Mercedes-Benz Forum banner

1 - 7 of 7 Posts

·
Registered
74 450sl
Joined
·
6 Posts
Discussion Starter #1
Trying to get ac working, r&replace compressor (A6-GMstyle),dryer,expansion valve,system charge will be with R12.
Probably will replace all three hoses, however i have concern mainly about the longest one, high side between dryer and expansion valve/evap...Anyone know what the Inside Diameter for this hose is to be? The literature i have access to only gives the length for each of the three hoses, two are correct, and the long high side is about 3inches short(75mm). I think maybe it was replaced at some point ... It is very different in appearance from the other two(red w/braid), black, very shiny and marking show it as 1/4"i.d.,where as the others are in metric ,i think, an 8 and a 10.
What really bugs me is, when looking into the hose, it does not appear to be near 1/4" but more like 1/8" to 3/16"...Should it be larger in diam ?

Anyone know what size diameter (i.d.)Mercedes intended for it to be?
I have also noticed from other threads that another compressor may have also been used on these early models, anyone know why? Would that have an affect on hose size?

Man ,:eek:its been hot here...
 

·
Outstanding Contributor
450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
Joined
·
22,569 Posts
I know the work on my compressor was a little frustrating getting the wrong tools for the clutch plate replacement. I expected metric threads and bolt sizes when many were sae. That's because it is a gm compressor. So having an sae size coolant line comes as no surprise to me. One of my lines is also red weave covered, but I believe the other is smaller with black insulation.

I am all set to vac out my system (free tool rental from auto-zone), but the heat is stuck on in my car because of some vacuum leak, most likely in the dash somewhere. Heck, I think I can hear it in the console at the ac knob switch. So I haven't even been driving the Sl in this heat. It is even too hot (and busy) to even get in there and try to fix the vacuum leak.

Back to your problem, have you been getting the part numbers from the EPC?
 

·
Registered
74 450sl
Joined
·
6 Posts
Discussion Starter #3
Back to your problem, have you been getting the part numbers from the EPC?
No, what is EPC?
Mostly I reference the on line manual and other material PO had.
PO had purchased most of what is being replaced, I thought might be good idea to do the hoses too. I guess the small size of that high pressure line is probably not a big deal since liquid refrigerant still has to travel thru expansion valve...
New comp already has new cluch on it, lucky for me-thats job 1 for today.
Removed expansion valved yesterday, also found OR DIDNT FIND screen/filter at exp valve missing...real bear to get to, pulled instrument cluster for access. Was good to find how outside air vent/flaps work via the older type dual vacuum lined servos, mighty vaced the one on drivers side and works well. Is it correct that, the round a/c knob is what operates the outside air vents? Was thinking if either show nonoperational, would just set them to closed...Unless?

Fonzi - i've almost had this car a yr now, learning how the acc controls work has been a hard trick for an old dog (lol),after last winter gave way to warmer weather i too had nothing but hot air. I confess i went the redneck route and disconnected the vac/servo from the hot water [email protected], as it's fairly easy to reach by hand to open or close valve. How is this servo controlled? Is it the two heat levers being all the way down/closed ,with either slightly raised/open ?
 

·
Outstanding Contributor
450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
Joined
·
22,569 Posts
RexC:

I assumed you had the lever system which I think is all vacuum controlled. I didn't think a 74 had a "servo" system, but I am still learning.
 

·
R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
Joined
·
32,357 Posts
He does have ACI. He is calling something else a servo. The fresh air flaps should close almost all the way with the AC knob rotated completely clockwise. Check the climate control section of the EGv107.
 

·
Registered
74 450sl
Joined
·
6 Posts
Discussion Starter #7 (Edited)
He does have ACI. He is calling something else a servo.
okay sorry Rowdie incorrect term , guess its a VACUUM ELEMENT that open/close the air vents and everything else on these cars. Kinda ironic, sometimes when i start my SL, i think i can hear that sucking sound that Ross Perot talked about in the 90's - But then i realize i have another vac leak...
 
1 - 7 of 7 Posts
Top