The Fordson Tractor Pages Forum

A while since ive required any advice on the forum.
Had the Dexta out for a good workout on the plough today. Diesel is leaking from the injector pump leak off pipe all the time while she is running it is dripping constantly. No fuel in oil and she is running sweet with no smoke and plenty pulling power. No misses either and starts no problem. Its a Lucas CAV injector pump that is on her rather than the SIMMS as its a 1965 Perkins engine. I did notice it leaking from the pipe when I had it out a few weeks back for a run but never thought anything of it. Its making a mess of diesel. Is this a faulty lift pump or is it the injector pump that lies at fault. Any advice appreciated.



Said Leak Off Pipe.

Hi Charlie
Mine also does this occasionally. My understanding is that this is normal as the earlier pumps are lubricated by diesel and the excess is dumped out of the leak off pipe. The later pumps have oil lubrication. Take a look at this post:

viewtopic.php?f=3&t=4786&p=33161&hilit= ... ump#p33161

Mike

Hi Mike,
Many thanks for the reply. I was sure my pump is lubricated with diesel and not oil but just thought that the amount of fuel coming out of the leak off pipe was excessive. I suppose its the same as oil and always looks worse than it is. I might just fit a bottle or container of some kind to the leak off pipe and measure how much fuel is actually coming out. Its making some mess as it is dripping on to the sump lip and running long it.
At least I know the pump is well lubricated.

Regards
Charlie.

Yes I saw this idea at a tractor show in the summer, someone had wired a glass jar under the pipe to collect the diesel

Ploughing looks good by the way

Hi Charlie, that is a very strange issue you have with the leak off pipe. Okay my pump is a mechanical pump with the leak off pipe having a pigtail curl in it 360 degrees, slightly different to yours. Just thinking aloud could it not possibly be your extra fuel valve button been stuck, not sure if there is one on the pneumatic pumps. , I hope someone can come to your rescue. Another thought the leak off pipe from the injectors, could it possibly be blocked.
Your ploughing looks very professional Charlie no problem there

Charlie, if you have the fordson workshop manual look up section 4 page11. There it refers to the "Spill Cut Off Setting" that may assist.

Hi Mervyn,
Thanks for the reply and info.
I had a look at the manual which I have a copy but all the setting up of the injection pump is done on a test bench. My pump doesnt have an extra fuel valve button. Ive checked that the spill pipe to tank is not blocked as well.
As Mike said in his reply that this is a common thing with the fuel pump being lubricated by diesel rather than oil so I am going to fit a small bottle to the pipe to see how much diesel is actually coming from it when it is running.

Regards
Charlie.

I can't answer your question directly but I have a Ferguson TE20 tractor which has been fitted with a Perkins P3 and there is no pipework at all to connect the leak-off system back to the tank, it just vents down the side of the block, and I have been told that this is how they came new? A little pollution maybe didn't matter so much in those days..

Hi Charlie,
It will be very interesting to see how much fuel you measure in a time frame.

Bob,

My pump doesnt have anything linking the leak off back to tank either and think Mervyn was referring to the leak off from the injectors. I made sure that this was clear but dont see that this would have any bearing on the leak off from the injector pump. I just thought that the fuel coming out of the leak off pipe was excessive but that might just be me.As you said I dont think they were worried about a bit of pollution back in the day. Its the same old story with oil and fuel a leak always looks worse than it is. Instead of it making a mess think fitting the leak off pipe into a small bottle is the way to go.

Charlie.

Hi Charlie,

You could maybe try putting a pigtail in the pipe, certainly all the Simms pumps have a pigtail, must be there for a reason although I don't actually know what the reason is.

Bob

Hi Bob,

Looking at my leak off pipe it might have had a pigtail in it and been straightened for some reason. Im unsure what the pigtail actually does as well. Worth a try and nothing to lose. Cheers for the info.

Charlie.

I always assumed that the loop in the pipe was to hold a ‘sump’ of fluid, thereby stopping dust ingress.

Old Hywel,
Your theory could be right. If you look at the photos on my first post it looks like the pipe should maybe have a pigtail in it and for some reason its been straightened out. I will put a pigtail back into the pipe and try that. If im still getting a bit of fuel coming out will just fit a small bottle to it.

Charlie.

Well I took Old Hywel"s advice and put a pigtail back in the leak off pipe today. Had the tractor running hard for at least a couple of hours and only a few drips from the pipe which I can live with. Thanks for the advice.



Charlie.

Further update on my leak off pipe on the injector pump. I thought the fault of it leaking diesel had been cured by putting a pigtail in it. Had her out ploughing last week again and found that it was still leaking fuel. Had another think about it and decided to change the lift pump as thought that it may have a small pin hole in the diaphram allowing fuel into the injector pump. Replaced the lift pump this morning and had her running most of the morning under pressure and also gave her a road run. Seems replacing the lift pump has cured the fault as no diesel whatsoever coming from the spill pipe now.

Good morning Charlie, I am delighted that you have found the leaking leak off pipe issue, very clever thinking on your behalf. Who would have thought of the lift pump with out previously having experienced the same problem, first for the forum. "Give the man a Bells or a beer"

Its been a while since posting anything on the forum and hope everyone is well and managing to stay clear of this dreaded virus.
The saga continues with the injector leak off pipe so decided to spend a bit of time getting to the bottom of it. I know that the Lucas CAV pumps are lubricated with diesel rather than that of the Simms being lubed by oil.
I think I need advice from someone that has experience of diesel injector pumps as it looks like it could be the injector pump that is worn.
Firstly, I removed the injector leak off pipe at the end of the rail and attached a clear plastic pipe, ran the tractor at full revs for a while and nothing came out of the injector spill pipes. Removed the spill pipe rail from the injectors and that is clear. How much fuel should come out of the injector spill pipe??
Secondly I removed the injector pump side plate that allows access to the pump valves/springs and started the tractor. When running there is diesel running down the second spring assembly and after a bit of time the same happens with No1. Now I know why the injector pump sump is filling with diesel. Does this mean that there is wear in the pump/seals and allowing the excess fuel back into the pump rather than pressurising it and putting it out the injector spill pipe? Also when the tractor is started from cold it is like it only starts on 2 cylinders and then clears and runs fine on all 3.
All injectors had new nozzles etc and were set up and bench tested.
Any advice much appreciated before I pull the injector pump and send it for a refurb.

Hi Charlie,
It sounds like no. 2 plunger and barrel assembly is leaking badly and no. 1 is going that way; a drop from time to time is normal, but if you can see it it's worn. You'll need to overhaul the pump. The seal is by lapping in the plunger and barrel; this is why if you read any manual it will tell you to change them as assemblies. After that the pump will need calibrating using special equipament.
Sorry to bring this massive bill, but the wear will get noticeably worse very quickly from that stage.
Sandy

Sandy,

Many thanks for the advice and confirming what I thought. Wasn't sure if there were upper seals in the pump but it all makes sense. Just kicking myself as the pump was the only thing that wasn't overhauled when I was doing the restoration. Pump is now off and dropped off with pump specialist for complete overhaul.

Everything disconnected.



Timing set up.



Pump Removed and ready for overhaul.

Hi Charlie
I worked my Dexta really hard last summer, renovating a rough old paddock that was thick with very tough nettle roots and rocks that I grubbed out with a heavy duty cultivator and harrows. I then ploughed, levelled, sowed and rolled it - all great fun but took weeks to do. The Dexta performed admirably but I noticed she's developed your problem with fuel dripping quite a lot from the injector pump. Did the overhaul solve your problem? If so where di you send it to and how much did it cost?

thanks

Mike

Have a look at the amount of fuel coming out, if it's only a drip that is perfectly normal, if it's more remove the inspection cover as Charlie did and see if fuel leaks visibly or not. Only then should you consider spending the large amount of cash needed for a pump overhaul and calibration.
Sandy

Sorry for the late reply guys. Hope all is well with you all. I ended up getting my pump fully overhauled and set up. In the end it cost me around ,£500 including postage charges. I used a company over on the West Coast of Scotland their name has slipped my mind. They have done a fantastic job, no more leaks and she starts straight away now as well. The guy said that the pump was in a poor condition. It was the only thing that I never got done when I was doing the restoration and hindsight is a great thing. The real test will be when I finally return home as it hasn't been started since last September when I was last home.

That sounds like a very good price, I reckoned it would cost at least £700 to just calibrate a pump, without doing a full overhaul, so definitely worth having in mind. Having said that, any pump overhaul is still going to be pretty expensive.
Sandy

I had no idea it would be that expensive. I've just been quoted £350 + vat from http://www.dieselbob.co.uk/

I connected a glass jar whilst I was topped a 2 acre paddock and it was 1/4 full at the end. I'll live with the jar solution for now as I am about to build a new workshop so need the cash for that.

Mike