1983 MC9 Air Conditioning - driver and coach system question.

plyonsMC9 · June 18, 2006, 06:29:33 PM

Greetings all,

I'm looking for more basic information on our MC9, an ex 1983 NJT. $:-\$

We have the original a/c still installed. Is the driver's a/c a completely separate system? If I have a leak in the coach a/c, can the driver's a/c be left installed, fixed seperately, etc.? Or is it the same r134a running through both coach and driver's a/c.

Thanks bus nuts!

Kind Regards, Phil

jeffacc · June 18, 2006, 07:48:52 PM

It is from the same compressor so this will not be possible. I also have a 1983 NJT and I am also a commercial HVAC tech it would not be possible to remove the main bus ac and leave the driver ac the compressor will not withstand the small amount of gas coming back to the compressor and would over heat and self distruct. I left my ac system in and fixed several leaks and I am glad I did.

Busnut83 · June 18, 2006, 08:05:07 PM

caution,,, I don't think you can run the drivers a/c without the coach air on... when I do the condenser fan does not run and this builds head pressure and blows a pop off valve,,, you loose freon???
Just my 2cents....

RJ · June 18, 2006, 08:37:23 PM

Phil -

The driver's A/C is tied into the main coach system. So if you remove all that stuff downstairs, you're going to lose what's up front. . .

UNLESS:

You do what a lot of other folk have done:

(1) Hang a small Sanyo compressor on the engine, driven by the camshaft pulley
(2) Mount a condensor equipped with a Hayden electric fan on the curbside engine access door.
(3) Plumb them into the original freon lines (capped appropriately).
(4) Rewire the switches appropriately
(5) Charge system w/ R134
(6) Enjoy!

HTH. . .

plyonsMC9 · June 18, 2006, 09:17:11 PM

Wow. Thanks Russ for the alternative suggestion. Interesting. I'm going to look into that. Thanks also to Busnut83 and Jeff. What started this is that I'm now trying to take care of a leak somewhere in the coach a/c. Mechanic is having a hard time finding. All major equipment doesn't seem to leak. The components look pretty new actually. So somewhere... is a leak! Either I fix or remove. Not a critical issue now, but would like to resolve it one way or another.

Best Regards, Phil

gumpy · June 19, 2006, 05:00:46 AM

Phil,

A couple comments based on my experience.

First, if you want to retain the system and have not yet changed out the 4 hoses in your a/c, now is the time, and it's definitely worth the money. My system had R12 in it, and worked when I first bought the bus. It subsequently quit cooling a couple years later, so I decided to convert to R134. When I took the bus in to have the R12 Gold evacuated, they checked it and laughed at me. It was empty. Turns out one of the main hoses on the compressor had cracked. I replaced all 4 at that time. Couple hundred bucks. Did the R134 conversion, a few hundred more. Worked great. That was 2004. Used it that summer and took it to AK in 2005. Worked good up and back.

After returning from AK, I took the bus to have the oil changed before another trip, and found I had no cold air. Very frustrating. I had the mechanics look for a leak, and after pressurizing the system to 200 psi with nitrogen and searching for a couple hours, they found that the main condensor had a very small leak in one of the tubes. They only found it because it was leaking a tiny bit of oil and it dripped onto the shop floor. Just by chance they saw it.

I put a used condensor in that a fellow gave me from his NJT and recharged the freon. That was last August, and It was still working as of a few weeks ago.

pete81eaglefanasty · June 19, 2006, 08:37:39 AM

phil
i found on mine the o rings were leaking in the hose's at the compressor. i replace all of then 3 years ago along with the hoses. we charged it up then and it hasn't lost any since, still cooling front and rear. we do all our own work, thank god for that.

pete
eagle fantasy

Busted Knuckle · June 19, 2006, 09:59:26 AM

Phil,
All good suggestions above! I have a guy about a 45 minutes from my place who is excellent with bus A/C any time I have one I can't solve the problem quickly I take it to him! He's awsome and reasonable too! Let me know if ya wanna get in touch with him! BK

darrenayres · June 21, 2006, 06:29:57 AM

Phil, how bad is the leak? I had a small leak in a MC-9 and couldn't easily find it. I got tired of paying my mechanic to charge the system so I bought the guage manifold and hoses and learned to do it myself. A 30 pound bottle of R134A was about $180 at Sam's Club.

Darren