I have a Caterpillar 935c and it has gunk in the bottom of the fuel tank. I can't even seem to figure out how to take the tank off. It looks to me like the fuel tank is practically a part of the machine. And I don't want to take it off if I don't have to. Does anybody have any advice on how to get the gunk out or how to get the tank off.
Is never easy nor direct on tank removals. Buy a ebay service manual and it will be in there. You will need to pressure wash then get the water remnants out to get the goo off the inside of the tank, some have had luck adding a heavy soapy water mix and rolling the tanks around but it will still need come off.
What DMiller said! But if you private message me with a direct email address I can send you the instructions from Cat in PDF. Couple notes the pictures Cat included are not the best, they need to work on their scanning software! Second even though I found this info under 935C in SIS the heading says 935B so maybe they did not change much between models. Once you have it cleaned and back on check to see if there is a drain valve on the bottom of tank to drain off condensation, most Cat machines do, if so I would suggest opening it at least once a week at first to get any water out you might get in while cleaning and then at least at every engine oil change. That was what I did on the equipment where I worked and seldom got more than a teaspoon of water out each time and never had problem with the sludge. Might also be an idea to use, at least for a time, some good fuel oil biocide. One example : http://powerservice.com/psp_product/bio-kleen-diesel-fuel-biocide/
Power Service awesome stuff KS, have used it for over twenty years now.
Is this fine sediment gunk? or slimy algae gunk? the slime you rinse out with lots of water, the sediment doesn't hurt as much to leave it there and the stuff that comes out you can catch with a prefilter before your stock filters. Either way, you can pressure wash it (with an extra hole cut if you need to), followed by either a vacuum with a suck bucket, or use dry rags on a wire to dry out the bottom. If you want it scrubbed a little better, something like 2"x2"x2" wood blocks that will float around as you run it (off a temporary tank) will help loosen the gunk.
Evidently I don't have access to send a pm. But my email address is [email protected] . I greatly appreciate your help.
It might be a little of both but I think mostly sediment. If I can figure out how to remove the tank, I think I'm going to try that. I closed the shutoff valve and poured a gallon of b52 to let it soak over night. Tomorrow I'll decide about removing the tank. The machine runs fine for about 45 minutes to an hour before the fuel line clogs up and I have to use an air hose to clear it.
I think I'd take the drain/water trap right out and try flushing the tank that way before completely removing it. Maybe block it on an angle so it drains more completely. An air nozzle or even a blow dryer in the filler should remove any water residue. The filter would catch any left over moisture. A pressure washer should loosen any gunk stuck on the bottom. Another thing to check is if it's a problem from the tank or if it's a screen on the fuel line by the lift pump that's plugged. I had that problem on my 931B. There's a hex fitting about 1 1/2" long going into the lift pump that has a screen inside it. If you take the fitting off you can remove the screen with an allen wrench to clean it. It was a bit of a nightmare on mine because I wasn't aware of this screen or how to remove it. Aftyer trying everything else, I finally figured it out. Sometimes even when people try to help you out, it's hard to understand them when you've never worked on that component before. My machine would bog down and not go above idle. If I waited a few minutes I could go again for about 30 seconds before it did it again. It would stall if I tried to give it throttle and eventually wouldn't start again. Cleaned that screen and all was good. The stuff plugging the screen looked almost like fine wood shavings.