'78 240D Brake Booster Test/Question
 

Hi Folks,

I've got a really hard brake pedal on the 240D lately, and am trying to do some tests to verify it's the booster or not. One test I did was to disconnect the vacuum like to the booster, then draw a vacuum directly on the booster with my vacuum pump. I can get it to pump up and hold 15hg (before my hand gets tired), but when I put the slightest pressure on the pedal (like 1/4"), all the vacuum drains out very quickly.

Sometimes it takes a while for the engine to shutdown, but I think I found a correlation between that issue and touching the brake pedal. I recently replaced the MC and put the new gasket in...that was working great for about a month. The booster had a lot of fluid in it at the time I replaced the MC, and I sucked as much out of there as I could.

Sounds to me like the booster is done, but wanted an opinion from you guys before I bit that bullet.

If I do bite that bullet, any thoughts on reman vs. new? Seems like reman would be fine.

Thanks!

JC :confused:

It sounds to me like its done too. You had a master that leaked fluid in it, and that fluid did in the booster. Pretty much what you suspect.

Awesome. Thanks for the confirmation.

I just did the exact same thing on my '78 240d. Replaced both the MC and booster. I used a reman. Shoot, the MB part was over $600, which is almost half what I paid for the car.

BTW, if you post questions like this over on the diesel forum you'll get a lot more response.