Lucas injection pump issues

Hi everyone,
I have a 96 scat trac 1700 skid steer and a about a week a go it was running on job and smooth as always, at about third of throttle while sitting still as guys were loading bucket it just slowed down a stopped, I changed filters did all the bleeding but can't get any fuel to pass into the pump and come out the bleeder on there, injection line are dry, never had any problems bleeding after changing filters before, so far I converted to an electric fuel pump, so there's plenty of pressure, I've checked return line to tank and it is open, this pump has electric fuel shut off but it stuck on me a few years ago and I removed it gutted the plunger and put it back in to keep it from leaking and now use the cable stop,,
Any ideas ?? I need to get it on my trailer and home, it sat for about 9 months due to health ploblems and it's been fine through this summer, just trying to get back on my feet and finish a couple small jobs and don't want to put it in a shop or buy a rebuilt pump if I can avoid it, thanks for any help you can offer, I plan to rebuild it myself if need be, just have to get it moved

There is a cylinder type gauze filter in the inlet on the back of the pump that might be blocked,remove the feed line then the nut holding the regulator valve,be careful as there is a lot of small parts inside,fish out the gauze filter and clean it,the sequence for bleeding is open all bleeders,when clear fuel comes from primary filter close the bleeder then the secondary,next lowest one on pump finishing with the top one,with all the air out and the bleeders closed keep on priming till the feed pump goes limp,loosen the injector line nuts a couple of turns,on full throttle with the stop in run crank the engine over till the line unions start to spurt fuel,tighten them up and you should have a start.
AJ

Thank you AJ, I have the inlet line off from filter to pump so I
should take the inlet nut out and seal picks to pull the filter out,
I only found one bleeder on the outside of pump, everything is
cleaned well to keep the dirt out, I tried back flowing from that
bleeder with deisel cleaner the one on the side of the pump
housing 7/16" bolt hole, using a universal plastic fuel filter and
clear hose held tight against the opening, and I had the return
fuel line removed from the filter and nothing came out the inlet
or return if that means anything, after that I tried with
everything hooked back up first using the hand lever on the lift
pump and cranking but still no fuel coming out on the side of
the pump, that's when I added the electric pump, so I'm going
to try to remove the inlet filter tonight, thanks for your help this
thing is driving me crazy, I've been around equipment and
trucks all my life and have never had a problem priming and
getting them running, if so I just replaced them 😂 Can't afford
that any more so decided to take the plunge a learn the
working of them, I have a core in my garage off one of my
trucks that I'm going to go through and reseal, I've rebuilt a
few engines with no issues, hope to learn more about the ip 's
Getting older but not brain dead yet👍 I will let you know how
things go, I'm new on here, I've been on here reading a lot of
posts before and a lot of good people and I hope I can be of
some help to others myself, I'm the kind of guy thats not
happy with just fixing it but why it happened other than
wearing out