Anyone here familiar with the engine vacuum pump on the w126 350SD (om603).

I bought a used one and I’m not sure how to test it before replacing it for the one that’s on my car at the moment. Seems like the bearing wheel is a little scuffed? Is this part still ok to use?

Two different pumps. One the bearings can get out of the races and do a lot of damage. The other they are designed so the bearings cannot get loose. Even if the bearing fails.

It is reasonably important to use the bearing retainer model.There are ways to identify them in the archives from each other.

NO! That pump is bad. Get a brand new pump from Pierburg (never use aftermarket here, only OEM or parts from the dealer).



Get this wrong, and it will cost you a thousand dollars or more to fix it, worst case scenario is you destroy your engine.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC