NissanDiesel Forums

So I got a new (rebuilt) alternator from Orielly today ($130). Got the old pump (which was working fine) bolted on and put the whole thing in the truck and fired her up.

No spinny spinny. I took it back out of the truck, thank god for air tools, and took a closer look. Its the vacuum pump rotor. When the two halves of the assembly are pushed together it binds the rotor. What the hell? Even when i just hold the pieces together it sticks. I put it together exactly like the picture in the FSM. Any ideas?????????

If at any point the pieces fell out of the pump (and it's easy to do), then you have the rotor in backward -- probably. It's got a counterbore on one end only, IIRC.

cseger1 wrote:SNIP- When the two halves of the assembly are pushed together it binds the rotor. What the hell? Even when i just hold the pieces together it sticks. I put it together exactly like the picture in the FSM. Any ideas?????????

Note closely, the radiused end of the rotor tip faces the "run" and the vacuum pump housing orientation to the alternator.

Vac pump oil supply

Thanks for the tip. Before I posted I thought I tried it both ways, but I must have been wrong. Anyway, I got the whole thing put back togerther and in the truck. I am charging again Woooohooooooooo!!!. That only leaves a million other things to fix.

Philip, I'll have the measurements you seek from the stock alternator this afternoon.