Mono Valve Repair Kit, what is your story? - PeachParts Mercedes-Benz Forum

whunter · #1 01-06-2006, 07:48 PM

Mono Valve Repair Kit, what is your story?

Don't deny it, I know you have a LOVE/HATE relation with the mono valve.

Who has the best mono valve DIY, and/or pictures?

Hit Man X · #2 01-06-2006, 07:51 PM

My story... the SD was missing the monovalve and aux water pump when I purchased it. The heat was ALWAYS on.

Once installed both, I could then control the climate within the vehicle.

I do not feel like spending $25 or whatever for the new monovalve guts, so I go used.

I've found three new ones out of the countless bad ones.

boneheaddoctor · #3 01-06-2006, 08:34 PM

Its so easy to do you don't really need a pictorial FYI....it takes longer to get the spare tire out of the trunk..........but then..much of this stuff comes to me as second nature......

Keith_otr · #4 01-06-2006, 09:38 PM

I was surprised how easy it was to replace the monovalve. On the "Easy to Difficult Scale", I'd give it a ".5" It quickly becomes a "2" if you drop one or more of the screws in the abyss.

Have fun doing it. There are very few repairs that are this simple that can make such a difference in your car.

Keith

whunter · #5 01-06-2006, 10:06 PM

Thank you Billybob

This is From TxBill's old site

http://mbdieseldiy.tripod.com/monovalve.htm

That is a fantastic mono valve DIY.

J. R. B. · #6 01-06-2006, 11:29 PM

Quote:

Originally Posted by Keith_otr

It quickly becomes a "2" if you drop one or more of the screws in the abyss.Keith

I used a magnetic phillips screwdriver. Mono-valve repair had to be the easiest fix on my car. I wish the rest would have been that easy.

Hit Man X · #7 01-06-2006, 11:50 PM

I find these S-Class pretty easy to wrench on.

kerry · #8 01-07-2006, 12:11 AM

My biggest complaint is that the stupid flimsy diaphragm is not available by itself (apparently). Why did I have to spend $50 for the whole guts when all I really needed was a $.50 diaphragm.

J. R. B. · #9 01-07-2006, 12:30 AM

Quote:

Originally Posted by kerry edwards

My biggest complaint is that the stupid flimsy diaphragm is not available by itself (apparently). Why did I have to spend $50 for the whole guts when all I really needed was a $.50 diaphragm.

I probably could have repaired my old one using diaphram rubber from a vaccum governor on an old Holley four barrel carb. But when I figure how much time it would take compared to installing a pre-made repair kit that I know is made of the right material I can't justify screwing around with it.

rg2098 · #10 01-07-2006, 01:10 PM

I love the monovalve compared to the old vac operated servo system I had in the SL. Never did get that thing working quite right.

pawoSD · #11 01-07-2006, 01:14 PM

I thought I'd have to repair mine this winter as last winter it was being mean to me and taking my heat away quite often, ironically, this winter it has given me heat every time I use it!

Very cool....I like being able to stave off repairs for an extra year (at least)

otto huber · #12 11-01-2010, 05:37 PM

I pulled one out of an '85 500SEL at the bone yard and dropped it into my 300SD. Now I have AC just in time for winter

. Seriously though, it will be nice to get cool fresh air in the cabin without having to wear out my window motors every day.

ashedd · #13 11-01-2010, 05:45 PM

not to hijack but I just pulled two really nice ones from the yard. I only need one for the SD. The other is up for grabs. Pm me

scottmcphee · #14 11-01-2010, 05:49 PM

If I didn't have two spares, I'd be tempted to replace a broken mono valve with a standard manual ball valve. Open it in the winter. Close it in the summer. Sometimes, just sometimes, Mercedes over engineers a solution.

ashedd · #15 11-01-2010, 05:59 PM

FYI...

I only recently figured out my diaphragm was torn in my TD, so I robbed one from my SD. This could explain... despite replacing almost all of the a/c AND charging with R12 my TD would not get real cold. I only assumed the mono valve was good to go.