1. I looked for, but could not find, a vendor offering 450SL hoses (mine is a 78) utilizing barrier hose. I bought a hose from MB, it used non-barrier. So I had them made by Charlie Griffiths, a friend of mine from the Porsche community. https://griffiths.com. He doesn't regularly do this but I asked him nicely and he delivered. I sent him my old hoses and he rebuilt them with Parker Futura.
No leaks, no issues.

2. #92 in diagram is in fact the complete hose assembly with crimped connectors, that goes between the outlet from the evaporator under the dash forward to the compressor manifold (as you correctly call it). This is the hose that I was able to source, has the right crimps, but not a barrier hose. Also, the original hose has a metal section on the evaporator end that is probably eight inches long-- the factory hose just has a conventional crimp connector on that end.

3. I used a four seasons TXV and compressor (a rebadged aluminum Delco) and these were both fine. I wouldn't have a problem putting their evaporator back in my dash.

Are you converting to R134a? The TXV is specific to that refrigerant and of course you need the correct oil.

Hope this helps

Good luck!

 

Thanks!

Yes - I am planning to use R134a (or maybe EnviroSafe - still investigating that). I didn't realize the TXV needed to be different, based on the refrigerant. As it sounds like you also went the R134a route, which Four Seasons valve model did you use? (I see 38604 listed at most sites for the R107, but I assume that's intended for the original R12). Also - did you use the 4S Model 58098 compressor? (it's good to hear some feedback on that, as I had been considering that..)

-Steve

Edit: Just found your thread covering your A/C rebuild - answers a bunch of other questions I had - definitely bookmarking that!!

 

Envirosafe in a '73 450SL; picture is from last summer but performance is the same this summer.

 

That would be nice

 

Do not use R134a. It works ok up to apprx 95 to 98 degrees outside temperature, and then it gives up. You will find that opening the windows with outside temps over 100 degrees is cooler than running your AC. Your cores are just not big enough to make up for its lower effectivness.

 

I used the 4 seasons TXV. No issues in two years. No experience with the evaporator.

 

Thanks! I've already bought the evaporator and TXV (both Four Seasons).

It looks like everyone is recommending EnviroSafe (thanks for all the recommendations), so I have some questions:

a) I'm assuming that the TXV I've bought ( 38604 ) will be ok for the EnviroSafe ( 304065 mentioned earlier in the thread that the TXV was refrigerant dependent). I'm wondering if there's a better option here - even though I've got the TXV ordered, I'm prepared to change if there's something definitely better.

b) Those of you using EnviroSafe, did you bother with getting modern barrier hose, or did you use OEM (My hoses are so old, I'm going to replace anyway, but trying to decide the route to go - finding OEM, or getting a set made up (304065 recommended a shop, but not called them yet). I'm kind of amazed that there doesn't seem to be a specialist I can order a set of hoses from 'off the shelf'

c) Any thoughts on the condenser? I see RockAuto lists the APDI/PRO 7014075 at a very reasonable price. Knowing that the R107 system is pretty weak to start with, if a modern condenser can give me a few more degrees cooling I'm happy to replace that (and I'm also worried about any debris/oil oils that might be lurking in the original after so long wrecking a new compressor. Currently considering the 'small' 4 seasons aluminum compressor (58098)

Thanks!

 

Why not pay a shop to do a full flush of the system. They do not need to do more than slap in some of the oil appropriate to your choice of cooling medium. The system was designed to run R12, which puts the R134 junk to shame. Find a replacement compressor that will function with R12, and you could use some of the canned air stuff (same cooling coefficient as R12) to recharge the system.

 

Unfortunately, not really practical at the moment - the car is in pieces, in the middle of a restoration. As the heater box is out, and the hoses looked pretty crappy I decided to replace them (and the evaporator) while I'm in there. Based on the recommendations here I do plan to refill with Envirosafe, though that's several months away - just want to get the hoses in place while it is easy.

Also: I've found a place in Florida (coldhose.com) who will be making up the hoses for me; I'll post here once I get them back. Their web site allows you to specify exactly what you need, or you can ship the hoses to them and they will copy them. I'm probably going to send them, just to avoid any mistakes (also, it appears that the firewall gasket for the hose to the condensor is probably easier to put on the hose while it is being manufactured)

-Steve

 

I miss the "old days" when AC work was straight forward. Use R12, add mineral oil, and install a new A6 compressor-- everything worked great, cooled nicely and it all lasted a long time. It’s complicated now-

1)R12 is a problem to get-- some of the aftermarket "propane" refrigerants seem to work. Don't use 134a unless your AC is specifically designed for it (not modified to use it).

2)Oils-- Pag is the better current oil now but it is not compatible with R12 or mineral oil, which might be still be in the system. Ester oil is cross compatible- but it is not as good of a lubricant. The compressor really must be one that is ok with Ester. --

The Delco A6 will work with ester oil, but it really doesn’t like it.
The Four Seasons compressor doesn't really like ester oil either.
The Pro6ten compressor is ok with Ester oil.

You can’t get a good new GM Delco A6 anymore- - The rebuilds are sometimes good, or very often, they are not.-- They run ok for a while and then many quit.

The new Four Seasons compressor is available and was also sold by GM/Delco "somewhat", but Delco seems to be avoiding it now - The Four Seasons compressors are really are not all that great- Some who use them have good luck and some don’t.

The Pro6Ten compressor is sold by Classic Air- -It is a modified Aluminum rotary compressor to match the dimensions of the original A6- - The early ones had some issues sometimes. They ones sold now seem pretty good. This might be the better current choice. And it will work with PAG, Mineral oil, or ester.

 

Thanks - that's a very useful summary!

Currently, it looks like the only two original parts left in my system once it's done will be the suction pipes (all steel on a '76 SL), and the condensor.

The suction pipes will be easy to clean out once they are out of the car. Would you recommend replacing the condensor as well? (given it probably contains old oil, and has been sat in the car unused for at least 20 years.?)

I'd seen lots of 'universal' condensors for sale at a surprisinly reasonble price (<$100 US), but was concerned about their fit, especially to the dryer and hoses (everything is pretty tight in that corner)

-Steve

 

The stock MBZ condenser coil was a good quality build, but- its current condition is important. If it is still solid- no bangs, crimps, corrosion, and such--- That is good. You say it was sitting. That is not a big problem as long as it appears basically clean and is not jammed with dirt. Absolutely use a specific AC flush solution and pressure force it through the coil. You can get pressure bottles for this purpose at a low cost, eBay or other sources. Fill the bottle with solution and pressure charge with an air compressor hose, then flush through the coil. Always flush one component at a time, do no flush multiple components. The coil must be dried out after the flush. Nitrogen is best but you may not have it available. You can use compressor air but be sure that it is not coming from a compressor line which sends out globs of water or dirt, you might need a filter, don’t run the pressure too fast as that tends to send out stuff. After a higher pressure blow out of the solution, a low-volume flow of air through the core for a while can assure it is a dry as possible.

 

Thanks - that's very useful to know; didn't realize you could get flush solution etc. I'll pull the condenser and take a careful look at it. The fins look a little bent, but can't see any serious damage to it.

-Steve

 

Okay, I ran into a problem with the high pressure hose on my 1977 450SL. MB new High Pressure hose connection to the compressor is fine but to the condenser its an incorrect fitting, as it has the same fittings as to the AC Compressor. My high pressure hose was previous replaced and as to when I was taking out the old receiver/dryer I had notice that the high pressure hose was clamp on the condenser by ordinary hose clamps (2). Today I removed the high pressure hose at both ends and you can see in photo what the my condenser connection looks like after I removed the hose clamps. So I now believe that I'm going to have to remove the condenser completely from the car and have the new high pressure hose cut and professionally attached. I'm assuming the factory condenser comes with the high pressure hose, a non removable permanently attached to the condenser. Can someone verify my conclusion.... or come up with a better alternative. I also attached a photo (marked 2) of my friend's 79 SL and you can clearly see how the compressed connection to the condenser came from the factory.
Thanks,
carltwo

 

Yes-- The early ones did have a crimped hose on the top condensor connector. Remove the core and take it to an ac shop. They can use a crimper to put a new hose on it. The hole on the core side of the crimp ferrel most generally must be ground somewhat to fit over the connector on the core.

 

rick,
Appreciate the confirmation...
carltwo

 

Attached is a clear pic of a 107 AC condenser for sale, new on eBay for $295.00. And it would fit the new high pressure hose that I recently purchased from the dealership. I also see another condenser also on eBay that is the same one that Rock Auto is selling for around 82.00. In my case the old condenser has to come out anyway so if the condenser for $82.00 has that same top male screwed fitting as shown on the condenser for $295.00, it would be best for me to purchase that one. I sent a email asking for a close up pic showing the top connection fitting for the $82.00 as all the suppliers who are selling the $82.00 and higher has no other pic that shows the top condenser fitting. Curious as to if anyone on the forum ever purchased the condenser from Rock Auto and if so what type of top fitting that connects to the high pressure hose does it have....

 

fixer,
I believe now, like you mention your condenser was replaced and your newer condenser came with the condenser to air compressor male fitting so you can use the screw on fitting that's on your high pressor hose and connect it to the condenser. Mine has the old original condenser with the crimp condenser to air compressor fitting. I now need to make a decision either keep my old condenser and have the compressed fitting recompressed or crimp using the newer hose that would have to be cut in the process or look for a new condenser that has the male fitting so I could use the new high pressure line without cutting it. I do prefer a new condenser, but at a reasonable price of around $100.00. The dilemma I'm having now is that condenser from rock auto or one that appears by many sellers are selling has that male threaded fitting. I asked many sellers but they do not have any pics showing the fitting. Fixer, did you decide to use the condenser that you have? Again, has anyone purchased the APDI condenser and can verify the high pressure line's fitting?
Thanks...

 

I've not yet decided whether to use the existing condenser; it probably depends on price - if I can get a decent replacement for something in the $100 range I'll go for it; the alternative is a full flush, and I'd need to buy a flush kit anyway. Like you, I'd want one with the flared/threaded fitting as I've already sent my hoses off for a like-for-like rebuild/replacement.

-Steve

 

I just went through this process myself, maybe this will help

https://www.benzworld.org/forums/r-...g/forums/r-c107-sl-slc-class/2672410-condenser-integral-high-pressure-hose.html

 

304065,
Yes, this helped a lot, thank you. Funny, I did a search days ago and this thread of yours never came up. So for me, I ordered the APDI condenser from Parts Geek. They told me if the condenser is not a direct fit they will refund my payment including the return shipping cost. So hopefully, the male threaded 3/4" fitting that connects the high pressure line on top, above the receiver/dryer will be intact with this new condenser I had order. Again thanks.......

 

Well, yesterday I received the APDI AC Condenser from Parts Geek and its not the correct condenser. Fittings are incorrect, its location and thread size.
In the process and waiting for a return called as it's definitely going to be returned. So if anyone was thinking about ordering the APDI condenser as there are many sellers selling this condenser as they all use the same photos, don't. I'm sure there has to be many complaints, I can't be the only one..... I just took pics with closeups and will post them later.

 

Reviving the old thread - which condensor did you use in the end - the $275 one from Ebay?

Mine is now at the shop being pressure tested and flushed, but if it looks like any extensive work is needed I'll probably buy a replacement.

-Steve

 

My new hoses have arrived from Coolhose. All the end fittings seem to be aluminum, as are the connections on the Four-Seasons evaporator I've got. The new fittings appear to be slightly different than the originals (which I'm pretty certain were steel)

This is the first A/C system I've ever rebuilt, so I'm pretty much a newbie with this, so I have another question.

Should I use copper washers (gaskets) in the joints? My guess is no - I'm assuming that the aluminum is soft enough to 'crush' and seal. There were no copper washers or o-rings in the original joints (the only ones I've not yet touched are the ones on the back of the compressor).

-Steve

 

When I removed my old low and high pressure hoses there were no brass bushing seals or rubber seals. So far the only brass bushing seal that I discovered is in the steel line coming from the bottom of the condenser which connects to the bottom of the receiver/dryer. Autohauseaz shows different size brass bushings in the AC system for my 77SL I believe, but so far I don't see where they go. Anyone here have some thoughts on where these different size brass bushings go ?.

 

Hoping to find out the answer to this as well.

I'm wondering if the copper is only required for steel/steel joins? My new hoses appear to have aluminum flared ends on all of them. I'm concerned that putting copper washers in there might damage them.

That said, I've not found any copper (or rubber) in mine yet.

Update: Emailed CoolHose (who made my replacement hoses). They indicate that no washers are needed for the flare fittings; I can use them if I want but they don't believe it makes any difference to sealing or longevity of the connection. So - I'm going ahead without them.

-Steve

 

This product is used in A/C install/repairs:

https://www.refrigtech.com/nylog-blue/


Would it be a good thing for the auto A/C?

 

Another update. A shop evacuated my system the other day. I added the industrial Enviro-Safe refrigerant with the enviro-safe 4oz can of Oil first. Then I added one can and a half of the other 6oz can of refrigerant, constantly checking the low side pressure. It's blowing cold now. I did have a previous problem with heat blowing and mixing with the cold air as I found out my heater valve was open and there was not any vacuum at the heater valve, vacuum element that would close the heater valve. I manually disconnected the heater valve arm from the vacuum element and then cold AC air only was finally flowing out of all the cabin vents. I also used those brass seals on all my AC connections, guess it can't hurt. I'm in the process of getting into the console to see if all the vacuum lines are hooked up correctly, especially the red vacuum line from lever 1 to the heater valve. I'm real happy with the results so far and a real thanks here to the forum members, so much invaluable information here....

 

I have a 1977 450 sl I would like to replace the compressor manifold hose Needless to say I cannot find one..The suction side is a rubber hose with a very funky fitting on each end. Wondering if anyone knows if there is a place who could replace the hose or modify the manifold with a different hose.The hose is sealed by treads , I dont see any o rings or compression fittings, If you have any suggestions please email me at lblank1324@gmail.com

 

Did you check Mercedes? What is the part number?

 

I did and was told that the part is no longer available..They suggested I go to a hydraulic hose manufacture. I did they do not have a fitting that will match..

 

It looks like I will have to buy a fitting for a A6 compressor and make up hoses .

 

I used Cold Hose - AC HOSE REPAIR . They will create a replacement for any hose (they did all of them for my '76 SL)

They indicated that (if necessary) they could re-use the old ends, but in the end they used brand new end pieces. They appeared to be made from aluminum (rather than the original steel).

All the hoses fit, except for one that was an inch short. They re-did this and sent me a replacement.

One thing though - the hoses are not identical to the originals. In particular, the hose that travels along the drivers side fender (I think that is from Dryer to Evaporator) was originally very small diameter - the replacement was a lot wider diameter. This made it a little problematic to thread through all the other fittings, but I managed to.

I have not yet filled my A/C (I want to ensure everything else is working on the car first and get it on the road), but the hoses appeared good quality, and fit. I don't expect any issues with them. They were also very helpful on the phone.

-Steve

 

What was the cost of repair through Cold Hose?

 

Also...I think you might be referring to the A/C manifold that has the hoses 'integral' to it. The earlier cars don't have that (the manifold is all metal), so I didn't have the issue.

However, the manifold is available NEW as a reproduction from the SL Shop - Mercedes-Benz A/C Hose Assembly - 1171300957 | The SL Shop.

Edit: Just added a couple of photos of the original all metal manifold out of my '76. This might help determine if the earlier manifold would fit a later car.

 

Also...I think you might be referring to the A/C manifold that has the hoses 'integral' to it. The earlier cars don't have that (the manifold is all metal), so I didn't have the issue.

However, the manifold is available NEW as a reproduction from the SL Shop - Mercedes-Benz A/C Hose Assembly - 1171300957 | The SL Shop

Do you think an older model manifold would work on a 1977?? I may have to buy a block fitting that will fit the A6 compressor that has hose connections and build it from there. Only talking about 2 hoses.

 

My manifold is all metal except for the suction hose and it looks like it may have been leaking. cannot get any hydraulic shop to fix because the suction hose fitting is something I have never seen before. I have looked at the hose you reference it looks like it may work but I would like to hear that someone has used it on a 1977.

 

I've just posted a couple of photos of the all metal manifold from my '76, as it looked when removed from the car. Hopefully this might let you work out if it fits the '77 (my guess is it will)

-Steve