Tuesday, February 20, 2024

Hapy Speedometer Cable replaced

I mentioned in my last NewOldHouse posting that Hapy's speedometer suddenly stopped working on the way home from a party. It worked on the drive there, but didn't on the way home. Fortunately, there was lots of traffic for me to keep pace with ,but it's still annoying not having a speeod. Today's post covers the adventure of replacing the speedometer cable. Before I begin, today's my birthday, so Hapy Birthday to me, I guess.

working on concrete!
It makes sense to start with the symptoms I noted before the speedometer stopped working. Other than the obvious of it not working, during the drives prior, I noticed that the speedometer needle was bouncing an awful lot. This is often a sign that the cable is binding either due to age or because it hasn't been lubricated recently. Since it was the original cable, and I had never lubricated it (I know bad owner), I concluded that the cable had broken. Had I recognized these symptoms earlier, perhaps I could have prevented the failure. Ultimately, I am not sure the cable actually broke, but at this point in my process, my conclusion seemed solid. Before I began, I disconnected the battery. I did not want to pop a fuse or smoke another wire.

Someone posted on the Samba that replacing a speedometer cable took 15 minutes. I know better, and assumed it would take me hours, which proved correct. Because of the size of the holes through which the cable passes, it can only be removed one way: from the wheel up through the back of the dash. So, I started with raising the driver-side front corner and removing the front wheel, and then the grease cap. With a pair of pliers, I removed the hard rubber boot on the rear of the wheel (that the speedo cable passes through) and then pulled the cable through. I wiped off the grease and then got under the bus, pressing back the 2 sets of tabs that hold the cable to the underside. Then, the cable easily pulls through to the front of the bus.

Next, I reached around the steering column and detached the cable. In Hapy, the cable actually enters a converter box that creates a wave pulse for collecting speed and mileage for the TDI computer. I hadn't connected the wiring for that, but it was between the speedo cable and the speedometer. With the speedometer disconnected, I could pull it up through, feeding from below with one hand while pulling taught with the other. Once the cable was out, I tried turning each end, and watched the other end turn, albeit sporadically. So, the cable was good, but not working very well. Since I had a brand new cable, I decided to keep going.

cable lubrication
I took the new cable over to the side and started working silicone-based cable lubricant into it. My process was fairly simple: shoot some into the speedometer-end of the cable until it pooled up to the lip. Then, wiggle and turn the cable from the other end until the puddle disappeared into the cable sheathing. I repeated this may times. Once I was satisfied that there was a lot of lubricant inside the cable sheathing, I laid the cable flat so the lubricant could spread out and took a long lunch.

I added a little bit of lubricant to the outside of the wheel-end of the cable so I could easily add the rubber boot and then started my re-install. I had purchased 2 circlips for the wheel end of the cable and a new grease cap. I shot the new grease cap with some wheel paint so the brassy cap would not be so grossly out of place. 

I started by passing the cable from behind the dash, choosing to not pass it through the oval hole in the steering column support. Why? That hole seemed to prevent the cable from easily installing, and actually seemed to force the cable to bend unnaturally. By skipping the hole, the cable had a much more gradual curve back behind the dash. Time will tell if this was a poor decision. Finding the hole through the floor in the nose proved to be the single most time-consuming part of my process. Since I had added holes and electric cables, I had more wrong ones to chose from. Once I found it (there are 2 original holes, one directly in front of the other. The speedo goes through the one that's rearward), the cable easily passed through and I was able to route it the rest of the way to the wheel. I refrained from securing the secure-to-body tabs at this point so I had the most play in the cable at the wheel.

I slid the rubber boot on and then passed the cable through the wheel. I left myself plenty of excess so I could add the grease cap and circlip. I found, however, that the new grease cap did not fit. It is just a hair too small. After many attempt to make it work, I abandoned the new cap and switched back to the original. Because of the nature of the grease cap, I found the grease had found its way to the edge where the cap needed to seat on the wheel. With grease on that lip, the cap would not rotate with the wheel. I think this may have been part of the bouncing speedometer needle. To remedy, I cleaned the edge of the cap and the seating lip with brake cleaner, careful not to let it near the greased wheel inside. Once clean, the cap fit on correctly and rotated in time when the wheel spun.

Satisfied with the cable attached to the wheel, I added a touch of silicone grease to outer edge of the rubber boot and fit it into the hole. I tried to fit it without the lubricant, and it would force the grease cap off. With the lubricant, the rubber seated and the cable is set. I moved to the body-securing tabs next and closed them snug. Last, I returned to the behind the dash to connect the cable.

Extra Conditions
Hapy as album cover
It was at this point, that I started to question the quality of the speedometer cable converter box. When disconnected from everything, spinning one end of the converter had no resistance: is spun normally. If I connected it to the back of the speedo and gave it a spin, the needle would move. What was interesting was when I connected the cable to other side of the box. The output would not be fluid consistent. I could spin the wheel and see the cable rotate freely by itself but as soon as I connected it to the converter box, the converter box output was all over the place. At this point I concluded that the box was the main problem. Since I had not been capturing or using the output of the box, I decided to not integrate it, connecting the cable directly to the rear of the speedo like everyone else.

To test, I spun the wheel a few times and I could see the odometer slightly move in the 10th-of-mile. I concluded that the main issue was resolved. Since I was back behind the dashboard again, I needed to confirm I hadn't done anything wrong, so I verified the running lights, fans and hazards after reconnecting the battery.

That's it for today. While it was a little frustrating getting the cable replaced, it re-excited me about working on Hapy. I have a serious backlog of things I want to do, so if the weather is willing, and I have some time, maybe I'll get after one of them next weekend. Thanks, as always, for following along-

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