Bobcat A770 Fuel Leak

[RichardMH]

Bought the machine in August and everything has worked fine since then.

Two days ago, I filled the fuel tank right up to the top of the filler neck at the end of the day. Yesterday, I found diesel fuel on the floor underneath the drain cover of the machine (directly under the drain plug of the fuel tank). When I opened the rear door and look under the engine, I noticed diesel on the top of the fuel tank, running from somewhere behind the engine towards the rear of the machine, and then down to the frame and out the drain.

The machine has never leaked fuel before (during running or just sitting in the shop) so the fuel tank should be ok. I noticed that the level of fuel has dropped right down the neck so I think fuel must have escaped through one of the openings on top of the fuel tank due to gravity pressure (as I filled the tank right up to the top of the neck - something I have never done before).

The Bobcat design does not make it very easy to inspect the fittings on top of the fuel tank but I can see there is no sign of leakage around the fuel filling hose and the two breather hose fittings. So I am left with the two fuel pickup lines and the fuel senor, but I cannot see these fittings at all since they are directly behind the engine.

I checked the online Parts Catalog and noticed that there is no overflow arrangement for the fuel tank and therefore the system should not leak at all even if I filled the tank right up to the top of the neck. Is this true ? Because if it is, then I will have to figure out how to check (and reach) the two fuel pick up lines (bad grommets ?) and the fuel sensor. Before I do that, I just want to check with more experienced users since this is my first Bobcat.

I can avoid a leak by not filling above the top level of the fuel tank. But if I have a unsound fitting somewhere, I might as well repair this before it gets worse and start to leak when the machine is running.

Thanks !

 

[SSdoxie]

Most likely a torn grommet on the pickup tube or return line tube. If that is the case it needs to be fixed because water could enter around the grommet and contaminate the fuel. Easies way to get at those gromments: riaise the cab, at the back just above the pump is the plastic fan shroud - held in place with 4 rubber strap - unhook the straps and pull the bottom fan shroud out. After that is out you can either lay a piece of heavy cardboard over the steering panel and lay on it to get back behind the pump. Some take the screen off the left side air discharge and reach through that hole after the fan shroud is removed, but the drive belt housing still hinders sight of the grommets.
If the is new and under warranty, let the dealer fix it.

 

[RichardMH]

Most likely a torn grommet on the pickup tube or return line tube. If that is the case it needs to be fixed because water could enter around the grommet and contaminate the fuel. Easies way to get at those gromments: riaise the cab, at the back just above the pump is the plastic fan shroud - held in place with 4 rubber strap - unhook the straps and pull the bottom fan shroud out. After that is out you can either lay a piece of heavy cardboard over the steering panel and lay on it to get back behind the pump. Some take the screen off the left side air discharge and reach through that hole after the fan shroud is removed, but the drive belt housing still hinders sight of the grommets.
If the is new and under warranty, let the dealer fix it.

Thanks Dennis for the pointers to the tubes. Yes, the machine is still under warranty so I will get the dealer to correct this.