Best way to install caster shims? (1 Viewer)

[405]

Hey All,
I am having wandering steering issues on my FJ40. All of my research here on Mud leads me to believe caster shims on the front axle may fix my problem. I have a 2" OME lift on 33" BFGs and it can be tough to keep it from wandering at speed (50-60mph), especially on uneven or rutted roads.

What is the best way to install them?
I'm thinking jack up from the front diff, take off the wheels, support frame with stands. Fully loosen U-bolts on each side of the axle. Then jack from the front diff again with the U bolts lose to separate the axle from the leaf's and insert the shims? Haven't done this before, will that work or am I missing anything?

 

[Mike Shull]

Depending on the shims that you get, your center pins will most likely need to be longer to reach the perch, plus be long enough to sandwich the shim with the spring pack. Think of them as if you were adding in another leaf.

 

[Mike Shull]

Given this, I don’t have recent experience with OME springs though 2” shouldn’t change your caster much. I’d start by checking for loose steering components (I.e. steering box, knuckles, tie rods, u-bolts, lug nuts, etc.). You might also start by taking a baseline measurement of your alignment. You can use an angle finder to generally check caster, and a tape measure to check toe, or take it to an alignment shop.

 

[405]

Thanks.

Yes, I will need to get the pins too, thanks for the reminder.
To address the steering I've done the following: Center arm rebuild, front knuckle rebuild, OME steering damper, and tightened up the steering box. The steering feels ok, it's just the wandering and nervousness I'm trying to iron out of it.

My truck also has powersteering fitted, which from memory I believe is a Toyota unit. It seems to be working ok.

 

[brian]

Need to verify what if any degree shim you need.
Get it level and compare degree findings between the input flange on the front rear and the transfer output to the front.
Iirc oem caster is only like 1 maybe 2 degrees.

 

[peesalot]

Shackle bushings worn, loose will cause this. I'm guessing your shackles are straight up & down ? What deg do get when you put angle finder across upper trunion studs with truck sitting level ?

 

[70fj40]

Have the TRE’s ever been replaced? As was said above 2” lift should not need shims.

 

[405]

Here is a pic of how the front shackle sits below. No quite vertical. I haven't done the TRE but they seem to be okay. They don't look or feel worn out. May be worth replacing anyway?

I can get some more pics. Looks like I need an angle finder or an alignment shop. There were a couple posts I;ve seen on Mud where 4* shims fixed steering wander after an OME 2 lift. My truck came with the OME lift done, so I am not exactly sure if its 2", may be 2.5".

 

[pb4ugo]

You need to know what your caster is , so youll know what degrees shims you'll need. Get the vehicle on level ground, equalize tire pressures and make dure the vehicle is level. Using a angle finder check your current frt caster. In the pic below, pretend the level is the angle finder. Don't use the nuts or studs. You should be able catch the bottom edge of the bearing cap.

I install my caster shims differently than others. I found when tightening the center center pin bolt with the shim installed, the head of the bolt distorts/bends because of the angle of the shim and weakens it.

 

[Green Bean]

My experience: We have a 2-1/2" OME lift. I got the 4 Degree Caster Shims from Cruiser Brothers. For the installation, I did pretty much as you outlined above. But the spring packs had to be drilled out to accommodate the larger pin diameter. I drilled one and it was very tough sledding. I took the second one to a machine shop and let them do it on their press.

 

[pb4ugo]

You need to know what your caster is , so youll know what degrees shims you'll need. Get the vehicle on level ground, equalize tire pressures and make dure the vehicle is level. Using a angle finder check your current frt caster. In the pic below, pretend the level is the angle finder. Don't use the nuts or studs. You should be able catch the bottom edge of the bearing cap.
View attachment 3613829

I install my caster shims differently than others. I found when tightening the center center pin bolt with the shim installed, the head of the bolt distorts/bends because of the angle of the shim and weakens it.

I usually drill out the shims hole so the shim fits the spring pin head. Then I install the shim and confirm the caster setting with the U bolts tight. If I'm happy with the angle and test drive, I weld the shim to the axles spring perch. This way the spring pins head is not compromised/bent and I don't have to deal taking apart the spring pack.

 

[Mark Jennings]

I get ‘Steel’ shims from WFO Concepts, 2.5” wide (I’ve bought 2 degree and 4 degree from them). I get the Spring Pack centering bolts from autoandtrucksprings.com. The centering bolts are 3/8 X 3.5 inches and I get the bolt head extensions (p/n CBHL2) that give you an additional 3/8 of an inch to get through the shim and into the centering hole on the axle.

A 2 degree shim should restore caster to original Toyota spec with 2.5” springs as long as the shackles are stock length. If you go with 4 degree shims in the front you may start to impact the front driveshaft pinion angle.

Bottom Line….Do Not use aluminum shim plates, they wear, so you’re always back under the rig tightening the ‘U’ bolts or they break under load.

I run Skyjacker springs, don’t know if OME uses the same bolt, but on the Skyjackers, the 3.5 inch bolt is a bit to long, so I just grind flush with the nut once installed. The 3/8’s bolts on my rig were the correct diameter. I would double check on your OME setup.

 

[Mark Jennings]

Attached is a picture of installed WFO 2 degree shims, if you zoom in you can see the centering pins poke up through the axle plate. The centering bolt extensions are uber helpful when dropping the axle back in position.

 

[Mark W]

Hey All,
I am having wandering steering issues on my FJ40. All of my research here on Mud leads me to believe caster shims on the front axle may fix my problem. I have a 2" OME lift on 33" BFGs and it can be tough to keep it from wandering at speed (50-60mph), especially on uneven or rutted roads.

What is the best way to install them?
I'm thinking jack up from the front diff, take off the wheels, support frame with stands. Fully loosen U-bolts on each side of the axle. Then jack from the front diff again with the U bolts lose to separate the axle from the leaf's and insert the shims? Haven't done this before, will that work or am I missing anything?

To answer your actual question...

I just finished adding some 2 degree shims to a '78 FJ40 with OME suspension a few minutes ago.

Rig was on the hoist to reseal the trany/TC, and while it was there I...

Removed all four ubolts and both ubolt plates. (Hit them all with some Ed's Red prior to breaking out the wrenches. Spring pins too.)
Used the tranny jack to lift the drivers side of the axle up enough to have access to remove the center pin.
Used a C clamp on each side of the spring pack, to hold them together firmly before removing the center pin from the spring pack.
Slipped a 14mm bolt over the shaft of the center pin to raise the head above the shim to ensure engagement in the spring perch.
Reinstalled the center pin, tightened it snugly and removed the clamps.
Set the shim on the pack and lowered the axle down, ensuring engagement of center pin into axle perch.
Moved tranny jack to passenger side and repeated the process.

Put the tranny jack away, reinstalled all ubolts and ubolt plates and torqued them down.

Called it done.

Easy and relaxed half an hour job, no sweat, no brains needed.

Yeah, I know you likely don't have a vehicle hoist, or a tranny jack to match. But you *did* ask for the easiest way. It ain't really a whole lot harder to do on the floor with jack stands and floor jack either.

Mark...

 

[franklin40]

i just did this. use the c clamp to hold leafs together for sure. it’s a pain trying to line up the centre pin hole while compressing the leafs.

 

[B y r o n]

I guess I'm one of the lucky ones. I installed OME lift springs and don't seem to need shims. I did replace all tie rod ends and set the toe-in to 1/8". I've had my FJ-40 into triple digit speeds and no problem with wonder running 33-12.5x15 tires. I also had to add a shim over the spring pin to fit the spring perch hole. If the axle isn't straight and the tie rods solid and alignment good you could have handling issues.

 

[franklin40]

it’ll depend on what length shackles you use too. it’s not just the springs

 

[Mark Jennings]

To answer your actual question...

I just finished adding some 2 degree shims to a '78 FJ40 with OME suspension a few minutes ago.

Rig was on the hoist to reseal the trany/TC, and while it was there I...

Removed all four ubolts and both ubolt plates. (Hit them all with some Ed's Red prior to breaking out the wrenches. Spring pins too.)
Used the tranny jack to lift the drivers side of the axle up enough to have access to remove the center pin.
Used a C clamp on each side of the spring pack, to hold them together firmly before removing the center pin from the spring pack.
Slipped a 14mm bolt over the shaft of the center pin to raise the head above the shim to ensure engagement in the spring perch.
Reinstalled the center pin, tightened it snugly and removed the clamps.
Set the shim on the pack and lowered the axle down, ensuring engagement of center pin into axle perch.
Moved tranny jack to passenger side and repeated the process.

Put the tranny jack away, reinstalled all ubolts and ubolt plates and torqued them down.

Called it done.

Easy and relaxed half an hour job, no sweat, no brains needed.

Yeah, I know you likely don't have a vehicle hoist, or a tranny jack to match. But you *did* ask for the easiest way. It ain't really a whole lot harder to do on the floor with jack stands and floor jack either.

Mark...

So did you notice a difference while driving. Before the shims, my rig was twitchy on the highway at 55 and 60. The shims helped substantially but she’s still susceptible to rutted roads and wanders a bit….no death wobble…just got to pay attention….I blame that on the light Saginaw steering and 17 inch steering wheel. I run 31 inch tires and keep the pressure at 30 psi. If I run them at 25 psi it exacerbates the wander. I’d run at 35 psi but the Skyjacker springs are unforgiving.

 

[Mark W]

So did you notice a difference while driving. Before the shims, my rig was twitchy on the highway at 55 and 60. The shims helped substantially but she’s still susceptible to rutted roads and wanders a bit….no death wobble…just got to pay attention….I blame that on the light Saginaw steering and 17 inch steering wheel. I run 31 inch tires and keep the pressure at 30 psi. If I run them at 25 psi it exacerbates the wander. I’d run at 35 psi but the Skyjacker springs are unforgiving.

I installed the shims this afternoon, and broke for lunch. The rig is still in the shop. Gonna re-jet the webber back down to sea level standards before I pull it out. I'll take it for a test drive, but I have never driven this particular rig, so I don't know how it drove before I installed the shims. The owner did not like it, said his wife refused to drive it LOL. Did not take long to determine that it needed shims.

Every '40 I have ever owned or worked on that had OME springs, needed shims to restore OEM caster. As did this one.

Personally I hate the usual "Saginaw" PS conversions. To the point that I will not do this conversion. (Saginaw made lots of other PS boxes, not just the intermediate GM box that everyone refers to as a "saginaw conversion".) As well, I have found that tires contribute far more to a rig being a Rut Slut than most people expect.

Mark...

 

[Mark Jennings]

I installed the shims this afternoon, and broke for lunch. The rig is still in the shop. Gonna re-jet the webber back down to sea level standards before I pull it out. I'll take it for a test drive, but I have never driven this particular rig, so I don't know how it drove before I installed the shims. The owner did not like it, said his wife refused to drive it LOL. Did not take long to determine that it needed shims.

Every '40 I have ever owned or worked on that had OME springs, needed shims to restore OEM caster. As did this one.

Personally I hate the usual "Saginaw" PS conversions. To the point that I will not do this conversion. (Saginaw made lots of other PA boxes, not just the intermediate GM box that everyone refers to as a "saginaw conversion".) As well, I have found that tires contribute far more to a rig being a Rut Slut than most people expect.

Mark...

Rut Slut…..I love it!!!!!!