FF rear axle binding

[Devil Frog]

I have a fully rebuilt FF rear on my 40. I am running an FZJ80 elocker, with air conversion. I do have the long spine axle for the short side, and elocker fork/hub engages no problem. The short side hub spins feel as it should without the axel, and when there is a gap of .5 mm or more between the axle and hub, but when I torque down the axle bolts the axle no longer spins freely. It will still turn but requires a lot of torque, I have to put a 33" tire/wheel assembly on to have enough lever arm, where as before I toque the nuts and there was a small gap between axle flange and hub it would spin with a finger pull of the lug stud. I am running a standard gasket between axle flange and hub with a light coat of RTV. Any insight to the issue? I think I can solve with a thicker gasket, but want to understand the root cause. Thanks.

 

[Living in the Past]

What FF did you start with? The 40 series never came with rear disc brakes. Your set up is custom and hard to say what the problem is. 60/80 series axle housing cut to short? Something with rear brake setup?

 

[Devil Frog]

The FF axle is from a JDM 40 series. As you can see in the pic the caliper is handing from 1 pin, so the brake setup is not the culprit.

 

[47coeman]

Check the other side to see if there is a shim on that side and not on the one that is the issue. BTW what is your set up for the air conversion need one for mine. PM me please. TNX

 

[LAMBCRUSHER]

yep, moar on air actuator please, and seems like there is a length issue....are all the bits from the same housing less the third? possible that the 40 series shaft bottoms out in the 80 series diff before it gets home? have you got the shaft that came with the diff to compare landmark measurements to?...maybe slide in a piece of 3/4" trade size pipe and mark depth of bottom to hub face and compare depths to axle dimensions...

 

[Living in the Past]

Since the short shaft is from a 70 series do you have the 40 series short shaft to compare lenghts? Never heard of a issue installing a E-locker in a 40 series FF axle with the long spline axle from a 70 series.

 

[Living in the Past]

Did your FF have the same brakes as a 60 series? I have two FF axles from 40 series. One newer one older. I believe looking at SOR site it showed a different axle shafts between the two.

 

[Devil Frog]

I don't have the original short shaft or drum brakes.

 

[Devil Frog]

Check the other side to see if there is a shim on that side and not on the one that is the issue. BTW what is your set up for the air conversion need one for mine. PM me please. TNX

Here is a vid of the air conversion, I am using Jstncse's implementation. This is the front, but same concept

 

[47coeman]

That is slick, when you get alittle time need to know more about the parts. Best Skip landon

 

[peteinjp]

And I just ordered custom cables for my locker..... Very nice setup. What Psi do you have to run to get it to work well?

As to your problem I'd get some dye-chem (or the stuff they use for setting the ring gear patterns) and put it on any areas that could be making contact (the splines being an obvious first choice) and look for where it gets worn off for signs of excessive contact.

Pete

 

[Devil Frog]

That is slick, when you get alittle time need to know more about the parts. Best Skip landon

I got the actuator and valve from automationdirect.com, part #s C170075D and AVS-527D1-PP respectively. You can also get the pneumatic lines and fittings from the same site. Jstncse, here on mud who is the guy that came up with this implementation, made me the shafts that thread into the actuator and bolts to the locker engagement fork. I am using it in double acting mode, so I have air locking and unlocking, but I also took apart the cylinder and installed a spring so that the system fails in the unlocked state if air pressure is lost. The video is shot at about 120 psi, which I will run at with my York based OBA system.

 

[Fast Eddy]

Is the locker locked, or unlocked when you're tightening it down?

If it's locked, I don't think it would be binding at the diff side. Not sure what the oil seal is like in a stock axle, but maybe it's binding there. (?)

If it's unlocked, try locking it and then torquing it down and see what happens. Maybe the air system is holding the collar further from the diff carrier than it should. (?)

 

[Devil Frog]

I actuated from lock to unlock and it has not changed the binding. I think I will try the dye-chem on the end of the long splined side.

 

[Fast Eddy]

When it's locked, neither the end of the axle, nor the splines have anything to bind up on. If it wasn't for the fat end of the axle you should be able to push it another 50mm into the diff. I'd be looking on the hub end if I were you.

 

[Stumpalama]

Did you confirm the axle housing is not bent?

 

[peteinjp]

Did you confirm the axle housing is not bent?

I was just thinking the same thing. Or the axle shaft could be bent right at the fLange?


Pete

 

[FJ60Seth]

I'd swap the hubs and see if that makes a difference.

 

[too tall]

I had an issue with a LSD from a japanese spec land cruiser FF . The axle would bind when tightened all the way in . I trimmed about 3 mm off the end of the shaft and it functions normally . Not saying you should cut your axle just that there may be interference on the inside end . You should not try to space it with a gasket . You should not use RTV on the gasket or flange . The FF hub/axle should be put together dry with a paper gasket . Otherwise you will break the studs . The RTV starts to act as lubricant when a certain amount of rotational torque is applied .

 

[Devil Frog]

I had an issue with a LSD from a japanese spec land cruiser FF . The axle would bind when tightened all the way in . I trimmed about 3 mm off the end of the shaft and it functions normally . Not saying you should cut your axle just that there may be interference on the inside end . You should not try to space it with a gasket . You should not use RTV on the gasket or flange . The FF hub/axle should be put together dry with a paper gasket . Otherwise you will break the studs . The RTV starts to act as lubricant when a certain amount of rotational torque is applied .

how did you trim it to get a clean enough cut as to not mess up the splines