Tracking down bus a/c leaks - MC9

plyons · August 16, 2006, 06:49:24 AM

Hi all,

On my 1983, NJT, MC9, I have an A/C leak - somewhere. When the bus a/c worked, it was terrific. COOOOLD. In addition, the a/c compressor looks brand new and doesn't leak, So, I would like to see if it is fixable. I had a bus mechanic come onsite with some kind of R-134 gas detector. He found NO leaks. A lot of what is visible of the a/c system looks pretty good. The receiver tank (?) if that is what is in the front bay with the HUGE fan & coils looks a bit rusty, but again, the mechanic found NO leaks with the magic wand - refrigerant detector. He covered the bus front to back. But wasn't an a/c specialist either.

And so my question, As my bus is finished inside, is it possible to find a leak if it is behind walls? Are there other places where these leaks are likely to be hiding? Or is it not even necessary to take the detector inside to find the leaks as most of the system is available outside?

I'm trying also to see whether I should invite the guy back with additional suggestions, or forget about it.

He was extremely fair, only charged (no pun intended) for the refrigerant he used. No labor. So I also don't want to waste his time again if he doesn't have a chance at finding the leak.

Thanks for your input!!

Best Regards, Phil

DrivingMissLazy · August 16, 2006, 07:00:29 AM

Phil, you did not indicate if he got it fixed. If so, how much refrigerant did he use? How long had it been since you had had it serviced before?
Richard

Busted Knuckle · August 16, 2006, 08:52:43 AM

Phil, I second Richards questions ? Also I'm no expert on A/C systerms but have a man 35 miles from me who is the best in West TN and surronding areas! I've got a church bus that has a leak I can't find and called and asked him about, he said 9 times out of ten the leaks are at the service ports or valves ! He told me when I get a chance to bring it to him and we'll use dry nitrogen (a lot cheaper than freon) to pressurize the system and find the leak! You may wish to have someone local do this on yours or I can put you in touch with my contact in Dyersburg, TN (he used to be in Memphis, but relocated about a yr ago and still has people from Memphis and all over bringing their coaches to him for A/C service!) BK

plyonsMC9 · August 16, 2006, 09:10:49 AM

OOps. OK. Thanks guys.

No. He found NO leaks. And he did not get it fixed. He charged me about $100 for refrigerant which at the time was about at cost for what he used.

Best Regards, Phil

Busted Knuckle · August 16, 2006, 09:15:47 AM

Hey Phil, If your coming to the "TN Fall Bus Bash" maybe I could get Billy to come up for the day and we could fix it then ! Just a thought ! And another shame less plug for the "TN Fall Bus Bash !" LOL!
BK

Nick Badame Refrig/ACC · August 16, 2006, 03:20:22 PM

Hi Phil,

If you are sure that the compressor has no leaks at the drive seal, than I would have the expantion valves checked both the one for the drivers air in the dash and the one in the evaporator coil in the condencer compartment, behind the service panel. Than I would check the copper spiders off the evap coil. If all checks out with them I would start removing the tunnel covers in your bays [If possible]. Thats where the refrig lines run in your 9.
Phil you can also do this yourself if you know that there is still freon in the system by, filling a spray bottle with soapy water and spray all the fittings you can find. Than start looking for bubbles..... Most of the time they are very visible. most likely the fittings or the compressor seal...
Good Luck
Nick-

plyonsMC9 · August 17, 2006, 06:10:33 AM

Quote from: Busted Knuckle on August 16, 2006, 09:15:47 AM
Hey Phil, If your coming to the "TN Fall Bus Bash" maybe I could get Billy to come up for the day and we could fix it then ! Just a thought ! And another shame less plug for the "TN Fall Bus Bash !" LOL!
BK

Thanks Knuckle! That is indeed a great inducement to come to

"TN Fall Bus Bash !"

I will let you know - thx! I'm going to give Nick's suggestions a shot first.

Kind Regards, Phil

plyonsMC9 · August 17, 2006, 06:13:01 AM

Quote from: Nick Badame Refrig. Co. on August 16, 2006, 03:20:22 PM
Hi Phil,

If you are sure that the compressor has no leaks at the drive seal, than I would have the expantion valves checked both the one for the drivers air in the dash and the one in the evaporator coil in the condencer compartment, behind the service panel. Than I would check the copper spiders off the evap coil. If all checks out with them I would start removing the tunnel covers in your bays [If possible]. Thats where the refrig lines run in your 9.
Phil you can also do this yourself if you know that there is still freon in the system by, filling a spray bottle with soapy water and spray all the fittings you can find. Than start looking for bubbles..... Most of the time they are very visible. most likely the fittings or the compressor seal...
Good Luck
Nick-

Thanks Nick, I'm going to print this out & give to the guy with the testing equipment. Going to work together with him on this. Will let you know.

Kind Regards, Phil

buswarrior · August 17, 2006, 02:49:24 PM

Phil,

You want to stuff that gas detector down the duct work in the coach when it is running. If the gas is leaking anywhere in the evaporator compartment, it will come out the ducts. The detector will scream as soon as you go into the bus, if you have a good leak.

On mine, the small line in the condensor compartment, about 2 feet long, leading to (Oh rats, which little thingy was that?) had gone solid from old age and was the source of leaks.

I had used the MCI conversion kit, that comes with all new hoses, including the small ones on the compressor, to switch to R-134.

happy coaching!
buswarrior

plyonsMC9 · August 18, 2006, 07:44:57 PM

Thanks Buswarrior,

That was the odd thing. The detector did not even squeak once inside the coach. Odd.

I will continue the battle!!!

Best Regards, Phil