Stuck in Perpetual Knuckle Rebuild Cycle (1 Viewer)

[CaptBeardilocks]

I rebuilt the knuckles my truck when it was first rescued/built 3yrs/40k miles ago. After 2yrs/~27k miles the knuckles obviously needed to be rebuilt again as both sides were leaking. I didn't find anything odd in the knuckle during the rebuild process and just chalked it up to the first rebuild being my first time and the trucks first time in a very long time. At this time I did the trunnion bearings a second time (they were showing some wear) and even replaced a one of the spindles.

So after only about 1yr and 12k miles I just drained the front diff for my annual service and it is Moly Soup. So thick it's barely draining out of there. Yikes. Did I lose a seal entirely?

Full rebuild kit last time was from Cruiser Outfitters so it wasn't garbage. Both CV axles were nearly new chromoly RCVs at the time of the truck build so they weren't grooved at the oil seal. I need to get it apart and inspect the seals to see if one obviously failed. The right side is showing slight signs of 90w drip right now and the left isn't. I haven't noticed anything that would suggest a bent housing, but I'm not sure that I could tell by eye. Not wearing tires in any kind of odd way. Diff vent was rebuilt and rerouted up higher during the build. I spent the last year in the desert and don't think the diff saw anything bigger than a puddle as far as shock water cooling.

Any advice for Repeat Offender Knuckle issues like this? I'll be pulling it apart in the next day or so, so I'm just curious if I should look out for anything in particular.

 

[KLF]

Might want to check for a bent axle housing.

 

[mudgudgeon]

Take it and get a wheel alignment readout before you tear it down.
If a housing is bent enough to cause an issue, is likely to show up as odd caster and/or camber.

Also check spindle bushing/ bearing in the inboard end of the spindle. These support and center the CV axle in the spindle. Looseness here could cause uneven wear on axle seals.
Your new spindle should be good, but definitely check the older one.

Use OEM axle seals

 

[Shipwreck]

Are your inner axle guide rings still in place? It's pretty easy to damage an axle seal when stabbing the axle shaft without that support.

 

[CaptBeardilocks]

Here’s the alignments numbers from when the truck was built. I haven’t wheeled it nearly hard enough to bend the housing it since then. I feel like I posted these numbers on here somewhere at the time and everyone thought they were good enough. Which is not to say that maybe the trunion bearings don’t need to be reshimmed. I’m not sure.

*Just remembered the obvious that these numbers were used to order correct arms from Delta, so the caster should be corrected now.

I used the axle seals that CO put in their kits the last time. Not sure if those are OEM or not off the top of my head.

I replaced one spindle in part because one side had the newer version (needle bearing instead of just the brass bushing) and the other side was old style with just the bushing. So I grabbed a new one to match the bearing side.

The last time I rebuilt it, I remember seeing the outer guide ring and guiding the axle through the inner. I’ll def double check this time when it’s apart.

 

[CaptBeardilocks]

I pulled everything apart today hoping to see something obvious but... no such luck. Everything looks more or less how it should.

The guide rings are both in place. The spindle bearings seem fine. The axle seals were in place & still had their circular spring intact and in place.

The axle seals are very slightly distorted in a top/bottom configuration. See pics below. The bottom of the seal on both sides seem somewhat pulled away from the metal frame, leaving a slight gap. The top is oppositely a bit compressed. Curious as that would go against gravity right?

Is it possible that having the incorrect trunnion pin shims could set the axle higher? trying to visualize that... Lol.

Both axle shafts are shiny from contact, but I can't feel a groove or depth change with my fingernail. These chromoly axles should have less than 50k miles on them so I'd be surprised if they were worn enough to leak this bad.

Any thoughts or ideas are welcome. I hate the idea of putting it back together without knowing anything was fixed.

 

[Squash]

Only thing you haven't mentioned are the diff vents. Your axles need to breathe.
If the vents are stuck then heat will pressurize the axle and blow diff oil out. On the other hand a cold dunk in a stream with a warm axle housing will suck in water.
Pull the hose off your diff(s) Make certain that the metal tube is clean.
Also make certain that the caps of your vents function properly.
Good idea to bring the front diff vent up into the engine bay.
For the rear I like bringing the vent cap up into the fuel door..drill bit makes this easy.

 

[CaptBeardilocks]

All vents have been redone and moved up higher. All new parts 3yrs ago. I’m going to doublecheck it but I can’t imagine it’s blocked.

 

[robnicko]

you mentioned incorrect trunnion pin shims could set the axle higher, looking at your elongated seal the below vid may be of interest

 

[CaptBeardilocks]

This has always interested me. I've done a ton of research on knuckle centering in 80s and as far as I can tell it's more or less impossible to "center" it. Please correct me if I'm mistaken. But because there are only shims for the top and NOT the bottom, all you can really do it set preload.

It seems from most of the examples I can find online, most people that think they need to center their knuckle then end up realizing that they can't and that they possibly have a bent housing. But of course then no one follows up with the thread to confirm or disconfirm. Lol.

@motormayhem had an almost identical observation about his seals as I do. He was looking to center and was convinced instead that it might be a housing issues but no one followed up.
Oil Seal Leak / Knuckle Centering - https://forum.ih8mud.com/threads/oil-seal-leak-knuckle-centering.1312309/

I'm not sure what I can do at the moment beyond putting new OEM seals in, reinstalling the axles CAREFULLY, and making sure my pre-load is good. And then monitoring it from there.

Happy to hear any other suggestions.

 

[Madcrix12]

ensure the brass spindle sleeve is installed correctly and its long enough to bottom out on the inside of the hub. this centers the axle and prevents it from moving around and causing the seal to leak. ensure the seal that sits behind the rotor is also installed correctly.

 

[CaptBeardilocks]

My new spindles came with the roller-bearing style bushings already pressed in. I'll double check that they're completely seated but they looked fine at a glance when cleaning them.

 

[Madcrix12]

man i only trust OEM parts when it comes to axle rebuilds... i got burnt to many times. if this is the 2nd or 3rd time doing a rebuild, it may be useful to use an OEM spindle with a brass sleeve and see if your problem goes away

 

[CaptBeardilocks]

The roller bearing in the spindle is an OEM part. Toyota replaced the brass bush with a roller bearing later.

 

[CaptBeardilocks]

Just out of curiosity... how much play is there usually with the axle in the spindle bushing/bearing? Zero? Just a bit and it rides in there?

 

[Madcrix12]

very little to none in my case. the axle is supposed to be seated pretty snug when u bolt on the spindle

 

[Hornd]

I have the same issue on my Drivers Side.
Rebuilt with Toyota Seal and Leaking like the Seal is Missing.
Have 2 New Seals. Intend to Overdrive the Seal so it rides on new spot on half shaft.
I have the Brass Bushing not the Bearing.
Have the Capability to measure the Bushings with Bore Gauge, but will likely check the Shaft to Hole Fit.

 

[BILT4ME]

Just out of curiosity... how much play is there usually with the axle in the spindle bushing/bearing? Zero? Just a bit and it rides in there?

Wheel bearing preload can affect this. Any movement will cause this on top and bottom. Tighten to 35 LB-FT on inner nut while rotating (3 times) then outer nut to 45 LB-FT.

Also if the lower steering arm was not tightened properly (deadblow hitting it up and down while torquing bolts) this could cause the same. This would cause the trunnion bearings excessive wear also.

 

[CaptBeardilocks]

Wheel bearing preload can affect this. Any movement will cause this on top and bottom. Tighten to 35 LB-FT on inner nut while rotating (3 times) then outer nut to 45 LB-FT.

Also if the lower steering arm was not tightened properly (deadblow hitting it up and down while torquing bolts) this could cause the same. This would cause the trunnion bearings excessive wear also.

I’ve always hammered on the studs/case (per the FSM which isn’t in front of me ATM). But I definitely am getting trunnion wear.

Is there a link to proper steering arm seating?

 

[Madcrix12]

i tq wheel bearign to 50 lbs spin wheel 3 to 4 times and then re tq to 45 both nuts