The bus has been giving very intermittent hard start problems lately. Would start fine cold, then would go thru a several day period of hard start, both cold and warm. Then the problem would go away for a few weeks, then come back. After Friday mornings bout, I decided to start by replacing the lift pump and the filter. The filter had maybe 5K miles on it, the lift pump was a corroded mass of grunge, no telling when it was changed last.
Anyway, the push rod fell out against the plate when I removed the old pump. Couldnt get it back up there no how, so I removed the plate and the rod fell out. The problem? The rod was broken. I have the two spare 6.2 on stands in the back of the shop. (a J and a C) I pulled the rod out of the C code motor(from '87 'burb 4X4), and fortunatly removing the broken piece from the block wasnt to difficult.
So now the question(s) first, what would cause the rod to break? It broke approximatly 1 3/8" from the top (cam side) end. I say approximatly, because, the rod I pulled from the C code motor is 1/16" shorter overall then the one that was broken. Did the C code motor have a shorter stroke on the lift pump rod because it required less fuel from the lift pump? Or did the other break because it was too long? Or am I really getting way to anal about the 1/16" difference on the length? Should I invest in a new push rod? Or just use the one from the C code? Anybody have a spec for the push rods? Any thoughts appreciated.
Oh, BTW, J code (broken) length was 5 1/4", C is 5 3/16".

never heard of a fuel pump push rod breaking. and i didn't know they were different between the two blocks. maybe its a year thing try ordering a new one and see how many choices they have. if you have a problem with the rod staying up in the passage while installing pump coat it with some really thick grease and stick it in the freezer for a half hour.

put a 6.5 electric lift pump on, I did and works great..a smallblock chevy block off plate where the stock lift pump goes. bolts right up

Update.......I went to the local Chevy dealer Monday morning, they said there is only one part number for the pushrod, one size fits all. Ordered one for $17.37 + tax(actually cheaper than what the local flaps wanted for the aftermarket part)and got here overnight. Put it in this morning, pressurized the fuel system til fuel got to the filter bleeder. Started tapping the key, no fuel. After verifying that there was no fuel coming from the pump, pulled it off again. To find the brand new pushrod snapped in half again. One thing is certain, something's wrong, me or the cam? I checked it for size against the other one that broke, same length.
I have a Walbro marine diesel electric pump.(Model 6095, aka 6805) It's a bit large, rated for 45GPH at 7psi. Think I'll give it a go. There's enuf space right in front of the fuel tank to mount a Racor style fuel/water separator filter there. Then I'll mount the pump itself about mid way up the frame rail unless anyone here thinks thats not a good idea.
I was trying to keep it simple and not get into any wiring hassles. The simple hook up of pos and neg to the pump is easy enough, wiring an inertia switch, or oil pressure switch may challenge my brain a bit. Anyone got a diagram handy?

My pump rod broke when I incorrectly installed the mechanical fuel pump. :o:

i have changed 20 fuel pumps and yes they are a pain to change but never saw a broken pushrod.