Crusty Knuckles: Best Way to Polish? (1 Viewer)

[CaptBeardilocks]

When I purchased my FZJ80 a few years ago the engine was removed. I have no idea how long it sat. She's finally getting refreshed and engine swapped and of course I'm finding all kind of ass-hattery from the PO...

The front axle was "re-done" to some extent by the PO. This was obvious by the RTV oozing out of every edge, the new knuckle wipers, and the rotors that had never seen even the softest caress of a brake pad. But rotating the knuckle around was anything but smooth and sexy: it was notchy and sticky. So I disassembled to inspect.

It appears it was assembled with regular grease (not moly) and that, while the middle of the knuckle/birf was packed, the outer knuckle was completely dry.

The "outside-outside" of the knuckle (the part that would be exposed to the world if the truck was parked and the wheels were straight) is actually in pretty decent condition.

So what's the best bet for cleaning this up? Sand with ~100 and paint? Buy a new truck?

I'd also like to get my hands on the drunken orangutan that installed the wheel bearings/seals apparently with one bleary eye open and only a vague understanding of which end of the hammer to use. But that's a different problem...

 

[Tedward]

I prefer a wire wheel / cup brush and paint, but sanding works too.

 

[BILT4ME]

I'd start with Brakleen to remove the grease and debris.
Then go to ScotchBrite pads to see if there's any pitting.
Then I would go to sandpaper.
There have been a few folks here that have had heavily worn (grooved) knuckle balls and they cleaned well, then applied Bondo to fill in the divots, sand smooth and concentric, then paint with an epoxy.

 

[Railwelder93]

I used a wire wheel on mine, I didn’t bother painting them figuring grease would keep them covered up.

 

[rolliges]

Could have done even more with that title....

 

[CaptBeardilocks]

I used a wire wheel on mine, I didn’t bother painting them figuring grease would keep them covered up.

The painting I had read about somewhere was less about keeping them from rusting and more about a way to fill the pits. With the wiper wearing the surface paint off and leaving a generally smooth surface eventually.

I hit it with the wire cup on the angle grinder and it cleaned up this well:

I'd call it moderate pitting? Thoughts? Sand it a bit? Throw on a couple coats of epoxy paint? WTF are you worried about, run it as-is??

 

[Fj80oregon]

I just finished my rebuild a couple weeks ago and mine looked about the same I used a poly carbon wheel and some light grit paper and that’s it. My thoughts are the grease will keep them wet enough. Know some people have used Jb weld to fill the pitting and sanded smooth.

 

[Rusty Marlin]

Its a rubber wipe backed with felt seal soaked in grease that operates as a total loss lubrication system at very slow angular velocity, it will conform and seal.
Personally, I would polish off the high spots so the rubber wipe doesn't get abraded and run it.

 

[Railwelder93]

The painting I had read about somewhere was less about keeping them from rusting and more about a way to fill the pits. With the wiper wearing the surface paint off and leaving a generally smooth surface eventually.

I hit it with the wire cup on the angle grinder and it cleaned up this well:

View attachment 2345716

I'd call it moderate pitting? Thoughts? Sand it a bit? Throw on a couple coats of epoxy paint? WTF are you worried about, run it as-is??

I would just go for it if myself. I’m not a perfectionist, I believe it will be just fine

 

[Kernal]

I sanded mine (not as bad as the OP's) by hand using the 3M pads but also long strips of Emery cloth so I could use two hands pulling the cloth back and forth until I reached bright metal except for the pits, then treated the pits with a liquid rust killer/rust stop and let it work, then painted with epoxy.

Also removed the trunnion races before sanding, but loosely placed them back in position to help hold the tape in place when I taped off the ball for painting.

I would not want to do this job again without power tools, the sanding was a ton of work and my hands/fingers hurt for a week afterwards.

Photo below shows one of the swivel balls a year later:

 

[BILT4ME]

I sanded mine by hand (and my hands hurt for a week afterwards) using the 3M pads but also long strips of Emory cloth so I could use two hands pulling the cloth back and forth until I reached bright metal except for the pits, then treated the pits with a liquid rust killer/rust stop and let it work, then painted with epoxy.
Also removed the trunnion races before sanding, but loosely placed them back
in position to help hold the tape in place when I taped off the ball for painting.

View attachment 2345997

This is what I would have done if mine were pitted like shown.

 

[LINUS]

This is what I would have done if mine were pitted like shown.

+1.

Us PNW folks are ‘rust b!tches’ - any of it anywhere is annoying— @Kernal did it like a boss

 

[Kernal]

Next time I'll use a more durable (2K) paint, something like this:

Eastwood's 2K AeroSpray™ Ceramic Chassis Black

Durability and Appearance of a Two Component Coating, but without the Paint Gun

www.eastwood.com

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CaptBeardilocks: don't mean to hyjack your thread, just adding some data
Thanks for starting the topic.

 

[CaptBeardilocks]

Hit it with some 200 and then again with 320. Didn’t come out too bad. I might polish again.

I am about to liquid rust kill and then paint the whole axle housing so I may just do the knuckles as well. I’m going to look at the chassis topcoat I bought again and see what I think.

 

[Darne]

Phosphoric acid to dissolve the rust. Then POR 15 paint to fill the pits. Polish with 400 grit sheetrock wet or dry, the kind with a screen type construction. Repaint with POR15 til pits are filled.

 

[Kernal]

Looking good, IIRC I may have started with 80 grit Emery cloth in strips, then worked my way up to get a smoother finish.

 

[scottryana]

Is that a large crack on the bell to housing?

 

[Kernal]

Appears there might be a defective (vs sloppy) weld (?crack) where the swivel ball section is welded to the axle housing??

 

[CaptBeardilocks]

I saw that too. It doesn't appear to be a crack per se and it appears to have been there for a long time. This axle in particular is a bit messily welded. I'll grab a more close up pic of that spot today.

 

[CaptBeardilocks]

Appears to just be a weld anomaly or grind mark?