W123 Speedo is suddenly very sluggish

[joshx202]

First off let me pave the way by saying that I doubt anyone on this forum, possibly the world, could know less about cars than me...I have just began working on my 1982 240D after owning it for 5 years, and growing tired of shelling out money to auto mechanics I decided to get stingy and learn how to fix stuff myself...and got hooked! 27 years into life and found a great new hobby that I would NEVER be able to do without all the comradery and willingness to share knowledge found on this and other forums...you guys rock!

That being said I think I broke something:

Like I said an 82 240D, I took out my instrument cluster and cleaned my rheostat switch to restore light to my dash, and fixed the stuck odom with nothing more than a little bit of wiggleing the gears, it may get stuck again but the lights were actually my main priority at that juncture.

The problem is, while trying to get to the odom, I stripped the phillips head that holds the rectangular black speedo lead, I eventually got it off with some vice grips, pliers and a razor to shave the plastic, but in the process I did some "tapping" to the back of the speedo, not "banging", but some hard tapping...anyways I reassmeble the cluster and go for a test drive, now my speedo acts very sluggish, responds slowly to accel/deaccel and shows about 15 mph less than what I'm actually doing...

I've heard about calibrating, but should you do that everytime you remove the cluster, it was working just fine before. I'm wondering if I did lasting damage or did I not insert the speedo cable in all the way? Hopefully its something simple...thanks guys

[vstech]

Hmm. the speedo is cable driven, to the odometer, but the needle arcs from friction of the turning gear on a wheel... if you banged on it, or striped a screw, the friction may have warped...
I've got a few 240D speedo's what's your location?

[joshx202]

I'm located in southern Maryland, if I replace the speedo...should I be concerned about putting the old odom into the new speedo? Since the odom broke, it's probably had about 20,000 miles on it so it's already pretty far off.

[barry12345]

I would not be concerned about the displayed total milage. With some exceptions one can not be very sure about whatever is currently indicated on 123 diesel cars is accurate anyways.

I would either take the kind offer from the site member or get one at a pick and pull. You could ask him since he has several what they are currently displaying on their odometers. Remember that head has to come from a 240d. It is calibrated to the rear axle ratio and all 240ds where the same except perhaps for the 240 station wagon that was never sold in north america that I know of.

I am always happy to see individuals start to do their own work. To me the total upside is much better than the other way on older cars. Also it helps when having to make decisions on perhaps other cars in the future.

Unfortunatly too many people do not know enough and quite often get abused when purchasing paid for service. The frustrations and learning experiences can stand you in good condition to make future decisions as well. Unless you are really rolling in money the maintenance of a thirty year old car can become very prohibitive with everything hired out. It is bad enough with you doing the work sometimes. All members that service their own cars as much as is practical knew about as much as you do when they started. Todays cars are too complex in comparison except for brakes,suspension and minor things to start on in my opinion. The 616 engined cars set up is an ideal starter.

[joshx202]

Thats basically what it came down to Barry12345, we bought the car from my uncle who is one of those guys with oil in his viens, and he told me it was a great car to learn basic auto mechanics because of the simplicity and logic of the engineering...and as they say old car: new problems...so I have no shortage of things to fix on the car, lol. I would go broke trying to pay a mechanic to do all the work and plus, that wouldn't be any fun.

I've done very simple jobs so far, but am eager to keep learning. Fortunately, it also helps that the community of w123 (and other older Benz Diesels) owners are very supportive and willing to share knowledge/time.

vstech, I sent you a pm, can't thank you enough for the help!