chees- Posted August 30, 2016 Share Posted August 30, 2016 So a while back i got a F series lsd diff off kurt that was working sweet in his celica. it developed a leak out of the pinion nut, i thought this was just the pinion seal but turns out the pinion seal was fine(until i ruined it). took it to a diff place to get a new pinion and they figure the pinion nut isnt tight enough. but when he tightened it down bearings seized up. so he reckoned the crush tube was missing. so i took it home and pulled it apart, crush tube is there everything seems in order apart from a tyre valve stem in between the bearings, WTF. so possibly this was seizing up the bearings? so im wondering where i should go from here? put it back together and see what happens? get a solid spacer made? or get a new crush tube(is this even possible)? Quote Link to comment Share on other sites More sharing options...
kicker Posted August 30, 2016 Share Posted August 30, 2016 I sourced a new crush tube for nissan diff but a lot of people just get a solid spacer made up for the required preload. Quote Link to comment Share on other sites More sharing options...
Popular Post Hemi Posted August 30, 2016 Popular Post Share Posted August 30, 2016 bit deflating finding that in there 21 Quote Link to comment Share on other sites More sharing options...
chees- Posted August 30, 2016 Author Share Posted August 30, 2016 I sourced a new crush tube for nissan diff but a lot of people just get a solid spacer made up for the required preload. i've cranked it back down again with the old crush tube and it seems to be ok now, not great. is it a bad idea to reuse the old crush tube? Quote Link to comment Share on other sites More sharing options...
Roman Posted August 30, 2016 Share Posted August 30, 2016 Toyota manual says dont ever reuse torque tube, even if you back off the nut slightly its a throw away item. Also, I had a problem where even though the torque tube was torqued down to spec, I had a shitload of end float. Turns out that the splines were jamming before the torque tube squashed up, hence the float. So take the tube out and make sure splines move freely on one another.lold at the tyre valve!! Random. 1 Quote Link to comment Share on other sites More sharing options...
Brdflu Posted August 30, 2016 Share Posted August 30, 2016 Trust you to have something as funny as this happen! 1 Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted August 30, 2016 Share Posted August 30, 2016 I super switched on dude once told me How to recycle crush tubes. He reckened stick a bit of round in the vice, and slip the tube over it. Then hanmer the tube ontobthe bit of round and rotate it. This takes the. Crush or crinkle out of the tube. Making it longer so you can crush it again. Might sound a bit dodgey, But the guy was smart enough to build ten second racecars. Haventvtried it myself though. 1 Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 30, 2016 Share Posted August 30, 2016 I've reused crush tubes, yes I know they need a new one. I look at it this way, the crush tube is there to make it easy and fast to get the preload right but a lot of older diffs just use shims, more time consuming but it works. So it all comes down to the preload, if it's right why change the crush tube, it's not hard to check preload you only need a torque wrench and a way the lock the pinion nut once it's right so replace the pinion nut with a locking type, Nylock or drill a hole and use a castellated nut or one of the over nut style ones wheel bearings use. Quote Link to comment Share on other sites More sharing options...
Hemi Posted August 30, 2016 Share Posted August 30, 2016 Cone nut is what you want ow. Quote Link to comment Share on other sites More sharing options...
Mof Posted August 30, 2016 Share Posted August 30, 2016 I super switched on dude once told me How to recycle crush tubes. He reckened stick a bit of round in the vice, and slip the tube over it. Then hanmer the tube ontobthe bit of round and rotate it. This takes the. Crush or crinkle out of the tube. Making it longer so you can crush it again. Might sound a bit dodgey, But the guy was smart enough to build ten second racecars. Haventvtried it myself though. Have you ever tried this? They're pretty fucking hard I tried it once, but must have hit it too many times in one spot, wasn't straight. Chucked it in the bin and bought a new one. Try the agents Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted August 30, 2016 Share Posted August 30, 2016 Havent tried it myself though. 1 Quote Link to comment Share on other sites More sharing options...
tim13 Posted August 30, 2016 Share Posted August 30, 2016 I am no diff expert (although I have broken a few ......) but if you have to reuse a crush tube I am pretty sure you can add a shim/small spacer to allow another stage of crush ? Quote Link to comment Share on other sites More sharing options...
Mof Posted August 30, 2016 Share Posted August 30, 2016 Havent tried it myself though. Ah, yeah, my bad Quote Link to comment Share on other sites More sharing options...
Roman Posted August 30, 2016 Share Posted August 30, 2016 I am no diff expert (although I have broken a few ......) but if you have to reuse a crush tube I am pretty sure you can add a shim/small spacer to allow another stage of crush ? True but why go to these lengths when you can just buy one brand new for 3 bucks or whatever. I paid one of the pro diff shops to sort mine out, and they fucked it up so bad. probably 5-6mm end float on the pinion because the splines were grabbing before the torque tube was reached. How could you not notice that??? They also hammered the torque tube back out instead of replacing it. Frustrating when you expect to get a good job done for paying $$$ and then have to do it yourself anyway. 4 Quote Link to comment Share on other sites More sharing options...
tim13 Posted August 31, 2016 Share Posted August 31, 2016 Agreed , with easily found models colapsable spacer replacement is the best answer .......but oddball stuff or late night before an event a spacer can save the day . Poor workmanship/service from 'Professionals' annoys me Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted August 31, 2016 Share Posted August 31, 2016 True but why go to these lengths when you can just buy one brand new for 3 bucks or whatever. I paid one of the pro diff shops to sort mine out, and they fucked it up so bad. probably 5-6mm end float on the pinion because the splines were grabbing before the torque tube was reached. How could you not notice that??? They also hammered the torque tube back out instead of replacing it. Frustrating when you expect to get a good job done for paying $$$ and then have to do it yourself anyway. Man I really hope you told them how shit they were. If you are employed to build diffs then you should really be able to build diffs. Quote Link to comment Share on other sites More sharing options...
drftnmaz Posted September 4, 2016 Share Posted September 4, 2016 I am no diff expert (although I have broken a few ......) but if you have to reuse a crush tube I am pretty sure you can add a shim/small spacer to allow another stage of crush ? The old guy that showed me how to do diffs when I was young used to do this for our own cars but not for customers cars, you would find a bit of pipe with close size ID+OD (or spin to suit in lathe) and then two spot welds at 180degrees from each other to mate the two together, then back in the lathe to part it off now 2mm longer and still square, then you can get a 2nd crush of them Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 4, 2016 Share Posted September 4, 2016 If it's seized up and been driven on then it's likely the bearings are toast. The muppet who put it back together when he believed there was no crush tube should be taken outside and shot. Setting up bearing preload is fairly important in a diff and in my opinion you can reuse a crush tube for certain situations like replacing the pinion seal, but you need to know where the nut was tightened to before pulling it apart. In this case, seeing as there is no obvious reference point, plus multiple hands have been in there and at least one pair sounds like a fuckwit then for peace of mind then I would pull the pinion out, chuck some new bearings on. Best thing about that is new bearing kits come with a crush tube. (normally) Do some reading up on setting pinion preload and go for it. Keep in mind that a crush tube is useless if you go too far so go in small increments when tightening it up. Plus they are normally really hard to start the crush but get much easier after that they start collapsing (like crushing a beer can with your forehead) 2 Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 4, 2016 Share Posted September 4, 2016 Also pinion bearings are not normally torqued up like head bolts to a torque value as there is no nut shoulder butting up against an immovable object to gauge. They are set up to a certain amount of bearing "drag" but do some solid reading on pinion bearings and you should get that. (think of trying to measure the air pressure inside a balloon) It will take a certain amount of maths and physics to create a tool that measures what you need to do but it's not overly complex. Quote Link to comment Share on other sites More sharing options...
kicker Posted September 4, 2016 Share Posted September 4, 2016 I used a digital scale to measure the force required to turn the pinion shaft when I swapped flanges on mine Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.