lordoeuf
NAXJA Forum User
- Location
- Vancouver Island
I have a PSC SG-621M variable ratio, big bore gear box that I recently rebuilt with seals, teflon slides, sector shaft bearing, and stub shaft bearing. My question is mostly concerning the thrust bearing pre-load.
According to this nicely documented saginaw rebuild guide: https://www.jeepforum.com/forum/f13/how-rebuild-your-saginaw-zj-steering-gear-1287958/ , I should tighten the adjuster plug (that large threaded cylinder with the two holes needing a "spanner wrench") all the way down until the thrust bearing is fully seated. Basically, until the adjuster plug cannot be turned anymore with normal pressure on the handle, meaning the assembly is fully bottomed out in the casting. According to another guide, that light-ish pressure is about 25 ft-lbs. As I don't think many have a torque wrench attached to a spanner, this 25 ft-lbs is by feel and experience. Basically, tighten it down just snug, but don't put your body weight into the spanner.
OK, so once the thrust bearing is bottomed out, this rebuild guide says to back off the adjuster plug by 0.5". Another guide says 0.2". That's a big difference, but anyway, when I back-off the adjuster plug by 0.5", I am a full 1/8th of a revolution TIGHTER than where the adjuster plug was before I took the box apart (I marked them with punch).
An 1/8th of a revolution seems like an awefull lot to me. I mean, the thrust washers can wear a bit, but I wouldn't expect them to wear that much. So what do I do - listen to the web guide, or put the adjuster plug back where it was previously? Cut the difference between the two?
Another issue I noticed is that just about no matter where I have adjusted the pitman adjuster screw to, the stub shaft, turned 45 deg. right/left, always requires about 7 in-lbs of torque, not nearly the 10 in-lbs noted in the web guide, or the 8-15 in-lbs noted elsewhere. I even tried it with having the thrust bearing not backed off at all, but I still get about 7 in-lbs. Obviously I can get it tighter, but at that point, there is a kink in the flow of the piston at about 90 deg. off centre while traveling in the bore, thus I've adjusted the screw so that I just don't feel that kink, but again, 7 in-lbs at the stub shaft.
My gut feeling is that these variances aren't a big deal, but this is only my second rebuild. What do I know. Any ideas? Thanks!
According to this nicely documented saginaw rebuild guide: https://www.jeepforum.com/forum/f13/how-rebuild-your-saginaw-zj-steering-gear-1287958/ , I should tighten the adjuster plug (that large threaded cylinder with the two holes needing a "spanner wrench") all the way down until the thrust bearing is fully seated. Basically, until the adjuster plug cannot be turned anymore with normal pressure on the handle, meaning the assembly is fully bottomed out in the casting. According to another guide, that light-ish pressure is about 25 ft-lbs. As I don't think many have a torque wrench attached to a spanner, this 25 ft-lbs is by feel and experience. Basically, tighten it down just snug, but don't put your body weight into the spanner.
OK, so once the thrust bearing is bottomed out, this rebuild guide says to back off the adjuster plug by 0.5". Another guide says 0.2". That's a big difference, but anyway, when I back-off the adjuster plug by 0.5", I am a full 1/8th of a revolution TIGHTER than where the adjuster plug was before I took the box apart (I marked them with punch).
An 1/8th of a revolution seems like an awefull lot to me. I mean, the thrust washers can wear a bit, but I wouldn't expect them to wear that much. So what do I do - listen to the web guide, or put the adjuster plug back where it was previously? Cut the difference between the two?
Another issue I noticed is that just about no matter where I have adjusted the pitman adjuster screw to, the stub shaft, turned 45 deg. right/left, always requires about 7 in-lbs of torque, not nearly the 10 in-lbs noted in the web guide, or the 8-15 in-lbs noted elsewhere. I even tried it with having the thrust bearing not backed off at all, but I still get about 7 in-lbs. Obviously I can get it tighter, but at that point, there is a kink in the flow of the piston at about 90 deg. off centre while traveling in the bore, thus I've adjusted the screw so that I just don't feel that kink, but again, 7 in-lbs at the stub shaft.
My gut feeling is that these variances aren't a big deal, but this is only my second rebuild. What do I know. Any ideas? Thanks!