M1010 fuel pump woes

[still standing still cyco]

The other day I was at a tavern and came out to find a puddle of fuel under my truck. I figured it was just a bad return line again, but it seems the lift pump has finally split a seam. So Saturday I will be tearing the truck apart to replace it. Any tips or tricks for me other than what's in my TMs? Thanks in advance!

 

[engineman2]

If you've replaced a similar fuel pump on any older vehicle you'll know that there is a plunger that is pushed by the camshaft to drive the fuel pump. This plunger has a shape and fits the cam and also has worn into a specific vertical orientation based on how it was in the engine. It's important to maintain this orientation and also to not allow the plunger to fall when you take the old pump off.

When installing the new pump it is a real pain to keep the arm of the fuel pump from hitting the plunger, which will prevent the fuel pump from being tightened all of the way and would cause some problems if you tried to start it like that. The easiest way to fix that is to get a strip of 14 or 16 gauge steel that's about 8 inches long and 1/2 inch wide. Use this to slip between the pump and block and keep the plunger up in its proper location. Once you've tightened the pump enough you can slip the metal out being careful not to harm the gasket. Some people try using grease to "stick" the plunger in place, but with everything coated in oil it was too slick for that to work on the two 6.2's I've replaced pumps on.

 

[Skinny]

Always thread the fuel line on partially before you bolt the pump to the block. Easier to start the threads while the pump can wiggle around.

 

[Warthog]

Double check the engine mount on the passenger side. They fail and allow the engine to sit lower on that side. It causes the pre-shaped fuel hose to rub on the crossmember. The hose can spring a leak and suck in air.

 

[still standing still cyco]

Thanks guys! I appreciate the tips, especially about the plunger. I've done fuel pumps on gassers in the past, but I figured this would be a bit more involved than that. Here's hoping it all goes smoothly.

 

[Hasdrubal]

"This plunger has a shape and fits the cam and also has worn into a specific vertical orientation"

What? I've had my rod out several times, the end is perfectly smooth and polished.

On the lift pump replacement ; Use a dab of grease to retain the rod in position. Its easier to get the rear most bolt started first as it has the worst access. Its the harder one to get in so do it first, doing the front one first can lead you to spend hours trying to get the rear bolt aligned. Just thread it on a few turns..then install fuel fitting and tighten fitting, its almost impossible to do if you do the bolts up first. Then install the forward bolt, lastly tighten the rear bolt. On rear bolt I use a 1/4" ratchet with combination of short socket and extension and just a deep socket. The clearance is very tight, Helps to put some gasket sealer on gasket so it stays in place.

 

[still standing still cyco]

Ok, so I got the pump installed a day or so after my last post and it ran great. Then a couple weeks ago it died and acted like I ran out of gas. I swapped the filter (filled with diesel before install) and attempted to bleed the system. I now have no fuel coming to the filter. It seems the new lift pump has already failed. So instead of going through the hassle of swapping it again, I'm going to an electric fuel pump and doing the spin on filter mod. Before I do it I'm going to blow air back into the tank on the off chance that the sock filter is clogged. Here's to hoping that my fuel system issues will be solved for good.

 

[Skinny]

Replaced my leaky pump with a genuine Delco pump ($30 off Rockauto) and has been trouble free for almost two years now. My thought is why overcomplicate it when the mechanical pump works fine and is cheap. If you are dead set of replacing it take a look at the Stanadyne FM series filters. You can get one with a pump module built right in. Then you could use your mechanical pump mount for an oil return if you go turbo one day. I love my FM filters and they even offer one with a manual hand primer pump if you decide to go non-electric. This will save your batts when changing and bleeding filters.