Mechanical fuel pump replacement

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Matt S

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I'm in the process of changing a leaking mechanical fuel pump. I have the pump off but I can't seem to get the rod to move back into the engine. It appears to be pinned to the outer mounting surface. I've tried rotating the engine but I can't get it to move.

Am I missing something obvious?
 

GREENMV

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Use a long pair of needle nose to grab the rod and push up. You have more room over the frame to do this.
 

cucvrus

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Easy as this. Take the 2 M6 bolts from the pushrod cover plate. You want to change that gasket anyway while you are in there. Remove the push rod. Lather the upper end with wheel bearing grease and push that greased end into the block hole. It will stay there now so you can install the cover plate and loosely install the M6 bolts. Now put the fuel pump lever in the hole put the rear bolt in first. Now attach the feed line let it have some wiggle room to get the flare nut started. install the front bolt. Leaving everything loose until you get them all started. A little tip. I can change one in under an hour from the top side. I remove the right alternator and the brackets. I also remove the short bolt with the clamp that secures the hard fuel line. After everything is on the pump and all bolts are aligned and hand started begin tightening the 2 main pump bolts the flare nut and finally the 2 bottom M6 bolts from below. While down there attach the main feed line and tighten the clamp securely. Before you begin do a close side by side comparison to the fuel pump. Make sure the pump lever has tension immediately when it is compressed. The 6.2 diesel pump had NO free play. The stroke is short and direct. Also look at the shape of the lever. It is a short lever. The pumps should be identical. Good Luck. I hope that helps. It is fairly easy. Start everything by hand and be patient.
 

Matt S

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I tried the needle nose but that didn't get the rod to move. I see the two bolts for the cover plate. I'll try that tonight.

Thanks for the advice. I'll let you know how it goes.
 

sneekyeye

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It is pretty easy once you figure it out. It's just kind of a pain. Like was said, you'll never get the push rod to stay back up if you don't take the second plate off and put a gob of grease on the end of the push rod. Hold it up in there while you rotate the engine using the crank bolt until it is as far back in as it will go. Then just slap it all back together. I've never had a rod fall back down once you put a goodly amount of grease on the end and jam it in.
 

pigpen60

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I watched the kid at the junkyard fight with mine for about an hour! His dad came over and showed him the error of his ways, He just couldnt take it anymore! And before you say I'm a ___ I've known this kid since he was a wee one. He earned some abuse! Used to chase me around the yard after he played in the drain pan. I'd yell at his dad to "control your animal I only have two pairs of pants"!
 

Matt S

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I eventually got the pump on. I'm saying eventually because I'm still tweaking the fuel output line so that it doesn't leak. That thing is on there tight! I had to take the plate off and the rod slid right out. I'm not sure how it got jammed where it was. I rotated the engine to pull the rod back in and added some grease to the end. It never moved on me. I ended up putting the pump on three times. First time I forgot the gasket and the second was to help get the output to thread into the pump. Truck seems to have more power than before. Thanks for all the help.
 

BradIXXI

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I eventually got the pump on. I'm saying eventually because I'm still tweaking the fuel output line so that it doesn't leak. That thing is on there tight! I had to take the plate off and the rod slid right out. I'm not sure how it got jammed where it was. I rotated the engine to pull the rod back in and added some grease to the end. It never moved on me. I ended up putting the pump on three times. First time I forgot the gasket and the second was to help get the output to thread into the pump. Truck seems to have more power than before. Thanks for all the help.
Did you install it from the top like was suggested above, or from below? About to start the replacement myself....
 

Matt S

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Honestly both top and bottom. I think if I'd done it a few times I could do it from the top. I'm not sure I can count my 3 tries as more than one...

If I wasn't trying to rush, it was pretty easy. I just ran into not getting the rod out and then forgetting the gasket. It's not given me any issues since the successful install.
 

cucvrus

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I do the entire pump job from the top after I remove the left alternator. I remove the push rod cover and replace that gasket. Some wheel bearing grease on the push rod and it stays up in place. Make sure you get the right pump the first time. I do go under at the last moment and tighten the 2 M6 bolts that hold the cover plate to the block. Makes the whole job easier and doing it right the first time is the best. Quick tip. Get all the bolts started before you tighten any of them. Good Luck.
 

BradIXXI

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I do the entire pump job from the top after I remove the left alternator. I remove the push rod cover and replace that gasket. Some wheel bearing grease on the push rod and it stays up in place. Make sure you get the right pump the first time. I do go under at the last moment and tighten the 2 M6 bolts that hold the cover plate to the block. Makes the whole job easier and doing it right the first time is the best. Quick tip. Get all the bolts started before you tighten any of them. Good Luck.
My alternator is on the other side of the engine bay. There is a AC compressor above my fuel supply pump.
 

w5ood

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Houston / Texas
I'm in the process of changing a leaking mechanical fuel pump. I have the pump off but I can't seem to get the rod to move back into the engine. It appears to be pinned to the outer mounting surface. I've tried rotating the engine but I can't get it to move.

Am I missing something obvious?
I always remove that cover plate and buy the seal that goes with it. Then I remove rod and make sure I mark the end that rides on the cam. Clean off the old gasket and install new gasket and mounting plate, Then I put grease on the rod not a ton but enough to hold it up in the engine while I get the pump gasket on and pump. Works well for me. Also start the pump bolts by had and leave them relatively loose while you screw the steel fuel line into the bottom of the pump, it gives you some wiggle room. Then tighten up pump mounting bolts once the steel line is threaded in by hand some.
 

kdaniels

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Just replaced mine today. Wish I had seen this thread sooner. Two questions, I took off the mounting plate to hold the push rod out of the way. The grease trick would have been nice To know. I saw some one use a Bent hacksaw blade to hold it up.

1st question, is there anyway this push rod can go back up and NOT be in the hole?

2nd question, I used a gasket making material on the backing plate instead of a paper type. Is the clearance on this item critical ?

It was late so I haven’t attempted a bleed and restart yet. Just second guessing my work.

Semper Fi !
keith
 

cucvrus

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The rod can only go in the hole. If you push it up with grease on it and it stays you got it in the hole. I use Permatex The Right Stuff. There is nothing in the fuel pump area that is critical tolerance. It is just an old diaphragm pump. And as long as the area is clean and not gouged the sealer will seal. Thank you for sharing. I was assuming you were working on a CUCV. This is the CUCV forum. No problem I have replaced 2 engines in HMMWV also. Same basic set up. I put 2 HMMWV 6.2 engine long blocks in CUCV's also. Good Luck. Be Safe and Take Care.
 

kdaniels

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The rod can only go in the hole. If you push it up with grease on it and it stays you got it in the hole. I use Permatex The Right Stuff. There is nothing in the fuel pump area that is critical tolerance. It is just an old diaphragm pump. And as long as the area is clean and not gouged the sealer will seal. Thank you for sharing. I was assuming you were working on a CUCV. This is the CUCV forum. No problem I have replaced 2 engines in HMMWV also. Same basic set up. I put 2 HMMWV 6.2 engine long blocks in CUCV's also. Good Luck. Be Safe and Take Care.
I am working on a M1009....
 
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