This is a great write up and pictorial. This needs to get placed in the DIY Articles.

A new Rheostat is about $90.00 by the way.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I should point out that in 4/5 cases of a failed rheostat I have dealt with, the resistance coil itself had completely disintegrated. Thus, a repair would be impossible unless a new coil could be sourced.

An excellent write up though, that process would work well for units that are only suffering from corrosion.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Thanks Charlie, I had no idea what a new one would cost. It's nice to have the rheostat working again, but the working rheostat reveals that I have some console bulbs to replace.

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

Well that would certainly put a damper on the fix. Thank you, I didn't realize it was that severe in that many cases. Luckily, you can see part of the coil without disassembling the unit, so at least you could get a sense of how good or bad the coil might be to decide if it is worth cleaning, or if jumping the rheostat is better.

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

I must admit this is one of the best write ups I have read on this site. I'm sure there are other good ones to as this site is amazing to say the least.

Very complete and extremely well written.

From reading it I feel like I had just accomplished the task!

In fact time for nappie! Great Job!!

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1982 300SD

My car had a semi working rheostat when I bought it. It eventually quit working all together. In the meantime I did a lot of twisting the knob back and forth till the bulbs lit up sufficiently. When the rheostat failed completely, I could feel that something, was hung up on something.

I took mine apart too, to see how it works and if it could be fixed. IMO it was beyond fixing, and I didn't want to lose functionality - so I bought a new one. When I opened up my Rheostat/Potentiometer, I was a little shocked to see how corroded it was inside. Two and a half years ago they weren't $90. Mine was $58.34.

I'm guessing the combination of living near the beach and a leaking windshield seal were the culprits. (28 years, is not a bad service life, though.)

As pawoSD mentions above, the coiled wire had coroded all the way through. What was left of it was stretched and bent from me twisting the knob back and forth after it broke.

I performed a few more steps while I had my cluster removed. Because the plastic tube the light passes through had become somewhat discolored, I painted the insides of the tubes with an ultra white paint. It's the flat white basecoat for my Pearl White Lexus. That lets a lot more light come through. I also repainted all my needles with signal red. I blended fluorescent orange with a little red, but it's still a little redder than the original, which to my eyes looks more like a pumpkin color. It's always bugged me how the needles fade unevenly.

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1979 240D, 4spd manual, Power Sunroof, manual windows, 147k miles, Pastel gray/Black MB Tex.
1991 300D 2.5 - Smokes like it's on Crack!

Perfect timing on the well-done DIY thread since I just discovered my rheostat only worked at between 6-9 volts. I refurbed it and all is well. The console lights work now.

One other tip I used for re-installing the gauge cluster - since the carpet/felt/cloth insulation is no longer glued to the dash above the cluster, I had a hard time getting the gauge back in without jockeying it around. I used a thin piece of cardboard (like cereal box thickness) as a guide/shim between the cluster and the insulation. The cluster slid smoothly across the cardboard and went it was almost in place I slid the cardboard out - a lot like using a shoe-horn. The IC seems to fit better in the dash this way.

I also used Stabilant 22A on the rheostat and the dash bulbs. Removed and replaced the bulbs a few times to loosen or remove corrosion, then put the Stabilant on for the final re-install.

Well, thanks for saying so, but you should also check out the DYI articles section if you haven't. Based on the complexity of the task, I don't think it can really compare to some of the great DYI articles (i.e. dmorrison's insanely thorough 123 AC evaporator replacement or bgkast's 123 front end suspension rebuild - which I will be thankful for when my replacement parts show up).

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

Glad someone got some use out of this. Thanks for the tips on reinstalling and using the Stabilant 22A - I've never used it, but might give it a try.

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

DMORRISON`s write up`s are incredable, college level.

I do a project, take pictures, document everything I do, then when Iam done and go back and look it all over.

Iam still in kindregarden doing finger painting .


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Maybe he's tripp'n from dropping too much LCD.

__________________
1979 240D, 4spd manual, Power Sunroof, manual windows, 147k miles, Pastel gray/Black MB Tex.
1991 300D 2.5 - Smokes like it's on Crack!

Well, you never know what kind of mods people are putting in these days - maybe I have seen too many episodes of Pimp My Ride. vstech has a good point though - assuming he did mean LEDs - that would brighten things up, of course the color might seem a little off. vstech or anyone else done this?

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

Or you could just solder a jumper across the two pins with the rheostat in place.
The pic shows this done in front, but you can do the same thing in the back, at the bottom two points.

Attached Thumbnails

 

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83 SD

84 CD

Two quick questions on this (great DIY BTW).

1) does the black knob have to be pulled off first from the frontside?

2) not to be too lazy or anything, but if one didnt want to break all the connections and take the risk pulling the cluster, how feasible would it be to unscrew the rheostat from behind and just pull it off with the cluster in place or just pulled out into the gap between its hole and the steering wheel? Sure it is a bit tougher to do it by feel, but there are other benefits to doing it this way.

Thanks!

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)

Any idea if you could do this refurbishment on an 84 W126?

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1984 300 SD 384,000 Miles