62 replies to this topic

[biga064]

Hi Adam , I give it a shot , on mine when the uni's were new and all the circlips fitted , the trunion ( the uni cross piece ) could move up and down inside the cups ( not in a twisting movement but vertically ). you could tap the cups in a but further to tighten it up ( this is on the diff yoke with the "U" bolts) but after couple of good flog the caps would move back out until stopped by the circlips and the vibe would return , I tried to get slightly thicker clips but could only get ones that made the uni too tight . So on the macined radius area where the uni sits i put 3 center punch dints equaly spaced arond the radius , about 1 mm away from the face where the circlip sits , the center punch marks made small raised section appear on the face of the yoke where the circlip sits , this effectively pulls the uni caps in a little . NOTE don't get too carried away with the punch as you only a couple of thou on each side of the yoke , Also try to make each punch hit as accurate as you can to keep it equal on both sides.The uni should have only slight resistance when sliding it onto the yoke , if too tight gently file the punched rased areas equaly on both side for a nice snug fit , not loose, tighten "U" bolts an check for end play What you want to accieve is to have each uni cap seating a little further in the yoke to keep the trunion from moving up and down inside te cups I.E keep it running true .

I have only ever needed to do this on the dif yoke and was told by a tailshaft dood that its because of manufacturing tollerances from to old imperial uni's to the average metric ones that you get now , he said the F100 utes are natorious for this.

let me know if its not all that clear and i'll dig out a yoke and take some pix

Geoff.Thanks Geoff i understand what you have done now !!! But a picture speaks a thousand words !!! thanks

[73TORANA!]

Cool I'll dig some up.

Cheers.

[73TORANA!]

Hi Adam here are some pix of the yoke on my spare dif . I also found some old uni's that came out of the cooks EH back in the early 80's , they won't fit in this center punched yoke with the circlips fitted unless I force it in but it it too tight to turn but a brand new TOYO uni fits nice and snug , I guess it old and new spec or something.
JUST MAKE SURE YOU PUNCH BOTH SIDES of the yoke to keep it all symetrical only one side shown in the pix .

Cheers. Geoff.

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Edited by 73TORANA!, 19 April 2012 - 08:55 AM.

[76lxhatch]

Toranas are bad for it once lowered, even with adjustable upper arms I couldn't get decent uni angles so in the end I fitted a two piece driveshaft... a bit over the top but sorted the problem!

[Ando]

I've also got the same problem. The car had the original banjo, tailshaft & aussie 4 speed in it. I lived with the vibration knowing the driveline would be upgraded eventually. The vibration would occur around 95 klms & you could feel it going through the car & through the seat. The universals were worn so that must have been the problem so I thought. The car is lowered & now has all new driveline eg. 9" diff, 3" tail shaft & tko 600 & guess what? That dam vibration is still there! So now I have to find the problem. The pain begins!

[Ando]

Well! My problem is narrowed down to the engine. I did replace the harmonic balancer a couple years ago so all I could think of, is either the flywheel or the engine crank & rotating mass itself. I can feel it through the front end while the car is in neutral & me playing with the carby throttle, while changing engine revs & leaning against the nose cone, I can feel the vibration oscillating. So I suspect I have an unbalanced engine & I have lived with it the last few years. Looks like a good excuse to bring forward my Hi-po 355 build.

[Redslur]

I would think that the engine harmonic vibration would be fairly obvious by placing the car in neutral and freely reving it until it the vibration starts. I have had very out of balanced 308's before and the vibration was very apparent by doing as I have mentioned. Have you tried this yet?