I've looked around and found conflicting information about the pump head reseal. The bosch dealer(helpful guy) said he didn't think it would work on the truck. I downloaded the VW instructions and bought the viton seal plus some extras. So has someone successfully done this "on the truck" or should I pull the pump? I'm selling this money pit soon and don't want to take it to a shop to be reassembled. And boy oh boy is it leaking, a blind clown could track this thing down in a rain storm.

 

Supposedly doable without removal. Just be REAL carful about how far back you pull the rotor.

 

I've done it twice on a TDI, no sweat.
1) Careful about how far you pull the head out.
2) Use a pick to make sure all the old o ring is out. (it will be brittle)
3) Don't pinch the new ring when you reassemble.

 

Pull the pump. It's so much easier that way. Too many things can go wrong trying to skip a few steps.

 

Take it from a guy who ruined his pump when I did not get the thrust washer, between the cam plate and piton head, back in place properly and it shattered and cracked the piton head. Then I had to buy another used pump and rebuild it.

Much easier to handle the springs, washers and other pieces that need to be lined up and held in place while it's nose down on the bench. I use an old crank pulley from a V8 to hold the IP when it's on the bench.