vanster

Can I replace the schrader valve in my '80 with one from a bike?

vanster

This is for the AC, sorry about that

Mark Anderson

mountain or road?
jk

The Forgotten On

I would just use a standard r12 valve from an autoparts store. I wouldn't trust a bike valve to hold back 40+ psi of pressure for long term.

dr bob

More specifically, get the correct Schraeder valves for the AC from your local auto parts store. These have HNBR seals, so will work with any common refrigerant and refrigerant oil (mineral oil, PAG or polyolester) without deteriorating.

If you are converting to R134a, the port adapters will already have the correct Schraeder valves installed. Take the originals out of the two main charge ports and toss them. Then replace the old Schraeder valves under the pressure safety switch, the temp switch (or pressure transducer on S4+ cars), and the two charge ports on the compressor manifold plates. Remember to replace the port caps, or at least replace the o-rings in the top of those caps with HNBR.

If you are sticking with R12, all of the above applies except for the part about the port adapters; you'll want to replace the main charge port Schraeder valves with the new AC rated Schraeder valves too.

vanster

Thanks Dr Bob. I'm keeping R12. I will follow your instructions to the letter

dr bob

Vanster, the temp switch on your car doesn't have a Schraeder valve underneath My bad. That started with the S4 cars that use a pressure transducer to tell the fans how fast to run and the flaps how far to open.

I still buy the HNBR refrigerant valves by the box. They work great in tires, and no chance of accidentally putting a tire valve in any AC ports.

928Collector

I'm replacing the Schraeder Valves on an R134a as well as an r12 system on two different 928s.
AC is my life blood so I'm tackling this step by step.
I'm a little confused with Dr Bob's comments - I lose the train of thought around the "port adapters".
I think they are the below. Any clarification would be much appreciated.Schraeder Valve Replacement
r134a

For r134a, the port adapters should already have the correct Schraeder valves installed. Take the originals out of the two main charge ports and replace with new r134a Schraeder valve (with HNBR seals)

-under the pressure safety switch,

-the temp switch (or pressure transducer on S4+ cars),

-the two charge ports on the compressor manifold plates.

-replace the port caps and o rings (with HNBR seals)

r12
For r12, all of the above applies except for the part about the port adapters;

Take the originals out of the two main charge ports and replace with new r12 Schraeder valve (with HNBR seals)

-replace the port adapters with new r12 valves and HNBR seals

-under the pressure safety switch,

-the temp switch (or pressure transducer on S4+ cars),

-the one main charge port on the compressor manifold plates.

Also replace the port caps, or at least replace the o-rings in the top of those caps with HNBR seals.