No brakes or vacuum locks on my Mercedes 240d 1975?

Question

have a 240d 1975 4 door. Had vacuum pump seal replaced, car, 1 week after, car brakes are rock hard, no brake assistance from vacuum. no door locks, car poors out black smoke with eratic idle when at operating temp. Has my vacuum pump gone?

Answer 1

I'm afraid this is very bad news. You have no vacuum. The reason could (hopefully) be a bad hose or brake booster. But more than likely, it's the pump. If the pump diaphragm has ruptured, it may have allowed oil to migrate out into your vacuum system. If this is the case, things won't be right even if you replace the pump.

Find the main vacuum line. This should be a large black plastic hose which runs from the booster to the front of the motor. It terminates at the vacuum pump. Disconnect it and see if there is vacuum at the pump. If there is, then it's a leak somewhere. If there is no vacuum at the pump, replace the pump. If there is a mess of oil, you may have to consider retiring the car.

Answer 2

If it runs alright when you press on the gas pedal but not at idle you probably have a vacuum leak. Check to see that hoses are all attached even the one going to the brake booster. Also there is a check valve in the booster, this is where the hose hooks on at the booster and sometimes they go bad and sometimes the grommet(the rubber piece that holds the check valve) might be bad. These are all easy to check and replace. If it is the grommet they are easier to work with when they are warm. Why I say this is I live in the north and when its cold rubber grommets are very hard to get in place. If its cold just hold it in your hand awhile till it warmer and easier to bend and twist. It could be a bad vacuum pump seal or something else but I would check for vacuum leaks first

Answer 3

Probably the pump, yes. You might want to check the main booster hose that runs from the pump back to the vacuum booster, to make sure they installed it tightly and hasn't broken or split. Could also be a bad booster.