wrenchmeister
Member
- Joined
- Aug 29, 2020
- Messages
- 14
Hello everyone! Two months ago I bought a pair of bobcats in desperate need of some attention.
The main project is a 1990 843B (5037620XX), which suffered an exploded u-joint coupler causing the rear pump shaft to break, damaged a couple hydraulic tubes, as well as blower and shroud damage. Aside from that it came with an extra 200lbs of grease sludge and mud coating everything under the cab and in the engine compartment, however the pins, bushings, chain drive and wheel bearings seem to be in great shape, and the hydraulic oil I've drained out looks very clean.
The side project / parts pile is a 1985 843 (5026-M-210XX) which came with the engine removed and partially disassembled with the diagnosis of a cracked cylinder head. It's no wonder why after seeing the hydraulic oil cooler completely caked in oily dirt, restricting airflow to the radiator. The rest of the skidsteer is in equally horrible shape, leaking everywhere, and extremely worn pins and bushings all around. There's no telling the condition of the rest of it, I haven't got that far into it.
The original plan was to swap the pumps from the donor to the 843B, but they are slightly different, and after seeing how easily they come apart, I'm thinking about welding the broken shaft back together. In the meantime, I have stripped all removable items from the 843B in anticipation of cleaning, painting, and resealing everything.
OK, now for the questions...
The 843B pump has 1 more connection than the 843 pump. It appears to be a case drain. Does the 843 pump not need a case drain, or does it flow through to the gear pump inlet? If so, is the drain line on the 843B just extra?
Pictures for reference:
843B with case drain -
843 no case drain -
Anyone have experience with making custom hydraulic hard lines? Is J524 tubing required or can you get a good flare with J525 tubing? Anyone tried cold roll A513 DOM tubing?
I know coupler failure seems to be a common issue. What are people doing about flywheel blower damage? Mine had significant blade and shroud damage. I'm not a fan of this design, so I was thinking about cutting off all the blades, trashing the shroud, and making a new smaller shroud to hold some electric fans. I have no education in aerodynamics, but looking at similar sized centrifugal blowers, I'm guessing the flywheel blower flowed somewhere between 2000 and 2500 CFM at 2600 rpm. I am able to fit 3 10" electric fans rated at 800 CFM each, which I am hoping would be sufficient.
I'll have to save any other questions for later. Thanks to anyone who may read this!
The main project is a 1990 843B (5037620XX), which suffered an exploded u-joint coupler causing the rear pump shaft to break, damaged a couple hydraulic tubes, as well as blower and shroud damage. Aside from that it came with an extra 200lbs of grease sludge and mud coating everything under the cab and in the engine compartment, however the pins, bushings, chain drive and wheel bearings seem to be in great shape, and the hydraulic oil I've drained out looks very clean.
The side project / parts pile is a 1985 843 (5026-M-210XX) which came with the engine removed and partially disassembled with the diagnosis of a cracked cylinder head. It's no wonder why after seeing the hydraulic oil cooler completely caked in oily dirt, restricting airflow to the radiator. The rest of the skidsteer is in equally horrible shape, leaking everywhere, and extremely worn pins and bushings all around. There's no telling the condition of the rest of it, I haven't got that far into it.
The original plan was to swap the pumps from the donor to the 843B, but they are slightly different, and after seeing how easily they come apart, I'm thinking about welding the broken shaft back together. In the meantime, I have stripped all removable items from the 843B in anticipation of cleaning, painting, and resealing everything.
OK, now for the questions...
The 843B pump has 1 more connection than the 843 pump. It appears to be a case drain. Does the 843 pump not need a case drain, or does it flow through to the gear pump inlet? If so, is the drain line on the 843B just extra?
Pictures for reference:
843B with case drain -
843 no case drain -
Anyone have experience with making custom hydraulic hard lines? Is J524 tubing required or can you get a good flare with J525 tubing? Anyone tried cold roll A513 DOM tubing?
I know coupler failure seems to be a common issue. What are people doing about flywheel blower damage? Mine had significant blade and shroud damage. I'm not a fan of this design, so I was thinking about cutting off all the blades, trashing the shroud, and making a new smaller shroud to hold some electric fans. I have no education in aerodynamics, but looking at similar sized centrifugal blowers, I'm guessing the flywheel blower flowed somewhere between 2000 and 2500 CFM at 2600 rpm. I am able to fit 3 10" electric fans rated at 800 CFM each, which I am hoping would be sufficient.
I'll have to save any other questions for later. Thanks to anyone who may read this!
