1995 E420 (W124) Brake Pedal
 

Hey everyone,

It always seems that the smallest things (annoyances) result in the biggest pain in the @ss to repair. My brake pedal is making a squeeking noise and has become increasingly louder over the past month. The brake functions just fine without anything out of the ordinary. It just makes a nice creaking noise when it's almost completely depressed. Having tried silicon and white lithium on it, I've come to consider the two following potential problems:

1) Gasket on the brake booster in front of the master cylinder (please no :()

2) Pedal itself just a little creaky on the pivot points

Is a gasket failure common on the 124s? Any advice on the issue would be most appreciated.

Thanks in advance!!

by the time squeaks start to be annoying, somethings is pretty dry ~~~ i'd use the white lithium spray and soak the pivot points while working the pedal

Sounds like someone uptight is passing gas, does it?
Believe it or not, several of us hear this noise when the radio is off. I've been hearing it ever since I bought it ...almost 100k miles ago.

Finally took the knee bolster out...
 

Well, after closer inspection tonight about that brake pedal noise I've come up with the following conclusion. Noise is definitely a rubber squeeking which leads me to believe that it's a rubber component/seal of some sort. Using a stethoscope I isolated the noise to the connection from the brake booster to the master cylinder which leads to one of two scenarios (I think). Brake fluid leaking from the master cylinder causing the seals to expand in the brake booster which in turn will cause the squeeking. Or the leak is simply in the brake booster itself. My guess is that it's brake booster. Either way, the parts and "Pain in the arse" factor are both pretty darn high for the job. Imagine what a little squeeking could be the cause for :mad:..

Anyway, just wondering what some others think about that analysis.

Keep me posted...

are you losing any brake fluid? normally when a master cylinder leaks internally, the pedal gets soft ~~~

tried the stethoscope under the hood on the brake booster itself? there's a large spring inside the booster but unless it breaks there's nothing it can rub against

you can disconnect the pedal from the booster rod and then try the pedal

Listen to This!!!
 

http://proudfoot-design.com/mercedes/annoying_squeeking.MOV

Here is a link to the sound my brake pedal is making. It kicks in after a couple of seconds. Let me know if this doesn't sound like the most annoying thing in the world! :mad:

I'm planning on swapping out the brake booster from Potomac but, because I'm kind of shooting in the dark, I wanted to throw this to the wind and see if anyone had any ideas as to what else could cause the squeeking before ordering the part.

Exact same noise I've been hearing for the past 100,000 miles. So far, the car still stops on a dime.
Maybe you can pretend it's an ex-girlfriend/wife talking, and just ignore her?

Problem fixed...
 

I wanted to post a quick update on the solution to the squeeky brake pedal in my e420. The replacement of the booster ended up resolving the issue.
(found a used one for $100 shipped)

The source of the problem (just a guess) was a blown gasket inside the booster causing the rubber components to swell following their exposure to excessive brake fluid from the master cylinder, in turn causing the most annoying squeeking sound in the world.

Removal and install of the booster was about as snug as it gets but it is doable with the removal of the master cylinder and loosening up of the fuse box. Total time for the job was approx. 2 hours.

I have the exact same sound. Been there for a couple of years. It drives me nuts.

I know the feeling...it sounds like something so minor but when you're stuck in stop and go traffic, every other positive aspect of the car seems to just fly out the window. It's definitely worth fixing and is fairly inexpensive. (fyi, I got my used booster from usedmercedesparts.com. (spoke with Pete) As I recall they have a 90 day warranty as well :).