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Discussion Starter #1
Hello everyone,
i have E200 1999
On a cold start, when I'm going to use my brakes, they don't work very good.
Basically what happens is that when I put my foot on the brake pedal, it seems like it's lost the "soft" touch to it. And the car barely stops when I hold it all the way in. Usually it's hard to push it all the way down, but when it's cold it's wayyy too easy.
The scary thing is that the car barely stops, so sometimes I need to use the park brake if it suddenly happens.

But! The brakes come back to life after revving the engine a bit, and pumping the brake pedal slightly. Then they work like nothing have happened..

Please if anyone can help me to solve this problem
 

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w163 02 ML500 W210 97 E50Amg w202 99 C230K w124 - need more space, time to build again
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Hello everyone,
i have E200 1999
On a cold start, when I'm going to use my brakes, they don't work very good.
Basically what happens is that when I put my foot on the brake pedal, it seems like it's lost the "soft" touch to it. And the car barely stops when I hold it all the way in. Usually it's hard to push it all the way down, but when it's cold it's wayyy too easy.
The scary thing is that the car barely stops, so sometimes I need to use the park brake if it suddenly happens.

But! The brakes come back to life after revving the engine a bit, and pumping the brake pedal slightly. Then they work like nothing have happened..

Please if anyone can help me to solve this problem
Since you posted this on the w202 forum, did you attempt to check / investigate any of the suggestions posted in that thread?

 

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Discussion Starter #3
I tried to contact the guy to find if he solved the problem but he didnt answer, his post is very old!
 

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w163 02 ML500 W210 97 E50Amg w202 99 C230K w124 - need more space, time to build again
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I tried to contact the guy to find if he solved the problem but he didnt answer, his post is very old!
Mahmoud Amawi, :)


That's was not my question.
And you are correct, it is an old thread.....SO...
Waiting for a response from a member that last visited this website in 2014, doesnt really help you.
This is a DIY forum where members can request help and assistance, and where members can look for solutions to their problems from past similar/ identical problems from those that have gone thru them.

Did you look into and apply the suggested options that were posted in that thread?
IF not, then I would suggest you look into them yourself
Your issue could be a variety of issues such as - vacuum leak somewhere (vacuum distribution priorities), brake fluid.....

1) doing a search of "soft brakes" for a w210 (you may find similar issues on other chassis styles.)
2) scan for any saved error codes (no CEL doesn not mean you dont have any saved error codes)
3) get your hands dirty by getting 'under the hood' to check the simpler things first, or find a good honest indie that knows and works on MBs
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Which engine do you have? You probably have a vacuum leak at the brake booster, or bad vacuum pump, depending if car has one, or bad brake booster.
 

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Discussion Starter #6
Mahmoud Amawi, :)


That's was not my question.
And you are correct, it is an old thread.....SO...
Waiting for a response from a member that last visited this website in 2014, doesnt really help you.
This is a DIY forum where members can request help and assistance, and where members can look for solutions to their problems from past similar/ identical problems from those that have gone thru them.

Did you look into and apply the suggested options that were posted in that thread?
IF not, then I would suggest you look into them yourself
Your issue could be a variety of issues such as - vacuum leak somewhere (vacuum distribution priorities), brake fluid.....

1) doing a search of "soft brakes" for a w210 (you may find similar issues on other chassis styles.)
2) scan for any saved error codes (no CEL doesn not mean you dont have any saved error codes)
3) get your hands dirty by getting 'under the hood' to check the simpler things first, or find a good honest indie that knows and works on MBs
I checked the vacuum leak i even changes the brake booster but nothing changed, no error codes!
I’ll search of soft brakes, thank you a lot :)
 

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Discussion Starter #7
Which engine do you have? You probably have a vacuum leak at the brake booster, or bad vacuum pump, depending if car has one, or bad brake booster.
[/QUOTE
Which engine do you have? You probably have a vacuum leak at the brake booster, or bad vacuum pump, depending if car has one, or bad brake booster.
I have the original 2.0 engine
We checked if there is a vacuum leak, we even changed the brake booster, nothing changed,
I dont know if there is a vaccum pump in this engine ,but if i do have problems with the vacuum i’ll have problems like starting the engine and it will not be stable which i dont have!
 

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1999 E430; 2005 ML500
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Assuming you have no ABS error codes, you have symptoms that could be the master cylinder or brake booster (or both). The pedal to the floor with no braking effect sounds like the master cylinder, and given the age of the car and the relative cheapness of the part, I would just replace it first. The hard part on that is bleeding the brakes, which goes best if you bench-bleed the master cylinder first.
 

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Discussion Starter #9
Assuming you have no ABS error codes, you have symptoms that could be the master cylinder or brake booster (or both). The pedal to the floor with no braking effect sounds like the master cylinder, and given the age of the car and the relative cheapness of the part, I would just replace it first. The hard part on that is bleeding the brakes, which goes best if you bench-bleed the master cylinder first.
I changed it with the brake booster and nothing changed!
this is really irritating!
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Did you follow the brake booster hoses? There is a check valve, and if that valve is bad it will cause those symptoms.
 

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You have engine who never made it to America, where most of the members here are from America.
Meaning we don't know your engine and can offer only generic help.
Gasoline engines use intake manifold vacuum for brake booster. The system has several tubings, vacuum tank usually hidden in fender and then big pipe going to brake booster.
Diesels use mechanical vacuum pump.
Sounds like your vacuum is not building fast, what to some degree can be normal, but hooking up a gauge would help A LOT in troubleshooting.
 

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1998 E320s sedan and wagon
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Sounds like you lose brake booster vacuum more quickly than normal with the engine off. Most cars still have a soft press or two after sitting overnight.

Is the pedal hard immediately after you shutoff the engine or dies it give you minutes? Hours?

I’ve read about this and suspect BAS is doing something after engine shutoff that uses up vacuum, so to speak. Yet no codes.

I don’t see what car you have but if it’s a Diesel look into a fresh check valve at the vacuum pump if it’s separate from one along the booster supply line and possibly a fresh vacuum pump. It’s one thing that you lose vacuum, another that it hasn’t built within a couple of seconds with the engine running. You might run out of assist with prolonged or rapidly repeated braking.

Sixto
98 E320 wagon 197K miles
 

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1998 E320 base sedan @ 160kmiles
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Am I misunderstanding what the problem is ?

First the car has an M111.942 , 4-cylinder engine. No diesel, and M111 engines are used in other models in the USA.

He claims (as I understood), the brake pedal sinks with reduced brake power when the engine is cold. Engine vacuum provides and maintains the vacuum booster, and the check valve ensures that the vacuum booster has vacuum with the engine is off (if it works). If check valve is bad (no one-way flow action), the vacuum booster will have no vacuum prior to engine start, so there would not be any pedal depression assist (hard pedal). If the braking is weak and the pedal sinks, it is more likely a master cylinder / hydraulic issue. Maybe air in the system. The poster needs to clarify what else has been changed, and who made the changes (himself / shop). Also a scan of the traction module is needed. Engine scan will not be enough.
 

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2000 E430 4Matic 142,000 miles
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Am I misunderstanding what the problem is ?

First the car has an M111.942 , 4-cylinder engine. No diesel, and M111 engines are used in other models in the USA.

He claims (as I understood), the brake pedal sinks with reduced brake power when the engine is cold. Engine vacuum provides and maintains the vacuum booster, and the check valve ensures that the vacuum booster has vacuum with the engine is off (if it works). If check valve is bad (no one-way flow action), the vacuum booster will have no vacuum prior to engine start, so there would not be any pedal depression assist (hard pedal). If the braking is weak and the pedal sinks, it is more likely a master cylinder / hydraulic issue. Maybe air in the system. The poster needs to clarify what else has been changed, and who made the changes (himself / shop). Also a scan of the traction module is needed. Engine scan will not be enough.
Hello everyone,
i have E200 1999
On a cold start, when I'm going to use my brakes, they don't work very good.
Basically what happens is that when I put my foot on the brake pedal, it seems like it's lost the "soft" touch to it. And the car barely stops when I hold it all the way in. Usually it's hard to push it all the way down, but when it's cold it's wayyy too easy.
The scary thing is that the car barely stops, so sometimes I need to use the park brake if it suddenly happens.

But! The brakes come back to life after revving the engine a bit, and pumping the brake pedal slightly. Then they work like nothing have happened..

Please if anyone can help me to solve this problem
What method did you use to bleed brakes? Sounds like air in system.
 

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1998 E320s sedan and wagon
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991 Posts
Hmm... I read the symptom as lack of assist and effectiveness, not long pedal travel with no braking (fade). Could be both.

Sixto
98 E320 wagon 197K miles
 

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1998 W210 E320 base saloon USA version
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What about this scenario:

The soft brake lines at one or more wheels have aged and are no longer rigid internally. This causes the callipers to drag and failure to release fully.

If I’m correct eventually the hoses will be so soft internally that a callipers will seize.

Just a thought. I believe the symptoms fit.

OP: lift each end off the ground and SAFELY check for a dragging calliper.
 

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1996 SL500, 2000 E430
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This thread is so old either you fixed it or it isn't that bad - but I was wondering what kind of brake pads you use?
 

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1998 W210 E320 base saloon USA version
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The more I think of it the more the idea makes sense — the brake is pressed just before turning off the motor; a calliper sticks; overnight this condition would explain how the pedal is soft in the morning.

External visual inspections of the callipers and the rubber lines would not raise any suspicions, and all the hydraulics would appear normal.
 
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