Vacuum pump question

[jb mills]

I bit the bullett and am pulling out my engine to overhaul. In the process I pulled the vacuum pump and cleaned it up and will revalve. (single piston type ) I found a very small and light weight spring less than 1/4 inch in length a small 3 pointed flat washer and a piece of plastic about 1/2 inch long. kinda looked like a needle valve. I really don't think this came from the V.P at all. Could it have been sucked into the pumr from the valve near the brake booster??

[h2odiesel]

Sounds like parts of one of the check valves in the pump.

I think h20diesel is right.

While you're rebuilding the pump make SURE that the roller is tight and rolls smooth. If it gives up it can fall into the engine and destroy it.

Good luck,

[Ken300D]

I had the same darned thing happen to my '82 300D vacuum pump. In my case the little plastic part managed to get itself placed just right against one of the vacuum pump valves so that it killed the system vacuum. (No brakes )

I asked here and people seemed to feel it was parts from a "rather ineffective check valve" located somewhere in the vacuum line near the pump.

In my case, I simply discarded the parts with no ill effect.

Ken300D

[jb mills]

Ken
I agree. The three check valves in the vac pump are all identical, and intact. I am almost positive they washed out from behind the single valve. That is the one that goes to the brake booster. Ken did you ever tract the line and pull apart the check valve??

[Ken300D]

The large diameter vacuum line from the pump to the brake booster (with a combination check valve/splitter in the middle) seems rather brittle. I bet it would break if I tried to mess with it. That check valve in the middle seems to be OK because the brake boost remains after the engine is turned off.

I was told the parts came from a check valve right at the vacuum outlet of the pump. This is in addition to the three small round disk valves that you gain access to when you remove the cover of the pump. The "extra parts" came out from behind the one valve at the top which I will call the vacuum "outlet" (it supplies vacuum to the car systems). I removed the extra parts, cleaned the three disk valves and it works great now.

Looking at the extra parts, a light spring and a hard plastic piece, I can't see how it would be all that effective anyway.

Ken300D

[jb mills]

yes, I took another look and pulled off the fitting that the vacuum line ( going to the brake booster) would attach to. This is the fitting that is screwed onto the pump, the parts came from that it is an additional check valve.very flimsy. I am not really sure how the three pronged washer stays in place, but I understand where all 3 parts go. This may have been a redundant valve or meant to keep oil out of the line in case of failure of the pump or other valve. Seems rather cheap. I will leave it out also, as I am sure even a new one will wind up in the wrong place eventually.