Hi

Since a while I have this strange problem - every morning when I start my car it stalls, on the second start I rev it up to 1500 rpm for about 40 seconds and after that it's better, at least it doesn't stop. When I get it running, I select reverse (it's an automatic) to get out of my garage and when I lift my foot off the brake it stalls again, and usually on the next start it's finally OK. But still the engine doesn't run smooth, vibrates harder, like it's going to stall again - the revs are quite unstable - they suddenly fall to 600 than go up to the usual 750. After the car warms up, usually above 40C engine temperature, everything is absolutely perfect, stable and smooth. I change the oil and filters every 10tkm, ispect it thoroughly even frequently. Recently the computer diagnostic showed only one error: the air intake sensor was not working, so I changed it immediately, ran the diagnostics again and it found no problems at all.

The other issue is with the brakes - it happened two times already, again in cold mornings - when I finally started my car, and reversed out of the garage, I pushed the brake pedal, but it was very hard and the car refused to stop at all. I was going very slow and I pulled the handbrake instantly because otherwise I would have crashed into a car parked on the street. It stopped, of course, and after that I pushed the pedal several times again, so it got a bit softer. I got out of the Merc to close the garage door and when I came back in the vechicle everything was back to normal, the pedal was soft and the brakes worked very good as usual. The disks and pads on all four wheels are perfectly fine, I inspected them already in a service. The only thing I can think of, is that the brake fluid is not changed since 150tkm or so. I shall repeat that up until now this happened only two times in cold weather in the morning.

I'm from Bulgaria and when I say cold mornings I mean that the air temperature outside is around 0C, I can't imagine what will happen in december and in january when it's proper winter: around -10C in the morning.

So please help if you got any ideas. Thanks in advance.

Update: I just found out something about the brakes - it seems that the vacuum pump is the problem, I'll check the gaskets and hoses first.

 

You have already enough indications that the brake oil should be replaced, besides being so old. It should be replaced at least each 50,000 Km.

I hope you have done something about it since april when you reported this.

 

Both problems seem like you have a vaccuum failure. Replacing the pump may fix both problems. Even so, I would take the previous poster's advice and flush the brake system with MB fluid.