[Jeff]

I have no experience with this but I have heard R134a will leak thru a R12 hose.

When replacing refrigerant hoses use #12 and/or #20 Eaton FC 558 refrigerant line.

[rafael]

This is going to be a damned if you do, damned if you don’t situation.

The correct answer is to change all hoses. It sure is easier to say than do. The hoses were not made to be serviceable or replacement components so changing some of them out is a serious effort.

If the planets have lined up, if you can flush the old oil from the hoses you can make the switch to 134 and see if they hold a charge. To make the switch you need to change dryer, expansion valve and clean out the old oil and if you can hold a charge for several seasons you might be happier than if you went through the effort to change hoses because to recharge is not going to be much expense.

[Archived]

Most DIY type don’t replace the lines between the condenser and evaporator bays. Those lines go over the fuel tank and are very difficult to access. I think I have seen posts indicating Jeff drops the fuel tank to access them.

I have seen photos of rerouting (not replacing) those lines. Most go thru the next forward bay but it may be possible to use the next rear bay. Go around the fuel tank. It takes about 7 ft of hose.

Full disclosure: I have not done this, I need to. but have not yet. I have seen photo’s and while it is not “factory” I think it is ok. In my case the generator is in the drivers side forward bay and the generator radiator is in the middle. I don’t think you will ever see those lines.

[Roscoeapproved]

Back many moons ago when I still had R-12 on my 94 Liberty, I was at Prevost Jacksonville and talked to John (rip) about the conversion to 134. He said the type hoses they used for R-12 was not compatible with 134 and would eventually leak. How long will that take, who knows. It was very expensive to do the conversion. R-12 was still available then, so made no sense to change it out.

I think some have been successful with just changing out compressor, oil, evaporator and freon.

---

Jeff and Lindsay

91 Marathon XL

[Mike]

Prevost JAX did my conversion from R12 to 134A. Replaced all hoses and compressor (I think it was bad anyway IIRC). It was about $6000 buck 15 years ago.

[DON]

Prevost Houston quoted me $20,000 a couple years ago. Everything new including the O5G Bus 41 CFM Carrier Compressor. Bought one myself off a Carrier Dealer (O5G) rigged up for 134A and never used it. Guess I’ll have a spare or have one if somebody needs it. Still using the original one. Heck 20K is about half what my coach is worth.

[Fred F.]

From my NAPA jobber days R-12 and 134 A are not compatible with each other.

We made a lot of hoses when shops were doing change over back in the day.

AL