Thread: Argh Double Cardan Unis

Ha ha, I was just thinking exactly the same thing!!
Only difference, after struggling for some time, and punching out the bottom of a cup (dropped needle) going to get a replacement, re-positioning all the centre bearing needles (again...) and getting it together, discovered that the last cup was completely loose in trunnion...... Needless to say, the spare one in the bin was flogged out even worse.....
New shaft inbound, never touching that double cardan ever again, under any circumstances!!! Gumnut.

Me neither, I would say very poor design, should not be that hard. Have done unis before but never this hard. Should really be a 4hr job, has turned into about 8hrs plus. Cant believe how stiff it becomes when the ball is in place. Certainly just does not push on like they show. Never again.
Cheers
Craig

Originally Posted by Gumnut

Ha ha, I was just thinking exactly the same thing!!
Only difference, after struggling for some time, and punching out the bottom of a cup (dropped needle) going to get a replacement, re-positioning all the centre bearing needles (again...) and getting it together, discovered that the last cup was completely loose in trunnion...... Needless to say, the spare one in the bin was flogged out even worse.....
New shaft inbound, never touching that double cardan ever again, under any circumstances!!! Gumnut.

Originally Posted by CraigE

Then putting in the last uni pressed a bit hard and cracked a uni cap, so off to get another uni in the morning.

Usually if the cap gets cracked is because one of the needle rollers has been dislodge and fallen and is resting on the bottom of the cap.Then when pressing the cap down it had no more clearance and hits the dislodged pin causing the cap top crack. Needle rollers are held in by grease and don't like to be disturbed much. Big Cable ties also help when reassembling the double joint , like an extra pair of hand to hold things.
Cheers,
Mario

^^^x2
It shouldn't be tight at all , as Mario said , you've dropped a needle roller, I wouldn't fit it if it was tight , and if the ball is tight on its own there is probably a dropped roller in that as well
Cable ties are your friend, or even better a friend is your friend
Don't forget to centralise it all when assembled
Or give it to someone else that does them on a regular basis to do

Originally Posted by discorevy

^^^x2
It shouldn't be tight at all , as Mario said , you've dropped a needle roller, I wouldn't fit it if it was tight , and if the ball is tight on its own there is probably a dropped roller in that as well
Cable ties are your friend, or even better a friend is your friend
Don't forget to centralise it all when assembled
Or give it to someone else that does them on a regular basis to do

No dropped roller on the ball, pulled off twice to make sure before pressing the last little bit, just very tight fit, much tighter than I would have thought. Only tightened up when we pressed the last 1cm on, would not push all the way home by hand that is for sure.
Will grease up the uni properly and check for rotation.

Now greased unis fully moves a lot better.

Originally Posted by discorevy

^^^x2
It shouldn't be tight at all , as Mario said , you've dropped a needle roller, I wouldn't fit it if it was tight , and if the ball is tight on its own there is probably a dropped roller in that as well
Cable ties are your friend, or even better a friend is your friend
Don't forget to centralise it all when assembled
Or give it to someone else that does them on a regular basis to do

The centre bearing housing has a tiny hole drilled thru to the back to relieve grease as its pressurised during assembly as the spigot is pushed into bearing. If this hole was blocked it would make assembly difficult.
Worth a look

Well tailshaft is done and painted, will go back in in the morning.
Had some advice from the Hardie Spicer guys that have done these.
1: Do not fill with grease before fitting unis, just a smear over needles to hold them in place as excess grease can cause needles to move and even damage including damaged caps.
2: Unis and ball will be tight initially, tap with hammer to seat correctly and then grease, rotate in a vice to lubricate and free up.