One for the experts - Cat 637D scraper.

Are you sure the fuel guy is filling the right tank?
Chuck C

Hi Team,
just thinking that if the engine has a fuel return line from the Injection Pump then it may or may not be possible that at some stage --recent work on unit--that a couple of small hoses have been miss-connected after the fact.

More info as to how long this has been occurring and if any hoses were disconnected recently--fuel pump changed etc. -- would be off assistance to gain further clues and so more informed replies instead of guesses.

The wrong tank refilled is a strong possibility with a new tanker driver if he has not been adequately trained--yes, a bit hard with a multi Brand and Unit Fleet.
Cheers,
Eddie B.

Hi, edb.
More info. At first, we thought it might have been somebody filling the wrong tank. How-wevver, it was way over-filled in the hydraulic tank when it was delivered here, to the point that it was spewing out the top of the tank when the ejector was right back. We drained 45 (U.S.) gallons - about 180 litres - out of it, down to the correct level and put it to work. It only had about 1/2 a tank of fuel in the front at the time and we didn't notice any change in the hydraulic level.

Then, during the vintage show at the end of May this year, the front fuel tank was filled right up. It took a whole four loads for fluid to start spraying out of the hydraulic tank. We thought then that somebody had filled the wrong tank. We drained the hydraulic tank and refilled with genuine hydraulic oil and it sat for about 3 months before we began putting it to work again. It didn't take long at all for fluid to start spewing out of the hydraulic tank again, so we drained it down to correct level and left it standing for two days - no change in the hydraulic fluid level.

Then I did 11 loads with it on Sunday morning to fill in a hole. When I parked it and checked the hydraulic fluid level again, it was outa sight above the top of the glass - again.

Your possible explanation makes more sense than anything anybody has come up with so far. I will have the mechanics check it out. Thank you.

Just my 0.02.

Hi Deas,
been a long time since being around one of these and now I have my mind sort of in gear I offer the following.

You do not say if it is the front or rear engine/hydraulics.

Is the rear engine fuel tank part of the scraper chassis across the rear of the bowl up above the engine so to speak.
Seem to recall breathers up in that area--rear trans/TC, Seems unlikely a Hyd tank breather relief but who knows.

613's had their fuel carried there and pumped to the front via an electric Transfer Pump. Do these have something similar.

I recall all sorts of odd issues on one 613 when hoses were mixed when the Scraper was removed for extensive repairs to the bowl slides and floor guides etc. Yeah, its not a 637D but!!!!

Grey matter is on a go slow recently so just trying to recall some odd similar things from "Way back in the dim darks" and give you and others some memory jog for similar issues on any machines they may have encountered that they can comment on.

Good luck with the Chinese type puzzle that could require thinking out side the box to get there.

Cheers,
Eddie B.

Hi Deas,
check if the Ejector Cylinder/s has/have a small diameter head/barrel seal leak-by drain hose/s--something dropped in about the before mentioned 613, 641/651's etc. whilst eating tea before the PTSD pills kick in.

I cannot recall if the floor cylinders have one but I doubt--a Parts Book here would be nice to confirm.
Likely wrong but anyway stranger things have happened.
Cheers,
Eddie B.

Deas,

I have asked Sprocket71 to come on here to give his opinion. Lets see what he thinks it is.

He texted me that two fuel filters and two hydraulic filters are on the front of the hydraulic? tank. A crossed line at that point would give you hydraulic oil entering the fuel day tank which is a small tank up front fed from the rear tank located back by the rear engine.

He says he will come on here this evening.

JanM

Hi Jan,
not really very familiar with these later machines Filter layouts on either the Front or Rear section but certainly crossed hoses on filters in such proximity to each other is possible. I feel flow rates at this point would be fairly high.

I cannot picture in my mind where the filters are on the Scraper section but the Engine/Tractor section, they from memory, are certainly close together on the right inner fender on the Tractor/Front section--as a 637D Scraper (which is Twin Powered) is mentioned in the title I am working with this Scraper/rear section of the machine in mind.

Cat do call these things Tractor Scrapers and so I guess we must be mindful of referring to which end we are dealing with--not being critical as, often I too get corrected for wrong and varying terminology as I write things here.

The Rear Section Engine Fuel Injection Pump return fuel flow rate is around 9 gallons per hour. This is relatively slow and might be more in line with the contamination rate Deas described, depending on whether we are discussing the Front or Rear section engines.

Things in reality are not always as they seem and I have an open mind on this and so am standing to be corrected as it is a good day when we learn something new to store away in the think box for future reference.

Best Regards,
Eddie B.

Hi, Folks.
To the best of my knowledge, the two engines and fuel systems ONLY share throttle controls and transmission controls. I believe that everything else is separate including the fuel tanks and systems.

Jan, the front and rear engines have what I believe are totally separate fuel systems. The fuel tank for the front engine is directly behind the hydraulic tank and ahead of the right front wheel, which is what had us wondering if somebody had filled the wrong tank when re-fuelling. How-wevver, with the hydraulic tank being drained down to the proper level and remaining unchanged for a day and a half while standing but over-filling with diesel fuel after only 9 loads when the motor was running, methinks there hazta be something more to it.

I was off-ranch all day today but will start digging deeper tomorrow.

Thanks to all for hints.

Just my 0.02.

:confused2: Front, rear, up,down, upside down,right side up,😆 I hope you don't lose your hair on this project Deas.






Hopefully a little common sense investigation will reveal the source of vexation.