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Rethinking My SAS

59K views 403 replies 40 participants last post by  jermil01 
#1 ·
For lack of a better word, I'm frustrated. After running into some major alignment issues with my rig I've decided to explore the option of redoing my SAS. Over the last 6 to 8 months I have been chasing gremlins with my front end. Fortunately, I don't have anything like death wobble. The problem occurs after accelerating and then letting off the gas the truck feels like it wants to pull off to the right.

I was told by a tire shop that I had a camber problem a second/ off road shop looked at things and said the c-bushings were shot and I had a very loose coil bucket. The 4 degree c-bushings were replaced with 7 and all of the bolts were tightened up, but the the problem still persists somewhat and now the passenger side tire is wearing unevenly on the outside.

The SAS I have is your run of the mill variety, extended radius arms with the coil bucket set up using the ttb coils and retainers, custom fabbed drop radius brackets and trac bar. The steering was made from DOM with heavy duty tie rod ends.

I know there is any number of things that can possibly go wrong with these components, but I have to believe it's something simple that's being overlooked.

That being said, I'm thinking about taking the axle and just starting from scratch, maybe going with cage arms or something like that, so for those of you who have done the swap and have had it for a while, what would you have done differently with your swap if you had it to do all over again?
 
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#2 ·
I have had and witnessed the change in direction on and off the throttle in a few jeeps before. It was because of the Detroit locker in the rear and the soft rear springs with no traction bar. The jeep with a healthy small block would torque to one side so the spring was twisting up and the locker was pushing both tires in one direction. Since the jeep was so short it would feel like nose was going in a different direction when you would let in and out of the throttle.

I don't know if I explained this very well, but I would take a look at your rear suspension and see if anything is loose. Maybe the springs are to soft and causing a little axle wrap on one side and changing the direction?
 
#5 ·
I do have a Detroit in the rear and can sense it has a tendency to pull I guess that is just something I have to live with. I've now gone back and checked and retorqued all of the bolts. The rear springs are definitely not soft, if anything, they're probably a little too stiff



Dust, as far as I know they're parallel, but that is definitely something worth looking into.

Are the front and rear axles parallel with each other?
Andy, I know what you mean I don't think anyone else would want to drive mine either. The wandering is really pronounced when getting off the gas, it almost feels like something is unwinding. Again if that's a symptom of the the detroit I can live with it, I just want to make sure I'm not overlooking anything.

I'll certainly check the wheel base, but I do know the last shop I was at said that one of my rad arm drop brackets was about a 1/4 of an inch lower than the other one. I'm not an expert by any means but couldn't that translate into a much higher number the closer to the axle housing it gets??

The tube has been checked and as far as I know is straight. I haven't personally put an angle on it but the guy at the shop said it wasn't bent..I do need to go back and find what the toe is.

Mine veers right just as you describled
sometimes i think i'm the only person brave enough to drive my bronco. it crab walks, veers right, and generally wanders left to right with vague steering. i've tracked down most of the problems.

it crab walks because the rear axle is ~3/4" off center, but with the 14 bolt in back the pinion is centered (vs 8.8 where it is offset) slightly to accomodate fords off center drivetrain idea. if the axle were "centered" i would have some pretty nasty compound angles at the pinion. broncos are also heavier towards the passenger side.

it veers right because of the detroit, staying on the gas noticeably improves straight line tracking. its not bad enough to make you change lanes, but you won't forget its there. not sure how long you've had a detroit, but it sounds like 75% of your problem.

it veers left and right because it has worn out leaf springs in front with no pan hard in front, so it is directionally challenged.

not sure how any of this helps you, but it is ideas as to what causes drive ability problems. i would check your wheelbase, and compare left to right. then i would check your radius arms, and mounts for front/back equal positioning. then i would tighten every single bolt i could find. have you checked your toe in/out? the unequal wear sounds more like a ball joint issue.

heres the big whopper question: is your axle housing straight and not bent from a crash, heat warping etc?
 
#4 ·
sometimes i think i'm the only person brave enough to drive my bronco. it crab walks, veers right, and generally wanders left to right with vague steering. i've tracked down most of the problems.

it crab walks because the rear axle is ~3/4" off center, but with the 14 bolt in back the pinion is centered (vs 8.8 where it is offset) slightly to accomodate fords off center drivetrain idea. if the axle were "centered" i would have some pretty nasty compound angles at the pinion. broncos are also heavier towards the passenger side.

it veers right because of the detroit, staying on the gas noticeably improves straight line tracking. its not bad enough to make you change lanes, but you won't forget its there. not sure how long you've had a detroit, but it sounds like 75% of your problem.

it veers left and right because it has worn out leaf springs in front with no pan hard in front, so it is directionally challenged.

not sure how any of this helps you, but it is ideas as to what causes drive ability problems. i would check your wheelbase, and compare left to right. then i would check your radius arms, and mounts for front/back equal positioning. then i would tighten every single bolt i could find. have you checked your toe in/out? the unequal wear sounds more like a ball joint issue.

heres the big whopper question: is your axle housing straight and not bent from a crash, heat warping etc?
 
#6 ·
I second or third the whole detroit discussion. gotta understand the affects of the detroit when gassing/letting off...understand that first as something totally unrelated to the front end (though a very soft suspension makes this more pronounced).

Andy, you can put your 14B in alignment and run a compound angle. Here's a good read from spicer, go to page 11 for compound angle, and how to calculate your true operating angle (ujoints) if you do run a tranny/tcase offset from the axle:

http://www2.dana.com/pdf/J3311-1-HVTSS.PDF

In doing my calculating, I likely have some vibe due to a true operating angle of a little more than 4* (rear pumkin of D60 is centered, tcase is about 2" toward passenger side).


As far as what I would have done differently, nothing. Have been very pleased. I did recently correct a C bushing issue I've known about for some time, but other than that...I wish I could run a 17x9 rim and tires, but I choose not to due to cost for that vs. what I run.
 
#7 ·
How are these holding up?





I've never really gone out and looked at all your SAS pics, not sure I like these, I see why you're curious about the cage arms. This would also be the time to move from ttb coil setup to solid axle springs.

How is all that heim stuff holding up in your steering, I see a lot of mud pics. Nice thing about chevy TRE's is they are greasable.
 
#8 ·
They seem to be holding up fine. Ultimately, I wanted to have them gusseted but it's not a priority now. Thinking back to before I did the swap my rig had been in accident where I hit a deer on the drivers side. It tweaked the frame pretty good. I was able to have it straightened out, but I'm thinking may be part of the problem and we didn't take this into consideration when making the brackets. Either way, both of them are identical since they were cut from the same template so it can't be the bracket itself.

Right, I would definitely like to move to the solid axle springs. In the process I would probably quite a bit of weight on the front end, those reinforced stock RA's and the extensions weigh close to 70 lbs a piece.

Steering is good, I haven't had any problems at all with that, down the road I'd probably go with the chevy TRE's but what I have has worked well so far.

How are these holding up?





I've never really gone out and looked at all your SAS pics, not sure I like these, I see why you're curious about the cage arms. This would also be the time to move from ttb coil setup to solid axle springs.

How is all that heim stuff holding up in your steering, I see a lot of mud pics. Nice thing about chevy TRE's is they are greasable.
 
#9 ·
yea my SAS with a detroit rear goes right on the gas and left off it or the reverse i can't remember right now. it also likes to pull a little when stopping. i think the stopping and accelerating stuff is partly detroit and partly a too steep track bar angle. i think the shado is right that the softer front end makes any little handling issue more pronounced, but none of that makes it undrivable. it's not a stock truck and it doesn't drive like one.
 
#16 ·
I totally agree that getting this gusseted is in order.




I do have ball joints. As far as the pulling goes, I haven't really paid attention to what it does on throttle probably b/c the pulling was so pronouced when I got off the throttle, that's when it feels like it's pulling to the right.

The first shop I took it to said there was a neg camber issue but then he confirmed that the ball joints were fine, the second place I took it to said there was nothing wrong with the axle tube.

outside edge wear on the right front and a pull to the right are both signs of too much camber on the r/f. Solid axles usually don't have camber issues, but it does happen. Is it possible that it pulls left on the throttle, then stops pulling off the throttle, (but then pulls right due to too much camber)? Usually when I see truck with worn ball joints, the camber goes negative. I don't even know if you have ball joints.
 
#14 ·
outside edge wear on the right front and a pull to the right are both signs of too much camber on the r/f. Solid axles usually don't have camber issues, but it does happen. Is it possible that it pulls left on the throttle, then stops pulling off the throttle, (but then pulls right due to too much camber)? Usually when I see truck with worn ball joints, the camber goes negative. I don't even know if you have ball joints.
 
#15 ·
Here are some more pics.. I got the Detroit after the SAS.

Shot from the front


Passenger side, you can see there is a little bow in the coil but not too bad, this was the side that the coil bucket was loose on



Drivers side



Not the greatest shot but here is a pic of the track bar bracket




Drivers side coil mount



Radius arm

 
#28 ·
Here are some more pics.. I got the Detroit after the SAS.

Shot from the front

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your drag link and track bar are not parrell from that picture. I would get a drop pitman of 2" less and see how it looks.

how ever I highly doubt thats the push pull stuff. Like rep said, it is probably the detroit pulling to the right.

double check your air pressure in the rear.

if it still does it, flip left and right rear tires and see what happens.
 
#17 ·
Hey Jeremy, how about a couple pics of the tires, inside/outside, both sides. I run 37 radial Iroks so I'd like to see how yours are wearing. Do you rotate them to the rear every 5k or (I didn't my first set due to bad balancing issues and can show you pics of outer tire wear after 20k up front, which also increases imbalance dramatically)?
 
#19 ·
I can shoot some more when I get home tonight. These tires have less than 4K miles on them and I'm sure that whatever the front end problem is has caused an already fast wearing tire to wear even more quickly..None of the other tires are showing near the amount of wear the passenger side, the rears looks almost new. To answer the question, no I never got around to rotating them.



No I didn't get an alignment printout, I'm kicking myself because I should have then I would at least have had a starting point..They're bias plys and I would agree that the bad wear is most likely making the pulling feeling more pronounced.

Did they give you an alignment printout? The only way to get outside edge wear with negative camber is a lot of toe in. Could be radial tire pull (if they're radials), or just the bad wear making it pull. X the fronts or rotate front to back and see what happens.
 
#18 ·
Did they give you an alignment printout? The only way to get outside edge wear with negative camber is a lot of toe in. Could be radial tire pull (if they're radials), or just the bad wear making it pull. X the fronts or rotate front to back and see what happens.
 
#20 ·
My votes goes to the detroit rear. Mine always pulled a bit to the right when i let off and it unloaded, but it became more pronounced with the shackle flip.

I think my D60 was bent when i installed it, as when i was done rebuilding/installing it, the camber on the passenger side was off by 2º, which made it pull to the right. A spindle shim fixed this, but i knew there was an issue right away, because it always pulled to the right, it wasnt just an on/off throttle thing, which is why im thinking your problem is in the rear. If one axle isnt straight underneath the truck id expect it to pull harder the faster you go, but all the time, not just when youre coasting. Same thing if one axle is shifted to the side; sure itll crab-walk, but it should do it all the time, not just decelerating.


Im with Dan, being able to see the alignment results would be nice.
 
#21 ·
Rep, thanks for the input. This is definitely just an on off throttle thing. Under normal cruising conditions it goes down the road great..So are you saying the rear axle isn't straight under the rig?

I guess there are really two problems here, and I think we've established that the pulling is primarily related to the detroit in the rear and could possibly be compounded by the axles not being parallel along with the uneven wear that has already occurred with the tire.

Can we agree that none of those issues would cause the uneven tire wear, then if so I'm looking at a negative camber/toe problem, so I need to get a tire shop to pull some #'s for me.
 
#22 ·
Well, id say that the pulling when decelerating is coming from the detroit, its a common thing. Rear axle im sure is fine, its rare for that to be off unless you moved the spring brackets on the frame.
As for your tire wear, id definitely get an alignment done by somebody who understands that it is not the stock suspension under your truck so that they follow the proper vehicle specs, and then post up what the results are. Theyll probably do it anyway, but get them to do a full 4-wheel alignment just make sure both axles are in their correct locations relative to the frame.
 
#23 ·
Alright that makes sense. I'm going to take it back to the shop this weekend and have them get me the numbers. Has anyone ordered from CAGE recently I saw a few threads from a week or two ago but nothing recently and I can't get to their website, I'm seriously interested in taking a look at their arms. Thanks.
 
#25 ·
Website works fine for me.

I spoke to Jim personally about two weeks ago, and he had told me that they are crazy busy, however he still managed to get me my parts in about two weeks time, and even told me about the FSB discount :thumbup Worst case, give em a call and leave a message, he said its taking some time, but they are getting back to everyone.
 
#24 ·
i agree with what's been said here the detroit in the rear will give you the pulling issues. I have one and soft leaves on the back and I have the same on off throttle response you are refering to. If you are like me and most others that have done the sas you did it for offroad capability and not road use that's why I did mine and I will just deal with it.
 
#26 ·
Explain to the alignment guy that you want measurements of vehicle symmetry/setback and axle offset. If you don't tell them, they will probably just give you a basic printout, that will include thrust angle, but no offset. They have to push a couple of extra buttons to get it to measure offset and setback.

So how does this detroit pull work? When you let off the gas and the locker disengages, it will pull, and then it stops pulling as you coast?
 
#27 ·
So how does this detroit pull work? When you let off the gas and the locker disengages, it will pull, and then it stops pulling as you coast?
The reasons a Detroit/locker would cause pulling would be either tires that are not exactly the same diameter (PSI different?) or the rear axle isn't exactly perpendicular to the frame. You would only feel the effects when the locker is engaged when power is applied.
 
#31 ·
he is knowticing the pull more than the push. it is just one of the quirks about the detroit, when you let off you knowtice the pull alot more than the slight push.

Jer, go measure hub to hub on both passenger side and driver side. if your passenger side front is farther forward that the driver front, this could be the cause of the tire wear.
 
#40 ·
Thanks, I'll check with him sometime this week.



Here are the pics of the tire wear, this is about the best I can do, the first is the passenger side, you can clearly see the difference in wear.



This is the drivers side you can see how much more evenly its wearing.



To test the theory about the axle possibly not being parallel, I got some string and ran it from the left side of the (drivers side)pumpkin to the rear axle tube got a measurment of 104 inches, did the same measurement on the passenger side of the front and real axles and got 102 and 1/2 inches, granted this was probably not the most scientific method for measuring but clearly the drivers side is out in front of the passenger side by about an inch and a half.
 
#41 ·
To test the theory about the axle possibly not being parallel, I got some string and ran it from the left side of the (drivers side)pumpkin to the rear axle tube got a measurment of 104 inches, did the same measurement on the passenger side of the front and real axles and got 102 and 1/2 inches, granted this was probably not the most scientific method for measuring but clearly the drivers side is out in front of the passenger side by about an inch and a half.
That's a significant amount. It'll constantly want to travel in an arc to the right. Now the trick is to figure out what needs to move where. I'd measure from known similar points on the frame to the axle tubes. Most likely using the nubs sticking down from the bottom of the frame rails.
 
#44 ·
i have a sneaking suspicion that your radius arm brackets are just in the wrong spot. i'm assuming that you're not completely useless :goodfinge with a measuring tape, but i would want to get the axle in the right spot before i go spending $800 on a new set of arms you don't even need.
 
#46 ·
I think you're probably right, and thanks for the vote of confidence..:goodfinge I definitely don't want to go dropping that kind of $$ if I don't need to, at this point I'm going to need it for tires.



That's what I was afraid, it's a good thing the Bronco doesn't see too many mile otherwise they would probably be bald by now.

I can tell you Jeremy, that is crazy bad wear on those tires. Your tires basically look like my fronts do (I never rotated either), but, I got around 21k on my fronts (which I still consider mediocre compared with the rear).

You've really been getting bad scrub on those fronts. Not just unusual wear, but also the whole wear down that much with so few miles.
 
#45 ·
I can tell you Jeremy, that is crazy bad wear on those tires. Your tires basically look like my fronts do (I never rotated either), but, I got around 21k on my fronts (which I still consider mediocre compared with the rear).

You've really been getting bad scrub on those fronts. Not just unusual wear, but also the whole wear down that much with so few miles.
 
#48 ·
with the passenger side being back 1.5" your passenger side tire is scrubbing the pavement when your driving. because your being forced to turn left to go straight.
 
#53 ·
Dan, draw yourself a picture, I am fairly confident this is whats causing his tire wear.

in order for him to go straight he has to turn the wheel a little to the left all the time. this puts the passenger side tire scrubbing the pavement all the time.
 
#54 ·
Jopes, while I agree this is likely the cause, it's not because of the steering always being turned.....this is how I visualize it:


I
--------I




I-------I


So going straight, it can be going straight in the front, just by aligning the front wheels...toe and straight forward on the tires. However, with any turning and a front axle not being parallel, every time you turn I can see a lot of added problems with tire wear up front.

And again, back to the whole detroit pull discussion, I'd think that an uneven wheelbase would accentuate the rear detroit pull to one side as well.
 
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