RancherGuy
Gold Member
- Joined
- Feb 2, 2010
- Messages
- 301
- Location
- Rosenberg, TX
- Tractor
- Kubota L3710; JD 5425, 6105R, 7130-P; IH 1086
* Public Service Announcement *
For your benefit, I created this post to describe failure with one of my steering knuckles. This note would apply to all vehicles that use kingpins (vs ball joints) for steering. Kingpin design has been used for 100 years, so its nothing new.
Do you have a wheel that leans in (camber) like this? Only 'sort of'?
The above picture has catastrophic bearing failure. Problem was addressed before there was catastrophic damage. The lower bearing roller pins have fallen out. The upper bearing roller pins have been displaced and are no longer between the bearing races.
The problem started when the tractor was in a flood where the water rose to the bottom of the axle, for days. This would have allowed water into the lower kingpin. Axles are designed to keep oil in, not water out. When disassembled, the upper kingpin surfaces were in good condition, but the lower kingpin had signs of rust all over the kingpin surfaces, including beneath the bearing race.
The impact was not immediately evident, but after a few years, I noted that the wheel had an inward lean - very slight. In fact it was only noticeable in certain conditions where the eye could discern.
This is my assessment of the events. The sequence began slow but accelerated fiercely.
1. Water got into the lower kingpin area.
2. Rust developed on bearing surface(s).
3. Roller pins began grinding and resistance force on the bearing cage caused the cage to fail. This would permit the pins to "stack up" against one another instead of being evenly spaced around the bearing surface. This would result in a very slight wheel lean.
4. Displaced roller pins continued to cause damage to each other and races.
5. Lower kingpin roller pins either disintegrated or fell out. No remnants found.
6. Upper kingpin roller cage was destroyed.
7. Upper kingpin roller pins were displaced, allowing bearing race-to-race contact.
Cost
I feel fortunate. Replacement parts were limited to kingpins, bearings, seals. $400. Labor was 6 hour disassembly, [optimistically] estimate same time to reassemble, thus $2,000 labor at a shop. I did not disassemble the hub:
If the knuckle casting was damaged, add $2,000 + more seals + lots more labor. If the axle casting was damaged, the added cost would have been "huge". At the end of failure, my situation was allowing casting-to-casting contact.
Moral of the story
1. Do not permit an axle to be submerged in water. Do not consider it to have 'no impact'.
2. If you see a wheel leaning, fix it immediately. If you are inspecting a used vehicle, consider the cost. I was thinking something needing to be adjusted, so I put it off. Wrong action. There is no adjustment.
For your benefit, I created this post to describe failure with one of my steering knuckles. This note would apply to all vehicles that use kingpins (vs ball joints) for steering. Kingpin design has been used for 100 years, so its nothing new.
Do you have a wheel that leans in (camber) like this? Only 'sort of'?
The above picture has catastrophic bearing failure. Problem was addressed before there was catastrophic damage. The lower bearing roller pins have fallen out. The upper bearing roller pins have been displaced and are no longer between the bearing races.
The problem started when the tractor was in a flood where the water rose to the bottom of the axle, for days. This would have allowed water into the lower kingpin. Axles are designed to keep oil in, not water out. When disassembled, the upper kingpin surfaces were in good condition, but the lower kingpin had signs of rust all over the kingpin surfaces, including beneath the bearing race.
The impact was not immediately evident, but after a few years, I noted that the wheel had an inward lean - very slight. In fact it was only noticeable in certain conditions where the eye could discern.
This is my assessment of the events. The sequence began slow but accelerated fiercely.
1. Water got into the lower kingpin area.
2. Rust developed on bearing surface(s).
3. Roller pins began grinding and resistance force on the bearing cage caused the cage to fail. This would permit the pins to "stack up" against one another instead of being evenly spaced around the bearing surface. This would result in a very slight wheel lean.
4. Displaced roller pins continued to cause damage to each other and races.
5. Lower kingpin roller pins either disintegrated or fell out. No remnants found.
6. Upper kingpin roller cage was destroyed.
7. Upper kingpin roller pins were displaced, allowing bearing race-to-race contact.
Cost
I feel fortunate. Replacement parts were limited to kingpins, bearings, seals. $400. Labor was 6 hour disassembly, [optimistically] estimate same time to reassemble, thus $2,000 labor at a shop. I did not disassemble the hub:
If the knuckle casting was damaged, add $2,000 + more seals + lots more labor. If the axle casting was damaged, the added cost would have been "huge". At the end of failure, my situation was allowing casting-to-casting contact.
Moral of the story
1. Do not permit an axle to be submerged in water. Do not consider it to have 'no impact'.
2. If you see a wheel leaning, fix it immediately. If you are inspecting a used vehicle, consider the cost. I was thinking something needing to be adjusted, so I put it off. Wrong action. There is no adjustment.
