as they have a higher coeficient of friction.