Shim question on leaf packs

[2020 Rocks]

Hello,

I recently had my rear break line pop on me and in the process of putting in a new break line I discoverd the center bolts on my front leaf packs were gone.

To provide some background, I installed extended shackles and a long AAL to the front axle. When I intalled the leaf packs I added a 4 degree aluminum shim. When the shim was added it has a hole in the center and we rested it on top of the button/end of the center bolt. The button, best as I can describe it, did not go all the way through the hole on the shim, but sort of rested flush with the top of the hole.

My question is, should the shim had been bolted to the rest of the leaf pack, using a washer to keep it from passing through the hole, or is it more likely that I did not have the center pin tightened enough, or to much. I think it was torqued at 60 foot lbs. I have some center pins I was going to use for the rear AAL, but I would like to fix the front correctly before proceeding. Also, does anyone know what grade bolt I can use as a replacement so I can proceed with the AAL on the rear axle? TIA

 

[NocalFJ60]

What do you mean the centering bolt is gone? Did the bolt break or fall out?

When I installed mine in the front the centering bolt went through the top of the shim and down through the spring pack. The lip of the centering bolt kept everything together and stuck out far enough to still align the hole in the axle to the centering pin.

 

[2020 Rocks]

Yeah, I can only assume the bolt broke and fell out.
So, when you had the center bolt run through the shim and leaf pack, nut being at the bottom towards the ground, and bolt head being at the top, did the bolt head sit flush within the shim w/ nothing poking out of the hole in the shim, or was the bolt head above the shim? Thank you for responding.

 

[boots4]

This is how I put on my shims. This is SOA of course. and yours may be opposite.

I put a grade 8 bolt from the bottom to the top so that the nut was on top of the pack. The bolt holds the shim on the pack and keeps it together. The bolt head fits in the alignment hole on the spring perch. The shim obviously needs to be between the pack and the perch and if you put a washer to hold it the shim won't sit flat against the perch. I would think this would eventually crack the shim with the washer acting like a fulcrum between the pack and the perch. If you have pics that would help us see what you are describing.

The pack bolt should be tight enough to hold the pack together but the ubolts are what really hold everything together. So get the spring pack bolt tight and put some locktight on it and the ubolts will take care of the rest.

 

[2020 Rocks]

Thanks so much, that was what I was trying to clarify. We had the shim just resting on top of the round bolt head, not bolted to the spring pack, so i figure the shim slipped going over a bump or something and then it sheared the bolt.

I wish I could post pics but I think our dig camera is busted.

The way it was set up before the head of the bolt did not stick out of the shim, and thus was not fitted snug into the spring perch as you stated it needs to be. The grade 8 bolts can be obtained from a Auto parts store, or should I be able to obtain it at a hardward store? I would like to get the bolts with the round head rather then grinding a hex round. What do ya think? Thanks.

 

[NocalFJ60]

Check this out. This is where I got my shims. He notches the top of the shim so the bolt sits in a pocket that is parallel with the rest of the springs.

4Crawler Offroad Products - Custom Leaf Spring Shims

I wouldn't mess with making some centering pins. Order some extra long ones from Cruiser Outfitters and you can cut off the extra length and they will fit correctly. My AAL's came with longer pins.

The wedge would be opposite of the picture (thick part closest to transmission) above since you SUA and adjusting for shackles.

 

[boots4]

Grade 8's are carried at most hardware stores even HD and Lowes. To get rounded heads you could try allen head bolts but I don't know the strength of those, drill out the hole in the perch to accept a regular hex head, or as you stated, round off the corners. Personally, I drilled out the hole in my spring perch to accept the larger hex hed without grinding.

 

[2020 Rocks]

Thanks again, I think I will go the route you took and just make the hole large enough to accept the hex. Oh the joys of cruiserhood. Looks like I have long Saturday ahead of me, hopefully I can get my new shocks on and tackle the rear axle that still needs to be done. Guess it depends on how long it takes me to fix the prior mistake on the front axle.

 

[boots4]

Check this out. This is where I got my shims. He notches the top of the shim so the bolt sits in a pocket that is parallel with the rest of the springs.

4Crawler Offroad Products - Custom Leaf Spring Shims

While I didn't get them from him, I too got steel shims with the notch. The steels are going to be stronger and with all that weight of the front of the vehicle (I put in a heavy diesel) and planned wheeling, I didn't think the aluminum ones would stand up to years of abuse, at least not the cheapy ones.

 

[2020 Rocks]

My AAL's came with the longer pins, but as noted above they got sheared and fell out. I have another set as I have AAL's to do the rear w/ but I will still be out a pair of center pins. If I can not find what I need locally to my satisfaction I may order another pair of center pins.

I am a little concerned about what you mentioned regarding the orientation of the shims. It was my understanding that the thin part of the shim would be pointing towards the middle of the truck/transmission, meaning the flat blunt side of the shim would face the rear bumper for the rear axle, and the flat blunt side facing the front bumber for the front axle.

Like this? REARo><oFRONT or should it be like this REARo<>oFRONT

Is this not so, if you could clarify and if others could verify that would save me further grief in not installing the shims incorrectly. Thanks again.

Check this out. This is where I got my shims. He notches the top of the shim so the bolt sits in a pocket that is parallel with the rest of the springs.

4Crawler Offroad Products - Custom Leaf Spring Shims

I wouldn't mess with making some centering pins. Order some extra long ones from Cruiser Outfitters and you can cut off the extra length and they will fit correctly. My AAL's came with longer pins.

The wedge would be opposite of the picture (thick part closest to transmission) above since you SUA and adjusting for shackles.

 

[inkpot]

Howdy! The pointed end of the shim should be aimed at the new longer shackles. John

 

[2020 Rocks]

Thanks!

 

[NocalFJ60]

The shackle is dropping the front of the leaf spring down which causes the axle to spin clockwise when looking at the passenger side wheel. You want to rotate the axle counterclockwise so the thick part would be on the radiator side or they would point to the driver. I stated it wrong above. Think the picture confused me since the wedge is on the bottom in that picture. :whoops:

 

[boots4]

I'm also adjusting my angle for a different reason so don't get the orientation from my pic. It's in my thread if you really need to know. I just posted the pic for bolting the shim to the pack demonstration.

 

[2020 Rocks]

Sorry to be a pest, so are you agreeing or disagreeing with Inkpot/John? I really need to know as I dont want to screw up a second time. Thanks.

The shackle is dropping the front of the leaf spring down which causes the axle to spin clockwise when looking at the passenger side wheel. You want to rotate the axle counterclockwise so the thick part would be on the radiator side or they would point to the driver. I stated it wrong above. Think the picture confused me since the wedge is on the bottom in that picture. :whoops:

 

[cruiser88]

oh s***

 

[cruiser88]

What do you mean the centering bolt is gone? Did the bolt break or fall out?

When I installed mine in the front the centering bolt went through the top of the shim and down through the spring pack. The lip of the centering bolt kept everything together and stuck out far enough to still align the hole in the axle to the centering pin.

So what you are saying is the centering bolts that broke was not long enough?On his?


Dammit i knew something stunk.

opps and facing the wrong direction

 

[cruiser88]

What do you mean the centering bolt is gone? Did the bolt break or fall out?

When I installed mine in the front the centering bolt went through the top of the shim and down through the spring pack. The lip of the centering bolt kept everything together and stuck out far enough to still align the hole in the axle to the centering pin.

Reading again .....if this makes any sense the center bolts on the leafs came up only partway through the shim...not all the way if i remember right.

So my assumption is the new bolt and shim should have been bolted down first...toghether(then the extra bolt length cut ) ...thick part forward for the front?

 

[NocalFJ60]

Sorry to be a pest, so are you agreeing or disagreeing with Inkpot/John? I really need to know as I dont want to screw up a second time. Thanks.

Disagreeing. Shim points towards the drivers seat or away from shackle.

 

[boots4]

Let discuss the reason to put shims on so that you know why. If you already know why then this will be a refresher.

The reason to put shims on the Front axle is to adjust the caster and the pinion angle. Since the caster is fixed to the pinion angle (meaning the only way to adjust those separately is to do a cut and turn of the knuckles) if you adjust one you will adjust the other. Caster is that geometry that makes the steering wheel center when you let go of it, it's good for highway stability. If there is too much, steering is heavy and doesn't recenter, if there is too little it wanders on the highway and feels loose making higher speeds scary. So caster is important and you can add several degrees and be good (if you have skinny tires you don't need as much as running wide tires). When you increase the front shackle length on an FJ60 you are reducing the amount of caster you have at the knuckles (the knuckle rotates or turns on an axis, i.e., your wheels turn when you steer. If this axis is straight up and down then you have 0 degrees of caster, you want more than this meaning the top of the knuckle will lean back towards the rear of the vehicle and the bottom will be kicked towards the front of the vehicle. Since will be running wide and large tires I decided to go with 8 degrees, mostlikely you'd need less like 4 or 5 degrees). So if you put in longer shackles you will adjust for this by tilting the axle back (leaning the top of the knuckle back) by placing a shim on a SUA with the point towards the rear of the vehicle which would be on top and reversed from the pic above. This will increase the caster but also the pinion angle; however, there is a compromise since the caster and pinion angle are tied together.

There are other threads on how to measure the pinion angle but the quick answer depends on the type for front driveshaft. If it is a DC joint then the pinion flange should point toward the front tcase output shaft. If it is a regular 2 ujoint shaft then the pinion flange on the axle and tcase should be parallel or close to it. Since adding shims to the front axle adjusts both you need to account for both when deciding how many degrees to add with the shim and make your compromise.

On the rear axle you add shims only to adjust the pinion angle. I don't think that changes much by just adding AAL's. Take measurements at the pinion flange with an angle finder before and after to see if there is a difference and that will tell you if you need shims back there or not and by how many degrees. The measurement should be taken with the weight of the rig on the springs and axle. I think many have added AALs without adding shims to adjust the rear pinion angle. If this raises more questions don't hesitate to search here, hit google, or ask more questions.