ABS clunking, noisy, felt in brake pedal, O.K.? w124
 

Well, I just got home from a 4 hour commute that normally take 1/2 an hour, because of the "blizzard" we got in New York today. My first exparience driving my 300e in the snow. I actually was suprised, it was not that bad. From this forum I had a preconception that it was horrible in snow, but it is much better than the 86 Regal I used to drive. Anyway the ABS brakes came on for the first time. I was suprised to hear loud clunking and feel vibration through the brake pedal when they engaged. Is this normal? They worked ok but all other ABS I've ever experienced were not noisy like this. I just didn't think that obnoxious clunking could be a normal sound.

That is perfectly normal. What you felt was the ABS system pulsing the fluid to one of the wheels to keep it from locking up.

Peter

Re: ABS clunking, noisy, felt in brake pedal, O.K.? w124
 

You're right. Feeling pulsation in the pedal is normal; loud clunking is definitely not normal. I don't know what it is but if it were me I'd have it checked out soon.

MB's ABS system is quite loud by comparison to other cars. have it checked out if you're concerned, but, it's more than likely, normal operation.

mine did exactly the same thing. I also had the ASR kick in for the first time. I just figured there was probably some ice stuck in there for a second or two. Braking was fine and the car felt 'solid' on the road compared to my wife's Dodge.

You will definitely notice the ABS on a 300E. I certainly did in Ft. Wayne last saturday AM while leaving, when I slid on some icey snow. Or didn't, actually, but the ABS action is both noisy and obvious at the pedal.

Probably very effective, and the pulsation is telling you to let up on the brakes.

Peter

"the pulsation is telling you to let up on the brakes"

It is counter-productive to modulate the brakes during ABS function. Locating the point of maximum traction is difficult due to the pulsing and you are likely to use less brake pedal pressure keepng the ABS from engaging than you would with a non-ABS car.

ABS gives longer braking distance than not sliding the tires in the first place. Vibration of the pedal is probably impossible to eliminate anyway, but I suspect Benz left more in so that you would KNOW you are sliding and the ABS is working.

Better to slow down and brake less than depend on the ABS, since all it does is prevent tire lockup, it doesn't decrease stopping distance any at all.

Peter

I agree. The idea is to provide some control over the car when someone panic brakes. In the 7 years that I have owned my 85 380SE, I think I have activated the ABS 3 times. Once was on purpose over ice to see how it would react.

Vibration through the pedal: normal

A pulsating noise from the ABS unit when ABS kicks in: normal

"Loud clunking" from ABS: not normal (in my book)

The clunk should get checked out. You could have some bad joints.

I agree, the ABS on my 300E doesn't produce a loud clunking.

When I lived in Minnesota I did a comparison test between our '84 190D w/o ABS and the 300E. I drove both down an ice covered road with an intersecting road.

Driving at a relatively slow speed and stepping on the brakes to make the turn off on the intersecting road simply locked up the wheels on the 190D and I skidded right past the turn.

With the 300E, I had complete control and was able to make the turn.

Note that Mercedes have a REAL ABS system which uses expensive, high speed solenoid's. For a while at least, American car manufacturer's had a cheap imitation that used cheap electric motors that did nothing but *pump* the brakes which (believe it or not) is not how ABS is supposed to work.

With ABS, the brake on the wheel(s) that is not turning is let up and then reapplied. In other words, it reacts to the conditions rather than simply imitating the old manual method of pumping the brakes.

Oh yeah? Well how would you like to be driving an '84 300SD out in the winter w/out ABS at all?:p

Had a real bad experience with this and smacked into a telephone pole once. There was damage, but fortunately none to the car. :p

I LOVE LOVE LOVE LOVE ABS!!! I don't know how I managed without it.