om616: crack in vacuum pump housing - PeachParts Mercedes-Benz Forum

schickm · #1 08-25-2015, 02:28 PM

So I think I found the source of my oil leak that happened yesterday in my w115 240D: crack in the vacuum pump housing. According to another thread, a break in the bell section is pretty common.

Any advice as to procuring a replacement. Bare minimum I just need the housing, should I just try and find a used one and swap my housing?

But the age of this vacuum pump in unknown, so perhaps a rebuild would be in order too?

leathermang · #2 08-25-2015, 02:48 PM

You could attempt to fix it... I don't know what kind of tools you have..... You could play with fixing yours while the replacement is in the mail....
There are things called Alumiweld and such..... read the instructions... many are zinc based and you have to try to do the final weld before oxidation forms in the place you prepped...
If you are equipped and want to give it a legit try.... a base plate to bolt it to would be in order....and place it in an oven before you weld or solder or braze it...... and after..... and let it cool slowly...

BillGrissom · #3 08-25-2015, 03:05 PM

Yours looks like a slightly different casting than those in my W123 300D's (I just replaced a vac pump last weekend). If yours has 6 bolts, they might interchange, though your early one probably has the 2 external tubes (so re-plumbing to use one). Rebuild kits for yours are much cheaper ($12 vs $120 for piston type), so better to stick with that.

I haven't read of the cases cracking in the vac pumps for my cars. In mine, the ball bearings failed, causing the roller to drag and make a clacking sound (~100 miles my son drove like that). The arm was almost worn thru, which might have soon put debris into the timing chain. I expect the balls just rolled past into the oil pan.

When you re-install, rotate the crank until the roller sits in a valley, so the pump housing is almost seated on the block w/ little spring force. Someone could have cracked the housing by torquing it down when the roller was on the high spot, and the crack only now presented itself.

dude99 · #4 08-25-2015, 03:11 PM

Have you opened it up to see if something internal may have caused the crack in the first place?

schickm · #5 08-25-2015, 03:45 PM

BillGrissom: I checked in the EPC and the diagram shows two different pumps for your 300D. One has a single external hose, and the other has two. I'm curious how there could be two different ones...a turbo/non-turbo thing?

I've got the two hose kind.

Dude99: I have yet to take it off and inspect. Actually in the middle of another piece of work on the car. But I'll report back as soon as I pull it off.

Any one got any idea what's going on with this 1 or two external hose thing? Also I see some on ebay that have their hoses at a 90 degree angle. Is that for older mercedes?

schickm · #6 08-26-2015, 04:24 PM

Well turns out there's waaaay more than just a crack. After pulling the pump off I found a whole chunk missing in the bottom of the housing. To make matters much much much worse, when I push and pull on the Injection Pump Timing Device (aka intermediate gear shaft I think), I've got about 1mm of play in it. From all the reading on the forum that leads me to believe that there's a worn bushing back in there...

The job is detailed in the FSM, but it seems pretty far out of my ability...any advice about that 1mm of play? Should I really be concerned about it? How much could I expect a shop to change to pull out that gear shaft and change that bushing?

For clarification, here's a nice breakdown Stretch has on that pesky little bushing

charmalu · #7 08-26-2015, 10:51 PM

The two hose type pump, discharges the air it pulls from the system into the Air Filter Housing.

The one hose type pump discharges the air it pulls from the system into the crank case,
then it comes up to the inside the Valve Cover and out the Blow by hole to the Air Filter Housing.

Charlie

sent from my pos computer