Still working on more updates - overhauls to the 646 and since I have the engine pulled off the frame, I looked into why there is so much slop in the steering and what I found were two things:
1. The large Sector gear did not fit the shaft well, it was worn in several places and had 1/16" slop in it.
2. The tapped (5/8 fine thread) hole in the end of the sector gear casting was worn and the bolt part of the rod end was moving inside the casting
When I started measuring things on the 'Steering Plate' I found that the stub shaft for the sector gear measured 1.032 inches? That's not a standard shaft dimension that I know of. When I look at the back of that plate, the welds don't look factory to me. So it's possible that someone previously replaced the shaft?
![Wood Art Font Gas Metal]()
To start to correct this I 'turned' down the stub shaft to exactly 1.00 inches OD on my milling machine:
Then I ordered a 1.00 ID by 1 1/8 (1.125) OD cast bronze bushing to install on the stub shaft. The sector gear itself has enough 'meat' to it that I cleaned up the bore and increase the ID to 1.125". Here is a shot of test fitting the bushing in the bore:
![Wood Machine tool Gas Metalworking Machine]()
I also needed some new - different thrust washers . all of the parts I used look like this before assembly. I epoxied the bushing onto the stub shaft so it would not rotate at that point. There is no way to easily get lubrication in between the bushing and the shaft. Since the Grease zerk is located in the sector gear casting it makes it easy to lubricate between the bushing and gear.
![Light Paint Wood Gas Art paint]()
All Installed and Assembled it looks like:
![Wood Machine tool Motor vehicle Automotive exterior Gas]()
To Fix the loose - slop in the tapped hole that the rod or Heim end screws into (because the rod end bolt is not long enough to go all of the way through the casting). I got a 5/8 x 4 1/2 fine thread bolt (that was the only NON Grade 8 bolt the local Fastenal had in stock...) I cut the head off the bolt and threaded the top part of it to take a nut. I also cut a section of 1/2 water pipe to serve as a spacer.
(A side note on bolts.. I initially attempted to take a standard 5/8 bolt from the farm store and thread it 5/8 UNF. But a lot of modern bolts are undersized and the threads are created by rolling, which increases the diameter at the threads enough to meet the specs, but the rest of the bolt is undersized. The bolt I got at Fastenal was a TRUE 5/8 - 0.625" diameter bolt, therefore the threads I cut on that bolt were full sized..)
The entire stack looks like:
![Light Wood Valve Red Line]()
Now I am able to have the 'bolt' threaded 100% of the way into - through the sector gear casting, (you can see the black end of it showing at the top of the casting, sitting there nice and flush) The bolt is locked into the casting by a thin locking nut that was on the tractor originally. Next my water pipe - Spacer (to align the steering rod with the opening in the frame), then a 5/8 Heim Joint, a lock washer and a standard 5/8 nut.. This is now all nice and tight and does not slop around at all.
1. The large Sector gear did not fit the shaft well, it was worn in several places and had 1/16" slop in it.
2. The tapped (5/8 fine thread) hole in the end of the sector gear casting was worn and the bolt part of the rod end was moving inside the casting
When I started measuring things on the 'Steering Plate' I found that the stub shaft for the sector gear measured 1.032 inches? That's not a standard shaft dimension that I know of. When I look at the back of that plate, the welds don't look factory to me. So it's possible that someone previously replaced the shaft?
To start to correct this I 'turned' down the stub shaft to exactly 1.00 inches OD on my milling machine:
Then I ordered a 1.00 ID by 1 1/8 (1.125) OD cast bronze bushing to install on the stub shaft. The sector gear itself has enough 'meat' to it that I cleaned up the bore and increase the ID to 1.125". Here is a shot of test fitting the bushing in the bore:
I also needed some new - different thrust washers . all of the parts I used look like this before assembly. I epoxied the bushing onto the stub shaft so it would not rotate at that point. There is no way to easily get lubrication in between the bushing and the shaft. Since the Grease zerk is located in the sector gear casting it makes it easy to lubricate between the bushing and gear.
All Installed and Assembled it looks like:
To Fix the loose - slop in the tapped hole that the rod or Heim end screws into (because the rod end bolt is not long enough to go all of the way through the casting). I got a 5/8 x 4 1/2 fine thread bolt (that was the only NON Grade 8 bolt the local Fastenal had in stock...) I cut the head off the bolt and threaded the top part of it to take a nut. I also cut a section of 1/2 water pipe to serve as a spacer.
(A side note on bolts.. I initially attempted to take a standard 5/8 bolt from the farm store and thread it 5/8 UNF. But a lot of modern bolts are undersized and the threads are created by rolling, which increases the diameter at the threads enough to meet the specs, but the rest of the bolt is undersized. The bolt I got at Fastenal was a TRUE 5/8 - 0.625" diameter bolt, therefore the threads I cut on that bolt were full sized..)
The entire stack looks like:
Now I am able to have the 'bolt' threaded 100% of the way into - through the sector gear casting, (you can see the black end of it showing at the top of the casting, sitting there nice and flush) The bolt is locked into the casting by a thin locking nut that was on the tractor originally. Next my water pipe - Spacer (to align the steering rod with the opening in the frame), then a 5/8 Heim Joint, a lock washer and a standard 5/8 nut.. This is now all nice and tight and does not slop around at all.
