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230E/230TE/S320/260E/320d
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87 Posts
Discussion Starter · #1 ·
Evening all....[:D]

After driving my S320 pretty hard I found that the brakes were very soggy and when I slammed on them the car came to a stop but the peddle moved all the way to the bottom. I was supprised that the ABS never kicked in??I tried it again but really gave it some grief and then the ABS kicked in and may be abit of BAS. I know the car has had some new pads about 200 miles ago but I would have thought the pads would have bedded in?The brake peddle felt very soft and it didnt seem like it was going to stop in a hurry.....it cant be brake fade as they were not being used much?

Any help would be great cheers

Yohan [:)]
 

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86 560SEL
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1,334 Posts
Also check the pressure line from the master cylinder to the rear of the engine. If that ...

Also check the pressure line from the master cylinder to the rear of the engine. If that cracked or leaking, replace it. If it break off, no power brake and the result would be scary.
 

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W140 S class, E31 850Ci, XC90 Exec AWD geartronic
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444 Posts
Evening all....[:D]

After driving my S320 pretty hard I found that the brakes were very soggy and when I slammed on them the car came to a stop but the peddle moved all the way to the bottom. I was supprised that the ABS never kicked in??I tried it again but really gave it some grief and then the ABS kicked in and may be abit of BAS. I know the car has had some new pads about 200 miles ago but I would have thought the pads would have bedded in?The brake peddle felt very soft and it didnt seem like it was going to stop in a hurry.....it cant be brake fade as they were not being used much?

Any help would be great cheers

Yohan [:)]

This is a common problem on 140's. It happens when the pads have been allowed to wear very low. The pad wear warning light only comes on when the front pads wear out. The front pads are always the first to wear out. What usually happens is that the front pads are replaced and the rears neglected. Unfortunately there will be no warning when the rears are due to be replaced. The system then takes excessive brake fluid from the reservoir and the result is a momentary simulation of brake fuild leak and excessive brake pedal travel ( All the way to the floor!!!...damn scary!).

I have seen soo many W140's with grinding rear discs (rotors) and worn rear pads.

The only solution is to make sure front and rear pads and changed at the same time (as the fronts wear out first)

If you take it to a shop for diagnosis they will tell you that you need a new master and slave cylinder not understanding the nature of this problem on W140's. This may be the case so dont be so quick to discount their advice.

What I would do, is to check the rear pads - replace them if necessary. 9 times out of 10 this will solve the problem.
[^]
 

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230E/230TE/S320/260E/320d
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87 Posts
Discussion Starter · #6 ·
I have never thought about the pads at the rear, I know the front was change before I boug...

I have never thought about the pads at the rear, I know the front was change before I bought the car 3 weeks ago so I'm guessin gthe rear were not chnaged.

Thanx for the help mate,

Yohan
 

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2001 CLK320 Convertible
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285 Posts
Anyone else have had this problem and found a solution?

My brakes feel spongy and there is a little bit of grinfing noise/feel when I press them too hard. That does not really happen all the time, but I can feel it every time I am stuck in traffic and using my brakes alot.
 

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1993 300SEL (Sold) 2007 X5
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7,336 Posts
ProvingGrounds said:
Anyone else have had this problem and found a solution?

My brakes feel spongy and there is a little bit of grinfing noise/feel when I press them too hard. That does not really happen all the time, but I can feel it every time I am stuck in traffic and using my brakes alot.
Your pads might be low.
 

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W639 Vito 110 CDI; Ponton 220S; VW Phaeton V10 tdi; 1995 S500 ex diplomatic car (gone)
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580 Posts
Warped rotors will give kick back related to wheel speed and a longer pedal due to pad knock off. If the pads are low and near to the end of their life, you can get more noise and a coarse feel from them as well as increased tendency to fade and driving in the wet can cause the warning light to flicker as the water conducts current over the decreased distance. If the indicator pins have become in any way broken or disconnected, you will not get a warning light of course no matter what the wear. Look through the rim and eyeball the pad wear.

If the rotors are healthy and the pads worn, then how do you get greatly increased pedal travel and sponginess as the system takes up all clearances as a factor of the way they work? The function may deteriorate, but the travel will be about the same unless the pads are burnt and greater effort is then needed to work the brakes.

One way to confirm the master cylinder is to flush the system and bleed the cylinder as well. If the fluid dirties up soon after then that is a sign of failing seals...bad luck as a new one is £700 ish and they are not DIY repairable...if you can get the kits! The level may well not go down though, so from that point of view all seems well, the fluid gets 'round the seals and back into the reservior. The rear of the cylinder is well sealed around the push rod and so you will not see leakage as you would on "lesser" vehicles and no fluid to wreck the servo.

Mine is in need of replacement and finding a good used one is difficult. I have a good one of the wrong type ('99 S420) if anybody wants it I will post a picture for you to compare with yours.
 

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2001 CLK320 Convertible
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285 Posts
The thing is that the brakes work just fine unless I have to push them all the way down to stop at a traffic light or brake suddenly behind a car in heavy traffic. The grinding happens pretty much during the one second prior to stopping.

I generally have some squeaking noise from the brakes, but that was the case since I bought the car.
 
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