A/C Leak: Accumulator/Clutch switch

[RobClark]

Car: 86 Town Car

My A/C was out of gas 4 weeks after my A/C shop fitted:

- brand new MOTORCRAFT A/C Clutch switch (Adjustable Pressure Switch)

to my

- 6 month old Accumulator (FOUR SEASONS brand).

He said it was leaking around the pressure switch thread (where it screws onto the accumulator).

Now ... both parts are virtually new. He said he could not get it to hold pressure and the dye test said that was the leak site.

My questions are:

1) There was no o-ring involved. Should there have been? What sort of seal is it? Just plastic-on-metal?

2) If it was me - I would have tried teflon tape on the male thread and maybe that would have fixed it. But the A/C guy dod not want to try that. Any suggestions/comments from you experts.

Rob the Aussie

[Tiggie]

No teflon, it might get into the system, and stop up the orfice tube. I guess you could use it carfully.

I think there should have been an o-ring up past the threads on inside the low-side cycle switch that you replaced. Sometimes they match the color of the plastic and you can miss them if you aren't careful.

[gadget73]

I think there is an O ring up inside the pressure switch where it screws on. It should just unthread and once its off it ought to hold pressure. There is a schraeder valve in there (like a tire stem valve) that will allow changing of the pressure switch on a charged system.

[RobClark]

Received the following tpday:

- New pressure switch
- New accumulator

No O-ring in Pressure switch.
But .. when you remove the protective cap covering the shraeder valve on the side of the accumulator (where the pressure switch screws on)....there is an o-ring in the 'cap' ... and the cap in normally thrown away.

So - here is my best guess of what happed to my last install

- A/C shop installed accumulator. Threw away the cap (and o-ring!!!)
- Installed pressure switch.
- Held pressure for 4 weeks!

Grrrrr!

Rob the Aussie

[gadget73]

Hmm, you know I think I threw away the cap that came with mine too. I didn't replace the pressure switch though, and it doesnt appear to be leaking oil from around the switch so I think either it had an O ring in it already, or maybe I replaced it with the rest of the seals in the system. I do have a slight leak on one of the hoses though, so whenever it leaks down enough to stop working, I'll swap out the hoses with new.