Fuel pump failure

[Yauchout]

Just curious if anybody has any ideas why the pump failed? The pump was rebuilt with new plungers and rollers around 130,000 mi ago Give or take I had no warnings leading up to the pump failure. The truck ran fine. No engine lights was just in the left lane doing about 70 and it was like somebody shut the key off that goes to the side of the interstate. Have fuel pouring out from underneath the truck. Roll the hood over and the pump head that is separated from the pump body. All four bolts sheared at the top of the pump body. The only thing I can figure from my own thoughts is the pump head bolts should have been replaced. The truck has 1.2 million mi on it. The pump's been rebuilt three times and those are the original bolts. What you're seeing in the top of the right hand roller is some dirt and grease from trying to get it out. Not parts of the plunger, although the front plunger did shear I don't know if it broke previous to the head separating or if the head separating caused it to break but it is a clean break

[Rawze]

were the bolts over-tightened during one of those rebuilds ??... did someone install them without a torque wrench once? and only used a speed-gun?.

That, or like you said .. maybe they only have a service life of one or two uses max before risk of failing.

[SquareOne]

What did the head gasket look like? Did it appear as it the head had been dancing around? Seems like there would have been some type of warning. Possibly fuel or oil seeping from the gasket between the head and body. Hard to tell as there's a good bit of dirt stuck to either a previous leak or a current continuous one.

As far as the bolts are concerned, when I do the internals, I replace the bolts as well (not part of the Cummins procedure, but a cheap peace of mind). Did you do the internals yourself? If so, were they torqued properly? Over-torquing will stretch them eventually causing failure I would assume.

Aside from the bolts, what does the inside of the pump itself look like? Is the roller on the right still moveable? Is it jammed in the bore?

...Rawze, you type too damn fast and beat me to it lol... thought I had the jump for once lol...

[Yauchout]

(Yesterday )SquareOne Wrote:  What did the head gasket look like? Did it appear as it the head had been dancing around? Seems like there would have been some type of warning. Possibly fuel or oil seeping from the gasket between the head and body. Hard to tell as there's a good bit of dirt stuck to either a previous leak or a current continuous one.

As far as the bolts are concerned, when I do the internals, I replace the bolts as well (not part of the Cummins procedure, but a cheap peace of mind). Did you do the internals yourself? If so, were they torqued properly? Over-torquing will stretch them eventually causing failure I would assume.

Aside from the bolts, what does the inside of the pump itself look like? Is the roller on the right still moveable? Is it jammed in the bore?

...Rawze, you type too damn fast and beat me to it lol... thought I had the jump for once lol...

The plunger to the right moves to the top of the bore but I couldn't quite get it out of the bore but my hands were pretty greasy. The bolts have always been torqued I have always done the rebuild.. it may have been leaking some oil but it is hard to tell as the motor has a slow leak above it from the oil filler neck.

[Yauchout]

Gasket looks ok to me but [/php]