speedometer gearbox spacer

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rgrigutis

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pulled my rear wheel to change the tire. a washer/spacer fell out from somewhere. parts illustration would suggest speedo gearbox spacer, doesn't seem to fit there tho'. it's about 1 1/4 od x 7/8 id and about .020 thick. i remounted the wheel and when i torqued the axle nuts the wheel got tight. i'll try to fit it to the inside of the speedo gearbox and see what happens. hopefully someone can identify this and get me on my way. thanx, rick
 
Perhaps part number 35 in the below diagram?

http://www.oldbritts.com/1973_g20.html

You really have to use a little "oomph" to fit all the parts in on reassembly. I used to have a heck of a time, til I realized that it take a bit more levering in of parts than you might have thought. Now I cheerfully shove them in there and all is good.
 
And then, too, you might have gotten the dogs on the speedo gear out of alignment with the hub and that's why it's too tight?
 
no. 35 is the thick washer under both axle nuts. this thing doesn't seem to fit anywhere. it's only about .020 thick, just enough to bind up the wheel if it was missing. thanx, rick.
 
Sometimes people put spacers in to take care of the "top hat" spacer, Item 31 because sometimes it gets short. Bottom line is the gearbox assembly must have the dogs in the correct position and the gearbox must not rub on the wheel hub cover item 36 or things will bind and not work right. Is the hub cover worn where the gearbox is next to it? Worst case the gearbox will rotate and break the spedo cable. There are some threads on this issue if you search.

Dave
69/70S
 
speedometer gearbox spacer
 
I found I had to change the position of the "outer" spacer washer on my MkIII's rear wheel (different assembly to the diagram above) to space it away from the sprocket (drive box is on the sprocket side on a MkIII) stop the box rubbing.
 
aha! oho! put the spacer on the top hat and that seems to be the trick! i've yet to remount the speedo gearbox but i think it's ok. i'd of really been scratching my head a while w/o your help. thanks much, rick
 
alas, my euphoria is shortlived. put the speed gearbox back on and it got tight again. i believe my problem is the gearbox spacer. i enlarged the parts manual illustration to try to get a better view of it but i'm a little confused.

is the gearbox spacer pressed into the gearbox or is it separate and riding between the axle spacer and gearbox?

it would seem to me that you could shim the inside of the gearbox to keep from rubbing the gearbox on the cover. that's where my interference is.

sorry for making something that should be simple into something that's complicated
 
I swear someone had the same problem recently. Pretty sure on this forum, did you try searching?
 
yeah i searched and found one relevant post which put me onto the gearbox spacer.

what i need now is a source for the spacer and as long as it's apart the rest of the innards. i can only assume the spacer is pressed into the gearbox body. i tapped it and it seem

ed solid to me. i really need to soak the gearbox in kerosene overnight and after i clean it up i can figure out the spacer thanks, rick
 
Yes, that spacer on the gearbox is held on with 4 little rivets. I wouldn't mess with it. You can add spacers on top of the tophat spacer to get the gearbox out farther, or you might try a new tophat spacer, apparently after changing tires several times they seem to loose clearance.

I did see a thread on this issue here not too long ago, here it is: post18607.html#p18607

Dave
 
The "tophat" spacer is NOT riveted to the gearbox. It is an interference fit (34 in the diagram posted earlier). I have found that these spacers can crush a little and cause the gearbox to scrape the wheel disc. Replacing this spacer helps and/or you could place a thin spacer washer between the tophat spacer and the bearing spacer.

To remove the tophat spacer, place the gearbox on a piece of tubing larger than the outer diameter of the tophat and tap it out with a hammer and solid drift.

The gearbox can also be distorted by overtightening, so make sure it is sill straight.

Those 4 rivets hold the inner retaining ring for the ring gear of the gearbox.

Ron L
 
Ron,

You're right, I drove it out into a 1" socket.

Sure looked like one piece to me. Oh, well.

Dave
 
ok, i soaked the gearbox overnight in kerosine. removed grease fitting, blew it all out, dripped some lightweight oil thru the grease fitting hole, let it sit and it rotates free now. i'll let it sit overnight, blow it out, soak it overnight again in kerosine, blow it out and fill it w/ grease. i ground a washer to fit the top hat and will install it w/ the gear box.

i read in one of my searches that you can drill out the rivets and gain access to the ring gear and worm replacing the rivets w/ small sheet metal screws. i like the idea of accessing the gears but am somewhat leery of the sheetmetal screws. anybody done this?

thanx rick
 
Removed the rivits in mine to repair the drive dogs which were broken off. My brother is into scale model steam engines and he gave me some small steel rivits used in them and they are a perfect fit after I cut them to length and peened them over.
Ian
 
The inner steel ring of the drive box should lever out reasonably easily along with the thick felt grease retaining washer and that gives access to the ring gear? Although to remove the ring gear, the riveted-in retainer must be removed.
 
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