w124 Speedometer Spring fix?
 

So my speedometer stopped working a few months ago. The odometer works fine. Opened it up today and looks like its the coil return spring that is disconnected.

Is this fixable?

The loose end should fit into a slot somewhere, and it's held in place with a taper pin. I have lots of taper pins from working with clocks, if you need on drip me a PM and I'll send you one. I may also have a spare 124 speedometer somewhere. Just let me know.

spot on
 

Just repaired mine . Well i have repaired a few of them now..Dont remove the pointer or the speed will be out when you replace it .Also as long as the spring is still in place all you need to do is get a retaining pin .Look inside the speedo you might just come across it in there .

Well I had to remove everything to find the retaining pin that got pushed in flat somehow, I see how this is held now..
Since the spring has been removed, how do I know what the correct spring position is to put it back in the right place and make sure it all works as designed?

The right answer is that you'd have to calibrate the speedometer, but that's probably more than you want to deal with. You should be able to get pretty close by observing the bends in the spring. It should have been bent to about 120 degrees where it enters the block, and will be indented where the pin held it in. If you can't find those marks, post and I'll try to explain how to calibrate it with an electric drill.

ps2cho go to Google search,, look to the top right for = images click on it . Then just put in the search box -

124 Speedo Disassembly With Pictures .

Did some further searching and found this thread:
www.peachparts.com/shopforum/diesel-discussion/238488-backyard-speedometer-adjustment.html

Explains what I have to do - I’ll see if I can get it figured out. I don’t care about perfect accuracy but within 5% should be fine.

So put it back together, odometer continues to work, but the speedometer is bouncing all over...10mph (actual) its bouncing from 0mph to 80mph. It used to wobble before, but not this bad..

Is this related to the spring, or did my prior issue just get worse? (i've previously replaced the speedometer cable, but no change)

EDIT: I got my dewalt drill on the back of the speedometer head, 2000rpm on the drill held firm at 30mph (uncalibrated speed)...no bouncing...so must be the cable then right?

A few things could cause this. The first thing you want to do is to determine whether the problem is the cable or the speedometer. To do this, you're going to need to pull the pod again.

You need to make a short cable to drive the speedometer. One way to do this is to get an old cable and cut about four inches out of the end. If you don't have a spare cable, get a finishing nail and file one end square. What you want to do is insert one end of your test cable into the speedometer, and drive it with an electric drill (if the drill is rated at 1200 RPM, it will drive the speedometer to about 70mph). Observe the action of the needle. If it's smooth, the problem is with the cable or transmission end.

If it's the speedometer, remove the face and try the test again. If the spring compresses smoothly, the problem is the spring or needle interfering with the face, which is easily fixed. If not, the drag cup may be impinging on the magnets, or the mechanism may need a clean and lube. Either way, observation is your friend.

If it's downstream, then begin by pulling out the cable and applying a light coat of grease to the lower 2/3 of it's length. Replace the pod and see if you're ok. If not, the speedometer gear may be slipping on the tailshaft, and that's a difficult fix.

Well when I spin the speedo using a drill it didn’t wobble...are you saying remove the speedometer cable entirely and grease the cable section that runs close to the side of the transmission, or where it enters the speedo head?

I know the issues not at the transmission end because it wobbled on my old transmission, got a replacement and it still wobbled after, so it’s likely the cable (although I replaced that too a while back...but applied no grease)

Yup grease the portion of the cable nearer the transmission. You probably should pull the cable completely out of the sheath, and clean & inspect it.