Very nice work. That looks like a great fix!
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Clutch Fork
- Thread starter RobinHood
- Start date
The new clutch fork is installed and works great. The slop it all but gone. The shifts are precise and smooth. Did i just say that? Well, that is true, but only after i made another modification to the shift mechanism....
First, here is the shift fork a bit cleaned up and the shift pads "massaged"
After the install, the shift linkage needed adjusting to compensate for the now removed backlash. That was expected. That's when i discovered that the apron lever would not stay in the REV direction (the control lever on the apron is UP and the operating lever - more about it below - is also UP) without me holding on to it. It was fine in FWD (both control and operating levers DN).
The culprit was a woodruff key; part number 71808-0, see diag. below
It connects the shift lever assembly shaft with the operating lever through bush #71738-0. The key is a BS 505 woodruff key - nominal dimensions are 5/32" x 5/8". The key seat, the key way and the key itself showed no wear, but the operating lever had almost 7/8" "free play" at its long end where it connects to the rest of the shift mechanism. The lever is over 9 inches long from center of rotation to the coupling. Turns out that the seat was 0.158" and the key way 0.159" wide, as determined by gauge blocks. The 505 key is only 0.15625". So too narrow.
I turned some O1, into a 0.625" disk (the full round diameter of a 505 key) and surface ground it to just shy of 0.159" thick. Then i cut it in half with a slitting saw (now i have one in use and a spare). I did not harden it. It was a press fit into the seat and a tight sliding fit into the key way. Result: all shaft-to-bush play is gone and there is no more lever free play.
"RobinHood CAD" with info out of the Machinery's Handbook. The old key is on the bottom right.
The new key is on top; you might be able to see the difference in width
In summary, the clutch fork and linkage repair were a great learning experience for me and overall i would call it a success.
I thank all of you for your helpful inputs and suggestions - they are always very welcome and appreciated!
Until the next project....
First, here is the shift fork a bit cleaned up and the shift pads "massaged"
After the install, the shift linkage needed adjusting to compensate for the now removed backlash. That was expected. That's when i discovered that the apron lever would not stay in the REV direction (the control lever on the apron is UP and the operating lever - more about it below - is also UP) without me holding on to it. It was fine in FWD (both control and operating levers DN).
The culprit was a woodruff key; part number 71808-0, see diag. below
It connects the shift lever assembly shaft with the operating lever through bush #71738-0. The key is a BS 505 woodruff key - nominal dimensions are 5/32" x 5/8". The key seat, the key way and the key itself showed no wear, but the operating lever had almost 7/8" "free play" at its long end where it connects to the rest of the shift mechanism. The lever is over 9 inches long from center of rotation to the coupling. Turns out that the seat was 0.158" and the key way 0.159" wide, as determined by gauge blocks. The 505 key is only 0.15625". So too narrow.
I turned some O1, into a 0.625" disk (the full round diameter of a 505 key) and surface ground it to just shy of 0.159" thick. Then i cut it in half with a slitting saw (now i have one in use and a spare). I did not harden it. It was a press fit into the seat and a tight sliding fit into the key way. Result: all shaft-to-bush play is gone and there is no more lever free play.
"RobinHood CAD" with info out of the Machinery's Handbook. The old key is on the bottom right.
The new key is on top; you might be able to see the difference in width
In summary, the clutch fork and linkage repair were a great learning experience for me and overall i would call it a success.
I thank all of you for your helpful inputs and suggestions - they are always very welcome and appreciated!
Until the next project....
Nicely done and well documented! It should be better than new.