Removing R4 compressor questions - PeachParts Mercedes-Benz Forum

funola · #1 08-11-2016, 11:11 AM

What size and type is the special fitting you need to connect to? Couldn't you replace the metal suction line across the engine with a hose with fittings?

Demothen · #2 08-11-2016, 11:41 AM

Quote:

Originally Posted by funola

What size and type is the special fitting you need to connect to? Couldn't you replace the metal suction line across the engine with a hose with fittings?

I thought about that. I'd need to add a low-side fill port at some point in the system. I talked to the rebuilders and they said that the crimp from the crossover tube to the compressor is the most likely to fail due to the extra strain caused by the sharp angle and thicker hose that curves down to the compressor. They offer a new metal line & hose assembly for that area for a very reasonable price, and I'm at the point where I really just don't want any more work to do - so I am going to order that. I'm also going to be cutting the TXV side crimp and end off and having a new slip-over fitting brazed on over it. Fortunately a member of my family is experienced in brazing high pressure systems, so I'll bring him the assembly when I'm in town shortly.

BillGrissom · #3 08-11-2016, 05:30 PM

Quote:

Originally Posted by funola

What size and type is the special fitting you need to connect to? Couldn't you replace the metal suction line across the engine with a hose with fittings?

Re-read my post #9. Re-use the outer fittings, just add new hose.

If you do want to procure new fittings, it will take detective work. I think they are an O-ring fitting w/ metric nut and perhaps not even the same tube size as SAE O-ring fittings. That is why Rollguy decided to just braze an old M-B fitting to form his custom hose assemblies. Don't assume that Europe was standardized on fittings in the 1980's. A Wheeler Dealer's episode explored that when trying to source a hose for an Italian sports car in England. They said Lamborghini (?) used an unpredictable mix of various fittings. Ditto for other rare fittings on your M-B.

funola · #4 08-11-2016, 07:03 PM

Quote:

Originally Posted by BillGrissom

Re-read my post #9. Re-use the outer fittings, just add new hose.

If you do want to procure new fittings, it will take detective work. I think they are an O-ring fitting w/ metric nut and perhaps not even the same tube size as SAE O-ring fittings. That is why Rollguy decided to just braze an old M-B fitting to form his custom hose assemblies. Don't assume that Europe was standardized on fittings in the 1980's. A Wheeler Dealer's episode explored that when trying to source a hose for an Italian sports car in England. They said Lamborghini (?) used an unpredictable mix of various fittings. Ditto for other rare fittings on your M-B.

Do you know what the core of the OE Mercedes hoses are made from? Just want to make sure I use compatible flushing agent on them. For now I plan on re-using all hoses if they pressure test good. I have 2 more hoses to do. So far I have found no leaks, including the compressor, which I had under water and no bubbles!. The first time I tested the compressor was still in the car. I did a input suction and output pressure test by hooking gauges to the inlet and outlet and cranking the engine. I got good vacuum and pressure. I did a pressure and vacuum test with the digital test set and it held vacuum but leaked badly with pressure. I think it may be due to the sad shape of the o-ring on the high side fitting by the alternator (see pic below). There are other o-rings in similar condition. If everything pressure test good, I will just install new o-rings and charge it with R12 and PAO 68 and see how it works out. If it fails, I'll consider barrier hoses then.

ROLLGUY · #5 08-12-2016, 12:48 AM

I will try to reply tomorrow with some photos, showing the different fittings.