Sudden Failure Of Vacuum Pump?

My 1965 CJ5 has the dual action fuel pump/vacuum pump. When I got the Jeep the diaphragm was ruptured for the vacuum pump portion causing oil to be sucked into the PCV system.

I bought a new dual action pump unit and it solved all my problems! But after about a month, the vacuum pump portion of the new dual action pump has suddenly quit working. I'd assume a bad diaphragm but two things: first, it seems weird a new part would fail after only a month and second, I am not getting any oil into the PCV system like I was before.

I could open up the vacuum portion of the pump to examine the diaphragm but before I do and risk damaging what may be a perfectly fine vacuum diaphragm, I wanted to brainstorm here. Anyone have other ideas as to why the new vacuum pump would suddenly stop producing vacuum.

Manifold vacuum is normal for my elevation. Fuel pressure is normal. No oil in the PCV system. PCV valve not clogged. Vacuum lines all new and high quality silicone/checked over and not leaking!

I'm not too worried about my wipers not working but I don't want to end up back with my old problem of oil being sucked through the PCV system! Thanks for any thoughts!

 

"it seems weird a new part would fail after only a month"

Unfortunately the quality of many "new parts" on the market today is questionable, and failure is common.

If the pump has suddenly quit working something is wrong with it, may not be the diaphragm, could be several things to cause it to fail and the only way to know what went wrong with it is to disassemble and inspect it.

I have had two "new" fuel pumps that didn't last long, they were Asian imports. I won't buy another "reproduction" pump. Instead I find and rebuild an original pump using a quality kit.

 

What brand?

 

I figured opening it up would be my only recourse. I do have the old pump fortunately (though it needs rebuilding of course). This is the replacement pump I bought: https://www.kaiserwillys.com/produc...n-fits-50-71-jeep-willys-with-4-134-f-engine/ For what it's worth I have made many purchases from this seller and this is the first and to date only time I have a possible quality concern with a product. I'm not asserting that the pump is defective or that it failed after just a month--I can't know that until I open it up. Just providing the exact one I bought for the sake of troubleshooting.

 

X2. I suppose you could try applying gentle air pressure to the vacuum port, or vacuum to the "out' port, see if it does any good. Or apply vacuum to the "in" side and and see if it holds.

But, first of all, check all the external lines and connections.

I had good luck with a rebuild kit from "Then and Now"

 

So this failed pump is sold with no warranty ?
I'd be sending it back, let them open it up.

 

The seller has promised to stand behind the part. He told me to open it up and if there's been a component failure he said he will make it right. Work has been busy so I haven't had a chance to get the pump on the bench to open it up and investigate yet but will report back when I do!