Hi everyone, new to this forum.
Car: Cls Grand edition 350 cdi
Year 2010
Engine om642
Milage 108000
This car is mystery!
Having issues on hard brake pedal in stop start traffic, if I release brake pedal while the engine is still on idle not revving or driving on idle not pressing accelerator. The second press on brakes is hard as rock no stopping force. But as soon as I accelerate brakes worked fine.
So I realised not enough vacuum produced for brake booster.
-First I checked vacuum pump very little vacuum produced( ordered new pump from main dealer) , fitted
Nothing same result.
-Second. Change new vacuum line to booster including check valve.
Nothing
-Third . Order new brake booster
Changed and Nothing
Now my other guesses changed:
Engine breather, new drive belt and tensioner, turbo seals oil cooler seals, full service etc.....
No help.
Then I brought my friends Eclass with same engine. His vacuum pump sucking very well. So I took it off put it on my car but guess no lack. His pump still doesn’t work properly on my car. Then I realised that his drive belt turns a lot faster on idle then mine. So I put my pump on his car and it works fine.
Ok now the revs on his car and on mine are the same on idle 600 rpm
Now the vacuum pump is turned by camshaft so is everything else by engine chain and alternator belt
Now why is my engine turning slowly on idle even everything else works fine and no screen faults. But not enough for pump to produce vacuum.
The only difference on my engine and my friends is I have factory fitted brabus chip when w219 was ending yr 2010 and he doesn’t.
Does anyone have any idea where to look next???
Please help
MUCH APPRECIATED GUYS
THANK YOU!!!
Car: Cls Grand edition 350 cdi
Year 2010
Engine om642
Milage 108000
This car is mystery!
Having issues on hard brake pedal in stop start traffic, if I release brake pedal while the engine is still on idle not revving or driving on idle not pressing accelerator. The second press on brakes is hard as rock no stopping force. But as soon as I accelerate brakes worked fine.
So I realised not enough vacuum produced for brake booster.
-First I checked vacuum pump very little vacuum produced( ordered new pump from main dealer) , fitted
Nothing same result.
-Second. Change new vacuum line to booster including check valve.
Nothing
-Third . Order new brake booster
Changed and Nothing
Now my other guesses changed:
Engine breather, new drive belt and tensioner, turbo seals oil cooler seals, full service etc.....
No help.
Then I brought my friends Eclass with same engine. His vacuum pump sucking very well. So I took it off put it on my car but guess no lack. His pump still doesn’t work properly on my car. Then I realised that his drive belt turns a lot faster on idle then mine. So I put my pump on his car and it works fine.
Ok now the revs on his car and on mine are the same on idle 600 rpm
Now the vacuum pump is turned by camshaft so is everything else by engine chain and alternator belt
Now why is my engine turning slowly on idle even everything else works fine and no screen faults. But not enough for pump to produce vacuum.
The only difference on my engine and my friends is I have factory fitted brabus chip when w219 was ending yr 2010 and he doesn’t.
Does anyone have any idea where to look next???
Please help
MUCH APPRECIATED GUYS
THANK YOU!!!