CL55 Front Discs - Wear Query

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martyp87

Active Member
Joined
Sep 26, 2012
Messages
535
Location
Edinburgh
Car
W166 GLE350d
Hi all,

Not been on here much due to workload (manic as usual) but about a month or so ago I had the car in to MB for a service and MoT, I was told the front pads wouldn't last another 10k to the next service so it would make sense to replace them.

Told them to just go ahead and was told the discs were fine.

Problem is, I hardly ever drive the car and it was sat outside the house for 3 weeks and when I went for a 50 mile round trip I came back and noticed some parts of the discs were back to looking clean however, there rings which were still rusty as if the pad wasn't touching that part (which was probably about 40%) of the disc!

The breaks feel fine, but aesthetically it doesn't look to good! Half shiny and half rusty rings!

I am getting the callipers removed and resprayed this month so wondering if the discs should be replaced when refitting or if I just need to do a few more miles for the pads to bed in?

Car will be towed from the bodyshop to a garage with STAR to bleed the breaks etc.

Tried a mix of light, moderate and very heavy breaking thus far (about 150 miles or so which is a lot for me in a month!).

Thanks in advance. :thumb:
 
Its just the pads bedding in.
 
STAR is not needed to bleed the brakes on a CL. You can bleed with a pressure bleeder.
 
Its just the pads bedding in.

Hmmm...we've had a couple of cars do that and once the rust gets embedded it tends to rub away the pad so the pad won't clean it off. Gradually the rust spreads across the surface of the disk. It's just one of those things in cars that aren't used much.

It was particularly bad on a car my wife had - it ended up with just a narrow band that was shiny. It's common on the inside face - my C Class is doing it and the outside looks fine.

One of neighbours has a Porsche weekend car he makes a point of doing a series of hard stops to clean the disks every time he uses it.
 
Hi,

Thanks for the input guys and sorry for the delay in replying. I'll give them a few more miles and see how it goes. If they do get worse I will replace the discs and ensure I do some heavy braking to clean them off when out and about.

The MB dealer said star is required to bleed the brakes but I've lost faith in them anyway after the last time.

I need to get the boot re calibrated and the body shop had issues with a cars 6 pot callipers so I'm not sure they'll have great success with 8 pots. I'll play it save and get a MB Indy to do it.
 
How far the boot opens?
If you have an auto-closing boot it has two settings, one fully open and another that only opens half-way or garage setting as it is sometimes known as i.e. if inside a garage it won't open fully and hit the garage ceiling.
But I could be wrong, again :dk:

Matt
 
The boot has a cycle which you need to run it through to determine how far it opens/closes.

I replaced two worn rams as it wouldn't open on it's own. It now opens completely, however, as I had to push the boot further than it would normally open to fit them it doesn't close snugly now.

I know about the garage feature as that was enabled when I got the car, got the dealer to disable that.

Regarding the breaks, spoke to the independent MB guy near me and he suggested giving the discs a clean and then trying going a good run to bed the pads in.

Worse news, was the fact that he told me not to let the bodyshop touch the breaks as they are hooked up via STAR. He said you need to go onto STAR and let the system know what you are going to do before doing it (ie. replacing pads etc) which is the same as what the dealer told me.

Therefore, won't be getting nice yellow calipers this week. Want to get them done but after being told they are powder-coated I think I will find a specialist to do them at some point...
 

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