New Holland 8340 Fuel Pump help please

[Grouse]

I have a NH 8340 which has a slight leak from the fuel injection pump - the location is hi-lighted outlined in red in the piccy - what is this part? - it appears to be held in by a circlip and is weeping diesel - is there a seal behind there ? Any advice / assistance would be very much appreciated

 

[agrimax]

Part no's 36 to 45 are what's in there...

There are 2 o rings in there. IIRC I removed 45 and 44 and applied siligasket around 44 and it stopped the leak.Likely not recommended but it worked.
Had to go into Messicks' USA web site to get this... The official CNH parts site is now absolutely hopeless!!

 

[forblue]

Excess fuel device o-rings 40 an 43 just be careful when removing.

 

[Grouse]

Fantastic ! Thank you both for your help - very much appreciated. Could this leak cause the engine to hunt / lose revs and then speed up ?

 

[Cowabunga]

Fantastic ! Thank you both for your help - very much appreciated. Could this leak cause the engine to hunt / lose revs and then speed up ?

Seems unlikely on its own. It just might suck air in as well as drip fuel out though so it is certainly worth changing the number 43 O-ring, which seems to be quite a straightforward job. However I would be surprised if it is quite as simple as it seems.

 

[forblue]

On pre-filter glass bowl where fuel inlet pipe fits there is a brass tap just make certain there is no debris in it, sounds like air in fuel could be primer they can go bad also check supply pipe, same one to tap, all the way back to tank any connector hoses getting cracks which will also cause your problem.

 

[Grouse]

Thank you Cowabunga and forblue, I will change the O ring and also I suspect that the primer diaphragm has gone as there is no pressure there when the Primer hand button is pressed - and I had trouble bleeding the fuel system last filter change. The filter and fuel was spotless and I have a filter also on the tank. Fingers crossed this sorts it - thank you all.

 

[Barleymow]

Part no's 36 to 45 are what's in there...

There are 2 o rings in there. IIRC I removed 45 and 44 and applied siligasket around 44 and it stopped the leak.Likely not recommended but it worked.
Had to go into Messicks' USA web site to get this... The official CNH parts site is now absolutely hopeless!!

The cnh parts site uses to excellent to look up parts on ,its a nightmare now

 

[agrimax]

@Barleymow
Just realised yesterday that the CNH website that I've been using is actually the USA version. The old one was OK but they have now completely overhauled it and it's hopeless. Have now the link to the European one which is in the same format as the CIH site. Takes a bit of clicking on consents etc to get to the parts lists but is ok to use when in...

MyCNHi Store | Site Selector

ngpc.cnh.com

 

[ACEngineering]

Fantastic ! Thank you both for your help - very much appreciated. Could this leak cause the engine to hunt / lose revs and then speed up ?

So didnt mean to like a random post thumb slipped on phone while looking at random posts

Air will normally be a cause of revs hunting though.

 

[brax7840]

I have a 7840 with the same part out on it so will have to look
cheers lads your lifesavers

 

[Grouse]

Apologies I should have updated on this - totally forgot. For what it’s worth on mine I changed the primer diaphragm / fuel filter housing and the problem was immediately solved - it was air getting into the system via a perished diaphragm Thanks everyone for input and advice

 

[Timbo]

Fantastic ! Thank you both for your help - very much appreciated. Could this leak cause the engine to hunt / lose revs and then speed up ?

Thatll be either sucking air or a restricted fuel supply. Both common.

 

[essexpete]

The original metal pipe out of the tank that runs across the transmission can leak causing surging.