I freshened up the transmission, and installed new seals in the speedometer drive side shift transmission on my 75 914.
After about 100 miles, the angle drive moved back toward the rear and bent/broke the speedometer cable.

I ordered a new cable, and moved and tightened the angle drive so it was facing toward the front of the car. After driving home today, it did the same thing and broke.

Is the angle drive supposed to be tightened so it can't move or is it supposed to spin freely when in place?

Anything else that could cause this condition?

Thanks!

if i recall the head pivots for freedom of motion but to move the head toward the back seems like too much cable slack. is it routed through the engine bar area and restrained at the clutch cable? this keeps it from moving around.

It is not supposed to spin like that when tightened. To me that is one of the indications of a bad angle drive. However, I suspect that most are like that at this point (so much so that people think it is normal), and they continue to work until the internal lubrication leaks out and they chew up the gears. That does seem to take awhile. So I think the angle drive is likely to be part of the problem, but maybe not all of it?

How are you securing the cable under the car other than the connection on the end (angle drive)? I would think that slack + the ability to move around = break.

Richard

Sounds like something, somewhere, is binding.

BTW, I drill a small hole in the tranny mount arm and safety wire the cable/angle drive interface to the arm. My intent is to keep the cable from falling to the ground when the angle drive breaks, something that's fairly common.

The Cap'n

Thanks for the replies:
I have the cable zip-tied to the same section where the clutch cable runs through the engine mount bar.
I have it zip tied to the clutch cable wheel housing (but does not interfere with its operation).
I have a new/unused angle drive and will try installing it. Maybe after 40 years and 118K in miles it's due to be replaced.
Good call on a permanent location for the speedo cable through the engine bar I'll give that a shot. Thanks everyone I'll circle back when I have the cable and angle drive in with some results.

I took the original angle drive off today. I noticed that if I pulled up slightly on the tab, it would bind-looks like that was the culprit. Unfortunately when it would bind, it absolutely would not turn, breaking off the speedometer drive gear tab in the process and the speedometer cable.

I have a new cable on the way and had a new angle drive replacement as a back up, now I just need the speedometer drive gear (posted in the WTB section).

Paul

Mine did the same thing, but it was caused by rotating the gauge vertical so I could see the most necessary mph numbers. Doing this introduced a bind that snapped the cable. I had to rotate the gauge, otherwise I was constantly dipping my head to see around the steering wheel to see my speed. To solve the bind, I shot the cable towards the glovebox, then looped it towards the firewall and then down to the tunnel. Fit like a glove and works perfectly.