Alignment- Measuring Caster

[OX1]

Thanks for those numbers. I'm assuming those are (negative) angles.



I'm in the process of narrowing the d44 and at the same time I'm going to rotate the 'C'.
Shooting for 59" wms, stock bushings, ideal pinion angle, and -5 to -7 degree caster.

It has + 4.5 at ride height now.

Nope, positive. Negative caster is going the wrong way.

Took it for short ride after resetting toe. Seemed better, but after 3 miles, front left caliper locked up hard. Wondering how long this has been going on and how much affect it has had on overall steering.

 

[surfer-b]

[QUOTENope, positive. Negative caster is going the wrong way][/QUOTE]
Correct, Pos is what you want.
I have been thinking on this caster issue, I know there are a lot of things that play in effect on how a Bronco drives. My 74 Ranger, which drives as good my 96 Land Cruiser, has +3.5* and +4.0* caster, I can relax, it never wanders and there is no need for steering correction. My 76, which has +4.5* and +5.0* caster, has the same set-up as my 74 but still has a slight wander to it on back roads, however not so much on long straights and Highways. I have tried everything and cant get this thing to drive the way it should. I think it has more to do with how quick the steering axis ramps up, causing the tires to try and roll up on the ball center when the steering wheel is turned. I believe on my 74 it starts to ramp up as soon as the steering wheel is turned the slightest, causing it to return to center and stay straight no matter what, where as on some others its such a gradual curve it allows the front to wonder around. It may take a 1/8~1/4 turn each way before the tires really start to try and roll up on the ball center. I believe the only way to get one to drive the way it should, if its not driving good to start with, is to rotate the yokes so it will have about +8* caster in it. This is just my theory I have no way of proving this but can't think of any other reason what would cause it. I am going to rotate the yokes soon and see what happens.

 

[siderbox]

Nope, positive. Negative caster is going the wrong way.

ohya
Little brain fade on my part.

 

[WASP1971]

Can someone explain "rotating the C" and "turning yokes" please? Thanks

 

[surfer-b]

Can someone explain "rotating the C" and "turning yokes" please? Thanks

When you turn the yokes you grind the weld from the yoke/tube all the way around so that the yoke can be rotated front or back depending on the caster you are looking for, rotating the top back will give you more pos caster and rotating it to the front will give more neg. The red arrow is the yoke and the blue is the weld that needs to be ground to get it to rotate.

 

[WASP1971]

Thanks surfer b. That's a little out of my realm of capability. I was asking because I too have the darting issue. My D44 is a narrowed high pinion from a 78 F150. From the advice of other members I'm going to try the 7 degree C bushings when I get home. I'm currently in Africa(until January).

 

[DirtDonk]

The existing caster readings on the '78 and '79 full size axles will almost always be higher than any given EB front axle. The factory spec for those was something along the lines of between 6 and 8 degrees positive, while the EB was more in the 2 to 4 range.
And even then, some of the EB axles didn't seem to have even that amount to start with. Be nice if we could get some caster readings on some stock Broncos to build up the database, but suffice it to say that most full-size axles will have more positive caster built right in.

Along with toe-in, tires play a HUGE part in how your EB feels acts on the road. Not only type and brand, but wear and condition of the carcass' innards.

Those of you with a little dartyness, are your steering boxes all perfectly centered? Even a little off-center when going straight can act real odd. Not that they all will, but I've driven several that were so bad that you'd swear something was coming apart up front!
Same with tires.

Very slight wandering and following of grooves and such can also be a trackbar issue. Even with good bushings, if your upper or lower mount is moving even slightly, a light wandering can result.
The stock lower mounts are just large bolts tack-welded to the lower bracket. If that tack weld breaks, even putting full torque on the bottom nut is not always enough to keep it from moving.
If the upper mount is extended and not welded, or the bolt is worn, or the rod end loose, wandering will likely result.

With custom steering setups like your OX, with the draglink not only mounted to the vertical front face of the tie-rod, and maybe even some acute angles from the different mounting point of the box, a little rotational movement of the tie-rod can result in a more vague connection between the tires and the steering wheel can lead to less control over the initial movements.

Just a few things to look at. Some of those things are only visible with the test using a helper at the wheel while you watch and feel all the rest of the components.
Won't work for you though OX, until you're done checking things and get the tires off the spinners and back on the ground.
Glad you're doing all this testing. Gives a lot of good info for comparison.

Paul

 

[Luke77]

I’ve been following this with the same symptoms. If the steering box is centered does it matter what clock position the pitman arm is?

 

[OX1]

With custom steering setups like your OX, with the draglink not only mounted to the vertical front face of the tie-rod, and maybe even some acute angles from the different mounting point of the box, a little rotational movement of the tie-rod can result in a more vague connection between the tires and the steering wheel can lead to less control over the initial movements.

Just a few things to look at. Some of those things are only visible with the test using a helper at the wheel while you watch and feel all the rest of the components.
Won't work for you though OX, until you're done checking things and get the tires off the spinners and back on the ground.
Glad you're doing all this testing. Gives a lot of good info for comparison.

Paul

I've thought of getting a cheap full length mirror and putting it horiz in front of the bronc, aimed my way. Usually, the person steering the wheel doesn't really know what your after and since many broncs have doors that come right off, it's easy to stand on the side of the rig and look at a mirror.

 

[DirtDonk]

I’ve been following this with the same symptoms. If the steering box is centered does it matter what clock position the pitman arm is?

From the factory, when centered the manual steering setups had the pitman arm pointed to the driver's side by 1 or 2 splines.
At least some pitman arms from power steering setups were keyed to be straight back along the frame.
Have never verified that this was the same for both "T" and "Y" setups, so that might be something to look in to one of these days.

Paul

 

[OX1]

From the factory, when centered the manual steering setups had the pitman arm pointed to the driver's side by 1 or 2 splines.
At least some pitman arms from power steering setups were keyed to be straight back along the frame.
Have never verified that this was the same for both "T" and "Y" setups, so that might be something to look in to one of these days.

Paul

78/79 ford 1/2 ton boxes are straight along the frame.

UPDATE:

Fixed my caliper issue and headed out for another ride. 12 miles to work, mostly decent pavement, level roads. Got up to about 55. Better than I remember, overall.

The spots with poor pavement quickly start to upset the chassis, but I am not atributing it all to steering or caster (3.5 lift, no sway bars, 33" tires, short wheelbase, etc...). My steering is very quick. Even minor bumps seem bouncy, and any input to my body/arms can somtimes tweak the steering wheel slightly (causing unwanted steering).

Going to tear out the front axle and add more catser.

I also think my shocks are too stiff (maybe even the springs). The are CAGE front and Deaver 11 pack rear, which are supposed to be softer for crawling, but the thing sure rides like complete brick (hence why I'm leaning towards shocks). Shocks are CAGE front, and some Rancho in the rear that I painted to match fronts.

 

[DirtDonk]

What was your caliper issue? If it was discussed, I forgot already. ;D

78/79 ford 1/2 ton boxes are straight along the frame.

Funny you mention that. I was thinking about editing that into my post this morning.
Good call. Lots of those boxes winding up on EB's nowadays anyway, so it's definitely pertinent info.


With your caster currently in the 3 degree range, you may still have other issues.
Mine is under 2 degrees on one side, and just a smidge over on the other. Drives sweet, with both 32" and 33" tires.
Got any current pics of your front end? You posted one, but I think you said that was a "before" shot. Got an "after" for us too?

I also think my shocks are too stiff (maybe even the springs). The are CAGE front and Deaver 11 pack rear, which are supposed to be softer for crawling, but the thing sure rides like complete brick (hence why I'm leaning towards shocks). Shocks are CAGE front, and some Rancho in the rear that I painted to match fronts.

Even though this is not the safest or surest test, you can actually disconnect the shocks and drive it a short distance to see if it takes away all of the harshness you're experiencing. That way you can verify that the springs are not something to be changed as well.
There is always this other thing to check too, when diagnosing harshness. Loosen all the fastening hardware. Since they're locking nuts, you can take some torque off of them and see if it reduces harshness too.
If your spring hangers were damaged by the original sleeves (very common to have deep grooves cut into the inner walls) then torquing down the bolts to spec could actually have your bushings squeezed too tight.

Air pressure is the other thing. Most 33's will respond to 25 to 30 lbs. Rarely are they happy at maximum pressure. Way too harsh in some cases.

All worthwhile tests.

Paul

 

[OX1]

Got any current pics of your front end? You posted one, but I think you said that was a "before" shot. Got an "after" for us too?


Even though this is not the safest or surest test, you can actually disconnect the shocks and drive it a short distance to see if it takes away all of the harshness you're experiencing. That way you can verify that the springs are not something to be changed as well.
There is always this other thing to check too, when diagnosing harshness. Loosen all the fastening hardware. Since they're locking nuts, you can take some torque off of them and see if it reduces harshness too.
If your spring hangers were damaged by the original sleeves (very common to have deep grooves cut into the inner walls) then torquing down the bolts to spec could actually have your bushings squeezed too tight.

Air pressure is the other thing. Most 33's will respond to 25 to 30 lbs. Rarely are they happy at maximum pressure. Way too harsh in some cases.

All worthwhile tests.

Paul

Current pic
http://luxjo.supermotors.net/70 EB ... LINK/CHEBBIE TIE RODS_DOM LINKS/DCP04573.jpg

Going to start with the caster increase, then need to do an engine since this thing is now blowing oil out some of the seals at this point (due to the blowby, see my other thread).

But will keep all your advice in mind, all good stuff there, really appreciatte all the suggestions. I like the idea of loosening up some bolts, especially on the suspension (I do have the bronco lean, maybe at least that would work itself out, if nothing else).

 

[DirtDonk]

Thanks for the update pic.
And since you're showing pics, how's about one from the side to show the angle of the draglink?

You're one of the few that's running the full-size box in that configuration, so it would be good to have some reference shots.
Did you mount the box in a relatively stock location?

Thanks

Paul