Can the vacum pump on my 83 300D-T go out a little at a time? It seems to be making vacum intermitantly, I pulled the line off at the brake booster put my thumb over it, had fair vacum, raised the RPM to about 2 grand the vacum went away. I then disconected the plastic line at the vacum pump had great vacum, reconnected at pump rechecked at brake booster had great vacum that time, raised RPM again everthing OK now.
Should I look into rebuilding the vacum pump? If so does the partshop stock what I need?

------------------
Keith Schuster
99 Harley Davidson Ultra Classic
97 Dodge Ram
83 300D
auto\hydraulic mechanic 20 yrs

Follow that vacuum line to the pump and you will see an adapter that connects the line to the pump. That is a check valve. They will come apart internally and cause this. You can replace the valve(after removal and taking out the parts that fell in with a magnet).

------------------
Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I rebuilt my pump, it isn't too difficult, just a bunch of stuff in the way...thats what takes the longest. I got my parts kit from the dealer back then, paid through the nose...Partsshop ought to have it for nearly half that amount.
My pump symptoms were a bit different though, I could not get vacuum at idle, only when driving after 30-45 secs or so did I have enough vac. to brake once or twice.
Have fun! -Larry

------------------
03/83 300D 184k
07/73 280 160k
-88 other 157k

Thanks for the input guy's. I'll check the check valve.



------------------
Keith Schuster
99 Harley Davidson Ultra Classic
97 Dodge Ram
83 300D
auto\hydraulic mechanic 20 yrs

OK I checked the check valve sure as Benzmac said the valve had come apart. My question now is haow important is this valve? It seems to make better vacum than ever!! I plan to replace it , but how big a hurry should I be in? or should I not drive it? thanks again for the input.

------------------
Keith Schuster
99 Harley Davidson Ultra Classic
97 Dodge Ram
83 300D
auto\hydraulic mechanic 20 yrs

My '82 has run 15 yrs and >120k w/o it !