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2012 CLS 550 sedan
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246 Posts
Discussion Starter #1 (Edited)
On the 80 450 I just got , the speedo has a top speed of 85mph. I’ve been looking at every SL I can look at. All the 1980s have speedos that go to 160 mph. What gives? Was mine changed somewhere along the line? I’ve see where some differences are electrical verses mechanical speedos. Are there other differences that I don’t know of or see? What are the steps for removing the cluster and either change the speedo or the entire cluster? What steps are required to change the entire cluster?
I also
Am changing the steering wheel. Anything I should not do, or should do?
 

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2007 ML320CDI, 1959 220SE, 1971 280SL, 1982 380SL
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710 Posts
There are differences in the speedometers. Most manufacturers use the same speedo in all the cars and vary the gears in the transmission. Mercedes has always used the same transmission gearing and installs different ratio speedometers. There are different electronic speedometers also. I hope someone has part numbers which will help determine which will work and properly interchange, I do not. My 380SL with the electronic speedometer had an 80mph speedo. I installed a 160mph speedo from the 560 and the calibration was correct. It was a plug-in installation but I suspect that the rear axle ratio matched between the 560 it came from and the 380.
 

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2012 CLS 550 sedan
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Discussion Starter #5 (Edited)

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1986 560SL with M120 V12 Engine, 1988 560SL Stock
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10,668 Posts
Good story about an 85 MPH speedometer. I never know if my old bosses stories are true or not but they all were bizarre and quite a few on occasion were proven true. I used to work in a Formula type race car shop about 35 years ago. This story occurred before I got there. The legend goes as follows: A few years before I got there the team running some Formula Atlantics in Georgia. One of the drivers wrecked as he always did multiple times so he ran out of spare parts. Joe, the owner of the shop made a few phone calls and was able to get one of the other car owners that was not present to sell him a set of corners (upper and lower control arms) that were at Joe's shop in Locust Valley NY. Now the problem is he had the parts but they were in Locust Valley NY and Joe needed them in Georgia the next day. So he decides he is going to make the drive for them. Well he didn't even get out of Georgia before being pulled over by a state trooper. The trooper asks him for his licence and registration and then says to him, "Joe do you have any idea how fast you were driving" Joe's replies "Well the speedometer only goes up to 85 but it was over here by the E". Allegedly Joe explains what he was going and the state trooper lets him off and tells him to slow down.
 

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1988 560SL 50K
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729 Posts
Had a new 1980 450SL "back in the day" and all US cars for a year or two (not sure the exact dates) had a mandated max of 85 mph. Thinking was it would save gas somehow. No idea how that was supposed to work and just made it an easier challenge to bury it.

I can't tell you how many time I pegged the needle. 1980 SLs are pretty pokey off the line due to the gearing but cruse very nicely.

Even stranger is also had a 1979 Ferrari 308 GTS that had the 85 speedo as well but that lasted about a month before it was replaced by one from a Dino. Sometime a guy needs to know if he's going 100 or 130.

But all you need is to replace the speedo with a 120mph unit. But keep the old one for proof of mileage and document the odo reading of the replacement as instantly convert the vehicle to TMU (True Mileage Unknown) which can be a hassle when selling a lower mileage car.
 

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'79 450SL, '04 CLK200 convertible; former A124, W210, A209.
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Interesting story and background with the 85 mph speedo, I always learn something interesting on the forum! Thanks for sharing.
 

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2012 CLS 550 sedan
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246 Posts
Discussion Starter #9
Had a new 1980 450SL "back in the day" and all US cars for a year or two (not sure the exact dates) had a mandated max of 85 mph. Thinking was it would save gas somehow. No idea how that was supposed to work and just made it an easier challenge to bury it.

I can't tell you how many time I pegged the needle. 1980 SLs are pretty pokey off the line due to the gearing but cruse very nicely.

Even stranger is also had a 1979 Ferrari 308 GTS that had the 85 speedo as well but that lasted about a month before it was replaced by one from a Dino. Sometime a guy needs to know if he's going 100 or 130.

But all you need is to replace the speedo with a 120mph unit. But keep the old one for proof of mileage and document the odo reading of the replacement as instantly convert the vehicle to TMU (True Mileage Unknown) which can be a hassle when selling a lower mileage car.
I’ve already made the mistake of selling my pristine 89 a couple of years back. I’ve been looking and found a 77, I was so eager to get one I grabbed it. Brought it to the best guy I could find and got my heart broken. Low and behold he had several he could sell me. Way out of my price range I found one in the back of his building(shop) that needed some loving and he could’ve I was serious , so he sold it to me and took the rust barge as a down pmt. so we put the two SLs together in a back building and I started taking what I needed to make a nice ride for myself. He’s changing the motor and I’m doing the fun things like learning on this forum from those who know and have experience. Which I am forever great full.
I learned yesterday just how small the two
Nuts are that hold the little chrome thingy that guides the tops in the center lock down on the rear deck!!! I’ve never seen nuts that small. It’s no wonder they use millimeters to measur things!
thanks all for the help and most all , the patience dealing with guys who think they know , but really don’t. God Bless is all.
 

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2012 CLS 550 sedan
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Discussion Starter #10
I changed the speedos from the 77 to the 80 today.
In all the things I've done with Mercedes Benzes in my life, this swap was one of the easiest things I've ever done.
Taking off the steering wheel was a breeze. Pull off the center pad, (no airbag) remove center nut holding steering wheel on, 22mm on the 77 and a Allen wrench on the 80. Both wheels came off with a slight tug. Then with a somewhat flexible putty knife slipped in around the cluster, working one side then the other, it came out about three inches, giving me enough room to remove the speedo cable and assorted wires. The rest is common sense. Take apart, clean, reinstall gauges and reinstall cluster. Under a hour.
 
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