"For a DIYer your vac pump will last forever if you will do two things; change the oil every couple of years or when it stops pumping a good,"--Larry Bible

The oil in the Vac Pump should be changed each time you evacuate something. This is standard procedure for people in the know.... and well spelled out on the Yellowjacket site mentioned above...
It is just a few ounces... how much can that cost compared to what is invested in each servicing of an AC system ? Peanuts....

I couldn't agree more. We used to evacuate large chiller plant machines a we would change the oil in the pumps twice a day.
Always replace the oil before using and again during evacuation if your running a long time.

Danny

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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Finally we have a few hot days (per Bayarea standard), the AC worked very well. Some passenger complained "its too cold". So I declared victory on my AC adventure.

The FJC vaccum pump woked very well and pull vaccum down fast. The Yellow Jacket manifold gage is of high quality. I bought an un-opened 30lb R12 cylinder for $325. The problem was a loose hose connection and a shrader valve.

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Shane83SD

I think I have seen pictures of fancy tools which can change shrader valves without loss of refrigerant...
Is that what you did on the faulty shrader valve ? Or something else ?
That was sure a good price on that container...
In Texas if someone says it is too cold we point the vents directly at their face.. LOL

I heard of such a tool to change the shrader valve without loss of refrigerant. But in my case, there was very little pressure left (1 psi) when I hooked up the manifold gage. There were quite a bit of refrigerant oil trace around the low side hose connection and shrader valve. So I pumped it down and within 15 minutes, it leaked down to 28 psi. I then changed the shrader valve and hose fitting, pumped it down and it holds vaccum this time.

When I took the car to an AC shop, they want $1000 to shot gun the system and convert to R134. I knew it might just be some silly leak somewhere. So I got mad and fixed it my self. I would glad to pay the shop for necessary work but I just don't like to be backmailed.

Someone closed down his shop and I got the freon for a good price.

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Shane83SD

"So I got mad and fixed it my self."--Shane83SD

We try to offer an alternative to that here... just being frugal and doing it yourself... LOL

I made my evacuation pump from a freezer that blew a line.
Works good, can also pressurize system to check for leaks.
Cost, about $4, that was for the 2 solder in adaptors.

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1985 300D California w/cat. (257,000 + Miles)
1980 300SD (208,000 + Miles)