I have to renovate my AC here in Oman on my 1971 300SEL 3.5. I have never had AC hoses redone and therefore I need some information what is technical standard, what is possible and what not.
I have Rotalock valves and all hose connections are without o-rings in my car.
I would wish to keep all the current fittings and just replace the hoses which are leaking.
I counted 5 hoses
1) from compressor to Rotalock.
2) from Rotalock to condenser
3) from condenser/drier to evaporator
4) from evaporator back to second Rotalock
5) from Rotalock back to compresspor.
see some of the fitting in the attached pictures.
Is it common practice to reuse all the old fittings?
Martin

Attached Thumbnails

         

Are you planning on using barrier hose?
It is possible to re-use fittings but I avoid it when possible. Looking at the pictures it might not be possible to re-use that type.

Thanks for responding,
I have no experience with remaking AC hoses.
Why are you saying you do avoid using old fittings?

Best would be if it were possible to redo hoses with the old fittings but I have no experience. I am in Muscat Oman, not in the US.
I'll look for a shop doing the hoses for me. However I do want to have some knowledge if it is a reasonable request to rebuild the hoses with the old fittings.
Martin

I have been there and done that, so here is what I ran into.

First is the cost. If you are trying to save money then reuse everything. It can be done if you are careful. If you can remove the fittings without tearing them up then the hard part is over. Just be sure to line them up correctly when installing them again as they are easy to cross thread due to the fine threads used on these fittings.

The danger you will run into is that after you are through your A/C system will be working great and your hoses will be old. Too much pressure and one of them will blow out, and the correct operating pressure might be too much for the old hoses.

You could likely find someone to make you new hoses since there is such a thriving oil business in Oman. If you get new hoses be sure to specify barrier hose for auto A/C as it has a plastic lining inside of it to contain R-134. If you are going to go back with the original R-12, which I would recommend if it is possible, then barrier hose would still be the way to go since you may want to switch to R-134 someday.

See if you can find a Gates dealer in your area. Gates is a brand name of hose and they make good ones.

You might also just walk into the service department of a Mercedes dealer and ask the service people what they use and where do they get their hoses?

Hopefully this will help a bit.

I am hoping to find a source for making red hoses like the ones furnished with our cars (so far my hoses aren't leaking). I think the dealer hoses are now black.

__________________
All the best,

J. P. Mose
1968 250SL
1970 280SE 3.5 Cabrio
1987 560SL
1990 560SEL

I try to avoid reusing fittings because I worry about damage to the threads. Plus new fittings are not that expensive compared to other AC work. I have a crimp tool I bought off eBay for $75 and usually budget about $100 for new hose + fittings when I do AC work.

I agree with Pooka's advice on using barrier hose (aka R-134a hose) even if you are using R-12. I am not sure what parts availability is like where you are but I wish you the best of luck!

Those fittings are reusable and are called aeroquip fittings. The braided hose is still available but unfortunately only in black. You should be able to find the black braided aeroquip hose by searching on the net.

John

The original hose is aeroquip 1540 and you can buy new black braided hose here.

1540 Refrigerant Hose

And here is a good link showing how to assemble hoses using aeroquip fittings.

Aeroquip 1540 Assembly Instructions


Hope this info helps,
John

John,
this is great information....
Does it mean that new aeroquip 1540 hoses and the old fittings can be assembled without any crimping tools?
If yes I just need to find the right type of hoses here in Oman.
I'll try and figure out the hose sizes I'll need.
Martin

Thanks Pooka,

it is true that here is some oil business going on and I hope to find a good way to renovate the AC hoses. I'll try and get Gates/barrier hose here.
However this seems to be another route than going with the old fittings and us the Aeriquip hoses? Aeroquip isn't the same thing as a barrier hose if I got this right?
it really depends what I can get here locally and I am going from there.
However if I could reman the hoses myself with aeroquip and the old fittings I'd rather prefer this and remake the hoses myself. Thus I could almost get the AC to the point where I just need the shop to fill the system.
Martin

I looked at the threads on the hoses I opened and they all seem to be fine.
Not sure about the worry with leaking metal to metal connections.
Martin

Martin, I need to do the same task, oil lines and A/C lines, just be careful on the disassembley of the hoses R/H and L/H fine threads, clean the metal and should be no problem with correct replacement size lines.

Hi Brian, nice to hear from you.
So you are going the same route: strip the current hoses to bare metal, then with the correct braided hose size I could install the existing fitting and thus redo the hoses myself? Great idea...if it works?
Is this how you want to do it?
Martin

I would suggest closing the valves on your compressor and then bleeding down the system. Then remove one hose and see how they are put together.

Before removing any hose the system MUST be bled down. Here in the States a special machine is used to recover the refrigerant gas for two reason: It is not legal to do it any other way and the fact that the gas cost so much.

If you don't bleed down the system you are woking with a line that could have as much as 325 psi on it. This is a lot of pressure to have come unwound on you and can slap the hoses back and forth to the point someone might get hurt.

The real answer to your question about can you reuse those fitting is: Maybe. It depends on their condition which looks to be OK. It entirely possible that you could buy enough hose that you could redo the whole thing yourself.

Aeroquip is a brand name and a good one. I suggested Gates since I have used their hoses a lot but there is nothing wrong with Aeroquip.

Hi Pooka,
My system has Zero pressure. As I said before one hose has a leak. I did knew there was no pressure ..and all good R12 gone...then did a pressure holding test with air and one hose leaked a lot.
I was renovating my R12 system in my 126 but the hoses were all good. Here with my 109 I have a different animal and ... I am in Oman.

Fittings: I think I want to try to reuse my fitting. I think they are in decent condition and the fittings look like heavy duty. It seems that the fitting end can be rotated relative to the hose itself. No clue how this rotating connection is working?

Hose material: Are you saying that I can use other hose material than aeroquip with my existing fittings? You mention Gates hose. How do you know that these hoses fit?
In my understanding that with my old fitting the way it works is: first the new hose is cut to length first, then it needs to fit exactly inside the 'sleeve' (the thickest part of the fitting with the hex or octagon). Then the male part of the fitting needs to be installed. Here the pressure of the hose between the female and the male part of the fitting is making it pressure tight? Therefore it matters essentially what size hose and thickness is used. Who knows about this?
Martin