Hi,
I just registered so I could post and ask this question...
I read posts about this issue for a couple hours in the non-newbie section
and I couldn't find an answer.....so

My 1994 Touring RX-7 holds an R12 freon charge for less than a week.
A leak has been found in the hi-side line from the compressor to the condenser,
thus the hose has to be fixed (common leak area I've read).
My RX-7 came with the black Mana Receiver with the raised rectangle.
Compressor and condensor appear fine.

I've read that anytime you open up the system and fix a hose/line you should
replace the receiver / drier. I scoured all the posts and read several dozen websites
searching for the Mana drier without luck. Websites say they sell it but the picture
never matches on top with the position of the holes.... (never mind the raised rectangle)
For pictures of both the Mana & the Nippon Denso driers see page G-60 in the
94 body electric manual posted at
Foxed.ca - Mazda RX-7 Manuals

Questions:
1) Does anyone know where I can find one of the Mana driers?
2) Will the existing drier still function reasonably well despite opening up the lines
for repair as long as we pull a hard vac and have it hot enough to boil off the moisture;
or is the H20 bonded to the desiccant?
3) Any other suggestions?
or do I have to have the whole system replaced with a Denso or even an R134 (sigh)?
(Denso has standard threads compared to the metric threads with the Mana)

thanx much.......Mark

 

I know nothing about AC, but...FWIW my system was professionally changed from R12 to 134 and they re-used the drier. That was about 4 hot summers ago and I've had no issues.

 

I did the exact same thing as you and reused my MANA drier. As long as you repair the line, pull a hard vaccum on the system, wait 24 hours and ensure there are no leaks you should be fine. As you indicated, the vaccum boils off any moisture that may still be in the system. My drier sat out of the car for more than 3 years before I hooked it back up, so I'm pretty confident that you'll be OK. Mine's been operating just fine now for more than 2 years blowing ice cold air. My guess as to why Mazda recommends replacement has to do more with potential contamination (i.e., metal shavings from "possible" compressor damage) more than anything else.

Keep us posted on your success!

 

Thanx for the information........we'll try it that way with the same drier...

Question: How long do you really have to do the hard vac for to clear out the moisture???
(some posts same 24 hours...seems a long time....others don't say)
(and is the temperature of the car and/or environment important when doing the hard van?)
and how long do you really have to wait after the hard vac before filling up with freon?

thanx...mark

 

I did mine for 24 hours and it worked just fine. As long as the system holds a vaccum, I think it's adequate time.

 

Well, kept existing Mana receiver/drier and the job is completed ;
it's been over 2 weeks and everything seems to be working ok.
(I gave them a copy of the 93-95 heater & air conditioner 65 pages from
94_body_electric_manual.pdf on Foxed.ca - Mazda RX-7 Manuals

125 PSI low 28 chill to 30
AC hose 85386 lp made hose
o-ring -- 407008
23 oz of r-12

They actually kept the "hard vac" going all weekend !!!

They had to remove (to check for leaks and to get at the hi-side line from compressor):
stabilizer bar, cold air box, intercooler, battery, entire power steering assembly, a couple shields
cost a little over $700....
Hopefully it will last for some time now.......

thanx all for info.....Mark