W203 2003, Spongy brake pedal again...

[bitonw]

OK, On Oct 9th 2006 I got a new Master Cylinder installed under warranty. This after complains of a sinking brake pedal see here: http://forums.mercedesclub.org.uk/showthread.php?t=20725

It was fine for the next 2 weeks but it's back on Yesterday! I could pump the brake pedal 3 times till I got a firm pedal... Today it was fine again...
The only thing what I could see is that for the last 2 weeks I got 5.6 L / 100KM. Since Monday I got the normal 5.1 L / 100KM (average). I drive every day the same route, same road, use the same diesel. I'm not heavy on the brakes hardly use them, use engine to brake most of the times.

Any ideas?

 

[television]

Aiir in system, or the new master cylinder is faulty, there is nothing else.unless we are about to learn something new.

Malcolm

 

[bitonw]

Thanks Malcolm,

Had contact with the MB garage and will visit them to check it out.

 

[bitonw]

Will get another new master cylinder including the black box behind it.

 

[bitonw]

New master cylinder and black box are installed.

After about 1 week I have the same problem...

 

[IAN MAC]

I had a similar problem some time ago, pedal would go to the floor, if left for a while it would be ok.
Master cylinder and servo were changed to no avail, although the seals were all gummed up in the old one.
Started the usual route of bleeding all the calipers again, all seemed ok, just one of the rear calipers didn't bleed quite as well as the others. Disconected the pipe from caliper....same, went further back to the next join and did the same. Now, when the pedal pressed the problem came into view, a little lump of something solidified ( probably the same stuff that had gummed up the seals ).
This was just big enough not to come through the join in the pipe, and obviously had enough room to drift back in the pipe when not under pressure. anyway, broke it up, bled the corner and never had the problem since.

 

[Chris_J]

Apologies for reviving such an old thread, but I'm having pretty much the same problem on a 54 plate W203 220 CDI Coupe.

I took my car to Lanes as the brake pedal was sinking, so they changed the dics and pads. However, the brakes still don't feel right, and the pedal depresses about half way before the pads even touch the dics. The other day I had to slam the brakes on, the Brake Assyst didn't kick in and the pedal lost all feel, and eventually felt (firmish) again after being pumped 3 or 4 times. In general they are pretty spongy.

Did you get this sorted, and if so, what was it?

 

[television]

OK Chris_J

Your brake master cylinder is whats known as a tandem type,it a safe type of braking system, so if the rear brakes have a leak,or fail, your front brakes will still work with a little extra pedal travel, the same goes for the other way round.

If you are having to pump the pedal to get it back to a reasonable position, and when you try again a few mins later its back to where it was, the master cylinder will have to be replaced.

With a leak of fluid,you would see it on the ground and on the insides of any of the tyres,plus the tank would have emptied itself.

With no leaking brake fluid,the only other thing is the master cylinder.

Any garage could change this part, as there is nothing special about it.

Malcolm

 

[Chris_J]

No fluid leak, as it is at the same level. Now you mention the rears, it does feel like they aren't coming on, and the car "travels" forward or kind of nose dives a bit too much and then the suspension bounces back up.

I know that probably doesn't make too much sense. On cars I've had in the past, if I pumped up the brake pedal with the engine switched off, the pedal went solid. This doesn't happen on this car, and obviously when the engine is back on, it's back to pads only touching when the pedal is pressed half way, and I'm at 2/3 to 3/4 down before the car is pulling up.

Thank you for your advice, television. You seem to be a very knowledgeable geezer

 

[bitonw]

Well I'm on my 3th Master Cylinder!!! And still have the same problem...

But this is not all. About 1 month ago suddenly the steering went stiff and the tracking was funny. I was under way from Weston Super Mare back to Birmingham via a friend who's living in Radstock. So I popped in Mercedes Benz of Bath to have a quick check. The Service Manager confirmed the stiff steering but couldn't find the problem (nothing broken) and told me to go to my garage to sort this out. He needed more time to analyse the problem and I was just passing by. My garage exchanged the steering rack...

So since I got this car from June 2006 I have:

All under warranty:
new screen washer valve,
new Radio Audio 10 CD
3 times new Master Cylinder,
1 new servo box,
new sub woofer,
some plastic bolts or nuts on the back bumper (they just fall off),
new front brake discs plus all new brake pads,
new MAF sensor,
new wheel bolds (rusty),
head lights readjusted adjusted,
new screen wiper mechanics,
new steering rack.


did my self:
4 new glow plugs,
new bulb in ashtray.
all new bulbs for back lights and licence plate lights.

So I'm very impressed with the quality of this Mercedes Benz C Class vehicle and I'm waiting for the next problem.

Will be looking around to buy something else before the warranty expires this June and it wound be a Mercedes Benz again. I think that they lost it. bear in mind I drove many Mercedes Benz vehicles in the past including lorries! But enough is enough, I'm fed up and tired of it.

Have fun with your C Classes (W203).

bt

 

[Chris_J]

I feel exactly the same. I can't believe how bad the camber sensitivity is, and I also feel a vibration coming through the car, for which no problem can be found, ok it could be tyres but we'll see. My steering is also too light, and a bit floaty but ever so slightly. It's like I turn it and the wheels take a slit second to catch up, but again no problem with the car.

Mercedes training includes the use of "we couldn't fault it" word for word.

 

[bitonw]

Today I took the Toyota Rav4 (5 doors 2001 Petrol Auto) of my missus to go to my work.

So I drove exactly the same road and guess what… I’m thinking to buy an Rav4 my self. The only thing I miss is the cruise control. Okay, I have a bit more noise from the tires but the vehicle drives better, the driving position is better, the steering is better, the tracking is better, etc etc.

So what the heck I having this expensive vehicle? Only to have a star on the bonnet?

The only thing what is better is the MPG of the Mercedes Benz… But the service is more than 50% cheaper on the Rav4…

 

[television]

No fluid leak, as it is at the same level. Now you mention the rears, it does feel like they aren't coming on, and the car "travels" forward or kind of nose dives a bit too much and then the suspension bounces back up.

I know that probably doesn't make too much sense. On cars I've had in the past, if I pumped up the brake pedal with the engine switched off, the pedal went solid. This doesn't happen on this car, and obviously when the engine is back on, it's back to pads only touching when the pedal is pressed half way, and I'm at 2/3 to 3/4 down before the car is pulling up.

Thank you for your advice, television. You seem to be a very knowledgeable geezer

If the new master cylinder is primed befor installing no damage can accure to the the rubber seals, it is the same principle as when you fit a new oil filter,always lubrcate the rubber rings, and the same goes for the master cylinder.
Air in the system can quickly be dispelled by usy power bleeding, on some cars you must use power bleeding owing to the nature of the constrution of the ABS pump. It cant be a leak thats letting air in as the preasure when braking is far greater than the air preasure.
Other than the above there is nothing else to it.

Malcolm

 

[Chris_J]

I dont know if I'm being paranoid, but I think I also have play in the steering. I can turn the wheel left or right and the car doesn't turn as it should when cruising. I turn it a little more and it goes, so I'm having to over steer it.

Could that be a fault with the car, or is it just flimsy steering on these?

 

[bitonw]

And the next problem are knocking on the door...

- Rough idle when cold temp lower then 6 deg. Booked in for 28 March.
- left tail light. (couple months i replaced then all)

 

[bitonw]

All problems sorted. Bought my self a Toyota today...

 

[television]

All problems sorted. Bought my self a Toyota today...

I for one will miss talking to you, a sad day

 

[Blobcat]

All problems sorted. Bought my self a Toyota today...

Hope it wasn't foretelling anything but I noticed a broken down 55 reg Toyota the other day on the A483.

 

[bitonw]

I for one will miss talking to you, a sad day

thank you for those nice words! don't worry i will stick around by times.

it was just to much and the list of problems was growing and growing. als i'm getting older and my back isn't the best one so the high sit position is better for me. also it's easier to get in and out the vehicle.

i'm dissapointed about these days mercs but i should have listen to my 2 brothers. the one in london told me that i was mad to buy a 'new' (w203) merc. he got 2 old ones him self and loves them. one he bought in the usa as restoring project!

bt