LoggyDriver Posted July 12, 2011 Share Posted July 12, 2011 How do I bleed the air out of my MJ fuel system? I had to fit a new fuel lift pump as it failed on Sunday. I've fitted the pump, but there is air in the sedimenter. I've turned the engine over with the fuel line removed from the pump outlet but with no success. The truck stopped dead as the one way valve in the pump fell out of it's housing. So there is no fuel in the injectors, pipes, injection pump, lift pump and about half an inch of air in the sedimenter. Turning the engine over has no effect in drawing fuel through, I presume because the lift pump is dry and needs priming and also because of the air in the sedimenter. Can anyone help please? Quote Link to comment Share on other sites More sharing options...
Sean N Posted July 12, 2011 Share Posted July 12, 2011 Mechanical lift pump, there should be a hand primer or priming lever on (under) the lift pump. Open the vent screws and work the primer until air-free fuel flows. It'll help to turn the engine so the lift pump lever isn't on the cam, to get maximum travel. Electric lift pump (though I thought these were MK only), switch on the ignition and let it bleed through. Quote Link to comment Share on other sites More sharing options...
Bran D Posted July 12, 2011 Share Posted July 12, 2011 Hello Andy, first you need to make sure that the feed from the lift pump to the injector pump is open to air so that as you pump the lift pump it removes the air from the sedimentor to atmosphere. This means you need find the recommended bleed points, then open the nearest to the output from the lift pump. Sometimes its OK crack open the output pipe connection from the lift pump, then pump away till you start to get fuel up through the sedimentor. Once this happens retighten the connections, open the next bleed point on the injection pump and remove the air by pumping. Sometimes the lift pump movement is at full stroke on the cam from the engine position so you may need to turn the engine 180 degrees or so. If you have plenty of battery power you can use the starter to speed things up, but make sure you dont run out of battery! Hope this helps. Quote Link to comment Share on other sites More sharing options...
LoggyDriver Posted July 12, 2011 Author Share Posted July 12, 2011 Mechanical lift pump, there should be a hand primer or priming lever on (under) the lift pump. Open the vent screws and work the primer until air-free fuel flows. It'll help to turn the engine so the lift pump lever isn't on the cam, to get maximum travel. Electric lift pump (though I thought these were MK only), switch on the ignition and let it bleed through. It's a mechanical lift pump. I turned the engine over for about 30 seconds with the outlet pipe from the lift pump removed but the air in the sedimenter is at the same level, so it's not sucking any fuel through. I'm at a loss. Quote Link to comment Share on other sites More sharing options...
LoggyDriver Posted July 12, 2011 Author Share Posted July 12, 2011 Hello Andy, first you need to make sure that the feed from the lift pump to the injector pump is open to air so that as you pump the lift pump it removes the air from the sedimentor to atmosphere. This means you need find the recommended bleed points, then open the nearest to the output from the lift pump. Sometimes its OK crack open the output pipe connection from the lift pump, then pump away till you start to get fuel up through the sedimentor. Once this happens retighten the connections, open the next bleed point on the injection pump and remove the air by pumping.Sometimes the lift pump movement is at full stroke on the cam from the engine position so you may need to turn the engine 180 degrees or so. If you have plenty of battery power you can use the starter to speed things up, but make sure you dont run out of battery! Hope this helps. Hello mate. Thanks for the reply. I've detached the fuel line from the outlet of the mechanical lift pump and then cranked the engine over for about 30 seconds. This has no effect on drawing fuel through the sedimenter. The sedimenter is lower than the lift pump. I think because there is air in the sedimenter, and the lift pump is dry, no amount of pumping will draw the fuel through. I need to get the fuel up to the lift pump but I'm at a loss how to do it. I need some sort of vacume to suck the fuel up to the lift pump. Any ideas? Quote Link to comment Share on other sites More sharing options...
Bran D Posted July 12, 2011 Share Posted July 12, 2011 Make sure the lift pump is working ok. Remove both the input and output lines, can you feel any suck on the tank connection if you operate the pump? Maybe a new old stock pump could do with a little diesel in it first to prime the pump and get the valves working ok. Quote Link to comment Share on other sites More sharing options...
LoggyDriver Posted July 12, 2011 Author Share Posted July 12, 2011 Make sure the lift pump is working ok. Remove both the input and output lines, can you feel any suck on the tank connection if you operate the pump? Maybe a new old stock pump could do with a little diesel in it first to prime the pump and get the valves working ok. How do I do this, by removing the dome on top of the pump and filling with diesel? Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted July 12, 2011 Share Posted July 12, 2011 If you have an airline available, try pressurising the tank to push fuel through the system. With pump outlet detached, one it comes to that point and wets the valves in the pump, you should be able to hand prime the rest of the system. to pressurise, stick the air blow gun in the tank filler with a wad of rag around it to seal. Quote Link to comment Share on other sites More sharing options...
Bran D Posted July 13, 2011 Share Posted July 13, 2011 Any progress? Hope you have it all sorted by now. Quote Link to comment Share on other sites More sharing options...
protruck Posted July 13, 2011 Share Posted July 13, 2011 Hi Andy. Not sure if you have it sorted yet but. make sure that the shut off valve on the top of the tank is open. or you will never get fuel up to the lift pump. There should be a lever on the bottom of the mechanical lift pump so that you can prime the system. I have sent you an email at home email address.. hope it helps. Regards Clive Quote Link to comment Share on other sites More sharing options...
protruck Posted July 13, 2011 Share Posted July 13, 2011 Hi Andy. Not sure if you have it sorted yet but. make sure that the shut off valve on the top of the tank is open.or you will never get fuel up to the lift pump. There should be a lever on the bottom of the mechanical lift pump so that you can prime the system. I have sent you an email at home email address;hope it helps. Regards Clive Quote Link to comment Share on other sites More sharing options...
Sean N Posted July 13, 2011 Share Posted July 13, 2011 Andy, what Clive said. You shouldn't need to turn the engine over with a mechanical lift pump. There is a lever underneath the body of the pump which you work up and down to make the pump work manually. The system must be sealed between the lift pump and the tank otherwise you'll just draw air, and it can help to progressively open unions and bleed screws after the pump. Richard's tank pressurising idea is good. You can see the lever in this photo (nb this is Landrover not M-type): [ATTACH=CONFIG]48140[/ATTACH] Quote Link to comment Share on other sites More sharing options...
extrogg Posted July 13, 2011 Share Posted July 13, 2011 Hi Andy, I had the same problems when I changed the fuel filters on the TM..Im afraid its just a case of get hand priming the fuel pump..after you've done a few hundred pumps and your fingers about to drop off try turning the engine over and see what happens!! Ive got a spare 7 Sqn windscreen sticker if you want it..ill send it to you. Andy. Quote Link to comment Share on other sites More sharing options...
LoggyDriver Posted July 13, 2011 Author Share Posted July 13, 2011 (edited) Hello guys, Well I've been on the truck again tonight and didn't finish until 22.00hrs. OK firstly I'd like to thank you all for your help. I've bled countless fuel systems without much trouble. I was doing it the correct way but couldn't understand why the air in the sedimenter just stayed where it was and the fuel wasn't being drawn through the system. I'm lucky in that where I work there is a fully equiped workshop. So I borrowed a vacume pump that you plug into the fuel system to bleed it. I connected it up and guess what..... STILL no fuel coming through. SO I thought I would remove the fuel line from the back of the sedimenter (tank-sedimenter end) and blow down the pipe to see if there was a blockage. When I blew I couldn't hear any bubbles in the tank and it was just too easy to blow down it, so this raised my eyebrows. I split the fuel lines either side of the fuel tap housing so that I could remove the fuel pick up elbow out of the tank. You just wouldn't believe it. :shocked: The fuel pick up pipe had come away from the elbow, so no wonder I couldn't bleed the system!!!!!! There was NO PIPE to pick up the fuel in the first place.:angry So I had a bit of rubber hose that just so happened squeezed into the elbow. I thought I would just try this to see if it worked. I did everything up. Bled the system up to the F.I.P. in a matter of minutes. As I was on my own I had to crank the engine over then loosen a fuel injector union to get rid of the air. I did this for all 6 injectors. I then turned the key and SHE FIRED UP. :yay:So the problem is solved. The fuel lift pump was still knackered as one of the one way valves was dislodged and hitting the top of the housing, however, it looks like the main reason for the breakdown was the fuel pick up pipe falling into the tank. TWO problems at once. I've now removed the elbow and I'm going to see if I can rig something up at work. Hopefully they will have some pipe the right size. I will post up some pictures sometime soon. Once again thanks for all your help guys.:-D Edited July 13, 2011 by LoggyDriver spelling Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted July 13, 2011 Share Posted July 13, 2011 The fuel lift pump was still knackered as one of the one way valves was dislodged and hitting the top of the housing, however, it looks like the main reason for the breakdown was the fuel pick up pipe falling into the tank. TWO problems at once. Hi Andy, That was an age old problem with Bedford MK and MJ. I have had numerous ones brought in to the REME Workshops, having been recovered, with broken pickup pipes. Strange about the pump valve falling out, because I had problems with a forklift recently, found a valve had come out, replaced it, still did not run, turned out it was an electrical fault on solenoid cut out, so just proves they will run with faulty pump valves. Quote Link to comment Share on other sites More sharing options...
SEGREQ Posted July 14, 2011 Share Posted July 14, 2011 Andy, Excellent news, not sure all your kit was going to fit into the 110. See you Sunday. Quote Link to comment Share on other sites More sharing options...
extrogg Posted July 14, 2011 Share Posted July 14, 2011 Well done mate:) Glad you got it sorted!! Quote Link to comment Share on other sites More sharing options...
LoggyDriver Posted July 14, 2011 Author Share Posted July 14, 2011 (edited) Thanks guys. Well took the elbow into work and have managed to acquire a nice piece of brass (or copper) pipe just the right size. Trouble is the fitter who was sorting it out for me had to go on a course so couldn't finish it off. I've now got to find a welder who can braze the pipe to the elbow. Not many about but there is one local to me, so I will chance my luck tomorrow. I was going to W&P first thing in the morning, but wont be going anywhere until I get the pipe welded in. Richard, Quite a few fitters at work are ex REME. I spoke with one today and he said the same thing, that the pick up pipes were always falling out. Surprised they didn't do a mod! PS, Oh forgot to say. I got some crap in my right eye last night. I thought I washed it out, but by the time I got to work this morning it was pretty bad. So I went to the company Med Centre and the Nurse said I had something stuck in my eye. I had to go to Hospital where I found out it was a tiny piece of metal that was stuck in the tissue. The Nurse got it out after numbing it and using a big microscope type machine. I'm now on eye drops as the metal left rust stuck to my eye.... My week hasn't been the best I can tell you, I hope my luck changes tomorrow!! Edited July 14, 2011 by LoggyDriver Quote Link to comment Share on other sites More sharing options...
LoggyDriver Posted July 14, 2011 Author Share Posted July 14, 2011 Well done mate:) Glad you got it sorted!! Thanks mate. You coming to W&P in your lovely CALM? Quote Link to comment Share on other sites More sharing options...
extrogg Posted July 17, 2011 Share Posted July 17, 2011 (edited) Hi mate, Id love to come up to W&P but its a bit of a trek from down here in the west country and doubt ill get the time off work. I work in Southampton and live in Plymouth so it gets a bit tricky finding the time! Would love to see your MJ sometime..they are fantastic trucks, absolutley bulletproof!! We certainly put them through thier paces when i was in Cyprus for 7 Sqn's UN tour in 92. I was witness to one rolling over the edge of a cliff in the Troodos mountains, i was driving the truck behind, The vehicle and occupants barrel rolled over 200 feet down a wooded mountain side..the MJ was unrecognisable when it finally came to a stop..amazingly the engine was still running!! I was first on the scene and the first thing i did was pull the engine stop..no idea why!! The 2 engineers were in a real bad way..the driver had gone all the way with the truck and was thrown clear..he was lying about 10 feet to the side of the cab...the passenger got thrown clear about halfway down and had had his face smashed in..what also gives me a chill is the driver had virtually all his uniform torn from him so can only imagine the violent forces his body must have gone through. They got casevac to Akrotiri hospital..they both survived though seriously injured. They had to use a sky crane to lift the wagon out and it got taken back to our REME wksp..quite a sobering sight but a good advert for its strength. Andy Edited July 17, 2011 by extrogg spelling Quote Link to comment Share on other sites More sharing options...
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