Fergy 135 diesel pipe threads

[Rick Beament]

Hi. I've managed to cross-thread the diesel return output of the injector pump into the long pipe back to the filters (idiot !!!) Only solution is to run a tap down the threads to get it sorted but I cant find anywhere what the threads are. Is it a 1/4" BSP or BSPF etc etc. I know the lift pump is a UNF thread but I've got a die set for this and it doesn't seem to fit the pipe union (unless, of course I've cross threaded that too !!! Help !!!

 

[Dieseltech]

It's 1/2 inch NF BOLT thread for that line nut and fitting, NOT pipe thread. I've used brake line nuts before at inlet/outlet lines to crush the rubber sleeves that prevent leaks. I would REMOVE the front adapter fitting and clamp in a vise while working on it.

 

[Rick Beament]

Thank you for this ... do you mean UNF thread (not NF)? Yes, I was thinking of removing the adapter, but it's so close to the pump drive cover that I'd have to slacken-of the injector pump threads to move the injector body enough to one side to get a socket on it .... are there any risks in doing this - I only need to shift it a few mm.

 

[Dieseltech]

I know a 1/2-FINE THREAD bolt will thread into that fitting IF the threads are not damaged.

 

[used red MN]

Hello Rick, (my name as well) welcome to YT! Your wording is a little odd, “slacken-of(f) the injector pump threads” do you mean the mounting nuts for the pump? If so that is fine. If there is no mark to index the pump mount flange to the timing cover I would add some with a chisel so it can be placed back in the same position for timing. I believe the mounting holes in the pump mount flange are slotted. If you are moving it just to use a socket instead of a wrench, I would just go with the wrench instead of loosening the pump.

 

[Rick Beament]

Thanks to both on this ... used red MN - yes, I just need to move the whole injector pump slightly to the right in order to get a wrench onto the adapter, so I'd planned just loosening the two nuts that hold it onto the pump mounting flange so I could get a few mm of extra space - dont want to inadvertently disconnect the pump's drive shaft and end-up with an even bigger problem than I already have !!! Dieseltech ... I just wanted to clarify because there are UNF and NF threads that are the same size and pitch, but the screw profiles are slightly different. I know that the lift pump flexible line has UNF threads but wasn't sure if that applies throughout the tractor's fuel system. Anyone ?????

 

[Dieseltech]

Thanks to both on this ... used red MN - yes, I just need to move the whole injector pump slightly to the right in order to get a wrench onto the adapter, so I'd planned just loosening the two nuts that hold it onto the pump mounting flange so I could get a few mm of extra space - dont want to inadvertently disconnect the pump's drive shaft and end-up with an even bigger problem than I already have !!! Dieseltech ... I just wanted to clarify because there are UNF and NF threads that are the same size and pitch, but the screw profiles are slightly different. I know that the lift pump flexible line has UNF threads but wasn't sure if that applies throughout the tractor's fuel system. Anyone ?????

Use NF tooling, I know that will work. If you can't save that front fitting I have some good used ones here too.

 

[Rick Beament]

Thanks, I'll do that .... thanks also for your offer but I'm in Britain !!!

 

[Rick Beament]

OK, so I finally got the thread problem sorted by simply taking the adapter off and hand-filing the threads with a needle file to get rid of the cross-thread. Got it all back together, primed and started Yeah !!!! ...... No !!!! same old problem .... runs for 5 mins, another minute at higher revs, then sputters and stops and wont re-start without re-priming. Tractor has got new main filters (the old ones were disgusting!) and the fuel pump seems to produce reasonable squirts of fuel so am I just left having to drain the tank down and put a new tank filter on the tap ??? Could it be anythng else ???? Help !!!!

 

[ADB-Ia]

OK, so I finally got the thread problem sorted by simply taking the adapter off and hand-filing the threads with a needle file to get rid of the cross-thread. Got it all back together, primed and started Yeah !!!! ...... No !!!! same old problem .... runs for 5 mins, another minute at higher revs, then sputters and stops and wont re-start without re-priming. Tractor has got new main filters (the old ones were disgusting!) and the fuel pump seems to produce reasonable squirts of fuel so am I just left having to drain the tank down and put a new tank filter on the tap ??? Could it be anythng else ???? Help !!!!

I've had a leak at a fitting between the tank and the primary pump that was not leaking fuel out but would allow enough air in to cause the injection pump to starve for fuel and eventually lose its prime. When under full load there was enough vacuum on the line to draw in air. May have been caused by filler cap not venting properly or some restriction at the sediment bowl but tightening the fitting solved the problem.

 

[Janicholson]

Thank you for this ... do you mean UNF thread (not NF)? Yes, I was thinking of removing the adapter, but it's so close to the pump drive cover that I'd have to slacken-of the injector pump threads to move the injector body enough to one side to get a socket on it .... are there any risks in doing this - I only need to shift it a few mm.

Same thing! Jim

 

[Dieseltech]

OK, so I finally got the thread problem sorted by simply taking the adapter off and hand-filing the threads with a needle file to get rid of the cross-thread. Got it all back together, primed and started Yeah !!!! ...... No !!!! same old problem .... runs for 5 mins, another minute at higher revs, then sputters and stops and wont re-start without re-priming. Tractor has got new main filters (the old ones were disgusting!) and the fuel pump seems to produce reasonable squirts of fuel so am I just left having to drain the tank down and put a new tank filter on the tap ??? Could it be anythng else ???? Help !!!!

YES, it can be something else. On top of a filter base is a constant bleed orifice that when plugged will allow air to enter the injection pump and WILL cause shut down. The orifice can be a straight fitting, or a banjo bolt and the line usually connects to the injector top leak off return line. Make sure that orifice is not plugged. Also, what brand filters are you using? If NAPA/WIX, MAKE SURE there's NO O ring placed in the filter top outer groove, that's the fuel inlet and must NOT be plugged/restricted.