Now it's the vacume pump, I think. - PeachParts Mercedes-Benz Forum

andy · #1 10-02-2002, 01:02 PM

Just replaced the 3-way valve on top of the valve cover. Wow. That was the problem. Car shifts better than ever! I was so happy, Until today. Now it seems my vacume pump has died. The car wouldn't turn off( i checked all of the lines) Brakes no longer had power assist, Hooked vacume gauge up to vacume line and gauge read only 5 psi. Could it be anything else? I already took the vacume pump off, the bearing in it seems to be perfect. I have a few options. Buy a new pump for hundreds! Rebuild the one I have if possible, get one off of a junk yard gem. I don't know how to rebuild one. Any special tools? Any help would be appreciated. Thanks , andy

leathermang · #2 10-02-2002, 01:33 PM

Did you do a search ?....

Try this: Vacuum Pump going south!?!?!?!?!?!

andy · #3 10-03-2002, 03:15 PM

Thanks, I found that post after doing a search. I took my pump apart and found a big hole in the diaphram. I ordered a rebuild kit. Seems easy enough to rebuild. andy

leathermang · #4 10-03-2002, 03:20 PM

Keep in mind that, as you are putting it back together, there is a proper position of the plunger in the pump to be when you attach your new diaphram... It should be in some manual ... or someone be able to describe how to recognize it...you turn the engine (by hand) to get it to the right place I believe..

jcd · #5 10-03-2002, 05:31 PM

Also note that to replace the diaphram, you do not need to remove the entire pump, just the top housing, the one has about 10 screws, flathead screwdriver, not phillips head, attaching it to the base housing of the pump.

I found that if I removed the fan and the fan shroud, then getting the front housing off was alot easier.

Also, when you replace the diaphram, make sure you align it by screwing the housing screws through the holes in the diaphram into their corresponding holes in the the base of the diaphram pump. This will allow you to keep the diaphram aligned as you tighten it up and prior to replacing the top housing.

Finally, use Loctite blue. You don't want to have any of the screws or the hex bolt come loose (like happened to me)

Greg.....maybe I was just lucky, but I did not have any issues with plunger position, but then I'm not sure how I would have recognized it. I just know that I was able to get my diaphram off and on with minimal difficulty.

Good luck and if you would like to discuss, just send me a private message with your number.

JCD