Cocky_Rocky 5 #1 Posted August 9, 2014 Can anyone explain what's going on with this, and hopefully a remedy? The hubs that hold the rear wheels on the axle keep creeping off the axle. The left side actually came completely off recently when my son was mowing. The hubs are keyed to a keyway in the axle and set screws with grub screws are supposed to keep everything in place. When I originally fixed the left side there was no indication thread locker had been used at the factory, so I didn't use any either. It continued to creep, as well as I noticed the right side was creeping also. When I had a friend over to help me diagnose an electrical problem I told him about the hubs and he said he would have used thread locker. So while I was working on re-assembly from the electrical problem I used thread locker on all 4 set screws on both hubs. I just finished mowing and sure enough both hubs are creeping off the axle. What gives with this? Share this post Link to post Share on other sites
daveoman1966 3,738 #2 Posted August 9, 2014 Each of the 4 set screws should have a jam nut on them to lock them in position after tightening each screw to the axle. Without a jam nuit on each, they MAY tend to work loose. Loctite wasn't used at OEM and shoudn't be needed. It is likely that the woodruff keys are worn some, or that the slot on axle or hub is worn, or both. Share this post Link to post Share on other sites
Wishin4a416 2,190 #3 Posted August 9, 2014 If the keys and keyway are good and the axle to hub is tight, I have redrilled the grub screws in a vice on a drill press to sharpen them up again so they grab good. Just did one this past week. Share this post Link to post Share on other sites
Lagersolut 630 #4 Posted August 9, 2014 If you have axle seals leaking under the hub they will move , doesn't matter how tight you torque the set screws . 1 Share this post Link to post Share on other sites
Cocky_Rocky 5 #5 Posted August 9, 2014 (edited) Each of the 4 set screws should have a jam nut on them to lock them in position after tightening each screw to the axle. Without a jam nuit on each, they MAY tend to work loose. Loctite wasn't used at OEM and shoudn't be needed. It is likely that the woodruff keys are worn some, or that the slot on axle or hub is worn, or both. My bad. I meant jam nut, not grub screw. 2 set screws with jam nuts on each hub. Also, I have parallel/rectangular key/keyway If the keys and keyway are good and the axle to hub is tight, I have redrilled the grub screws in a vice on a drill press to sharpen them up again so they grab good. Just did one this past week. Axel to hub is definitely tight. Keyways look good to my eye. The key on the side that actually came apart got a little chewed, but not excessively and it still fits the keyway. The key on the side that creeps but hasn't came apart looks good to my eye. Can you give more detail on the redrilling and sharpening procedure? I was kinda suspecting that might be the issue. I wasn't aware you could "sharpen" the set screws. If you have axle seals leaking under the hub they will move , doesn't matter how tight you torque the set screws . No leaks. Axel and hub are bone dry. I assume you mean trans oil leaking. Edited August 9, 2014 by Cocky_Rocky Share this post Link to post Share on other sites
doc724 925 #6 Posted August 9, 2014 If you want to fix this for good, get a new woodruff key and new HARDENED sq head set screws for each wheel and a new jam nut. Don't buy the cheapie set screws as they are not hardened and the cup point will get dull. If you have 2 set screws per hub, then replace both with new ones. To sock down the set screws get an 8 point socket. (you cannot get them tight enough with a 3/8 wrench-not enough leverage) A 12 point will do in a pinch but to fit a 3/8 sq hd set screw, only a metric 12 point will work. I forget which size metric socket will work, but is is a common one, maybe 9mm 1 Share this post Link to post Share on other sites
specialwheelhorse 174 #7 Posted August 10, 2014 There are special sockets made for these square head set screws. Got a five sixteenths 8 point Japan and a three eights 8 point Craftsman number 44343. Proper tools are wonderful !!! 1 Share this post Link to post Share on other sites
can whlvr 993 #8 Posted August 10, 2014 I agree to replace the hardware with good quality screws and keys,i guess you could drill a SMALL spot on the axle where the set screw sits on the axle if all else fails,its funny they are usually a bear to get off when a person wants them off Share this post Link to post Share on other sites
Cocky_Rocky 5 #9 Posted August 10, 2014 Proper tools are wonderful !!! Couldn't agree more! Still going to wait for Wishin4a416 to elaborate on drilling and sharpening the set screws. Share this post Link to post Share on other sites
pacer 3,160 #10 Posted August 10, 2014 I think what he means (at least the way I do it) is grind a slight point, a bit blunted on the end of the threads. I also find the seating point on the axle and with a drill bit closely matching the newly ground set screw, drill a shallow 'pocket' for the screw to seat in. These dang axles are frustrating - you either cant dynamite them loose or cant keep em tight :banghead: Share this post Link to post Share on other sites
Lagersolut 630 #11 Posted August 10, 2014 (edited) No leaks. Axel and hub are bone dry. I assume you mean trans oil leaking. Yes, I meant the trans oil, I had an axle seal leaking and getting under the hub, I could tighten the set screws to the point of rounding them off and tighten the lock nut , inside of 1 hour the hub was back to floating on the axle. Sorry I didn't clarify more in my first post. Also learned ( here ) set screws have a special indentation on the bottom to grip the axle - dry axle - new seals and set screws finally solved my " moving hub ". Edited August 10, 2014 by Lagersolut Share this post Link to post Share on other sites
meadowfield 2,570 #12 Posted August 10, 2014 It's true, you either need 10 tons to pull them off, or they drop off by themselves. My cure, besides new set screws is the grind a step into the woodruff key where the screw sits. That way there's no chance it can move as it sits in it's own pocket... 1 Share this post Link to post Share on other sites
tkol1969 92 #13 Posted August 10, 2014 mine run in???? maybe we could get them together and the two of them can find a nuetral and stay put. ha 1 Share this post Link to post Share on other sites
Cocky_Rocky 5 #14 Posted August 10, 2014 It's true, you either need 10 tons to pull them off, or they drop off by themselves. My cure, besides new set screws is the grind a step into the woodruff key where the screw sits. That way there's no chance it can move as it sits in it's own pocket... Yes, this sounds like something I have done before, believe it or not, with r/c cars. 1/10 scale axel pins held by set screws definitely benefit from a small notch where the set screw sits. I like it. I'm gonna try this fix since it won't cost anything. I'm flat broke... 1 Share this post Link to post Share on other sites
Don1977 604 #15 Posted August 10, 2014 (edited) If the keys have a mark on the the sides you can see they will move and you will never be able to keep the hubs tight. Replace the keys and the setscrews, hubs are not cheap and will get looser if it keeps moving. Edited August 11, 2014 by Don1977 1 Share this post Link to post Share on other sites
Molon_Labe 731 #16 Posted August 10, 2014 It's true, you either need 10 tons to pull them off, or they drop off by themselves. My cure, besides new set screws is the grind a step into the woodruff key where the screw sits. That way there's no chance it can move as it sits in it's own pocket... Yup +1 Share this post Link to post Share on other sites
