JunkCrzr89
Competent Ignoramoose
For the TLDR crowd: I rebuilt a manual gearbox sourced from another 40, which may have had issues that were not divulged by the person/not noticed by me when rebuilding (e.g., possibly bent worm gear shaft or sector shaft???), and there is now a deadspot in the steering and the steering will not attempt to return back to dead center on its own (i.e., it gets stuck when turned left or right, and must be forced back to center).
Detailed:
We have a '73 FJ40 that my Dad bought new from a Toyota dealer back in the early spring of 1973; he is the original and only owner of it. Between 1998-2004, we did a complete frame-off restoration and returned everything back to (or as close to) original as possible (adding an Aqualu tub being the most notable exception). In the last few years, we've added City Racer OEM replica 16'' wheels wrapped in Yoko G003 MTs, converted the front from drum brakes to disc brakes, upgraded to a City Racer booster and FZJ80 non-ABS master cylinder and added a proportioning valve, and replaced all of the hard and soft brake lines and clutch lines. My daughters love the damn thing and my did still cruises around in it regularly on his mountain farm and around the local towns.
Original Problem:
We started having a lot of slop in the steering beginning about 5 years ago (roughly 15 years after the rebuild). Last year, I traced the slop to a combination of play in both the manual steering gearbox and center arm. Fast forward to this spring and Dad calls me complaining about the steering slop having gotten so bad that he can barely keep the 40 between the lines when driving over 20 mph. I have him video call me and sure enough there was ~6" of rotational freeplay at the steering wheel before resistance was felt. So we conclude that the box is likely fubar and now is a good time to just completely overhaul the entire steering system.
Attempted fix:
Earlier this month, I pulled out the entire steering system and replaced everything - all end links, pitman arm and joint, steering stabilizer, steering coupler, etc. - and I also rebuilt the center arm and rebuilt a spare manual steering gearbox that a friend gave us 10 years ago from a '74 FJ40. When I pulled the original '73 gearbox out, it was clear that was the source of most of the slop: There was 2.5-3" of rotational freeplay at the output/worm shaft, and the preload adjusting screw was screwed all the way in. By the time we got the original box out I had already "rebuilt" the spare '74 box following the FSM instructions the night before. This rebuild included replacing both bearings with new Toyota units, the worm shaft output seal and sector shaft output seal with new Musashi units, and a new gasket for the sector shaft cover, and setting preload per the FSM's specs. I noticed no irregularities in the sector or worm shafts, or the teeth on worm or sector shaft gears; it all looked to be in really good condition. So we swapped in this '74 box that I had rebuilt and bolted it all back up.
Results/Issues:
The steering is now substantially tighter and more responsive, and we are at the low end of the FSM-spec'd freeplay at the steering wheel, all of which is GREAT. However, it feels like there is a dead spot in this gearbox just a bit right of dead-center. Additionally, the steering will not even attempt to start returning towards center (or straightening out) on its own and instead requires forcing the steering back towards center. In other words, if you turn left or right and let go of the steering wheel, the truck is going to keep going left or right and never start straightening out. I've pulled this box back out, disassembled and reassembled it, and reinstalled it two more times and cannot figure out what is wrong. Thus, I've come to the conclusion that there is something wrong with either the worm gear shaft or sector shaft - perhaps one is slightly bent enough to cause it to get stuck and not return towards center?
Questions:
1) Can anyone think of what might be causing the above issues, and 2) Is there anyone who still rebuilds these manual boxes that I could send the original '73 box to? I'm thinking that having a professional rebuild the original box and then swapping it back in might be the best course of action at this point, since my attempt at rebuilding the '74 box has apparently led to issues; although, said issues may have been present in that '74 box 10 years ago when it was given to us and that's why we got it for free . I do not know.
Detailed:
We have a '73 FJ40 that my Dad bought new from a Toyota dealer back in the early spring of 1973; he is the original and only owner of it. Between 1998-2004, we did a complete frame-off restoration and returned everything back to (or as close to) original as possible (adding an Aqualu tub being the most notable exception). In the last few years, we've added City Racer OEM replica 16'' wheels wrapped in Yoko G003 MTs, converted the front from drum brakes to disc brakes, upgraded to a City Racer booster and FZJ80 non-ABS master cylinder and added a proportioning valve, and replaced all of the hard and soft brake lines and clutch lines. My daughters love the damn thing and my did still cruises around in it regularly on his mountain farm and around the local towns.
Original Problem:
We started having a lot of slop in the steering beginning about 5 years ago (roughly 15 years after the rebuild). Last year, I traced the slop to a combination of play in both the manual steering gearbox and center arm. Fast forward to this spring and Dad calls me complaining about the steering slop having gotten so bad that he can barely keep the 40 between the lines when driving over 20 mph. I have him video call me and sure enough there was ~6" of rotational freeplay at the steering wheel before resistance was felt. So we conclude that the box is likely fubar and now is a good time to just completely overhaul the entire steering system.
Attempted fix:
Earlier this month, I pulled out the entire steering system and replaced everything - all end links, pitman arm and joint, steering stabilizer, steering coupler, etc. - and I also rebuilt the center arm and rebuilt a spare manual steering gearbox that a friend gave us 10 years ago from a '74 FJ40. When I pulled the original '73 gearbox out, it was clear that was the source of most of the slop: There was 2.5-3" of rotational freeplay at the output/worm shaft, and the preload adjusting screw was screwed all the way in. By the time we got the original box out I had already "rebuilt" the spare '74 box following the FSM instructions the night before. This rebuild included replacing both bearings with new Toyota units, the worm shaft output seal and sector shaft output seal with new Musashi units, and a new gasket for the sector shaft cover, and setting preload per the FSM's specs. I noticed no irregularities in the sector or worm shafts, or the teeth on worm or sector shaft gears; it all looked to be in really good condition. So we swapped in this '74 box that I had rebuilt and bolted it all back up.
Results/Issues:
The steering is now substantially tighter and more responsive, and we are at the low end of the FSM-spec'd freeplay at the steering wheel, all of which is GREAT. However, it feels like there is a dead spot in this gearbox just a bit right of dead-center. Additionally, the steering will not even attempt to start returning towards center (or straightening out) on its own and instead requires forcing the steering back towards center. In other words, if you turn left or right and let go of the steering wheel, the truck is going to keep going left or right and never start straightening out. I've pulled this box back out, disassembled and reassembled it, and reinstalled it two more times and cannot figure out what is wrong. Thus, I've come to the conclusion that there is something wrong with either the worm gear shaft or sector shaft - perhaps one is slightly bent enough to cause it to get stuck and not return towards center?
Questions:
1) Can anyone think of what might be causing the above issues, and 2) Is there anyone who still rebuilds these manual boxes that I could send the original '73 box to? I'm thinking that having a professional rebuild the original box and then swapping it back in might be the best course of action at this point, since my attempt at rebuilding the '74 box has apparently led to issues; although, said issues may have been present in that '74 box 10 years ago when it was given to us and that's why we got it for free . I do not know.