Venturing out of the diesel forum for a little broader knowledge base here..

I've searched and found everything BUT how to remove the actual needle from the gauge itself. Specificaly on the oil pressure gauge. Can this be done without breaking something?
I need to swap out an oil pressure gauge and not the others if at all possible. Thanks..

83 300D

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Wolf, i'm not sure if this will apply to your 300 , but i recently put white face gauges on my 190 baby.
Basically after getting the cluster out , and removing the instruments, use a fork ( preferably a plastic one so you'll not scratch ) and easily pry it off. It will take a bit to do it , don't use too much force , take your time and eventually will pop out.
Now when it comes to placing it back , put the needle on top of the axe and gently tap it ( preferably with the handle of a plastic screwdriver).
When it comes to calibration, well i can post for the 190 , but i'm not sure it will help you.
In any case ( this applies to the 190 ) once you have the intruments out, will notice that as you move the needle it has a "min and max" position ( you can't pass those without getting resistance ). Make sure the "max" position will be next to 3 ( again this is for the 190, don't know if the 300 D has the same layout). Tap the needle in that position the let it free. As you will play with the needle will see that it will go to 3 ( as max position) and when you let go to the needle will go down to 0
I hope it helps.

I *think* our gauges are pretty close. I am reasonably sure they just have a friction fit holding them on, but a fair amount of pulling(with a metal fork, though of that all by myself too) has acomplished nothing. I'll hunt up a plastic one and give it another shot. Thanks..

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Got it, there just EXTREMLY tight on my two clusters. Plastic fork did not do, had to very, very carefuly use a small pair of needle nose pliers..

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Sorry I missed this "extraction" thread. Instead of forks, I use a pair of spoons, positioned 180 degrees or so apart, and using the curve of the spoon as a fulcrum, lever the pressed on needle from the pin mounting with a slow rocking motion.

My dad modified a gasket/band wrench, or "opens when you squeeze it wrench" by notching it to receive the needle shaft...it had flat ends and was not in risk of hitting the face.

then as the needle was 1/2 up or so we marked teh needle to the shaft with a scribe, sharpie, or the like (take your pick) and had a good reference to go back to.

i made up my white face gauges and put the needles back on after painting them red. no problems, although i some how misaligned the fuel gauge and it reads less than actual - i like it...helps me keep a full tank.

also...we did notch a set of flat nose plyers first and that worked well too.

as far as the speedo calabration is a little more involved as you need to align the speedo shaft, eddie current, and needle up.

Hope this helps
Jake

I use a curved hemostat and pry upwards on the bottom of the needle hub. One of those curved (90º) needle nosed pliers should work well, also. Before removing the needle gently lift it over the peg stop (if it's one with one) and mark the "at rest" position with a little triangle piece of tape. Makes replacement easier to the position you want. I also put some blue painter's tape on the face where I'm levering against so it doesn't get scuffed. Work in an area where it's easy to retrieve a "flying" needle. When replacing I'd advise to just press it on with finger pressure as they stay on quite tightly and you will want to remove it again, perhaps, for calibration. I've had to take the needles off a lot to get a fuel gauge and a converted econo-to-boost gauge just right.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

I had the same experience with moveing the gauge needles a bit after replacement. I actually took the opertunity to pull the fuel sender and verify it's reisitance value at full and empty as stated in the FSM. I really wish there was a middle value or so, half tank or something.

Ditto the actual gauge, it would be really nice to have a stated resistance value that should give say 80 degrees on the temp guage, half a tank on the fuel gauge, rather than trial and error.

I think I know a shade tree way to calibrate the speedo at a given speed, but I imagine there is a more techincal way to calibrate it that would lead to it being accurate at all speeds(maybe). I did not remove my needle, but it's been 5mph high at 70mph since I've known it, and never apart before. I believe it's either slightly more or less off the slower/faster off 70mph it gets.
But it helps keep me from speeding.

I can calibrate the temp gauge to a known good sender with hot water, a thermometer, and a meter to get the resistance reading I guess. Though mine's pretty darn close to where it was to start with.

The oil pressure, it's close, which is all it probibly was to start with if it's like any other OEM gauge I've ever checked. Mine peged 3bar at 1000rpm when fully warm, and it does so at 900rpm now. I may try and adjust it a little later.

Short of a T fitting and a known good(maybe)mechanical gauge to cross refrence it, I don't know a way to calibrate the oil pressure gauge on the bench so to speak.

Yes I'm a little obsessive..

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Use an inexpensive "watch hand remover" like this found here ($11):
http://shorinternational.com/WatchClockRemovers.htm

or here (nicer screw-typer one, $30):

http://www.ofrei.com/page_209.html

:-) neil
1988 360TE AMG
1993 500E

I believe it was Gilly who said there markings on the dial faces where the needle should be pointing when pressing it on to the shaft.

You then have to carefully lift the needle over the pin. I know this is true for the speedo. It gives a speedo jus the right amount of "preload".

haasman

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'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)