Hi, First, a thank you to all the people before who have posted tips, methods, and detailed pictures ot the web. Gives me much more confidence to attempt tackling such a repair. Much appreated.
I'll post my experience here as I had some variations relative to approaches described by others. Primarily, I ended up avoiding taking the speedo needle off to make the repair. And rather than gluing or peening the grey gear wheel hole to decrease the diameter of the hole for a better mechanical interference fit, I enlarged the diameter of the shaft where the grey wheel sits. Finally, I avoided the problem that the digits were mis-aligned when everything was reassembled again.
I found the following sources of info useful.
1)- Pull gauge cluster out as per
- Check if plastic gear or grey wheel are cracked (mine weren't). Using small screwdriver, try turning grey wheel on end of odometer digits wheels (grey wheel is on passenger side of odometer). Mine turned on the shaft so I guessed that's where the slippage was occuring. Also, using pliers I turned the shaft relative to the small plastic gear on the driver side end of the same shaft. The plastic gear seemed tight on the shaft. Everyone points to these 2 gears as problem areas.
- An observation that no one mentions the worm gear nor the plastic gear at the other end of the worm gear, furthest from the digit wheels, as problem parts. So focus on the grey gear wheel and the plastic gear on the same shaft as the digits wheels.
- I contemplated pulling the needle off the speedo but others cautioned that the spring can come out or break. I tried, but the needle is tight on the shaft.
- Instead I pulled on the small plastic gear with my fingers and pulled out the the attached shaft that runs through the digit wheels and the grey wheel. The shaft came out easily.
- I marked off on the shaft where the grey wheel normally sits.
- Using a metal work centre punch, anvil, and very small hammer, I put little divets into the shaft between my two marks. The sharp, raised edges of the divets (craters) effectively increased the diameter of the shaft. Others have suggested using ridged pliers to apply ridges to the shaft, but the width of my pliers is wider than the width of where the grey wheel sits on the shaft. You don't want to create extra friction either on the housing or on the adjacent digits wheel.
- I then reinserted and pushed the shaft back through all the digit wheels and finally through the grey wheel and out the otherside of the casing. I used a small upholstry hammer (couple of ounce weight) to tap the shaft back in. At first, it was too tight a fit going through the first digits wheel. Back to the anvil, I gently hammered the divets back down a bit (decrease diameter of shaft). Second try, the shaft went in with some resistance and I drove it home (lightly) into the grey wheel. If I measured correctly, that part of the shaft with enlarged diameter should only be where the grey wheel sits.
- On re-testing using a small screwdriver, I could no longer turn the grey wheel on the shaft. The divet edges securely grabbed the grey wheel.
- Re-assembly was reverse. Tip. keep everything clean so there are no smudge marks on your speedo face or debris beind the plastic window of your gauge cluster.
- In the end, I didn't have to take the needle off and I found the digits wheels lined up properly in each of their little "windows". No half numbers showing.
Other tips
- If you really need to pry the speedo needle off, cover face of speedo with paper or cardboard to avoid scratches (using the above method, you don't need to take needle off). Also, before taking needle off, raise the needle over the stop pin and let it come to rest. Compare the needle position realtive to the tiny reference paint mark on speedo face. That's where you position the needle when you put it back on.
- The gear mechanism is lightly oiled/greased. Avoid transferring lubricant to speedo dial face, hard to get clean again (yeah, that would be me).
- Lubricate the shaft lightly before reinserting.
- Lubricate gears with light grease before reassembly
- Check to see that the holes in the digits wheels and grey gear wheel are lined up with shaft before tapping the shaft with the hammer.
- Replace all 3 dash board lights while you've got the cluster out. This is your only expense on this job.
- Road test with bare minimum of dash re-installed. Don't want to take the trim off a second time in case something didn't work.
- Bentley manual suggests disconnecting battery ground before taking gauge cluster out. Seems like a good idea for avoiding a short.
- A trick I learned elsewhere: put screws and other small parts in the cups of an egg carton, in order of disassembly. On re-assembly, run through the cups in reverse order. Less chance of forgetting something plus it's a guide to the order in which the parts go back in.
Other things I found with the '85 Golf (A1).
- the trim around the gauge, heater controls, radio comes straight out, no fasteners, just some pins that go into holes in the dash. Pull straight out with your fingers and pry gently as needed. After 20 years, the plastic is brittle.
- As others have mentioned, the speedo cable disconnects from behind the speedo rather than from the black box beside the coil and coolant bottle in the engine compartment. Squeeze hard on the ridged plastic keeper and cable will slip off back of speedo. A really tight fit for hands though.
- Oh, the '85 Golf had 20 years use and 235,000 kilometres on it before the gear failed. Not bad.
-Tony Vancouver BC.