lseguy

JoeJErnst

My best guess would be the master cylinder. It may be on its way out, but still *kinda* working. I can't think of anything else that would give those symptoms except air or water in the brake lines.

lseguy

thanks. Had a mechanic friend check it out (briefly), and his opinion was that the brakes were "fine". He started the car, pumped the brakes a few times, held firm, noted that there was zero sinking. Asked me how the brakes were working, I told him fine. No pulling/grabbing, but just not a really firm pedal like in my 2006 E55. He Asked me if my concern was the somewhat long pedal travel. Told him yes, and the lack of firmness, both of which are present in my E55. He said in his opinion, difference is the EBC system in the E55 thats somewhat skewing my opinion of the CLK55 brakes. So for now, will leave alone.

JoeJErnst

Interesting. I am in the same situation. The brakes on my 2002 CLK55 are mushy compared to my E55 (which are still mushy compared to my old C230, but that's another story). I was hoping that a fluid flush and bleed would help, but now I'm not so sure. I'll do it anyway when I put on new pads and see if it helps.

lseguy

yeah, its like night and day. My wife has a 2011 RX350 (totally different manufacturer, I get it) but even compared to that, my CLK's brakes are mushy. Only other thing that was suggested is a flush that includes activation of the ABS system (My autel Mk808 doesnt offer that function for the CLK, but I think it does for the E55) to ensure zero bubbles in the ABS unit. (altho I've read thats highly unlikely, unless you've allowed the system to go completely dry and/or you've just replaced the ABS unit).
Oh, i also found another thread that claims this can also be caused by having the caliper pistons pushed too far back into the caliper during a pad change, and a suggestion (that seemed to work for several posters) was to use some sort of shim (like an old used brake pad thats worn down to almost the backing) to use as a temp brake pad, install pad/caliper, get into car, depress brake to allow the piston to come out quite far (but not pop completely out), then remove those temp pads/backings, very carefully push the piston back into the caliper JUST enough to allow your actual brake pads to fit, then rebleed one last time.
For me/for now, I plan to live with it. I have a friend with a shop so in a few weeks I may rebleed using his computer to activate the ABS during the bleed

The Fantom

I recently bought a 2002 CLK55 AMG and have to add a +1 as I have exactly the same symptoms; long/soft pedal travel before the brakes grab. I'm coming from a long line of various BMWs so I'm used to a firm and responsive brake feel. The previous owner of my CLK just had the brakes professionally serviced before I bought the car so I was very surprised at the poor feel of the brakes. I am still planning on doing a brake bleed with a Motiv pressure bleeder to see if that sorts the problem but it's interesting to see quite a few people with exactly the same issue. I'll report back after the brake bleed.

CLK55_NYC

same mushy brakes here.. 02 clk55 70k miles. My wife wont even drive the car, which is fine with me

GatorMB

Normal provided you are not adding fluid on a weekly basis.
big brakes are not always rock hard like a normal passanger car. As the rorors caliper and pads wear extra effort is required.
Quick brake check when entering the traffic signal will help.
Cheers Gator
forgot to mention loose wheel bearings will attribute to this phenomena.

quik55

tannat

I found dry rot in the brake lines of my 2001 CLK55-you might consider brake line replacement.

quik55

Brake lines seem in pretty good condition. All new brake lines I feel like is something I definitely not want to do. I have the resovoir filled right below where max is printed and not directly at the arrow above max. Could that little difference in fluid in the resovoir make a difference in braking?

lseguy

tannat

I wonder if Prestone dot 4 is up to OEM standards

lseguy

per the local Benz dealer, it's "fine", and when pressed, master tech said it meets the specs set forth by Benz for brake fluid. He said brakes are normal on my car. (followed up after this thread). Said I cant compare the SBC brakes on my e55 with these brakes.

GatorMB

If anyone experiments to get a full time hard petal.

some master cylinders and clutch cylinders have a pushrod adjustment that corrects clearances in hydraulic travel.

I urge those that do not understand hydraulics and braking systems do not attempt.
Behind the master cylinder is the vacuume booster which has a push rod. Since we are all feeling this problem an adjustment might correct it.
Lengthen the pushrod in 1/4 increments until the pedal is medium.. The hydraulic system must recover for some time engine running to test each adjustment.
Too much adjustment will end up in cooked brakes and fire red rotors in normal driving. Caution is advised when working on brake booster push rod travel.
Theory only as I have never removed the master cylinder to inspect.

Gator

quik55

Chadzu

My take on this. The early AMG cars used ATE big 2 piston sliding calipers. The later AMG cars use fixed 4,6,8 piston Brembo calipers. A sliding caliper is usually going to have more slop in it.
If you want better brake pedal feel a swap to '05 clk55 brakes and steel braided lines will get you headed in the right direction.

quik55

GatorMB

When installing new wheel bearings in the front an initial preload torque must be achieved to seat the bearing. followed by loosening the adjustment nut a bit.
Pack the bearing and hub with grease thoroughly.
2 more cents,
Cheers