We have a very slow leak in our AC system and want to replace the easy access o rings.
I have read the forum but cant find anyone recommending a o ring seal kit.
Can anyone recommend one or maybe someone has the sizes needed?

We are starting with the seals on the dryer.

 

You have to replace them all. If you replace one then another will fail that wasn't failed before.

You don't need a "kit". Buy the assortment box from any parts store and some pag oil to lube them with

 

Thanks we did that.
Since we have no refrigerant in the system I would like to replace the pressure switch.
Looks like they are NLA from Mazda, does anyone know of a replacement switch that will work?

 

unless faulty, which is very rare, the pressure switch does not need to be replaced. jp3 has found a suitable replacement but it comes attached to their entire kit lol you will likely have to experiment to find one otherwise just use the stock one unless its not working.

 

The pressure switch is not too likely to go bad - this could be pretty easily tested once you recharge the system with a bit of refrigerant.

I recently did the R12 to R134 retrofit on my 93 with a MANA system by using this o-ring kit from Rock Auto: Four Seasons 26754

It worked well as most of the o-rings in the kit matched pretty closely to what came off the old system. I got lazy and skipped the TVX valve o-rings inside the evaporator, but you should really do as many of them as you can. However, the compressor o-rings included definitely doesn't look like they'd fit the Denso FD compressor so I left those o-rings untouched.

Unfortunately, my new system didn't stay cool for too long and I traced the leaks with UV dye to the old Denso compressor. Some refrigerant were leaking out from the old seals on top and a relief valve I didn't tighten properly. I did some more research and saw people recommend Santech Compressor Gasket Kit MT2064 for the FD, which I got from Ebay here. Still waiting to install them, but the shapes look correct. Would definitely recommend you do the compressor o-rings at the same time as the rest of the system.

 

We changed what we could and recharged, it's holding up so far.
The compressor seal looks impossible with out removing the compressor, and that looks super hard.