How difficult is it to rebuild a A C servo - PeachParts Mercedes-Benz Forum

ray m · #1 02-10-2007, 09:11 PM

The a c servo is not working on my 1980 300d. The lines to the servo are hot but the lines leaving to the heater are all cold. A new on is far to much for me. I've checked the yards and couldn't find one. Is there a kit out there to rebuild one. Is it very complicated once you've opened one up. Perhaps someone knows of a DIYS tutorial i can link to. Is there a part of it that fails more often than the rest. Are there any places they sell them cheap. My car is a keeper, I would just like HEAT. Thanks RAY M

ray m · #2 02-10-2007, 10:57 PM

Does anyone think it could be my heater valve. I've never seen one of these but along with my servo i have a heater valve. see pic.

MB-Owner-in-ind · #3 02-11-2007, 09:41 AM

Where did you find that picture? I own a 79 and haven't seen that part. I think that the rebuild would be easier than finding the parts for it. There are several places that run auctions on E-Bay that rebuild them for aprox 350 exchanged. This is the way I would go.

ray m · #4 02-11-2007, 09:50 PM

Quote:

Originally Posted by MB-Owner-in-ind

Where did you find that picture? I own a 79 and haven't seen that part. I think that the rebuild would be easier than finding the parts for it. There are several places that run auctions on E-Bay that rebuild them for aprox 350 exchanged. This is the way I would go.

I found it on ebay for $17.00 Item number: 300079746973
I don't understand why I have both. or are they both suppose to be there. RAY m

kerry · #5 02-11-2007, 09:53 PM

Perhaps someone has bypassed the servo in the past. There shouldn't be a heater valve and a servo. The servo serves the function of a heater valve.
I don't recall anyone successfully rebuilding a servo on this board. A used, rebuilt, and the new solid state ones are your best choices I think. Or, bypass the hoses (which may already have been done).

retx · #6 02-11-2007, 09:59 PM

ray, kerry
i have the servo and the valve. well at least i have a valve that looks a heck of a lot like that, just next to the firewall on the passenger side.

ray m · #7 02-11-2007, 10:04 PM

Quote:

Originally Posted by retx

ray, kerry
i have the servo and the valve. well at least i have a valve that looks a heck of a lot like that, just next to the firewall on the passenger side.

Thats exactly where mine is. The vac line that goes to it comes from the servo. it is a white vac line. Do you think this was an unsuccessful attempt to by pass the servo. RAY M

MTUpower · #8 02-11-2007, 10:02 PM

when you suck on the line does the part move? if it does then the part is good.
Your A/C servo is like a giant watch. my 1980 300TD and I went around this issue for a year before she would work properly- and that was because I had acces to a/c servos in the yards here of south florida. Lithium grease, digital pics and a steady hand are your friends if you intend to repair your current unit. I could find several unit in the yard her that may or may not work- but my cost is $40-$60$- no testing at all- and I have a 30 day return. Finding, pulling, packing, shipping and taking the risk of returning and non payers makes the do it/dont do it value to me in dollars about twice my cost. So take yours apart, slowly, carefully, with pics, and see if you cant fix it- if you are mechanically inclined and have tools. If not, buy a $15 12 volt space heater.