Steering Problems With Lifted Truck

[FJ80HI]

Just wanted to provide some information that may help you with steering problems with lifted truck.
Son bought a 1990 Toyota pickup with a 5 inch Trail Gear lift. PO also did a solid axel swap. Engine is 22RE. The truck had just been lifted and axel swaped when we bought it. Axel and lift gear all new. When we first got the truck, it was basically undriveable. Most of vacuum hoses were missing from the engine, engine was always stalling and did not idle well. Fixed those issues. Next problem was steering was scary and dangerous. 110% attention to keep the truck in the lane. Totally unsafe. I took the truck to some off road shops and the comment was that is how solid axels handle. I have been driving solid axels for over 40 years and never had one handle like this (IH 1965 4WD pickup, my first car 1978 FJ40 bought used in 1982, and my current 90 FJ80)
So What fixed the problem: 1. Shimmed the front axel with 3 degree shims from Woodys (this increased front caster from about 4 deg to about 7 deg)- this made a huge difference. Now the truck would self center after a turn and track straight without constant wheel adjustment. We adjusted toe in about 1/8 in as compared to front and back of the 35 inch tires. We tightened up the loseness in the shackle bolts and we also adjusted the pitmen arm so it was aligned straight forward to back (making sure steering wheel lock to lock had equal turns from center). We installed a OME steering stabilizer. Once we did this we had interference with the tie rods and found the tie rod from the pitman arm was in the wrong location on the axel knuckle. When installing the PO had installed wrong. We swapped location of tie rod and trailing rod on the knuckle. The truck now drives with one finger steering. When buying a used truck, check everything, took us a year to figure this all out. We also replaced rear drive shaft with a new Woods' that have the cardan joint at the transmission and universal at the diff in addition to shimming the rear axel with 12 degree Woodys shims to get the diff to point at the transmission output shaft- this solved the original drive shaft vibration due to the extreme angle and out of syn issues the original two universal drive shaft had. Woods shaft and shims were great as well as that company.

 

[gnob]

the tie rod placement was your primary issue.
i drive a sas on 37s with 1° caster and it drives and tracks perfectly.

 

[FJ80HI]

the tie rod placement was your primary issue.
i drive a sas on 37s with 1° caster and it drives and tracks perfectly.

After we increased caster from the 4 deg to 7 deg the truck drove great. It was only when making tight turns the tie rods actually started rubbing and prevent turning the wheel further. Swapping the tie rods solved this problem. I have read with high lifts (this truck has a 5 inch lift) the more caster is needed in order to provide steering return and more settled steering, and for us, this was the case. I should also add that when we added the shims, it causes the from axel to rotate backwards (increased caster) and that is what provided twist to the two tie rods which then caused them to rub as one rod over lapped the other.

 

[gnob]

the rods being swapped was screwing with the Ackerman.
im not arguing, just saying, that much caster isn't really necessary.

 

[FJ80HI]

gnob,
It is generally agreed that more lift and larger tires require more caster. The OEM specs are irrelevant:

Truck Set Up	caster	camber	toe in
2–3 inch lift with 33 inch tires	3.5° to 4.5°	0° to -0.2°	0.05° to 0.10° toe-in
2–3 inch lift with 35 inch tires	4.0° to 4.8°	0° to -0.2°	0.05° to 0.12° toe-in
4–6 inch lift with 35 inch tires	4.5° to 5.5°	-0.1° to -0.3°	0.08° to 0.15° toe-in
4–6 inch lift with 37 inch tires	5.0° to 6.2°	-0.1° to -0.4°	0.10° to 0.18° toe-in

 

[gnob]

gnob,
It is generally agreed that more lift and larger tires require more caster. The OEM specs are irrelevant:

Truck Set Up	caster	camber	toe in
2–3 inch lift with 33 inch tires	3.5° to 4.5°	0° to -0.2°	0.05° to 0.10° toe-in
2–3 inch lift with 35 inch tires	4.0° to 4.8°	0° to -0.2°	0.05° to 0.12° toe-in
4–6 inch lift with 35 inch tires	4.5° to 5.5°	-0.1° to -0.3°	0.08° to 0.15° toe-in
4–6 inch lift with 37 inch tires	5.0° to 6.2°	-0.1° to -0.4°	0.10° to 0.18° toe-in

plenty of internet legends are "generally agreed upon"

i personally don't like heavy caster and heavy return.

imo the heavy caster legend is built on a band aid for death wobble.

 

[FJ80HI]

plenty of internet legends are "generally agreed upon"

i personally don't like heavy caster and heavy return.

imo the heavy caster legend is built on a band aid for death wobble.

Well everything I have read, including from expert alignment shops agree that the higher the lift and larger tire size require more caster to settle the steering. Has nothing to do with bump steer. True bump steer is due to the fact the steering tie rod has one end connected at a fixed point (vehicle frame) and the other end connected to a vertically moving point (axel when hitting bump). The bump creates and arc that must force the pitman arm in very slightly which both move the steering wheel and the front road wheels. More caster, by physics settles the steering, like a chooper bike has more settled steering than a 0 caster kids tricycle. However if your rig is good at 0 caster, leave it at that.

 

[bkg]

Well everything I have read, including from expert alignment shops agree that the higher the lift and larger tire size require more caster to settle the steering. .

not accurate

 

[FJ80HI]

not accurate

Like you said not everything online is true. And no one drives a vehicle on public road with 0 caster unless they want trouble. I cannot find any oem vehicle spec stating 0 caster. On the contrary spec is 2 to over 5 and more for commercial heavy duty. In any case happy I do not take your advice as our lifted 90 pickup driving like a 911

 

[bkg]

Like you said not everything online is true. And no one drives a vehicle on public road with 0 caster unless they want trouble. I cannot find any oem vehicle spec stating 0 caster. On the contrary spec is 2 to over 5 and more for commercial heavy duty. In any case happy I do not take your advice as our lifted 90 pickup driving like a 911

Meh. Drive an f350 on 35’s for years with 0 degrees. It was not ideal, but drove just fine. If you’re using caster to try and fix other things, you’re doing bandaids.

What is the wheel bearing situation?
Have you rotated tires?
How much preload is on the knuckle?
Is the axle straight?

 

[FJ80HI]

Meh. Drive an f350 on 35’s for years with 0 degrees. It was not ideal, but drove just fine. If you’re using caster to try and fix other things, you’re doing bandaids.

What is the wheel bearing situation?
Have you rotated tires?
How much preload is on the knuckle?
Is the axle straight?

Yes reread my my post. Front axels was all new. This was a solid axel swap. All suspension and shocks new. Frame good. All bearing pre loads good. We checked alignment several times during trouble shooting and all good. Steering box and all steering rods and ends new. Absolutely no play in anything. Tires and wheels brand new and balanced. Vehicle did not pull to any side. Just would not self center and required constant steering due to ability not to self center. Caster corrected the issue. We probably could have gotten away with 5 or 6 deg. But 7 is great. Once castor was increased. All steering issues gone. Need to also understand the 5 inch lift is actually for articulation. Hitting a bump can actually reduce caster due to very small axel rotation that happens with leaf springs on a solid axel. Coil springs will not cause axel rotation.

 

[FJ80HI]

I should also add the reason for cater is to allow a vehicle to self center and will allow you to drive down a straight flat road without touching the wheel. Don’t believe me search caster for off road Baja trucks and nascar cars. Facts are facts. None of these vehicles would have 0 caster

 

[bkg]

Yes reread my my post. Front axels was all new. This was a solid axel swap. All suspension and shocks new. Frame good. All bearing pre loads good. We checked alignment several times during trouble shooting and all good. Steering box and all steering rods and ends new. Absolutely no play in anything. Tires and wheels brand new and balanced. Vehicle did not pull to any side. Just would not self center and required constant steering due to ability not to self center. Caster corrected the issue. We probably could have gotten away with 5 or 6 deg. But 7 is great. Once castor was increased. All steering issues gone. Need to also understand the 5 inch lift is actually for articulation. Hitting a bump can actually reduce caster due to very small axel rotation that happens with leaf springs on a solid axel. Coil springs will not cause axel rotation.

Your original post mentions none of what I asked about. No mention of the axle being new or used. No mention of checking knuckle preload. No mention of checking wheel bearings. Etc. in fact, you listed a bunch of stuff wrong with the engine, so it’s not at all a stretch to think there may have been shortcuts taken elsewhere.

Coil springs have nothing to do with axle caster changes. Nothing. Links and link geometry control caster changes. Coils only hold weight.

 

[FJ80HI]

Your original post mentions none of what I asked about. No mention of the axle being new or used. No mention of checking knuckle preload. No mention of checking wheel bearings. Etc. in fact, you listed a bunch of stuff wrong with the engine, so it’s not at all a stretch to think there may have been shortcuts taken elsewhere.

Coil springs have nothing to do with axle caster changes. Nothing. Links and link geometry control caster changes. Coils only hold weight.

Fully understand that. The issue is with leaf springs The font to back horizontal length changes due to reduce radius on compression this is compensated for by spring shackles. But not 100% as font spring mount fixed and fixed on axel by u bolts this can cause a change in caster degree although normally slight for low lift. However large lift with low spring constant articulation springs it can be an issue

 

[FJ80HI]

Your original post mentions none of what I asked about. No mention of the axle being new or used. No mention of checking knuckle preload. No mention of checking wheel bearings. Etc. in fact, you listed a bunch of stuff wrong with the engine, so it’s not at all a stretch to think there may have been shortcuts taken elsewhere.

Coil springs have nothing to do with axle caster changes. Nothing. Links and link geometry control caster changes. Coils only hold weight.

Sentence 5 states “axel and lift gear all new”. You need to re re read post.

 

[bkg]

Sentence 5 states “axel and lift gear all new”. You need to re re read post.

All new doesn’t mean “correct.” Especially considering what you documented as incorrect in the engine.

Is the axle aftermarket? Did you actually check the knuckle shims and preload?

You’re WAY over thinking caster and leaf spring behavior. The impact on caster is minor.

 

[FJ80HI]

All new doesn’t mean “correct.” Especially considering what you documented as incorrect in the engine.

Is the axle aftermarket? Did you actually check the knuckle shims and preload?

You’re WAY over thinking caster and leaf spring behavior. The impact on caster is minor.

bkg,
I think at this point your just joshing me. For others reading this post do you own research and actual experimentation and testing with your rig to see what works for you.

Facts From Internet AI:

Yes, caster can change on a solid axle truck with leaf springs through both mechanical adjustments and dynamic suspension movement.

Mechanical Adjustment Methods
Because the steering knuckles are typically fixed to the axle housing, changing the caster requires physically rotating the entire axle or altering the steering axis:

• Caster Shims (Wedges): Tapered metal shims are placed between the axle housing and the leaf spring pack. Thick ends facing forward reduce caster, while thick ends facing rearward increase it.
• Shackle Length: Installing longer shackles on one end of the spring rotates the axle housing, thereby altering the caster.
• Offset Ball Joint Sleeves/Bushings: On some newer solid axles (e.g., Ford F-250/F-350), specialized upper ball joint bushings can be rotated to adjust caster without tilting the axle itself.
• Cut and Turn: For extreme adjustments (often after a lift), the "C" knuckles are cut off the axle tubes, rotated to the desired angle, and welded back in place.

Factors Causing Unintended Changes
Caster is not static and can shift due to several factors:

• Suspension Travel: As leaf springs flex, their length changes between the fixed mount and the shackle, which can cause minor rotational changes in the axle.
• Ride Height & Load: Significant changes in vehicle rake—such as heavy towing or spring sag—can alter the caster relative to the ground.
• Lift Kits: Raising the vehicle typically rotates the axle forward, which reduces positive caster and can lead to steering "wander" or "death wobble".
• Worn Components: Loose U-bolts, worn shackle bushings, or sagging springs can allow the axle to shift or tilt, leading to inconsistent caster readings.

Note: Adjusting caster by rotating the axle housing directly affects the pinion angle. If the axle is rotated too far to gain caster, it may cause the driveshaft U-joints to bind or vibrate.

What's the recommended caster range for a lifted solid axle truck with leaf springs?

For a lifted solid axle truck with leaf springs, the recommended caster range is generally
4° to 7° of positive caster.
While factory specifications for many solid axle trucks fall between 2° and 4.5°, lifted applications with larger tires typically require more positive caster to maintain straight-line stability and steering "return-to-center".

Recommended Settings by Application

• General Lifted Use: 4° to 6° is considered the ideal "sweet spot" for most trucks with 33" to 35" tires to balance stability and steering effort.
• Large Tires (37"+): Aim for the higher end, roughly 6° to 8°, to counteract the increased leverage and "wandering" effect of oversized tires.

Key Considerations for Lifted Leaf Spring Trucks

• The Pinion Angle Trade-off: On a leaf spring axle, caster and pinion angle are physically linked. Rotating the axle back to gain caster tilts the pinion down, which can cause driveshaft vibrations or U-joint binding.
• Measurement Timing: Always measure caster with the vehicle at its final ride height and full weight on the springs.
• Cross-Caster: To compensate for road crown, the passenger side is often set about 0.5° higher than the driver’s side to prevent the truck from pulling toward the curb.
• Correction Methods: Use tapered caster shims (wedges) between the spring and axle for minor adjustments (up to ~3-4°), or cut and turn the axle's "C" knuckles for significant lifts to maintain proper pinion geometry.

And bkg not that our 4x4's are F1 cars, however we can learn from what F1 engineers do. You seem to think postitive caster is a bandaid fix for poor suspension design, manufacturer, installation and maintenance. I am sure F1 auto engineers do not agree with you:

what caster do f1 cars use:
F1 cars typically use
a significant amount of positive caster, often in the range of 9 to 12 degrees, and sometimes even more. The exact setting is part of a custom car setup and can vary by team and track, though it's generally a fixed element of the suspension design rather than an adjustable one during a race weekend.
Rationale for High Caster
The high degree of positive caster is used for several reasons, primarily to enhance stability and cornering performance.

• High-Speed Stability: Positive caster creates a strong self-centering effect on the steering, which helps stabilize the car at the incredibly high speeds reached in F1.
• Camber Gain: As the steering wheel is turned, positive caster causes the outside wheel to gain desirable negative camber, while the inside wheel gains positive camber. This helps keep the tires at an optimal angle to the track surface during cornering, maximizing grip.
• Steering Effort: While a large caster angle increases steering effort, F1 cars use power steering to mitigate this, allowing them to run more aggressive caster settings for performance benefits without overly fatiguing the driver.

In general, more positive caster improves straight-line tracking but makes the steering heavier and can cause "weight jacking" (changes in ride height during cornering) if the angles are excessive. F1 teams carefully balance these effects to optimize their car's handling characteristics.