Teflon or bronze bushing - mfwd axle

[Extreme-Duty]

Happy Easter BITOGs,

I'm facing a recurring issue with the drive shaft bushings in a tractor mfwd axle, an ordinary steerable drive axle with outboard planetary hub reductions by Carraro.

The old design used steel bushings with some kind of copper based babbitting. The newer ones are lined with a thick layer looking like sintered bronze (used by many OEMs I guess).

Also, I might be able to "misapply" some teflon lined ones from an other axle.

Which one is "better", what are the pros and cons?

Shall I flip a coin?

Some more details:

- Shaft diameter = 35 and 40 mm
- Speed = From near 0 to 1200 rpm
- Lubrication = Oil immersed nearly 100% of the time.

The real problems, IMO:

- Too many starts and stops, and low average speed, resulting in poor hydrodynamic lubrication.
- "Off axis load", not only when steering, but also because of the clearance in the bushing vs. the opposite shaft end being nearly 100% centered (one in the differential, the other between 3 planetary gears).

Please help me over-think this.

 

[Texan4Life]

I'm not sure. If I had to take a guess I would say the teflon bushing might be of newer design. I think the teflon bushing would have good compatibility with all GL5 gear oils. (some GL5 gear oils are "hard" on yellow metals)

As far as lubrication goes, just prelube the new bushings and you will be good to go. I would use either a engine assembly lube or gear oil. Gear oil is great at crawling up and around even in slow applications..... unless there is some kind of known lube issue with that axle.

 

[Extreme-Duty]

Thanks, Tex and sorry I forgot this thread. It turns out that the teflon bushings aren't teflon bushings, but use some sort of different plastic such as POM, and that the bronze bushings are fare from sintered....Will be flipping a coin 99 or so times.