Bobcat 331 stalling out

[willie59]

No, it's some other compound, can't remember the chemical name for it. Plain nylon tubing gets hard to the point of breaking very quickly when immersed in fuel. The tubing that Bobcat uses is some other compound, lasts much longer before failing. The stuff Bobcat uses is much more flexible.

 

[melli]

I was being a little facetious, but I see the need to buy once with an item that requires me to do a near complete teardown to replace. I have diesel jerry jugs (plastic) that have been around for 10 years...they also get UV abuse.

 

[melli]

Note: I'll always be slightly disgruntled about Bobcat's desire to keep their hydraulic fluid secret...it is one of those c'mon man! moments. What it accomplishes is irritation, and because I live far away from a dealer, I don't change the oil as much as I'd like...grumble grumble...

 

[willie59]

I was being a little facetious, but I see the need to buy once with an item that requires me to do a near complete teardown to replace. I have diesel jerry jugs (plastic) that have been around for 10 years...they also get UV abuse.

No worries, I only pointed this out (not to sell Bobcat parts) because at first glance one would assume it's ordinary vinyl tubing. Not so, it's something much better in fuel applications, just wish I could remember the damn chemical name for it. :Banghead

Note: I'll always be slightly disgruntled about Bobcat's desire to keep their hydraulic fluid secret...it is one of those c'mon man! moments. What it accomplishes is irritation, and because I live far away from a dealer, I don't change the oil as much as I'd like...grumble grumble...

Well, it's always subject to debate as to what would be equivalent, but I've been using good quality AW46 oils for years in all manner of Bobcat machines with no issues. After all, it's a hydraulic system, pumps, motors, valves, nothing special about Bobcat components that are not common for any other hydraulic system. True, Bobcat may, in fact, have some form of "super tri-calification quad polymer substrate matrix modifying friction modifier" that increases component life, but like I said, it's a hydraulic system, good quality oils have been doing the same thing in the industry for years. JMHO.

 

[melli]

OT - Probably time for me to try an off the shelf HF. While the Bobcat HF is only about twenty more than a store brand, getting it shipped adds another 30.....
My little window in the reservoir is starting to look like steeped tea....how does one know when it is time to change...I never make the hours.

 

[willie59]

Well, I don't want to derail nepondguy's thread, but the info is still relevant. Changing hyd fluid? Most schedules of any brand say 1K to 2K hrs. But it's not really possible to completely change the oil in a system, unless you want to take the entire system apart. At best, you can change what's in the reservoir, but there's still a considerable amount of oil in the pumps, motors, oil cooler, valves, and cylinders, and lines. Aside from taking the entire system apart and draining, there's no practical way to completely way to completely change the hyd oil in a Bobcat machine.

 

[nepondguy]

Still haven't had time to change the primer bulb but am hoping to sneak out shortly and do it. Just my two cents on the hydraulic fluid...I have not used Bobcat fluid for years in either of my machines with no issues...hydraulically that is!

 

[Railman]

Have you sorted the stall problem? i have a issue with my Bobcat mini were it stalls sometimes when stretching the boom out and lifting it at the same time, It will re start and run fine, it seems to be some hydraulic issue, and is one of a few funny things that happened, one track running faster than the other etc, after someone tried to steal the hydraulic pump unit, causing the machine to pump out its hydraulic fluid? What causes hydraulic stalls when the machine is obviously not lifting anything heavy??

 

[nepondguy]

Sorry for the long delay. I had to do some traveling for work but finally had a chance to swap out the primer bulb today. It is super cold today and after the swap it fired right up! That never happens when it's this cold. I didn't work it too much but so far so good. My fingers are crossed that was it. Thanks for the help guys.

 

[ctheddy]

Same problem on 337 d. The tank had some debris in it. My tank is a gravity feed so there was no pick up tube. The tank has two divots in the bottom therefore draining it probably wont help. It is a real job to pull the tank so I removed the seat and then the access plate behind it to get to the fuel level sensor. I then reduced a shop vac hose down to some 5/8 vinyl tubing and began the tedious job of vacuuming the bottom , eventually i came out with a piece of plastic. When the stars aligned just right the plastic piece would cover the fuel drop tube and cut fuel flow, machine would still run but not when you put a load on hydraulics. Hop of when it behaved that way to discover the fuel bulb collapsing. Good luck, and btw I would purchase a new bobcat fuel filter first to rule that out. Our bobcat filters tend to rust at the top if stuff sits for too long.

 

[nepondguy]

Just thought I would give a quick update. The machine has been running perfect since replacing the primer bulb. It fired right up in very cold temps the other day and then ran like a champ. Thanks again guys. You saved me a lot of money and aggravation!

 

[willie59]

Thanks for the update neopondguy.