5035 Fuel System Leaks

[Bentbarz]

Hello Group, I need some help.

I have a 5035HST with 162 hrs that is within a few weeks of being 1 year old. The tractor has been great and no real issues until now. A few hours (operating) back i started to get a fuel leak that appeared to be coming from the area above the tank. It was a few drips here and there at first, then within a use or two was enough to leave a small puddle on the floor. I thought it was just a loose clamp or something along those lines, but they all seems to be tight. After studying it some more it seemed to be a leak in one of the fuel lines itself. This propmted trip #1 to the dealer. Their prognosis was that it was leaking from the connection, not the hose, and they put a new clamp on. I was skeptical, but figured they should know.

After getting it back, about 30 minutes into running it fuel started gushing from under the hood and running out. To put gushing into perspective, I would say on the order of 1 qt in 30 seconds. I noticed that one of the lines on the back of the injectors (low pressure return?) had come off. I pushed it back on and it was ok for another 30 minutes before it blew again. This time I used a cable tie to clamp it back on. That seemed to hold it. After a little more time I had gushing fuel again...back to the dealer.

Dealer prognosis was that the return from the injectors had come off where it goes into the connection by the filter. The thought was that I might have pulled it off when putting the other one back on. I was pretty sure this was not the case has i checked the rest of the lines after the first one blew off. Got it back yesterday and ran it last night for 30 minutes or so and had another gushing but at about half the rate of the previous ones. When I stopped and raised the hood I could not see the exact source of the leak. All drain lines were connected, but I could tell it was coming from high up on the engine, in the neighborhood of the injectors. I double checked all of the connections closed it back up and ran it a bit longer. The rest time was only a couple of minutes. It was ok.

This morning I started on one of my significant projects that would require a few hours of seat time, and lo and behold, gushing. I am not sure exactly how long it had been running, but probably between 30 minutes and 1 hour. This time I left it running while I got the hood up so that I could see where the leak was exactly. I could see two places, one being what I am calling the drain line from the injectors, the other on the fuel pump. The hoses were not blow off the injectors, but it was clearly coming from the line between the front most and the next injector. On the pump the is a braided line that attaches high and to the rear on what I assume is the fuel shut off solenoid. It was leaking at this connection, but it looks more like the line itself than the fitting.

I don't know alot about how a diesel system works. It would seem to me that the return lines from the injectors should be low to no pressure based on the type of tubing they used. If that is the case, should that drain directly back to the tank or does it go through some other component that could cause the restriction? Any idea of where to look? Good guys at the dealer and they are trying, but my confidence level in them isn't real high.

The tractor runs fine during all of this.

Thank you,
Travis

 

[Harry in Ky]

You're right in that the return flow to tank should be under little or no restriction. In your case, it would seem there is more than a "little", for whatever reason. The system can and will build pressure if the return passage becomes blocked, in which case the weakest link becomes a leak. Since you have experienced and repaired each, the leak simply move to the next weakest point. I would look at the return line from the system to the tank return port, determine the easiest end to remove, and run the tractor with the line removed. A small amount of fuel should be trying to flow back to tank with the engine running. If you don't see this, try backtracking along the return system to determine where the flow stops/starts. You might also try removing the inlet side of the final return to tank line and blowing gently into the return line. You should feel and hear air escaping into the tank and out the filler if the passage is clear.

 

[Bentbarz]

Thanks Harry. After i posted this I did part of what you suggested. I removed the end the last section of line going back to the tank and used a compressor to blow it out thinking that if there was something in there I would get it out. It appeared to be free flowing. I also removed the line from the shut off solenoid and blew from there to where I removed the other line and that was clear. I put it back together and ran it for 20 minutes or so with the same problem. I shut it down for about a minute and did touch anything and it was ok for for a few more minutes.

I am starting to wonder if it isn't as much a restriction as it is an oversupply to the injectors. It sure seem like a lot of fuel coming out of that line once it starts leaking. How much fuel would you expect to see returning through that line?

 

[Mahindra 5035]

I own a 5035 HST and noticed the leaking fuel problem. I have about 24 hours on mine and it would only leak after being under pressure. I had the technician coming out for another problem (covered under warranty) so I made the dealer aware before he left the shop. Upon his arrival I explained what was going on and he told me that the hoses they use during assembly fail, and the replacement tend to fail. So they just go ahead and replace them with quality rubber hoses. So with a little help from me and pulling the rear tire off to get at the tank. New hoses and no problems. I am extremely lucky/happy with my dealer and their service department. As for the other part, I had it mailed to me and on the tractor in less than a week after the phone call. Again I really like my dealer. Good luck and get the hoses changed out.

 

[Harry in Ky]

Return flow from the injectors should be minimal, the bulk of return flow will be from the injection pump. Since it's still under full warranty at this point, I wouldn't fool with it too much. I would maybe try to separate the two return systems(one from the pump and one from the injectors) if possible without damaging anything that might hinder a warranty claim. Let each side run free into a can or jug and see just how much flows from each - might help diagnose the problem.

 

[Bentbarz]

I agree about fooling with it too much. I will have the dealer come get it in the morning. The good news is that the dealer is only 15 minutes from me. How much flow would you expect to be coming back from the pump?

I would agree that the fuel hoses do look to be pretty low quality and was already suspect of them. Aside from my gushing problem I think that return hose is still leaking too.

 

[Harry in Ky]

The flow would be hard to measure in GPM, I'd think it would take a few minutes run time to fill a quart container

 

[JerryK]

Seems to me that I read on this forum several years ago that Mahindra had some fuel line problems on the earlier built 35 series. Fuel line inserted or crimped wrong. So the dealer should be able to get the info from Texas, or Dave in California.....

 

[OldGinTractors]

Fuel lines have been an issue on these models. You should ask your dealer to replace all the fuel lines that run to the tank, cause it's a pretty good job getting the tank loose to get to the connections.

Dave