Author Topic: Servo replacement with Mercedes Fix unit  (Read 113 times)

jjccp

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Servo replacement with Mercedes Fix unit
« on: 14 April 2019, 01:29 PM »
I spoke with Davis who makes the unit. He took the time to answer my questions and I ordered one. Here's what came in the package. I'll start installing it soon. My ultimate goal is to get the air conditioning working again. I've been reading everything I can to see what the best approach will be to get the a/c going again and would appreciate and tips or advice.

1977 280 SE
1979 6.9 #6846

Harv

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Re: Servo replacement with Mercedes Fix unit
« Reply #1 on: 14 April 2019, 02:21 PM »
I believe Davis had an account here and even posted a few times.
1980 300SD
1983 240D
2000 E55 AMG

OLDGOLD

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Re: Servo replacement with Mercedes Fix unit
« Reply #2 on: 14 April 2019, 06:48 PM »
I bit the bullet on the Unwired Tools ACC servo upgrade last year and it was one of the best things I ever did to my car. There are some things that are better left stock, the servo isn't one of them!

jtwoods4

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Re: Servo replacement with Mercedes Fix unit
« Reply #3 on: 15 April 2019, 04:03 PM »
I went a little bit different route and both of my w116 300SD. I replaced the cracked servo housing with the aluminum housing replacement. Works outstanding and connects to all the existing factory connections. I really don't remember the company I purchased from but it did a quick internet search and came across this link I'm pretty sure this is where I got it. It was years ago.

http://www.perfanalysis.com/climate-control/acc-version-i/
1980 300SD

jjccp

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Re: Servo replacement with Mercedes Fix unit
« Reply #4 on: Yesterday at 12:54 PM »
jtwoods4,

I put the aluminum housing servo in my 6.9 several years ago and it's still working fine. I went a different route this time because it only costs $350 for the Mercedes Fix unit. Beside the servo cracking, it's still prone to other types of failure.

Now that I have my car tore apart, I've found that the little auxiliary water pump is bad. I can't believe what some people want to charge for them. I took apart the electric motor and did my best to troubleshoot it, but I can't get it working and I'm not spending $600 for one.

I wonder if anyone has a suggestion for an alternative pump that might work or does anyone have a working auxiliary water pump I can purchase?

1977 280 SE
1979 6.9 #6846

daantjie

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Re: Servo replacement with Mercedes Fix unit
« Reply #5 on: Yesterday at 01:04 PM »


I wonder if anyone has a suggestion for an alternative pump that might work or does anyone have a working auxiliary water pump I can purchase?

Yup, I ran into this a while ago, those pumps are horrendously expensive, and do not even think of putting in a crap MTC brand one.  Here is one I found:

https://www.ebay.com/itm/Mercedes-Benz-Sprinter-Auxiliary-Electric-Water-Pump-BOSCH-0392020026-MB-/132679176767?_trksid=p2349526.m4383.l4275.c1#viTabs_0

Full disclosure, have not tried installing this one as my original still works fine, but if it does go tits up I will for sure swap it out with this bad boy.

Also on amazon:

https://www.amazon.com/Bosch-Electric-Water-Pump-0392020026/dp/B0083HR744



Daniel
1977 450 SEL 6.9 - Astralsilber

jjccp

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Re: Servo replacement with Mercedes Fix unit
« Reply #6 on: Yesterday at 01:12 PM »
Daniel,

Thanks for the link. That's a more reasonable price compared to the other one's I've seen. Just curious, how did you determine that this one is compatible?
1977 280 SE
1979 6.9 #6846

daantjie

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Re: Servo replacement with Mercedes Fix unit
« Reply #7 on: Yesterday at 02:13 PM »
Well to be honest, I eyeballed the thing, looked at the connector which should fit, might need minor modification on the plug side.  Also it runs on 12V, so all is good there.  I would say if you want to be absolutely sure you would need a flow/pressure test of sorts to compare them, but I would be shocked if there is much difference between the 2, other than the knee buckling price :o
Daniel
1977 450 SEL 6.9 - Astralsilber

jjccp

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Re: Servo replacement with Mercedes Fix unit
« Reply #8 on: Yesterday at 05:04 PM »
I agree with you. An auto engineer friend of mine told me that without knowing the actual specs, if the inlet size and outlet size of a pump are similar to the subject pump and it's 12 volts, it should be fine.

I think you are on to something, thanks. I'm checking a couple of other sources and it they don't pan out, I'm going to try your idea.

Of course, the originality police would have me buy the OEM unit for $600. I like keeping everything as original as possible, but I won't lose any sleep about using a substitute.
« Last Edit: Yesterday at 05:17 PM by jjccp »
1977 280 SE
1979 6.9 #6846