Lifting rear spring pack to service trunnion

[A Blind Man]

So, noticed what seemed to be too much play in the rear trunnion bushings (springs a bit cockeyed in the perches on the axles)
no biggie, I knew the U-bolts needed to be changed as well, so I figure tackle it all at once no problemo
managed to get the nuts off the u-bolts but they were so solidly rusted in place no amount of beating was going to get them out
so cut the bolts so that I could lift the pack out, Spring pack won't budge,
My question is, before I start fabricating something to forcefully jam a wedge underneath the spring pack, or pull all the torque-rods so I can spread the axles, do the 2 bolts on either side of the trunnion need to be loosened to remove the spring pack, or are those just there to add stiffness to the casting. It doesn't call out loosening them in the TM, but I figure you all have far more experience dealing with this.
(and yes I prolly need to replace the tired springs as well, but I was hoping not to have to drop 1k on some new springs just yet...)

 

[simp5782]

They are just rusted.

Just unbolt the spring clamps on the outside. And cut the center compression nut under the lifting shackle then remove springs one at a time etc.

Lowers will slide thru the one side enough to get out

 

[A Blind Man]

Awesome, Thanks!

 

[simp5782]

Awesome, Thanks!

If you want it to ride better you may just have the lower 2 springs replaced. That will help a bunch

 

[A Blind Man]

Well got it off and got the ubolt stubs pressed out, Thanks again! (maxed out the little 12t shop press and had to heat and beat to get them out hahahahaha)
going to hit up the local spring shop and see if they can make me up some leafs

 

[INFChief]

Well got it off and got the ubolt stubs pressed out, Thanks again! (maxed out the little 12t shop press and had to heat and beat to get them out hahahahaha)
going to hit up the local spring shop and see if they can make me up some leafs

Were your trunion bearings solid cones or roller bearings? Those bearings should be the same as the wheels. Same for that inner trunion seal.

 

[A Blind Man]

Solid bushings, I haven't been able to verify though are cups the same for both the bushings and the bearings?

 

[gringeltaube]

...... do the 2 bolts on either side of the trunnion need to be loosened to remove the spring pack, or are those just there to add stiffness to the casting.

You may have noticed already that the housing is slotted both sides, so that when you tighten those bolts it actually clamps both lower spring leaves, thus eliminating any possible lateral play, there.

So yes, ideally those two bolts should be loosened before removing the spring pack - although these often come off without doing so.

Solid bushings, I haven't been able to verify though are cups the same for both the bushings and the bearings?

Yes, they are. (#3920)

 

[A Blind Man]

So yes, ideally those two bolts should be loosened before removing the spring pack - although these often come off without doing so.


Yes, they are. (#3920)

Makes sense, I did make an attempt to loosen them both with a jack under a box end wrench, and the 1/2" impact but didn't make any headway, so I figure it'll be fine one way or the other

 

[gringeltaube]

Usually those bolts are rusted in place and won't budge with common tools - unless you had a torch and heat the area to almost red.

 

[INFChief]

Solid bushings, I haven't been able to verify though are cups the same for both the bushings and the bearings?

Those solid “bearings” should have a spiral groove on them - the spiral channel / groove is supposed to let the grease ooze in to the entire bearingYou should knock out the cups (races) and replace them too. I bet they’re pitted something wicked.

If my memory is correct, the Army did away with those solid bearings and used standard deuce wheel bearings. I believe the seal on the inside is also the same for the drive wheel hubs.

We have a auto parts store here that can make U bolts. Can you get some made near you?

Be sure to remove the grease zerk from the trunion and clean out the crud; would not surpass me if it’s dang near like cement! We used a very heavy grease back in the day; we called it “peanut butter” because of the color and thickness! Lol. When that stuff sets up it clogs the grease hole.

 

[INFChief]

Did any bolts break off in the trunion bearing cover? One or 2 of those usually break too.

 

[gringeltaube]

If my memory is correct, the Army did away with those solid bearings and used standard deuce wheel bearings. I believe the seal on the inside is also the same for the drive wheel hubs.

Not so; it was the other way around: early trucks all had roller bearings there... (Until someone realized this was/is a design flaw...)

These roller bearings just aren't built for a low amplitude oscillating motion. The lubricant doesn't get pushed around enough and micro-fretting between rollers and races, especially at the lower area of the cup, is inevitable.
Add to that the fact that the spring seat (or trunnion part) isn't as rigid as it appears: the machined bearing seat (for the cup) has a tendency to ovalize; that is, it widens, horizontally. We are talking a few thousands here, but that already is way over what any bearing manufacturer would allow.
Obviously even a new cup will adopt the seat's shape, once pressed in. That means that only a few rollers at the bottom portion actually carry all the weight, even if we set the bearing preload "correctly".

 

[INFChief]

Not so; it was the other way around: early trucks all had roller bearings there... (Until someone realized this was/is a design flaw...)

These roller bearings just aren't built for a low amplitude oscillating motion. The lubricant doesn't get pushed around enough and micro-fretting between rollers and races, especially at the lower area of the cup, is inevitable.
Add to that the fact that the spring seat (or trunnion part) isn't as rigid as it appears: the machined bearing seat (for the cup) has a tendency to ovalize; that is, it widens, horizontally. We are talking a few thousands here, but that already is way over what any bearing manufacturer would allow.
Obviously even a new cup will adopt the seat's shape, once pressed in. That means that only a few rollers at the bottom portion actually carry all the weight, even if we set the bearing preload "correctly".

That makes sense. I know I had dealt with them in some way or another! Lol Thanks!

 

[A Blind Man]

Did any bolts break off in the trunion bearing cover? One or 2 of those usually break too.

Nope all came out just fine Thankfully
managed to get replacement u-bolts NOS from a couple different ebay listings and picked up the extra length Hex nuts off mcmaster

Also you mentioned some pretty hefty grease, plan is just to use mobilgrease xhp 223, since it's what I've been using on everything else on the truck. good washout, high temp, prolly a bit thick for the axle roller bearings but the temps on the hubs have been fine so we'll see how everything looks when I get around to re-checking them later this year (though I should prolly be using thinner 222 on the u-joints...)