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+--- Thread: Three speed crash box (/showthread.php?tid=9390)
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Three speed crash box - Colin D Smith - 29-05-2024
Hello.
I would like to sort out the gear stick on my 29 chummy.
My question is how does the gear stick come apart to facilitate welding the ware on the casting.
RE: Three speed crash box - Colin D Smith - 29-05-2024
Sorry if me questions seems a little
abrupt. I'm at work and trying to type on my mobile device.
Any help would be great thanks
RE: Three speed crash box - Mike Costigan - 29-05-2024
Early 1929 cars had the gate-change lever, late 1929 cars had the ball-change lever.
These can be seen on page 30 in the relevant parts lists:
https://archive.a7ca.org/wp-content/uploads/PL_670.pdf
https://archive.a7ca.org/wp-content/uploads/PL_670B.pdf
The early cars can be dismantled by removing the three vertical set screws to split the assembly, whilst the later gear-lever is removed by undoing the single horizontal screw and lifting the lever out.
RE: Three speed crash box - JonE - 29-05-2024
The ball change one needs the big hollow threaded retainer/ grub screw thing removed from underneath to expose the casting.
RE: Three speed crash box - Alan - 29-05-2024
Not sure that’s right, Mike. The ball change lever withdraws from below, having first removed screw Bh 119 and threaded ring BH 118.
RE: Three speed crash box - Mike Costigan - 29-05-2024
Silly me; of course it does!
RE: Three speed crash box - Colin D Smith - 29-05-2024
Thanks for the information chaps..
The gearbox on my car is the older type gate-change lever.
With the grear stick in my hand, how does one take it apart! I can drill the rivets out of the reverse lift up rod thing, but that would only get me so far as the aluminium knob looks like its riveted to the stick. I have no idea how the ball is fixed on the selector end. I don't fancy cutting the gear lever in half just to make the repair..
RE: Three speed crash box - Howard Wright - 29-05-2024
Hi Colin
I think the shaft is peened over the aluminium ball.
I have replaced the old ball on my Special with a modern aluminium ball that came with an M8 females thread. By grinding the shaft to approximately 8mm I was able to use an 8 mm dye to thread it. Perhaps not for the purist but it worked for me.
Howard
RE: Three speed crash box - Tony Griffiths - 29-05-2024
It would help to see the problem if you could post several clear pictures of the area showing wear. There might be more than one solution to the problem.
RE: Three speed crash box - Colin D Smith - 29-05-2024
The ball on the end of the gear stick that moves the gear selector has a steel pin going through it. This steel pin protrudes from the ball 5mm on either side and this protrusion has worn the aluminum slot that it rests in. The aluminum casting with the gear selector gate is the top part and the bottom part is bolted onto the top of the gear box. These two parts encapsulate the gear selector ball and pin. The pin allows for the gear stick to move side to side, forward and back while not allowing any rotational movement however, over time the steel pin as worn the slot in the aluminum into a fan shape allowing the gearstick to rotate.
When changing from 1st to 2nd this rotation has the undesirable effect of enabling the shift not to stop against the reverse stop but ride over it. Not great! So I have adopted slapping the gearstick into neutral before moving to 2nd.
Taking the gearstick apart to remove the upper casting from it would enable me to weld up the slots and machine a new ones. Thus as good as new.
Taking the peening off the aluminium ball may be the way to go. I suppose I could make up the metal with brass and repeen it.
The bottom of the upper casting without the pin in place