300D vs 280 (gasser) odometer gears... - PeachParts Mercedes-Benz Forum

jesserobot · #1 07-20-2008, 09:22 PM

So finally got around to replacing the ignition switch on my 85 300D. Decided while i have the instrument cluster out I should look into fixing the broken odometer and the instrument cluster housing. The odometer and trip hasn't worked for a few+ miles so it was about time.

I went to the local pullapart and found a nice instrument cluster intact in a 83' 280. The housing was the same so for $12 I figured it would be worth it to see if the odometer worked. It had roughly the same about of miles (minus the ones since mine stopped working

).

Switched out the housing and the speedo/odometer and hooked everything back together and viola! The odometer worked! But now the problem is that it is not calibrated the same as the old odometer. The speedometer reads slower and the odometer records less miles.

My question is... do I just need to switch some of the gear(s) out of my old speedo and put it in the new one or... is there some kind of calibration that needs to be done (and is it easy to do)? And which gear(s) need to be switched if that is what needs to be done. Anyone ever dealt with this issue???

79Mercy · #2 07-20-2008, 09:51 PM

did you buy the whole cluster? If so, does it have a tachometer in it with a silver center cap? If it does I want it, how much.

#3 07-21-2008, 01:13 AM

Quote:

Originally Posted by jesserobot

My question is... do I just need to switch some of the gear(s) out of my old speedo and put it in the new one or... is there some kind of calibration that needs to be done (and is it easy to do)? And which gear(s) need to be switched if that is what needs to be done. Anyone ever dealt with this issue???

No. The speedometer is calibrated to match the rear end ratio of the car it was designed for. Your car uses a 2.88 rear end while the 280 uses a 3.54. The only way to fix it is to get another speedo from an 85 300D/TD/CD.

jesserobot · #4 07-21-2008, 08:20 AM

it is the whole cluster from the 280 and didn't have a tach. it had the bigger clock instead. i can make you a good price on that...

so for the speedo I will have to use the original one. that would be easier than switching out the rear end. the speedo was still working, just the odometer and trip were broken. would it be possible to use parts from the 280 odometer to fix the 300D odometer since it should be all the same gears/parts? i guess I will have to pop it open and see what is broken first. thanks for the info.

vstech · #5 07-21-2008, 08:37 AM

http://www.dieselgiant.com/repairyourodometer.htm

jesserobot · #6 07-21-2008, 08:42 AM

thanks for the link. i just ran across that as well. are all the images not showing up for you too?

i will try this tonight and see how it goes. i have gotten way too good at taking all this stuff apart. sheesh...

dannym · #7 07-21-2008, 12:41 PM

www.odometergears.com

79Mercy · #8 07-21-2008, 01:36 PM

I have a clock, thats my problem, I want a tach. Does the fuel/oil/temp gauge have a silver center cap, is the temp gauge in F or C? I maybe intersted in that at a good price.