W208 CLK230K Grinding Brakes

[Mattyn]

Hi All

Mrs M came home from work today and as we were chatting over tea, she mentioned that her brakes were making a grinding noise. Now I immediately thought worn pads, as you do but was bothered why the wear sensor did not indicate anything.

So took it to the end of the road - really loud grinding from drivers side. Now we have not had this long, and I know when I checked the car over the pads had a good amount on them - so took off the drivers front wheel and looked to see if I could spot anything wrong.

It appears there is loads of life left in the outboard pad, absolutely nothing left in the inboard pad - I never took the caliper off as it was getting late and dark - but have tried to find some guidance on here for a similar fault.

Do you think the caliper is shot? The pads are definitely, as is the inboard side of the disc - very scored. She is certain she only noticed the grinding on the way home - it looks to me like the pad is missing on the inboard side. Passenger side is ok.

Anything I can do aprt from change the pads and discs? Is it essential to change as a pair (L and R) or ok to change just the drivers side?

Cheers for help and thoughts

Matt

 

[Ian B Walker]

When changing brake pads always do them in pairs. Left and right side. Take the calliper off and press in the piston then bleed the brakes, not guaranteed to work but it might. Also free of the calliper on its retaining bracket if it is a single piston calliper, it may be binding.

 

[Mattyn]

Thamks Ian

Could you please point me in the right direction of a How To for freeing the caliper?

I have found this thread which seems awesome.

http://www.mbclub.co.uk/forums/wheels-tyres/55200-howto-front-disks-w208-poss-others.html

Mrs M gave me a tool kit at the weekend for an early Fathers day present - now I am not cynical but......!! Lol!

Thanks again - much appreciated

Matt

 

[bolide]

If you don't know your way around them I'd get an expert to work on brakes. I'm perfectly capable of replacing pads but someone who does it every day may spot something I miss - so I leave it to the experts

Nick Froome
the independent Mercedes Estate specialists

 

[Mattyn]

Hi All

Right then - picked up some discs and pads today - and set about the change tonight.

All went well - I used the HowTo mentioned earlier and all went well - the caliper was difficult to retract so had to refit to get leverage to push it right back in.

Now - when i went to fit the pads I found they were slightly too long and don't fit - they are only too long by about 3mm - but thats enough. Now I am no expert but can the caliper mounting be adjusted for this?

The geezer in the auto part shop did say when i picked them up I should have these pads as opposed to those as they were better and only 25p more - they are the same make as the pads too! Delphi LP1589 and the box does say Merc CLK. I wonder if they are for W209s!

So its back to the shop tomorrow and get them changed. I will take the old ones so I have no more disappointment!!

Any one else found this with the pads?

Matt

 

[Mattyn]

Ah an update!

Almost a successful morning - pads replaced at the shop, and fitted with no problems.

Cleaned and greased as per the how to. Pressed the pedal a few times before I drove it.

The brake pedal had a long and soft feel, though they seem effective albeit further down the pedal travel. Pumping makes the pedal feel stiffer so I am assuming air in the system.

I intend to do the two person brake bleed process later - with mrs M sat on the pedal, me bleeding each caliper as she presses the pedal.

This should work right, unless there is problems with the master cylinder?

Any thoughts? Thanks in advance

Matt

 

[Mattyn]

Hi all again

Right have bled the brakes at all 4 corners, did not seem to get much air out at all, so this is a slight concern. I bled them by the mrs being on the brake pedal, and applying pressure whilst I undid and closed the nipple. She was applying pressure all the time the nipple was open. In my eyes this should in principle work!

The pedal with the engine off is extremely firm, as it should be. With engine running, the brakes feel spongey - though a slight improvement from when i first finished the job.

Do you think it just needs more bleeding? Bear in mind I got very little air from any nipple. I did do them in the right order - furthest from the cylinder first. Have done the procedure twice, with engine off and then on.

Note - with the engine off there was a distinct slack of the pedal when I opened the nipple, as I would expect.

One other point i have noticed - there is a air woosh sound as i press the pedal - i have not checked with the BMW if thats the same but I am just wondering - this is with engine off!

My thinking is that the brakes need a run to bed in, but would like some advice before i travel to work tomorrow. After that if they are still spongey I will bleed again. I have not taken enough fluid to warrant replenishment (the level is between min and max). Is it because I simply need to man up on the bleeding and do loads more?

Thanks in advance

Matt