For background I have an original 16:1 fast ratio manual steering box from my 1966 Barracuda that long ago lost an ear on the case. I recently disassembled the car to put it on the rotisserie and with both the replacement 24:1 box and the original box off the car I decided to swap cases, so a rebuild was in order. I have detailed some of the disassembly elsewhere along with some questions I had along the way. I will post the box reassembly with the Firm Feel and other parts. In order to do that I needed to disassemble, clean, and reassemble the worm gear and ball nut. Some folks say just soak the ball nut/worm gear assembly in mineral spirits and then regrease, but I am too curious to avoid disassembly and inspection. AND, you can bet that the thing will fail upon final completion of the car would be anything I do not fully disassemble and inspect. This steering rebuild is also a MUCH harder job with the box ON the car.
I just completed this part of the project. Given nearly no info on this otherwise, I thought I would summarize what advice I did get and show the reassembly step by step for those interested.
After disassembly you have the following parts (plus the ball bearings).
clockwise from lower left corner you have the Ball Nut, ball guide screws, ball guide clamp, worm gear (this is the 16:1 gear), and the 4 halves of the ball guides. In addition there are, in the fast ratio worm gear, 54 ball bearings. I have read that the 24:1 version has fewer, but be careful with your disassembly and don't lose any balls. I used the gallon bucket of Gunk Parts Cleaner and the basket to make sure I did not lose them The ball bearings are split into two separate circuits so I have split the bearings into two groups of 27 ball bearings.
Judging only by pictures of the other ratio ball nuts it looks like everyone has two independent recirculating groups, so my guess is you should have an even number of ball bearings, so split them into two same-sized groups.
Before you put the worm gear in the ball nut you need to confirm the proper orientation of the ball nut, as the sector shaft and ball nut have meshing teeth that can only fit one way. The teeth are all long wedge shaped and the wedges of the sector gear point DOWN, and interlace with the ball nut’s teeth, so the ball nut teeth need to point UP. For LHD the worm gear is on the left of the sector shaft so, hold the worm in your left hand and insert it into the ball nut with the ball nut teeth on the right side and the teeth facing UP. See the orientation in this picture.
Before you assemble the two, slather some NGLI#2 grease of your choice on the worm gear.
The pieces should mesh like this:
Then set the worm/nut pair down on the worksurface with the teeth on the bottom. This will leave the ball recirculation holes facing up. You want to slide the worm, which is very loose in the ball nut, until the ball channel of the worm lines up with the channel in the ball nut. Then you can take the first half of your ball bearings and work them into the left side circuit. I used a pencil with the eraser removed, but any sufficiently small diameter utensil with work as you will be greasing the ball bearings and stuffing them in the hole. The goal is to get the thread channel between the upper left and lower left holes filled with ball bearings.
If you insert them in the upper left side hole you need to make sure you do not let them migrate toward you and to the left (see arrow) or past the lower left hole toward the screw hole, as they need to go only down into the thread channel between the .
Once you get about 17 or 18 loaded in you should see them coming up in the bottom left hole (the grease will show up first as it is pressed along). At this point you will want to make sure that 19 of them are in the worm channel, at least for the 16:1 ratio worm.
[CONTINUED IN THE NEXT POST]
I just completed this part of the project. Given nearly no info on this otherwise, I thought I would summarize what advice I did get and show the reassembly step by step for those interested.
After disassembly you have the following parts (plus the ball bearings).
clockwise from lower left corner you have the Ball Nut, ball guide screws, ball guide clamp, worm gear (this is the 16:1 gear), and the 4 halves of the ball guides. In addition there are, in the fast ratio worm gear, 54 ball bearings. I have read that the 24:1 version has fewer, but be careful with your disassembly and don't lose any balls. I used the gallon bucket of Gunk Parts Cleaner and the basket to make sure I did not lose them The ball bearings are split into two separate circuits so I have split the bearings into two groups of 27 ball bearings.
Judging only by pictures of the other ratio ball nuts it looks like everyone has two independent recirculating groups, so my guess is you should have an even number of ball bearings, so split them into two same-sized groups.
Before you put the worm gear in the ball nut you need to confirm the proper orientation of the ball nut, as the sector shaft and ball nut have meshing teeth that can only fit one way. The teeth are all long wedge shaped and the wedges of the sector gear point DOWN, and interlace with the ball nut’s teeth, so the ball nut teeth need to point UP. For LHD the worm gear is on the left of the sector shaft so, hold the worm in your left hand and insert it into the ball nut with the ball nut teeth on the right side and the teeth facing UP. See the orientation in this picture.
Before you assemble the two, slather some NGLI#2 grease of your choice on the worm gear.
The pieces should mesh like this:
Then set the worm/nut pair down on the worksurface with the teeth on the bottom. This will leave the ball recirculation holes facing up. You want to slide the worm, which is very loose in the ball nut, until the ball channel of the worm lines up with the channel in the ball nut. Then you can take the first half of your ball bearings and work them into the left side circuit. I used a pencil with the eraser removed, but any sufficiently small diameter utensil with work as you will be greasing the ball bearings and stuffing them in the hole. The goal is to get the thread channel between the upper left and lower left holes filled with ball bearings.
If you insert them in the upper left side hole you need to make sure you do not let them migrate toward you and to the left (see arrow) or past the lower left hole toward the screw hole, as they need to go only down into the thread channel between the .
Once you get about 17 or 18 loaded in you should see them coming up in the bottom left hole (the grease will show up first as it is pressed along). At this point you will want to make sure that 19 of them are in the worm channel, at least for the 16:1 ratio worm.
[CONTINUED IN THE NEXT POST]
