Mercedes-Benz Forum banner
1 - 2 of 2 Posts

·
Registered
1977 240D 4-speed
Joined
·
37 Posts
Discussion Starter · #1 ·
Guys,

I am at my wits end.
I just rebuilt my vacuum pump (except for the bearings). I am not unfamiliar with mechanical things, and I believe that it is back together properly (video on youtube helped). I got the kit from autohausaz.

OK, here's the problem, the pump seems to work great, it pulls a rock steady 21", without accessories, straight from the end of the hard vacuum hose, tee plugged.

(I did notice oil at the point where the hose screws into the booster)

Now, everything works great, I keep my locks off, but the shut off is instantaneous IF I am not pushing the brake pedal down- it will keep dieseling until I let the pedal up, then it will shudder to a stop.

More dangerously, after a few pumps, the pedal gets hard- doesn't matter whether just started rolling, or on the freeway- same thing every time.

I did the brake booster test, and my pedal does start to sink to the floor after 45 seconds or so.

SO- what could it be? Any ideas.

Could the new and improved, pulling 21", vacuum pump (the old one had a ripped diaphragm), somehow compromise the brake booster?


I did my brakes as well, my front calipers were sticking, and leaking, so I rebuilt them, got new brake hoses, pads

I had to put a new clutch master cylinder in, slave as well.

But in both of these procedures, I bled them well (clutch from below)

I don't think that these repairs (to the brakes) would make the pedal hard and cause the other vacuum problems.

Please help :surrender:
 

·
Premium Member
W-1-2-3 Go!
Joined
·
16,161 Posts
Did the shut off problem manifest before the rebuild?

All vacuum lines nice and tight? No leaks?

Double check with a Mity Vac.
 
1 - 2 of 2 Posts
Top