Changing the steering knuckle angle on the Dana 30

[firehawk]

Been thinking, would it be possible to change the knuckle angle to allow someone to get the caster angle they need, and also have the correct pinion angle?:confused:

I've studied my axle and why couldn't you cut the axle tubes, rotate the pinion where it should be and reweld the tubes with the knuckles at a caster angle that gives good drivability? You could make a sleeve of some sort to slide over both ends of the cut tube and weld it up. I don't think there would be any issues with LCA mounts, or spring perches since the change would not be that drastic.

Anyway, just something I've been thinking about.:rolleye0018:

[DETOURS]

You can do that, but most folks dont bother doing it to a 30, with the ammount of work involved, try to secure a HP 44......build it and swap it in on a Saturday afternoon. ;)

[muddeprived]

Couldn't you just unscrew the axle tubes, turn em and then weld em up all the way around?

You having caster issues? I was having issues getting caster and pinion dialed in. I was trying to stay within specs but it just wouldn't work so i said screw the caster and aligned the pinion so it's parallel with the driveshaft PERFECTLY. I don't know how much caster I am running but it's not really noticeable. It's just a tiny bit sensitive. It doesn't do any harm running above or below normal caster I believe. I was told the return-to-center steering would suffer with changes in caster but mine still returns to center regardless of caster changes. I ran 3.1 degrees of caster when i didn't have adjustable arms, and now i tilted the pinion up quite a bit so that probably increased to whatever.

[gorman]

The axle tubes are pressed in and plug welded, so they won't unscrew easily. I agree with the caster - at first I thought it was quite important to have good caster, but since I've installed my drop bracket to get control arm angles right, I'm also running with very low caster and it tracks perfectly. When I had my alignment done my caster was 2.8 degrees and it was a bit weavy on the road not centering quickly, but then I made 5mm shims (as per go-jeep's site) and stuck them in behind the control arms and now it's perfect (I would quess my caster is now around 4 or so degrees.)

Firehawk, you could just get yourself a HP Dana 30 axle - there you have alot more room to get both pinion and caster optimised as with the low pinion axle.

[firehawk]

Firehawk, you could just get yourself a HP Dana 30 axle - there you have alot more room to get both pinion and caster optimised as with the low pinion axle.

I did swap out the LP for a HP axle out of a '96 XJ. The problem really went away when I did that. I still have a very, very slight vibration around 65-70mph since the pinion is still not pointing directly at the TC. It is pointing down a degree or so. For some reason I need to be running 6*-8* of caster to stop the damn thing from wandering.

It's NOTHING compared to the problem's I had with the LP axle, and I can live with it. I asked the question just to get feedback IF it could be done.:D

[BlueXJ]

If it can be done to a D44 then it can be done to a D30 but the expense is the same so why not use the stronger D44 in the first place. It is definitely a project which can be done.

[gorman]

I did swap out the LP for a HP axle out of a '96 XJ. The problem really went away when I did that. I still have a very, very slight vibration around 65-70mph since the pinion is still not pointing directly at the TC. It is pointing down a degree or so. For some reason I need to be running 6*-8* of caster to stop the damn thing from wandering.

It's NOTHING compared to the problem's I had with the LP axle, and I can live with it. I asked the question just to get feedback IF it could be done.:D

Firehawk, if there is only a 1 degree difference between your pinion angle and the propshaft angle, that is most definately not the cause of your vibration - the factory service manual mentions a 3 degree difference as acceptable and I've been running a 5 degree difference when I still had my LP axle without any vibrations.

How much caster do you currently have? You can gain a few degrees (not sure how much) with offset balljoints that are available specifically to either adjust caster and/or camber. This should be much easier that doing a cut and turn on the knuckles. If however you do decide to do the cut and turn - have a look on the various write-ups that have been made when people did it on D44's. You don't cut through the tubing - only cut through the weld on the knuckle and the with a big sledge hammer you knock the knuckle until it starts to move. On a D30 this might be difficult with the original spring perches in place.

You can also just build yourself another front axle with the caster and pinion angles already tuned to exactly what you want. This is what I'm in the process of doing. In South Africa the local pickups are all using a locally designed and manufactured diff with factory locker. I've used the housing of such a diff and I'm busy building a front diff out of it. It will be a low pinion setup, but I'll adjust the angles to suite. Here's a couple of pics:

I've bought an old bent D30 axle from a TJ for the knuckles and I've had the axle tubes machined to go into the diff housing and to fit the knuckles. The diff internals are also using 27 spline shafts, so I'll be re-using my Jeep side shafts. In the pic I'm using a threaded rod to pull the axle tubes into the housing:
http://i165.photobucket.com/albums/u77/gorma900/IMG_7189.jpg

http://i165.photobucket.com/albums/u77/gorma900/26072008091.jpg

[firehawk]

Firehawk, if there is only a 1 degree difference between your pinion angle and the propshaft angle, that is most definately not the cause of your vibration - the factory service manual mentions a 3 degree difference as acceptable and I've been running a 5 degree difference when I still had my LP axle without any vibrations.

How much caster do you currently have? You can gain a few degrees (not sure how much) with offset balljoints that are available specifically to either adjust caster and/or camber. This should be much easier that doing a cut and turn on the knuckles. If however you do decide to do the cut and turn - have a look on the various write-ups that have been made when people did it on D44's. You don't cut through the tubing - only cut through the weld on the knuckle and the with a big sledge hammer you knock the knuckle until it starts to move. On a D30 this might be difficult with the original spring perches in place.

You can also just build yourself another front axle with the caster and pinion angles already tuned to exactly what you want. This is what I'm in the process of doing. In South Africa the local pickups are all using a locally designed and manufactured diff with factory locker. I've used the housing of such a diff and I'm busy building a front diff out of it. It will be a low pinion setup, but I'll adjust the angles to suite. Here's a couple of pics:

I've bought an old bent D30 axle from a TJ for the knuckles and I've had the axle tubes machined to go into the diff housing and to fit the knuckles. The diff internals are also using 27 spline shafts, so I'll be re-using my Jeep side shafts. In the pic I'm using a threaded rod to pull the axle tubes into the housing:
http://i165.photobucket.com/albums/u77/gorma900/IMG_7189.jpg

http://i165.photobucket.com/albums/u77/gorma900/26072008091.jpg

I should have been a little more specific. I just threw out the 1* figure, it probably is more than that. What it truly is I don't know. I guess I should really find out what it is.

I never did plan on actually modifying an axle, I was just wondering if it COULD/HAD be done. It obviously has.

I was driving yesterday towing the quad behind the Jeep, and didn't have it in overdrive. I sped up to 65-70 mph and didn't experience the slight vibration. I'm beginning to think it is because the engine while IN overdrive is not in the powerband of the 4.0 causing the vibration. Guess I really need to regear before I pound the rod bearings to death, huh?:cool: