Reverse lights inoperable due to reverse shift rod rotating?

[slowpatina]

Will try to be brief. 1971 88" late 2A.

Reverse lights not working.

Pics show original Lucas reverse switch slider isn't being pushed by the black metal tab when reverse is engaged. The tab is too low and missing the slider trigger...
14020 14021

Cause seems because the reverse selector rod is rotated 'outward', which directly results in the black push tab rotating downward, and becoming too low, ie: black push tab moves as one with the shift selector rod.

Pic shows reverse selector rod rotated outward...
14022

I can get the reverse selector rod/black tab back to vertical with gentle hammer taps on a piece of wood but when engaging reverse again the rod and black tab just rotate again and the tab is back to being too low.

I have a temporary solution until there's time to remove the gearbox cover (internet pic below) and try tightening the reverse fork/arm mounting clamp bolt at the selector rod (red circle in below pic).

14023

...But a few questions before doing/trying all that:

1. Does the selector rod have a notch or groove in it that the reverse fork/arm clamp sits in when tightened? (ie: curious if the rod could slide back and forth in the arm/fork mounting clamp if the clamp bolt is too loose?)

2. How tight should the arm's clamp bolt be... is there a torque spec? (no luck finding it yet)

3. Assuming my 'loose bolt' diagnosis is the cause, is there any harm driving it for a while with the reverse selector rod rotated? (aside from at some point possibly not being able to get into reverse)

Thanks much.

[roverp480]

The selector shaft does have a notch/ groove , but there is an amount of slack to allow alignment of the two parts. The Series 3 manual states 20 lbf ft as torque and my fear of continues running could allow the bolt to come so loose it hits the case so you have bits of metal in the oil. or damages the thread such as to need a new fork. It would need a lot of use to do this but ! . When you take off the top cover make sure none of the detents and balls/springs get lost & fall into the box, worth following the manual about packing with grease. See attached picture
14025

[slowpatina]

The selector shaft does have a notch/ groove , but there is an amount of slack to allow alignment of the two parts. The Series 3 manual states 20 lbf ft as torque and my fear of continues running could allow the bolt to come so loose it hits the case so you have bits of metal in the oil. or damages the thread such as to need a new fork. It would need a lot of use to do this but ! . When you take off the top cover make sure none of the detents and balls/springs get lost & fall into the box, worth following the manual about packing with grease. See attached picture

Thanks very much, @roverp480. As always, your reply is perfect and extremely helpful. Much appreciate the diagram, too.

The Rover isn't driven daily, so, since the fork arm clamp seemed fairly snug around the selector rod when I did the hammer/wood-tap rod rotation correction/experiment, I'd guess (not always good to do!) there's some time before the clamp bolt potentially loosens more. I'll add the project to the list. Fix one thing, add another project... guaranteed tinker value on these rides.

Thank you once again!

[vlad_d]

@Elsa: Good on you for having reverse lights! My 1973 Series 3 didn't have them, so this is a treat to see the mechanism.

Another thing you could try is replacing the switch for one with some adjustment. There are a couple of candidates for this: a brake light switch, or door interior light switch. The brake light switches come with a threaded base and nut so you can adjust the fit...move it in and out to adjust the moment it connects the circuit. Its not a complicated circuit or switch. You could even add two plates sandwiched together with slotted holes in one , on the vertical axis. That would give you 2 axis adjustment. Up-down, and forward-backward. A little fiddling with the nuts and you could dial in exactly where it actuated.

I would go with a brass one over the plastic kind(a bit more durable):
https://rimmerbros.com/Item--i-575166P--SelectedCurrency-3?gclid=Cj0KCQjwlK-WBhDjARIsAO2sErR96JbfPaUI-2ykN_abS0ji4e7oLAAZC6wrefiuXDrI-Tg-bD1mP-caAnpQEALw_wcB

[slowpatina]

Thanks for the thoughts, @vlad_d. On my set up it's the vertical axis being an issue, so my temp solution was basically as you mentioned; I lowered the switch temporarily so the push tab now hits the switch trigger. But, I don't want to leave it like that forever for reasons mentioned above. When I have time I'll take out the flooring ...again ...remove the gearbox cover and check the fork bolt torque, etc. I'll need a chunk of time for that job as I'll likely replace at least the selector rod seals at the same time, and I'm not the fastest "mechanic".

[MJL]

Just in case anyone is interested, I posted a query back in 2017 about the reverse light switch on my 1972 Series 3.

https://forums.roversnorth.com/showthread.php?17047-Series-3-reverse-light-switch

A completely different set up, which I know is original (and still works).

Mike

[slowpatina]

Just in case anyone is interested, I posted a query back in 2017 about the reverse light switch on my 1972 Series 3.

https://forums.roversnorth.com/showthread.php?17047-Series-3-reverse-light-switch

A completely different set up, which I know is original (and still works).

Mike

@MJL, Your 2017 referenced post is the same set up as my above photos. The only difference seems to be my photos are of a late 2A vs. your Series 3.