4 links and HP44 front problems

[Capt. Nemo]

After reading Richard's 3 link update, I had some questions and concerns of my own. I felt a hijack coming on so I started this post to avoid that... Anyway-

I just finished my HP44 front. I cut and narrowed it to Waggy width blah, blah, blah... I've been running Full-Traction's long arm kit for over a year with no complaints. My goals were to keep everything as close to stock as possible so that I could move the axle from one XJ to another with the least amount of modifications. Yes, this is a long arm set-up, but please don't dismiss the post yet :laugh3: .

Afer a month and a half of having it finished, I finally got to test it out yesterday. It's running great on the street, but on the trail I'm finding that when the driver's side tire is fully stuffed, the driveshaft hits the UCA pretty hard. After reading this post and hearing that this 3 link front has worked very well, I'm seriously considering eliminating the driver's side UCA altogether. Since the length and angle of my arms are different, should I give this more thought before removing the arm?

Here are a couple of pics of the driveshaft and UCA relationship along with evidence of the problem...

My pinion angle is a little steep, but even if it is dropped a little bit, the rubbing still continue.

This is the pass. side UCA. I tried to get pics that would show the angles well and the relationship to the rest of the suspension.

If eliminating the UCA on the driver's side will create huge problems, I would guess that putting in larger bumpstops would be my other alternative. I don't know how much travel that would eliminate, but if I can avoid it, that would be ideal. Any thoughts?

 

[David Taylor]

This might be over simplifying it. But. what about a slight bend in that arm ?
With the 44 in mine with RE arms I had to make a new short one on the drivers side that had a bend to clear the drive shaft.

 

[FernXJ]

I agree w/ David, sleeve the uppers and bend them. I had the same problem w/ my D30 pinion, but I flat out needed to lower the pinion. I made my CAs alot like FullTraction with 4CAs. But followed the same lines as stock for the most part to mount on the frame. CA lengths are lca28" uca27".
Have you tried to lower the pinion. You have disc. hubs no worry about vibes. I say if its working leave it be unless you feel like reworking all CA angles as far as a 3link. Goatman's angles are very different than yours.
Rensing

 

[Capt. Nemo]

This might be over simplifying it. But. what about a slight bend in that arm ?
With the 44 in mine with RE arms I had to make a new short one on the drivers side that had a bend to clear the drive shaft.

Do you have any pics?

I think I'll jack it up with the forklift at work and see just how much it would need to be bent to clear the shaft. I would really like to try and keep everything as close the way it is right now as possible as far as control arm angles and pinion angle. No sway bar, no steering dampener, and I can drive at 90mph as smooth as glass...

 

[FernXJ]

I don't doubt you on the smoothness. I'm just saying that dropping your pinion angle to at least level with driveshaft won't hurt. I don't know your Caster pitch but bringing the pinion down would only increase your Caster.
The bend you would need would be only slightly up and out towards the wheelwell.Rensing

 

[BrettM]

i'm in favor of putting a slight bend in the upper link.

you could run it with just the passenger side upper, but in that scenario it would be best to have no rubber or poly in all your joints, just heims or flex joints, and maybe add some more bracing to the axle mount. Also, like Richard's it wouldn't be the "right" way with an upper link sloping up on the passenger side, but in practicality it will most likely be totally fine.

 

[David Taylor]

Do you have any pics?

My junk is to much junk to post pics of it. I just cut of the ends of the old arm.
Bolted them back up, then bent tube to fit. Weld it up and your good to go.

 

[Capt. Nemo]

I don't doubt you on the smoothness. I'm just saying that dropping your pinion angle to at least level with driveshaft won't hurt. I don't know your Caster pitch but bringing the pinion down would only increase your Caster.
The bend you would need would be only slightly up and out towards the wheelwell.Rensing

Right now I'm at approx. 7*castor. The only concern I have of lowering the pinion angle is binding that might occur at the UCA's on the axle end. The mounts are "pigeon towed" which limits the amount of flexibility I have in adjusting the pinion angle up or down. I still think that even with the pinion adjusted it will hit. It was hitting pretty hard... Thanks for the input.

 

[Goatman]

Are you sure that you have 7* of castor? If so, then you probably set your pinion too high when you built the axle housing. The cure for your problem is more castor........if you can do it. A slight bend in the arm should also work, hopefully those arms are adjustable so you can lengthen it a little if you need to bend it. If you want to run only a passenger side arm, it should work. From what I remember of the Full Traction kit, the mounts are pretty beefy so the frame mount for the upper arm shouldn't be a problem. You'd have to get rid of the rubber bushing in the axle end mount, but Currie, and maybe RE, make a JJ that will fit in the stock mount.

On my old D30 setup, my pinion yoke would sometimes hit the upper arm, but on full droop. The way the geometry was, it would tilt my pinion up too much when the drivers side drooped, I had to play with the arm adjustment and castor to get it right. I broke a few pinion yokes before it got resolved, the u-joint would get pushed over and it would break the little tab on the yoke that holds the u-joint cap.

 

[Capt. Nemo]

Are you sure that you have 7* of castor? If so, then you probably set your pinion too high when you built the axle housing. The cure for your problem is more castor........if you can do it. A slight bend in the arm should also work, hopefully those arms are adjustable so you can lengthen it a little if you need to bend it. If you want to run only a passenger side arm, it should work. From what I remember of the Full Traction kit, the mounts are pretty beefy so the frame mount for the upper arm shouldn't be a problem. You'd have to get rid of the rubber bushing in the axle end mount, but Currie, and maybe RE, make a JJ that will fit in the stock mount.

On my old D30 setup, my pinion yoke would sometimes hit the upper arm, but on full droop. The way the geometry was, it would tilt my pinion up too much when the drivers side drooped, I had to play with the arm adjustment and castor to get it right. I broke a few pinion yokes before it got resolved, the u-joint would get pushed over and it would break the little tab on the yoke that holds the u-joint cap.

I set the pinion at 13*, the castor at 7*, and the coil buckets at 0* respective to the pinion and inner knuckle angles. I'm running close to 7" of lift in the front, so it could be that I set the pinion too high when I set everything up. I would much rather just put a bend in the UCA than eliminate it altogether.

 

[Goatman]

I set the pinion at 13*, the castor at 7*, and the coil buckets at 0* respective to the pinion and inner knuckle angles. I'm running close to 7" of lift in the front, so it could be that I set the pinion too high when I set everything up. I would much rather just put a bend in the UCA than eliminate it altogether.

Just for reference, I set my pinion at 10* and my castor at 5*. If I did it again, I'd add 2*, but that still puts you 5* higher than I am, and 3* higher than I'd be willing to go.

Is it arm bending time?

 

[Capt. Nemo]

Just for reference, I set my pinion at 10* and my castor at 5*. If I did it again, I'd add 2*, but that still puts you 5* higher than I am, and 3* higher than I'd be willing to go.

Is it arm bending time?

Your math has me a little confused, but it's time. Time to figure out how to bend the sucker with the least amount of work involved - which really means cutting, grinding, bending, testing, and repeating several times until it works... Fortunately, I have some small sections of DOM tubing left over from my steering set-up which should come in handy.

 

[Goatman]

Ok, with your pinion set at 13*, you have 7* of castor. With my pinion set at 10*, I have 5* of castor. If you lowered your pinion to 10*, you would end up with 10* of castor...too much. So, considering your problem, your pinion is a little too high, but it's too late now.

In my case, I'm actually running about 11-12* on the pinion, which leaves me about 3-4* of castor. My double carden joint binds at full axle droop, so I have to turn the pinion up slightly to avoid it, loosing a little castor......so I wish I had put in a couple of more degrees on the pinion. To be safe, I don't haul ass in 4wd, or if I do I leave the limiting strap in the shorter trail length.

 

[FernXJ]

I know the FullTraction uppers are angled on the axle side mount. This may work in your favor. With the amount you may need to bend your arm. You may be able to spin your arm so the angle mount faces towards the wheel, then bend your arm and bring the angle back without cutting. Either way you may still need to cut the mount off, just a stupid thought.
I don't blaim you for not wanting to only one arm with that CA setup. Maybe if the LCAs followed a line closer towards the tranny. I'm not sure why FullTraction wanted to mount their LCAs under the frame, except to keep from building a whole crossmember.Rensing

 

[Capt. Nemo]

Ok, with your pinion set at 13*, you have 7* of castor. With my pinion set at 10*, I have 5* of castor. If you lowered your pinion to 10*, you would end up with 10* of castor...too much. So, considering your problem, your pinion is a little too high, but it's too late now.

In my case, I'm actually running about 11-12* on the pinion, which leaves me about 3-4* of castor. My double carden joint binds at full axle droop, so I have to turn the pinion up slightly to avoid it, loosing a little castor......so I wish I had put in a couple of more degrees on the pinion. To be safe, I don't haul ass in 4wd, or if I do I leave the limiting strap in the shorter trail length.

Makes sense now. Thanks for the clarification. I just went down to a local off road fab shop and for $20 they'll bend the upper arm for me. It doesn't look like it will need much of a bend to clear the pinion. He kept mentioning about 10*. My only concern is that the arm will be shorter after it's bent, and I'm not sure if I have enough threads left to compensate. We'll find out.

FernXJ (Rensing)- Your idea of flipping the UCA over and using the tow-in in the opposite direction was a great idea. However, it's just too much of an angle.

 

[FernXJ]

I was talking about bending you arm in the toe out position. And the bend might bring the mount back to position. But, you probably don't need that much bend. Hope itall works out.Rensing
When your crawling hows the sway compared to short arms. I was surprised mine stayed the same after I put my arms together.

 

[Capt. Nemo]

Well, I think the problem's solved. I went down to a local fab shop and had them bend the UCA. I think the final bend was 8*. I also rotated the pinion down, making it inline with the driveshaft. Looking forward to the 'Con in a couple of weeks!

 

[Goatman]

Looks like you got it. :thumbup:

 

[bj-666]

I'm not sure why FullTraction wanted to mount their LCAs under the frame, except to keep from building a whole crossmember.Rensing

they mounted the lca's under the frame rail becuase they needed some seperation at vehicle side of the links if they mounted the lca's to the crossmember they would have to move the uca's up into an area with verry little space and possibly not keep the kit bolt on.