Steering issues on lowered straigh axle

[LordDevlin]

Good day,

I haven't been on here for a while but have been looking in from time to time. I received great information and heads up from you folks in the past and I really appreciate that, and was hoping for some more.

I recently got a new truck, came from California... its a bit more on the rod side of things, something different for me as my father has always been more of a purist, and having grown up with him, I adopted to same taste I suppose.

Either way, the truck has had a lot of work done on it, some really good work. However, when lowering the front, they seem to have simply taken out some leaves, 3 total, with 3 remaining. Its not plated yet so haven't had a chance to drive it other than around the block due to our Canadian winters. It did bottom out a bit, but that's not why I'm writing. The steering is awful.... meaning, when you go around a corner, the wheel doesn't come back straight in your hands on its own. Is this a sign of a worn steering box, or could it be from the changes in steering component geometry from the lowering?

I know that if you use a dropped axle you need to modify your pitman arm and some other stuff, but didn't necessarily know that the case would be the same when simply lowered with springs.

Could anyone provide some insight or advice? The truck is at the transmission shop as the 700r4 needed to be rebuilt and having the speedo calibrated, it didn't have a 3 gear it seems. Should be back this weekend.

Thanks for your help

[tmoble]

yes, this is from the amateur attempt to lower the front. The guy apparently graduated from the "quick-n-dirty" school of automotive engineering. The front axle needs to tilted back at the top, or think of the kingpins needing to be tilted back at the top. the tilt is what causes the natural self-centering action of the front suspension. This was lost because the spring is now arched the wrong way.

If you go to a real truck alignment shop they'll have wedge shims that can be mounted between the axle and the spring. put the fat part of the shims towards the front. With radial tires you'll want like 5 degrees of caster. the original specs were for bias ply tires and don't work well with radials.

Or, get new springs with all the leaves and use a dropped axle. you'll still need caster shims in that case.

Or, install a 2nd gen Camaro front subframe and forget all this BS. A little more involved though.

[LordDevlin]

Originally Posted by tmoble

If you go to a real truck alignment shop they'll have wedge shims that can be mounted between the axle and the spring. put the fat part of the shims towards the front. With radial tires you'll want like 5 degrees of caster. the original specs were for bias ply tires and don't work well with radials.

Or, get new springs with all the leaves and use a dropped axle. you'll still need caster shims in that case.

Or, install a 2nd gen Camaro front subframe and forget all this BS. A little more involved though.

Thanks TMoble. Yes, I have read about the shims in the past when I was looking into dropped axles from Sid for the red truck in my avatar pic. I really appreciate the input. I will give that a try and hopefully it does the trick. I wonder if perhaps the steering box is now ruined from having been driven like this for a while by the p.o.?

My plan for this summer is to keep it lowered with springs... whether that be another original leaf pack with only a couple leaves (and different ones than what are currently removed) or buying some Posies or monoleafs. The problem is that the rear has been lowered a decent amount so I need to make sure to try to get the front down enough to match, and I worry about how well I can do that with just springs.

Over the winter, I hope to do something better/safer with the front, either an IFS or the dropped axle route. I prefer to not cut any frames, but I worry about the limited clearance I will have from axle to ground, as well as all the additional steering component considerations that come with that. The truck already has a disk brake set up in front so its not like I will be gaining that from installing a clip.

[tmoble]

I don't see why it would affect the box any. It's probably just loose from being 65 years old with a million or so miles.

The only thing that affects the axle to ground clearance is the diameter of the tires unless you're referring to the dropped axle. That's only a couple inches.

My 57 has had a 77 Camaro subframe under it since 1993. It has no issues and has needed no work done till I stripped it to bare frame for a total rebuild last summer. 1.25" front stabilizer bar, 12:1 WS-6 T/A power steering box, disc brakes, drives like a go kart on steroids. in 2013 I added a C4 Vette rear axle assembly, really helped the ride and now drives even better.

[tmoble]

BTW, I think the stance of your truck is about perfect now. Looks great.

[LordDevlin]

Tomble,

Thanks so much for the help... this makes this little steering issue seem so much more manageable than what I anticipated. Not sure what the steering is actually like, because all I notice is the effects from it being lowered without the shims... the steering box is just one of the things I thought it could be.

Yes, I was referring to clearance with the dropped axle... getting a 3 inch drop lets say would put me that much close to any bumps that are between my wheels. I suppose it would only be tight when I would go up to the cottage.

Thanks for compliment on the ride height.. it does sit nice and level, but haven't spend enough time with it to decide whether or not I am happy with height or would prefer lower. As mentioned though, in the near term I need to find a spring only solution to make the front not bottom out but still be low enough to match the rear.

any advice for that would be appreciated as well.

[dwcsr]

It could be one or several issues.
Caster is way off
The box is not centered.
Box is improperly adjusted. They may have cranked in the adjuster to get the slop out of it
King pins are bad.
The geometry is to far out from the drop
Something is binding in the steering linkage or pins

[gwsut]

Lord Delvin,
Amazingly I have a truck just like the one in your avatar .....LOL. I have the one you and your father once owned. And I too have been working to get it to ride, steer, and handle better. I know don't if your father told you but I replaced the front shackles and spring bushings. One shackle pin was completely frozen and the rear bushings were worn badly. I left the all the leaves in the springs but put poly liners between the leaves after disassembling, bead blasting, and painting the leaves. This improved the ride over what it was and probably rides as good as when it was new (my father bought a new 59 that I used to get my drivers permit so I remember how it rode). I tighten up the steering as far as the adjustment would go. Again, it was better but still wandered some but would pull badly on uneven road surfaces. So last night I put a pair of 6 degree caster shims and that really helped and made it go straight. It still wanders some but the steering box is the culprit because it is badly worn. Next project is to replace the steering box with a CCP power steering Toyota style unit. Then with new radial tires, it should steer right.
However, with all due respect, I believe one of the previous posters above mistakenly gave you some wrong advise. He said you want to lean the axle or the top of the kingpin to cant to the rear which is correct to increase the caster. He said you wanted the thick end of the shim to the front. That is incorrect. The bottom of the spring stays stationary or level and the thick end of the wedge rotates the back of the axle downward and the top of the king pins cants rearward increasing the caster. Also, the factory stock shim that came on the truck has a dimple in the thick end of the wedge that fits into a recess on the back of the spring mounting pad on the axle.
Tomorrow, I'm going to rebuilt the rear springs-shackles-bushings.
Tell your Dad "The Guru" I said hello.
Gary

[tmoble]

That would be me, I guess. I've had my truck since 84 and installed the the Camaro front in 93. Apparently I've forgotten whether the axle was on top or underneath the spring.

Thanks for being nice about correcting me.

[LordDevlin]

HI Gary,

Thanks for your info... I am glad you are enjoying that truck. It was my first one. I think you will find that the radial tires will make a huge difference, I used to hate getting caught in those tar strips on the high way only to get thrown out at high speeds.

Ok, so we want to cant the axle towards the rear? I understand that that would require the fat end of the shim being towards the rear. Would I be doing it the other way if lets say I had a dropped axle? It seems to me that many ppl on here have talked about putting the fat edge to the front when they have lowered straight axle front ends.

I suppose its not about front or back, its about looking at the set up and determining if it needs positive or negative caster. Originally my dad said he figured it needed to be to the rear, so he appreciates the validation haha.

Thanks for all the help.

OH and Gary, I told him you wrote me on here. sorry for still having your truck up there, I looked to change it but can't seem to find the option to do it on here anymore.

Elliot

[MARTINSR]

Just removing leafs from springs isn't going to change the caster enough to make a difference, you have something else going on here. One thing that happens when you lower it like that is you end up with bump steer because the drag link is going up at an angle instead of level. But honestly, you have something else going on here. They may have tightened up the steering box and went too far.

https://www.youtube.com/watch?v=qtXQvVNg6vI

I know that I did this on my Rambler, it wouldn't turn back on a tight corner and I had to back it off a bit.

Brian

[LordDevlin]

Martin,

The truck is down as far as it can go with just springs removed... they took out 3, which is too many, and on top of that took out the wrong 3. Its to the point that the spring bushings/shackles are almost at the same height as the axle.... the springs are essentially flat... add an extra 220 lbs from me while driving and its getting pretty low.

Earlier Gary mentioned putting 6 deg caster shim in his truck (my old one) which is not lowered at all and said it tracks much better. Will putting these in hurt things in any way if in fact they aren't needed?

thanks again.

[gokellurself]

Originally Posted by tmoble

put the fat part of the shims towards the front.

Hey thanks for this info. Literally, last night out working on my front end and staring at my shims wondering if they're in the right way. Sure enough they weren't. Good catch

[MARTINSR]

Originally Posted by LordDevlin

Martin,

The truck is down as far as it can go with just springs removed... they took out 3, which is too many, and on top of that took out the wrong 3. Its to the point that the spring bushings/shackles are almost at the same height as the axle.... the springs are essentially flat... add an extra 220 lbs from me while driving and its getting pretty low.

Earlier Gary mentioned putting 6 deg caster shim in his truck (my old one) which is not lowered at all and said it tracks much better. Will putting these in hurt things in any way if in fact they aren't needed?

thanks again.

Adding caster won't hurt, but we aren't talking about how it tracks down the highway, we are talking about taking a corner slow. Yes caster will effect this, but honestly, lowering it like that didn't change the caster more than a fraction. And that just isn't going to make much of a difference. I would say 6 degs is way too much, that truck probably had only one from the factory so a couple or 3 degrees is plenty.

As others have said there is likely a few things going on, I certainly don't have all the answers. But it sounds like something is binding to me, and the steering box is very likely.

Brian

[dsraven]

a steering box is equipped with gears that are ground to be tighter in the middle of it's lock to lock travel than when not in the middle, like when you are turning. that is so it will be tight when you are driving straight, no slop, and when you go around a corner it will easily come back to centre. the king pins are set up with an angle (kingpin inclination) so when the steering is turned the wheels actually move in a slight upward arc and will naturally want to come back to centre because the weight of the truck will want to push them back to centre, google kingpin inclination for more info. it has to do with the angle of the kingpin in the straight axle. if the steering box gear backlash is not set up when the box is centred in the middle of it's travel, lock to lock, then it will naturally cause issues because the gears are not in their "tight spot" when adjusted so when the box is turned to a point where it is actually in the "tight spot" it will be really tight.
try this. centre the steering box and adjust the gear backlash when it is at it's mid point. now check the wheels to see if they are going straight ahead. if not you may need an adjustable drag link so the box can be in it's sweet spot when the truck is going straight ahead. the steering wheel should be centred at this point as well. also, it goes without saying that if the box is worn out then you are fighting an uphill battle.

[dwcsr]

Originally Posted by gokellurself

Hey thanks for this info. Literally, last night out working on my front end and staring at my shims wondering if they're in the right way. Sure enough they weren't. Good catch

This is not correct, The fat part is toward the back so it tilts the top of the pin backwards, Use a protractor and see for your self. Putting it toward the front tilts the pin forward.

[dsraven]

getting back to the start of the thread, the question was why the steering won't self centre after a turn. have you disconnected the tie rods and checked for a tight kingpin? if the kingpins are starting to seize up they won't want to return to centre.
personally I would check-
-kingpins for ease of turning-disconnect tie rods for this so you isolate each kingpin. grease each one after, with the wheels off the ground. ensure you get nice clean grease out of every spot.also check for bushing wear while you are there, before greasing anything, and wear on the thrust bearing that is between the steering spindle and the axle. these have a tendancy to sieze up because they don't see enough grease or guys don't hang the suspension when they grease the front end and the grease just can't get in there. they also may have sat for many years in one spot with dirt and possibly water etc so may have some rust divets in the bearings and not want to move out of those divets. loose kingpin bushings can actually affect steering return as well because they bind and also change the inclination angle.
-check the steering box to ensure it is adjusted properly and doesn't bind up at any point. make sure it is centred, lock to lock, when the tires are straight ahead.
-check the steering column for ease of turning to ensure you don't have a bearing starting to seize up.
-it goes without saying that the rest of the front end should also be checked for wear. spring bushings, tie rod ends, drag link etc etc.


here is a quick blurb from wikipedia on kingpin inclination that may help you understand what brings the wheels back to centre by themselves.

On most modern designs, the kingpin is set at an angle relative to the true vertical line, as viewed from the front or back of the vehicle. This is the kingpin inclination or KPI (also called steering axis inclination, or SAI).SAI is non-adjustable, since it would change only if the wheel spindle or steering knuckles are bent. This has an important effect on the steering, making it tend to return to the straight ahead or centre position. This is because the straight ahead position is where the wheel is at its highest point relative to the suspended body of the vehicle - the weight of the vehicle tends to return the kingpin to this position. A second effect of the kingpin inclination is to set the scrub radius of the steered wheel. This is the offset between the tyre's contact point with the road surface and the projected axis of the steering down through the kingpin. If these points coincide, the scrub radius is zero. Zero scrub radius is possible without an inclined kingpin, but requires a deeply dished wheel so that the kingpin is at the centerline of the wheel. It is much more practical to incline the kingpin and use a less dished wheel, which also gives the self-centering effect. Zero scrub radius is not necessarily desirable - larger scrub radii lead to less steering effort (especially on vehicles without power steering), but more force applied to the steering components by road surface imperfections, braking, etc. Zero scrub radius isolates the steering from these effects but can lead to a "dead" feel for the driver which is undesirable, especially on performance vehicles.

[MARTINSR]

Originally Posted by gokellurself

Hey thanks for this info. Literally, last night out working on my front end and staring at my shims wondering if they're in the right way. Sure enough they weren't. Good catch

HOLY CRAP, I missed this! The shims were in the back putting your caster at - yeow! That will do it alright! Good catch! How is it driving now?

Brian

[dubie]

easy fix, caster shims of 4 or 6 degrees will fix it right up. But can you do us a favor and take a picture of your drag link? It's gotta be parallel to the frame to aid in better steering geometry. I used mono leafs and a dropped axle to lower mine 6 inches so i know exactly what you're dealing with

[MARTINSR]

What a darn minute here! Is you axle on the top of the springs or below the springs?

If it's on top, the shim would be put in the front so it tilted the axle back. If it the axle is under the springs then the shim would go in the back to tilt the axle back.


Brian

[MARTINSR]

Originally Posted by dubie

easy fix, caster shims of 4 or 6 degrees will fix it right up. But can you do us a favor and take a picture of your drag link? It's gotta be parallel to the frame to aid in better steering geometry. I used mono leafs and a dropped axle to lower mine 6 inches so i know exactly what you're dealing with

Yep, Bump steer like mad with a drag link going up hill!

Brian

[dwcsr]

Originally Posted by MARTINSR

What a darn minute here! Is you axle on the top of the springs or below the springs?

If it's on top, the shim would be put in the front so it tilted the axle back. If it the axle is under the springs then the shim would go in the back to tilt the axle back.


Brian

Yes

[LordDevlin]

Mine, being the original one from the top of this thread, is a 59 and the front springs are still on top of the axle

[LordDevlin]

Originally Posted by MARTINSR

Adding caster won't hurt, but we aren't talking about how it tracks down the highway, we are talking about taking a corner slow. Yes caster will effect this, but honestly, lowering it like that didn't change the caster more than a fraction. And that just isn't going to make much of a difference. I would say 6 degs is way too much, that truck probably had only one from the factory so a couple or 3 degrees is plenty.

As others have said there is likely a few things going on, I certainly don't have all the answers. But it sounds like something is binding to me, and the steering box is very likely.

Brian

Hi Brian,

When you said the truck probably had only one from the factory, did they come with only one shim originally? I looked at one of my dads trucks, the yellow one in pic, and it only had one shim. automatically assumed it must have lost one or something. Perhaps that's just the way they were.

that's mine in there on the left as we get the steering issue sorted out.

[LordDevlin]

GENERAL UPDATE

I drove it back from the transmission shop and experience the scariest drive of my old truck driving career. I have read a lot about bumpsteer, but for the first time I experienced it baaaad. So, the wheel doesn't turn back on its own, and the truck has bad bumpsteer.

on-going:
- king pins didn't turn well... greasing them, the tops took it but tough getting it in the bottom
- I expect that the steering box/wheels are not centered properly, meaning that its not in the tight gears when its straight ahead, based on our initial investigation.