Brake issue

[v3burn]

HI All,
just looking for a bit of your excellent knowledge and guidance.
Have a c300 20 plate which i dropped off at airport carpark on 1st march, collected on 17th and on way home noticed a judder when braking, not enough to wobble the steering but the best way i can describe is its similar to driving over the slowing down strips in the road when approaching a roundabout on dual carriageway.

checked dashcam to make sure car park addendants didnt do anything silly with it...they hadnt.
took it to Dealer on Monday, they did a visual inspection and quoted for new pads discs, but said they thought it was corrosion which should disappear by the end of week. do you think it may be corrosion and /or disc / pad wear...approx mileage 37.5k or something more sinister like the ABS....
Braking seems to be ok...its just the juddering thats casuing concern.

any advise appreciated.

 

[Rockron]

More than 2 weeks unused and in the open presumably? Driving rain = corrosion. At a guess I'd say the dealer is correct, particularly if everything was ok before the park up. A few miles of hard brake useage should clean them free of rust. Unless deeply rusted, unlikely in just 16 days.

 

[mercmancdi]

Brakes should clean up ok no need for hard braking. Not so sure about shuddering unless a caliper cylinder has seized, but unlikely in few wks

 

[Blobcat]

Good chance the roads had been salted so discs will no doubt have corroded whilst you were away. Should clean up with braking

 

[v3burn]

thanks for the answers, to clarify the car was stored in an off airport compound and only moved to park and then collected, discs dont look that corroded and did around 40 miles today, tomorrow will be at least 100 miles perhaps more..
all was working fine before i dropped off at airport, and visual inspection yesterday detailed 50% worn....dont want to drop £500 on new pads/discs if not needed. i will give another week or so to see if issue goes away.

as long as it wont be anything like ABS activating when not needed..
did try some harder than normal breaking today to try and resolve.....will see ongoing.

worth spraying anything like WD40 into calipers? or will this lubricate the pads/disc to prevent effective braking?
as you can tell im not a mechanic of any sorts

thanks

 

[Blobcat]

Don’t spray them with WD40…

 

[EmilysDad]

....
worth spraying anything like WD40 into calipers? ....

Noooooo!

 

[mercmancdi]

Did you notice if any brakes were sticking , if you could go shortish drive and ( don’t get burnt ) park up go round each wheel carefully touching the rim then disc to see if
1 of them is heated up much more than any of the others that would point you in direction of problem if it was . Or if you could get the car up and spin each wheel to see if one is harder to turn.

 

[v3burn]

this is a picture taken after driving 150 miles today, dont think any corrosion is there now...

ok with the WD40.....wont do that...

might be able to try the temps on the discs tomorrow depedning on weather.,...raining hard today...

do you think dirt could be stuck between pads / discs? will give them a good pressure wash at weekend if weather good

 

[malcolm E53 AMG]

At 38k miles they probably are past their best did they check the runout on the discs? Is the judder speed relative?

 

[v3burn]

Dealer did a visual check and discs/pads 50% worn, the faster you are braking from the more noticable the judder...

going to get a second opinion nex tweek hopefully from a friend of my son, if he says discs etc are worn i will get him to change and use OEM parts

visual inspection also noted a "Slight Play NSF Spring Control arm".....could that be involved?

 

[Blobcat]

Could be a calliper sticking

 

[Wighty]

Don’t spray them with WD40…

Spoilsport

 

[M80]

1st check for me would be the calliper sliders, and fee movement of pads.
For that, wheel/s off, callipers off, check they're sliding freely. Probably best asking a mechy to check it out.

 

[Blobcat]

Spoilsport

Use high temperature grease instead…

 

[M80]

and careful what you us around the rubber components.
Wrong grease, rubber swells, brakes bind.

 

[mioba]

Not uncommon at all for debris between pad and disk this time of year - caused by the grit on the roads.

I am assuming thats the pad to the RHS of the pic (hard to tell). Looks like plenty of meat on them.

 

[v3burn]

cheers guys, although the problem has got better, braking from higher speeds the judder is still there....
will get my sons friend to have a deeper look and get the wheels off to check for debris and calipers / pads etc.

 

[LostKiwi]

If you have corrosion on the disc do not use hard braking to clear it. The heat chemically transforms the rust into a hard substance that effectively Bruins the disk as the area exposed will have been rusty but the part under the pad will not.
If you've generated enough heat with stopping from speed or hard stops the only option is to change pads and discs. You'll never get rid of it if the discs have got hot with the rust there.

 

[v3burn]

If you have corrosion on the disc do not use hard braking to clear it. The heat chemically transforms the rust into a hard substance that effectively Bruins the disk as the area exposed will have been rusty but the part under the pad will not.
If you've generated enough heat with stopping from speed or hard stops the only option is to change pads and discs. You'll never get rid of it if the discs have got hot with the rust there.

the dealer said to brake harder than normal
i will wait for someone to look at them, if they need disc pads i i will have to get them done.

cheers for all replies