Bobcat 543 Fuel Tank and Hydraulic Filter questions

[jkwilson]

Hello all, I have a 1990 543 that has an issue that I've been working on for a couple of days. After a half hour of running, I lose power and can't get any fuel to run through the primer bulb. Seems worse when the fuel level is low (below a half tank). I figured I either have a clog or an air leak that's keeping the pump from pulling fuel. This will probably be fairly straightforward to resolve, but I'm not sure if the fittings on the tank are removable, or if they are how to do it. Pull, twist, pry or what? Also, does this unit have the brass filter on the inlet side of the hydraulics like some of the bigger ones have? Thanks in advance for any advice. John

 

[Tazza]

The elbows on the tank should be removable, you just need to pry it out. Your hose may have a crack in it causing it to pull air, very common. There should be a filter screen on the end too. As for a hidden suction line filter, i don't know. I have never worked on a 543, sorry. How is the drive? plenty of power? you can turn in a circle in one spot without issues? When my 731 was plugged it would refuse to spin, it would squeal, changed the filter and it would plow up the dirt as it spun around.

 

[jkwilson]

The elbows on the tank should be removable, you just need to pry it out. Your hose may have a crack in it causing it to pull air, very common. There should be a filter screen on the end too. As for a hidden suction line filter, i don't know. I have never worked on a 543, sorry. How is the drive? plenty of power? you can turn in a circle in one spot without issues? When my 731 was plugged it would refuse to spin, it would squeal, changed the filter and it would plow up the dirt as it spun around.

Thanks for the info. Plenty of power, but I bought the unit from an estate and know nothing about its maintenance history and want to make sure all the filters are good when I change fluids. I tried tonight hooking directly to the fuel elbow on the tank with a new piece of fuel line and new primer bulb and wasn't able to suck gas out of the tank. It comes out easily when I tip the tank, so I guess I'll be pulling the line out of the tank tomorrow. Thanks again, John

 

[Tazza]

Thanks for the info. Plenty of power, but I bought the unit from an estate and know nothing about its maintenance history and want to make sure all the filters are good when I change fluids. I tried tonight hooking directly to the fuel elbow on the tank with a new piece of fuel line and new primer bulb and wasn't able to suck gas out of the tank. It comes out easily when I tip the tank, so I guess I'll be pulling the line out of the tank tomorrow. Thanks again, John

It would be an idea to get the new hard plastic lines from your dealer, these are not prone to cracking and falling apart in the tank. Standard rubber does work fine, and will last many years but if you plan on keeping it, i'd go for the hard plastic.
Let us know how you go.

 

[jkwilson]

It would be an idea to get the new hard plastic lines from your dealer, these are not prone to cracking and falling apart in the tank. Standard rubber does work fine, and will last many years but if you plan on keeping it, i'd go for the hard plastic.
Let us know how you go.

Pulled the tank today and I couldn't believe how brittle the line had become. There was still 8 inches or so connected to the elbow, but it broke off when I was pulling the elbow. The line could be easily broken into crumbs. The screen and the tank were clean as a pin considering the machine is 18 years old. I replaced it with more fuel line since I wanted to get some lime moved before it got rained on. Nearest dealer is almost an hour away. I also learned a lesson to be careful with dropping bolts on a disabled machine. It went under the bucket, but it might as well have been on the moon until I could get it started to lift the arms. Thanks again for the advice and for the existence of the forum to help. John