I didn't buy a kit but had a known working monovalve from a 123 that I stole the guts out of and inserted into my 126 monovalve. it has an extra connection on it.
Anyway, is there a trick to installing these parts?
I just pulled the top cover, took the entire guts out and inserted into the body then replaced the cap.
probelm is the thing doesn;t seem to be consistant and either gives me full heat or no heat. I do not hear it cylcling making me think I installed soemthing wrong here.
Thanks in advance.

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'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

I recently installed a monovalve repair kit in my 300D. It gave full heat most of the time (but not all of the time). I removed the monovalve assembly so I could connect it to a 12 volt supply and see what it did. What I found was that the plunger was a tight fit in the bore, so it would physically stick partially open. I took it back and got another kit, now all is well. Bottom line is, you could have a simple mechanical problem like that. i's easy to take it out and test it using a battery or other 12 volt supply.

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Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

They decided to tuck them down behind that firewall and it is a pita to get to the hoses.

I presume I could test it in place though. I noticed that the top screwed down and seemed to have to go another 1/8 inch before sealing so I wonder if I get that gasket crossed up in there?

Thanks

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

It's at least sort of like that on the 123 as well. When i replaced my monovalve (just the guts), I disconnected it from the firewall first. After that, I could move the monovalve to a point where I could get to all 4 screws and pull the guts out without the firewal lip being in the way.

Maybe it's different on a 126...

Hope that helps some...good luck!

I had a little trouble with my monvalve a few months back just around the time when I needed the heater to work. The problem was it was only getting current intermittantly. I found the that the electrical connections were a little loose and I cleaned and bent the terminals a little and then coated the connections with some dielectric grease to keep the connections clean and constant. I also tested it by listening to it when I turned the heater switch on and off with the key in the on position but without the car running.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

The upper gasket was blown out on the thing. Luckily I had another monovalve with good gaskets, put them in and voila. I have no idea how long this will last but if it gets me to and from SF on my trip next week that suits me just fine.
Thanks

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'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

The cost of a rebuild kit being what it is, I don't bother with used parts on the monovalve. I'd rather fix it once and get on to other things.

Just my $.02,

Cheers,
Wes

I concur but when you need to fix it and the parts are at least two days out and you have a trip you have to take I will put in whatever I can find to make it work...

I'll order the kit when I get back or while I am in CA since they have dealers that actyuially stock parts for the 60's vintage cars.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique