This has been mentioned in various threads scattered about the forum, and since I had an opportunity to encounter this very problem today, thought it would be appropriate to show everyone the infamous fitting that can cause a machine to come to a dead stop. The banjo bolt screen Typically found on the inlet of a fuel/water seperator, fuel strainer, or fuel lift pump. Used on many excavator fuel systems, but certainly not limited to excavators. This one was on a Komatsu CD50R crawler dumper, so time to go to work in my new office for the morning...underneath the machine in the mud. LoL Was obvious it had a fuel delivery problem. First replaced the fuel filter, no change, engine would barely run. Next checked the fuel supply from tank, had good flow from line. No other filters or stainers in fuel supply line, so check out the lift pump. Removed the banjo fitting at inlet connection to lift pump, and there was the problem, this seemingly harmless fitting. Doesn't seem like much, but pull it apart and you get this, crud clogging up the two holes in the bolt for the banjo fitting. Remove the small plastic strainer from inside bolt, and it's packed with crud. A portion of it appears clear, but that's what was scraped off during removal from inside of hollow bolt. Ok, now I may not be college edjumacated, but it's not a bad idea for design engineers to provide a strainer to prevent crud from going through and fouling the lift pump. But this wimpy itty bitty strainer screen? Maybe in the perfect paper world. But here in the real world, diesel fuel is some nasty stuff. So this hillbilly opts for more practicle plan B. First, throw the worthless headache of a strainer out of your sight and mind. Then re-install the banjo fitting and fuel line. Lastly, somewhere in the fuel line from tank, preferrably in an easy to get to spot, install a much more appropriate size inline fuel filter. In my opinion, better still, it's really not necessary to filter the fuel with a filter media inline filter, as small micron debris won't affect lift pump, and considering the machine will have a fine micron filter to clean fuel before it goes into the injection system. The inline filter I use is a strainer filter for 3/8" fuel line, it will stop the large debris that will foul lift pump, and the fuel filter gets the fine stuff. You can use either a Wix 33270 or Hasting FF946. Choice seems simple to me; itty bitty crappy strainer, or a strainer that is actually big enough to do its job yet allow machine to do some work.
Ah but master, if you use big inline filter, you likely not know your tank is full of "gunk" until its very bad. See ATCO's disel tank cleaning thread. -grasshopper
Ahh, true, grasshopper, a tank that's full of "gunk" brings its own worries. Any strainer, large or small, stuggles to deal with that stuff, one just clogs faster than the other. :tong Oh the joys of owning/operating a machine.
Here ya go, never clean your fuel tank again:
Holy friggen filters Batman! Does that take the place of the counterweight on an excavator? :tong
You'd poop your pants if you knew the hours I've spent driving out into the bush just to cleanout those strainers on Hitachi machines out logging. I also usually bring a filter base and filter for the poor sap to fit on the tidy tank in his work truck to keep him from having to pay for a 800 dollar field call for no good reason,in the future. Tidy tanks are the devil....tidy tanks without a filter are George W Bush.
I hope people with the common rail engines take better care of their fuel system than that. The fuel system needs to be clean to keep them running or it will cost you a set of injector, pump and lines. That brown sludge looks like algae, There is a treatment to help fix that problem.
You got that right Lee-online. These newer tier 3 engines with common rail fuel systems, one better keep their filter and water separator well serviced. Stuff like this can make them do some real wierd stuff. :yup
The banjo bolt strainer is only to catch the rocks that can get through and damage the transfer pump. The inline filter is OK but one needs to know that you can't put just any garden variety Napa inline "gas line filter" in a diesel fuel system. You need one that has a brass strainer inside instead of paper. Paper filters are made of cellulose which is the fancy name for plant fiber. When water hits plant fiber the fibers swell up and close off the flow of diesel through the filter. I have seen those filters run less than three hours before they close up and shut off the fuel flow. If you want an inline with the brass strainer I suggest you go to either the Cummins or International truck dealer. Another nifty little piece of info is that you can clean the brass filter. Soak it in solvent and then blow backwards through the filter with air pressure and reinstall. I don't think you will find any of these banjo bolt or inline strainers in the newer common rail systems.
Paper or Plastic? I'm not sure I follow you John? Every diesel fuel filter I have has a paper element, from the Dodge Rams to the Zaxis. The primary filters on our Kenworths have a paper element and they double as the water separator. Are you saying just the pre-filter before the lift pump should be a brass screen?
RobVG, I'm only talking about the in line gas filters they sell at auto parts stores. The water separator types of filters for diesel use have a coating on the paper that rejects the water and makes it drop into a cup where it can be drained off. I didn't mean to confuse anyone.
I get it now. Thanks John.
I shy away from using inline media filters as well John C. I agree with you, the lift pump really only needs protection from heavy debris that would affect the internal check valves, an inline strainer will provide that protection. An inline media filter, being they're small, will clog rather quickly, and results in the fuel filter on the engine isn't even doing much to filter fuel because everything's stuck in the inline media filter. I've worked on so many JLG lifts with Deutz F4L912 engines that isn't running properly just to find someone installed an inline media filter instead of an inline strainer. The thing is, if you put a Wix 33270 (strainer) alongside a 33033 (media), you wouldn't be able to tell the difference. It's what's inside is the difference. It just makes no sense to me to leave that little strainer in the banjo fitting, it takes very little debris to clog it. Besides, it is a strainer. Why not use a larger strainer to accomplish the same task, strain the large debris. Algae in this case wouldn't matter, it will pass through the strainer, through the lift pump, and get trapped in the fuel filter. And I have had a long time habit of pouring out what's in the fuel filter when changing them just to get an idea of what's in there and possible actions that need taken. If one uses an inline media filter, algae will clog that thing very quickly and shut the machine down, frequently. BTW, to agree with you, this thread info doesn't necessarily apply to newer common rail engines. Different animal.
WOW ! ..... talk about the ghost that was in my closet .... those pics you posted of the little Devil are EXACTLY what mine looked like, right down to the color of the fittings. I agree with the in-line brass or stainless filters .... that's exactly what I did and what I do ... is when it cloggs or begins to clog I pull it out and shake it up and blow it out , a tin can or water bottle cut off, a bit of diesel soak it, shake it, blow it out again put it back in less than ten mins, and good till the tank gets low again ..... sooner or later I will get that frigg'n tank clean ....LOL Another BAD example of those paper/media filters is guys who put them in-line to a 2-stroke outboard, it separates the oil from the gas and OOOPP'S seizure and a badly worn not rebuildable engine ! There is a thread going "Cat 312" begun by woodboy .... and I think thats what is going on with his, he now claims that his fuel or a fuel problem is cured but it took me over 2 yrs to eleminate all of the "What Ifs" Wished back then I new of HEF it woulda saved me alot of coin ! .... :notworthy
Thank you for posting this. Your advice fixed my starting problem
I prefer this one because I can see what's going on, and, I've never had one crack, break, or leak.
Second that and they even make a larger one than that on longer with 3/8 fittings on it.