4ha axle problems

61klassic · Post by **61klassic** » Wed Jun 09, 2010 9:45 am

Hi, am after a bit of technical help, i have a scimitar 4ha fitted with a powr lok lsd, i have not yet used this axle. queries are...

1, have just fitted new axle shaft bearings but seems to bee way too much end float?

2, removed the 2 shafts and looking down the axle tube I can see a hole through the middle of aprox 8-10mm, looking at a pic on the net there should be a pin here??

3, lastly, I cant get my head around the theory on how it works, apparantly it relys on the axle shafts moving up the tube to push on the clutches to lock it up, but how can the shaft move up the tube if the end float on each shaft is only 0.8-0.13mm??

All help muchly appreciated.

Post by **katanaman** » Wed Jun 09, 2010 12:38 pm

Half shaft bearings should be shimmed to give the correct end float. I cant remember what the figure is but I can get it tonight if you dont have it.

Hole in the middle, middle of what? Are you on about the hole on the offside axle tube? If so this has probably been drilled out to fit a bit of brake pipe which is turned upward. It should just be a small hole and is the axle breather but it gets blocked very easy hence the mode above.

61klassic · Post by **61klassic** » Wed Jun 09, 2010 8:46 pm

Hi, the problem is that even without any shims and the bearing retaining plate on you can push the shafts in a further 6.2mm, also the hole is wievable by looking down the axle tube with shafts removed, the hole is in the pinion cross shafts.
Thanks

russell_ram · Post by **russell_ram** » Thu Jun 10, 2010 7:34 am

Hi klassic,

In a standard (non LSD) scimitar axle there is a spacer which holds the two half shafts apart - about 1" diameter and 2" long with a large hole in it which the diff cross pin goes through. This part is retained inside the diff by the diff cross pin. What you are doing is pushing the shaft in untill it hits the diff cross pins. When you replace the standard open diff with a Jag sourced PL you need an additional part which isn't required in the Jag application. The bit you need replaces the original spacer and fits through the 'hole' you can see. It looks like a pair of 'mushrooms' which are held together with a roll pin. However, I don't believe these bits are available any more - certtainly not from GKN/DANA last time I tried. Fortunately I have a drawing of the parts you require - somewhere.

That's probably not clear at all !

russell_ram · Post by **russell_ram** » Thu Jun 10, 2010 7:41 am

The clutches work by relative rotation of the two halves of the diff. There is a set amount of preload in the clutch packs - this is the resistance you can feel when trying to rotate one wheel relative to the other when jacked up. However, when one wheel does rotate relative to the other under larger torques, the two individual diff cross pins slide up ramps inside the diff which tends to compress the clutch packs and allows less relative slip between the two outputs.

nothing to do with half shaft axial float, everything to do with relative rotation.

I build dozens of these things for the kit car fraternity.

HTH

Russ