Questions on finding good caster, and other leaf sprung axle concerns

[Utahcryogenics]

I have a leaf sprung straight axle conversion.
I am running about 6" over stock height suspension, and a shackle reversal set up.

My problem is at full dropp or full stuff I have issues.

Droop:
Driveline bind at the pinion yoke.

Stuff:
The tire rubs the inner fender near the firewall.

SO far I have figured I am going to have to get a shim, and spot weld it on my spring perches to correct the bind, and over-positive caster issues.
I also want to run a longer shackle and a poly bump stop to prevent the tire from rubbing the firewall at full stuff.

BUT, onto the questions:

1) I am obviously not an alignment shop, how can I figure out what degree shim to use so that my caster, and my pinion issue can co-exist?
I am obviously a little concerned with too much negative caster, and just an fyi I am sitting right now at too much positive caster.

2) I cant afford to have a custom front driveline made with a CV at the t-case end. I know this will help with a lot of the problems, but thats just not do-able right now.

3) Do you think I should eliminate the bump stop idea all together, and run a long enough shackle to prevent any rub?

Any ideas, thoughts, or advise is welcome.
Sorry its long, I just wanted to make sure people understand the elements I am against.

TIA.

 

[Hickey]

Post a lot of pics of your front end.

 

[Shawn]

1) I would never run a shim in the front. I don't care if you are tack welding it or not.
2) There is NO better way to fix the binding of the shaft than to get a CV in there.
3) Longer shackles may hurt more than they may help
4) As Hickey said. PICS!

 

[bobdog]

The solution to both of your problems is very simple. Eliminate the shackle reversal and put the shackles at the front of the leaves. Your tires will no longer rub the rear of the fender well because the tire will move forward at stuff, and the pinion will point up more because the shackle will lower the front of the spring in relation to the hanger at the rear of the spring giving the same effect as shimming. Ford put the shackle in the front of F350s and it works fine. Try to copy that.

 

[Caleb]

I agree with everyone else to this point has said...never been a fan of SRS anyways...one thing to add though is, you should deffinitely get some bump stops in there...especially with leaf springs, otherwise you will kill springs pretty quickly once you start flexing it a bit.

 

[BCGPER]

Wow, a pic would really help... Being the village idiot here, I'll give you my two cents.
Personally, I run a 2 degree shim in the front of mine to help with caster issues. I wouldn't worry about a shim up front, but make damn sure your centerbolt head is plenty long enough to align with the centering hole on your front perch.

At 6", I'm guessing this is sprung under?? If so, a good SOA would eliminate all these problems. If it's SOA now, you're going to have to bite the bullet and do it right. Lower your front spring hangers, or swap em end for end, CV driveline, ect.

Longer shackles are just going to make matters worse, and the longer you go, the worse it's going to handle. With the shackles reversed you'll be running into slip yoke issues, and make the rubbing even worse.

I guess the bottom line, as everyone else is saying, not enough info!

I have a leaf sprung straight axle conversion.
I am running about 6" over stock height suspension, and a shackle reversal set up.

My problem is at full dropp or full stuff I have issues.

Droop:
Driveline bind at the pinion yoke.

Stuff:
The tire rubs the inner fender near the firewall.

SO far I have figured I am going to have to get a shim, and spot weld it on my spring perches to correct the bind, and over-positive caster issues.
I also want to run a longer shackle and a poly bump stop to prevent the tire from rubbing the firewall at full stuff.

BUT, onto the questions:

1) I am obviously not an alignment shop, how can I figure out what degree shim to use so that my caster, and my pinion issue can co-exist?
I am obviously a little concerned with too much negative caster, and just an fyi I am sitting right now at too much positive caster.

2) I cant afford to have a custom front driveline made with a CV at the t-case end. I know this will help with a lot of the problems, but thats just not do-able right now.

3) Do you think I should eliminate the bump stop idea all together, and run a long enough shackle to prevent any rub?

Any ideas, thoughts, or advise is welcome.
Sorry its long, I just wanted to make sure people understand the elements I am against.

TIA.

 

[KToy]

for ur caster angle i had to get my knuckles on my axle cut and turned up 15 degrees. i broke 5 drivelines in 5 trips if u know what i mean.

then to fix ur stuffing tire issue u need to get a spring that moves ur axle forward.

or do a 3 or 4 link and put ur axle anywhere u want. u need to move ur axle about 2-3 inches forward depending on the size of tire u run.

i used rear toys up front hybrid pack and it moved my axle 2.5 inches forward and i still rub with my 37's.

i run 4 inch shackles up front and wouldnt run any longer ruin ur caster angle.

as far as a driveline goes. get a cv at a junkyard and buy urself reciever tubing and make a square or round driveline yourself. fronts dont rotate fast enough to be balanced, just semi straight.

hope that helps.

 

[Utahcryogenics]

Cool, thanx all.

I appreciate the info about the longer shackle, I will throw that idea in the "round filing cabinet"

I am not going to swap the shackles to the front. I wish I had pics to explain better. WIth my suspension it is obviously all custom. If I put the shackle up front it will ride very poorly, and I would have to build really odd brackets to box in the spring eyes through the frame, and the fuel lines, brake lines, etc. are all around there so that would be too much work for very little gain.

I know that their are many opinions on shims for the front, but I have seen plenty welded to the perch and never had any problems.
I might go that route due to convenience.

Cutting and turning the c's are too much work too. Plus I dont have near enough fab skill or the tools to do it right.

I will be looking for a cv driveshaft up front then.
Thanx again for the help all.
I will try and scrounge up some pics soon.

 

[Utahcryogenics]

These arent to great, I will try and upload more.

 

[Utahcryogenics]

more

 

[Tacoma]

having the shackle up front doesnt' make for a bad ride.... and I dont' see anything that makes switching a Bronco to a front shackle any harder than any other truck...

It's a lot easier to trim in front of the tire than to start chopping into the firewall in my opinion.

 

[Caleb]

having the shackle up front doesnt' make for a bad ride.... and I dont' see anything that makes switching a Bronco to a front shackle any harder than any other truck...

It's a lot easier to trim in front of the tire than to start chopping into the firewall in my opinion.

I agree, if you have a solid mount up front right now then it would be no harder to just swap the mounts around...also, notice in the one of the pics the sping is flex to the point its in negative arc...unless the springs are mdae to ride in negative arc, you WILL kill those springs very quickly by doing that...put some bump stops in there (I know, you wont be able to ramp 1000 if you do that though)

 

[Hickey]

DING DING DING!!
Here is your problem right here. It is also the very same problem I have with MOST shackle reversals. Your springs are not mounted anywhere close to level. This is a must with leaf springs, or your axle will move in unwanted directions when it is flexed. A CV will NOT help with your driveline problems. As your axle droops, your pinion is rotating down, which binds the joint. As your axle stuffs, it moves toward the firewall. I bet you get some good axle hop when you are climbing.

You need to either:
#1- Put the shackles on the front (easiest)
#2- Lower your front spring hangers (Rock Fang style)
#3- french you shackle hangers way up into the frame (I wouldn't suggest that.)

 

[Utahcryogenics]

Hickey: I see what you see, but that is just a bad pic.
If it were on level ground, the springs are level, and the shackles are sitting "inverted" at just the right angle.
Everything is measured correctly and it was double checked at the first alignment shop I took her too after the SAS was completed.

Like I mentioned before the shop only said that I had too much positive caster, and that I might experience bump steer. I havent experienced bump steer at all. I have wheeled the rig like this hard for the last year, the only problem so far is the one mentioned.
I posted a while ago on another board about it and all I heard was "Get smaller tires". I washed my hands of that thread

SO I guess come tax season I will have Tom build me a 1350 driveshaft with a CV end.

I just got a set of tuff country leaf springs that I might take apart and experiment with on my ride. I might try a 3 leaf pack instead of a 2 leaf pack and see how that feels. I will probably goof around on that until I get what I want.

 

[Tacoma]

I'm still curious though: why did the lift give you too much caster???

properly designed lift kits SHOULD, ideally, just lower the axle, thereby lifting the truck. This thread should be all about the horrible vibration and tortured life of the front ujoints, not caster!

sup wit yo springs, G?

 

[Hickey]

I'm still curious though: why did the lift give you too much caster???

Beerman, it is not a bad pic. It is a very telling pic. That is the reason you have too much caster. A CV will not correct your problem.

 

[Wanker Delux]

I have been runing a SR on my samurai for about a year and a half now and I have no no issues with it so far. Why? because it is a very well designed kit. A couple points: The front of your springs need to be located in the same location as the where when they had shackles. This way you will minimize problems with the driveline. I noticed that your shackles would also point backwards sugnificantly, thats not a very good thing for your springs. I'm sure you could run on that with no problems for a long time, but to me that just seems hazerdous.

As for extra caster, just live with it. Unless you can find springs the tilt the axel to just the right position, just deal with it.

As for stuffing, that will probably be fixed if you lower your front perches to the origonal positions, if that dosn't do it, use bump stops.

I'm no expert, but I've had a bit of experience...

 

[Utahcryogenics]

Tacoma" I wouldnt call the set up a "Lift".
My entire front suspension is custom.
Full size Broncos had the stupid TTB axle in the front.
I trashed that and got a 78 Ford D44HD with a HP. Rebuilt it as new, and then kind of mocked up the suspension with front leaves off of a 96 F350, and stock Bronco rear shackles. Shock mounts are from 80's F250's
Cross member, hangers, etc. is all custom.
My set up isnt original by any means, but it works. The friend who helped me has done it on 3 other Broncos with no major problems, except the minor stuff I am dealling with.

I think that if I make the front hangers sit any lower that would not only look stupid, but if they are too long and I bump a boulder I am afraid that might crack the mount, or bend it causing worse problems.
Like I said I will probably just stick with my original plans, experiment with different leaf lengths and etc., and shim it to correct the pinion angle. I will just have to find a patient and understanding alignment shop that would be willing to work with a custom suspension. If I can experiment and have the alignment shop dial in the correct caster with minor fixes, then I will be all set.
Dunno. I guess thats why they call it "Booty Fab" right? It can only get better from here and really it isnt that bad. If I wasnt a perfectionist I would just leave it alone but where is the fun in that

 

[Utahcryogenics]

#2- Lower your front spring hangers (Rock Fang style)

I dont know why I am just seeing this, but would you mind posting a pic, or a url showing "Rock Fang's" rig or suspension?
That would be great.

Thank to all that have posted. I appreciate it.
I am not trying to argue with anyone here, but there are some areas or things that I know are fine, and others I am unclear on.
Hickey I really think you are on the same page as I am.
I am not going for the 1000 score on a ramp, I just need my suspension to cycle without issues.
OH and yes I get stoopid wheel hop on deep inlines.
The first time I went over the waterfall on Rattlesnake I couldnt get a traction at first because my front end was wrapping like a MOFO!

 

[Hickey]

Rock Fangs. It's a slang term used to describe front spring hangers that hang very low and tend to bite into rocks when wheeling.