Engine/Transmission (1998.5 - 2002) Dissected Lift - Lots of Pictures

[RBallard]

Ever since I heard all of the commotion of lift pumps failing, I have been curious of what is in the lift pump and why are they failing. Two weeks ago I was thinking how good I was doing, 57,000 miles on the original lift pump. Well last week it took a dump, pressure was sporadic between 9psi and 5 psi. I have since taken the failed pump apart and taking pictures hopefully to learn something. I plan to test the regulator spring, which shows some wear, but beyond that I am baffled. The commutator and brushes are the only things that show much wear. Bear with me on the website, too many hits and geocities shuts it down for an hour or so.



Here is the website, website



Bob

 

[DKupfrian]

Any pictures you can add here while GeoCities recovers?

 

[Alan Reagan]

I posted a while back about a "road" fix for loss of pressure on these. What I found was, if you turn the big rubber plate gasket over, the pressure will usually come back steady. My theory is that the gasket gets compressed, allowing the cylinder that holds the vanes to move up and down and therefore lose pressure. I've performed this little trick and only had one that it didn't work with. That one was completely shot (electrical). While you have it apart, be sure to clean the filter screens. One more thing..... when you put the cover plate back on, don't overtorque the bolts or the vanes won't turn.

 

[RBallard]

This one is not going back together! It is in pieces, completely apart. (I was curious what was inside). I was surprised that the motor is submerged in diesel as well!

 

[RBallard]

I'll try posting some pictures.

 

[RBallard]

Pump housing top - Impeller removed

 

[RBallard]

Pump Housing Bottom - Bypass regulator shown

 

[Alan Reagan]

Good pictures. I did the same thing with the bad one I had.

 

[tgbol]

When I disected mine I found that the plastic insert in the rotor was broken. The motor ran but the rotor did not turn.

 

[MCummings]

Originally posted by tgbol

When I disected mine I found that the plastic insert in the rotor was broken. The motor ran but the rotor did not turn.

I have had 4 pumps on my truck, and handled 3 more all with the exact same problem. Motor runs strong, but the plastic insert is worn out. What was odd about my truck is, that even though the insert was worn out, I stil lost PSI gradually, instead all of a sudden like I would have expected with this type of fialure.

 

[DKupfrian]

Am I looking at these picture right? In the first picture I see the housing and what looks like the hub of an impeller above it? But the impeller does not have any blades on it?



And thanks for the pictures. I have a much better understanding of how these work now.

 

[tgbol]

In the picture the blades are to the right of rotor. There is no spring to push them out, only centrifical force

 

[RBallard]

Here it is with the top removed

 

[RBallard]

A better shot of the impeller

 

[Ncostello]

For future reference, you should really consider placing all the pics on your website location in a TDR Readers Rigs photo album... perhaps titled "Lift Pump Parts" or something to that nature. But I'd start it with the words "lift pump" something so it can easily be found on down the road. Good photos.