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Dana 30 Caster Correction

kkemp

kkemp

Active Member
Location
Salt Lake
Has anybody here ever adjusted the caster on a Dana 30 by removing the knuckles and rotating them and welding them back on? I'm curious how it went. After lifting my Jeep and correcting the pinion angle my caster is going to be +2 degrees. Before it was 6. I'm pretty sure I will notice the difference in my steering with that much change so I'm planning on the adjustment now. If I decide to get someone to do it, who's a good shop. I was thinking Six States would probably be a good place to go.
 
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I Lean

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
Rotating the knuckles is the best way to correct the caster and put the pinion where you want it, but even if you don't do that you should adjust your front axle so your caster is within an acceptable range anyway. Pinion angle is secondary.
 
1993yj

1993yj

.
Location
Salt Lake
How much lift do you have? Most people just leave the caster as is on a D30 and then deal with a pinion angle. It is usually not too severe since the front drive line is a decent length.
 
kkemp

kkemp

Active Member
Location
Salt Lake
1993yj said:
How much lift do you have? Most people just leave the caster as is on a D30 and then deal with a pinion angle. It is usually not too severe since the front drive line is a decent length.
Click to expand...

I really hate vibration. This jeep is a daily driver so I want to keep it drivable. In the past, I've had to get the pinion angle right at 1 degree higher than the drive shaft or I'd get vibration. Right now I'm 2 degrees below, so I'm off by 3 degrees. I've thought about just putting it together with the pinion set the way I want it and just see how it drives. But with only 2 degrees of caster, I'm sure it's not going to be good. So I'm thinking I'd rather just do everything right while it's apart. The lift was supposed to be 3 1/2 inches but it's more like 4 or 4 1/2. And I also have a belly up skid plate that is taking the drive line up another 1 1/2", So I'm looking at an equivelent of about 5 inches or more of lift as far as the driveline is concerned.
 
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kkemp

kkemp

Active Member
Location
Salt Lake
Chevycrew said:
Here ya go http://www.4xshaft.com/driveline101.html
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That's a good site but it doesn't actually address my question. I'm good with the driveline angle stuff. I'm just curious if anyone has rotated their knuckles and how difficult it was to get the buggers off. BTW, I have "CV" shafts on both ends. And since I have leaf springs, there is less vibration if the angle is slightly less rather than absolutely straight. In my case, 1 degree less works very well. This way you account for the little bit of axle wrap while you're at cruising speed and especially during acceleration.
 
ChestonScout

ChestonScout

opinions are like Jeeps..
Location
Clinton, Ut
With 2 degrees it will stil turn right. It will just wander a bit and probably have some bump steer.

As for the knuckles...Just do it! If you know how to weld and you obviously can read degrees there is no reason you cant do it. Just be carefuly grinding down the weld and you will be golden.


Post up a tech thread on it with pics!
 
kkemp

kkemp

Active Member
Location
Salt Lake
ChestonScout said:
With 2 degrees it will stil turn right. It will just wander a bit and probably have some bump steer.

As for the knuckles...Just do it! If you know how to weld and you obviously can read degrees there is no reason you cant do it. Just be carefuly grinding down the weld and you will be golden.


Post up a tech thread on it with pics!
Click to expand...


Sounds good. I'll give a shot and let you know how it works out.

thanks
 
Badger

Badger

I am the Brute squad
Location
South Salt Lake
ChestonScout said:
With 2 degrees it will stil turn right. It will just wander a bit and probably have some bump steer.
Click to expand...

I would like to know how your caster angle induces bump steer. There is no way that it can bump steer is from having your track bar and drag link at different angles causing them to travel on different plains through the suspension cycle.

I think what you meant to say is that it will cause some death wobble since the axles ability to return to center will be diminished.
 
1993yj

1993yj

.
Location
Salt Lake
Personally, I would not put that much effort into a D30. If you are going to go through the hassle of grinding of the knuckles and then re-welding them at the correct angle, I would at least be putting that effort into a D44 or something.
 
kkemp

kkemp

Active Member
Location
Salt Lake
Chevycrew said:
I agree...cut and narrow hp44?
Click to expand...

I hear you there. I have been considering that. The next time I blow the ARB, I probably will. Right now I'm not ready to toss out the ARB and chromoly shafts. Actually, for what I do, the Dana 30 seems to be holding up. I did have an ARB come apart, but that was the old style. This one seems to be hanging in there.
 
Chevycrew

Chevycrew

Well-Known Member
Location
WVC, UT
Point noted...If it was a stock 30 I would give you s**t for keeping it.


I understand trying to get the use out of parts you have bought.
 
waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
Why not save the hassle and just install a dual cardan style driveline like out of an XJ? :confused: Then you can set your caster at 6-7* and have the pinion angle you need.:D
 
kkemp

kkemp

Active Member
Location
Salt Lake
waynehartwig said:
Why not save the hassle and just install a dual cardan style driveline like out of an XJ? :confused: Then you can set your caster at 6-7* and have the pinion angle you need.:D
Click to expand...

I have a Tom woods double cardon shaft already. I plan to set the caster to 7 degrees, but in order to do that I have to move the knuckle 5 degrees.

Here's where I stand right now...
The drive shaft is at 6 degrees and the pinion is at 4 degrees. So, the pinion is 3 degrees lower than I want. I want it 1 degree higher than the drive line.

Since the pinion is at 4 degrees, my current caster is 5 degrees. Not too bad. but! I need to rotate the pinion up 3 degrees. that will put my caster at 2 degrees. Not good. To get it right I need to rotate the knuckles back 5 degrees.

I'm using plasma cutter to remove the perches, so moving those will be apiece of cake. I've already done the rears. The fun part will be grinding the welds off the knuckle so I can rotate them. it shouldn't be that difficult, yeah right!
 
kkemp

kkemp

Active Member
Location
Salt Lake
So here's an update. It went like this...

Day 1

I pulled the front axle, and removed the old perches. Now that was fun. Those stock perches are almost solid. It took about five hours of cutting with an angle grinder to get them off. The plasma cutter wasn't feeling so well so I didn't end up using it. It probably wouldn't have been much help anyway with a 2 inch thick piece of metal.

Day 2

I placed everything back in position with the new perches not welded in. Then rotated the axle to get the pinion angle set. It ended up at 7 degrees with the driveshaft at 6. Since the difference in pinion angle and the caster is 9 degrees, that left me with 2 degrees of caster. I tack welded the perches on and pulled the axle out again to properly weld the perches on, then put it all back together.

I have a telescoping trackbar and the bolt that tightens it up was shot so the trackbar was left loose. There was also no place to mount the steering stabilizer, so there's another project to do.

I then repeated the same for the rear. I put it all back together with the u-bolts only tightened down to about 50 lbs, so I can remove them and reuse them.

I was pretty worn out and the welding got rushed and it looks like buggers. I guess I'll be pulling it again and weld it right. Also the rear track bar is slightly off now and it's not adjustable. More fab work. I know you guys will say toss the track bar, but I drive the Jeep on the highway a lot and it makes a big difference.

So I took it out for a test drive on Wasatch Blvd. Oh I forgot to mention, I have a broken rear shock mount that I didn't get around to fixing yet. So I only had one rear shock, no track bars and no steering stab. Well, I was surprised how it handled. It defininately needs the shock mount fixed. The 2 degrees of caster was pretty obvious but, I'm not sure it's all that bad. I really need to fix everything else before I decide to fix the caster. If I do, I'll probably get a pro to do it. I don't feel good enough about my welding skills to weld the knuckle which is casted to the mild steel tube.

Oh, and there was no vibration from the drive shafts at all. I took it up to 60 and didn't notice anything.

BTW, the springs are Teraflex 3 inch springs. They are apparently more than that. They are noticebly softer than my old 2.5 inch Skyjackers. I'm also using 1" over greasable shackles.

I think with the lift it has now, probably around 4 inches, plus the teraflex bellyup skid plate and a one inch body lift, this YJ is certain going to be a lot more trail worthy than it was.

So there you have it. Sorry, I don't have any pictures yet.
 
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