oil pump tang wear?

[sdwarf36]

On the TD I'm building, the tang on the oil pump where it goes into the vacuum pump had significant wear-has anyone else seen this?

[burn_your_money]

I think every engine has that problem. Look inside the vacuum pump, it will be worn the same.

[rabbitman]

I think every engine has that problem. Look inside the vacuum pump, it will be worn the same.

Yup......I asked about this same thing a while back and everyone said it's normal.

[fatmobile]

The vane-style vacuum pumps wear better.
 the diaphram style have a bushing on the bottom and as the slot wears it ramps,..
 shoving the shaft in towards the vacuum pump.
 When the bushing wears enough; the shaft will be high enough and far enough away from the oil pump to let go of it.

[Rabbit on Roids]

you can wear a vacuum pimp that much? i think if it were worn that much something else in the engine would also let you know that its on its last legs.

[fatmobile]

Nope, my first Rabbit was free.
 Sat for 2 years with the fuel cap off and the window open.
 Knowing what I know now, I'm not sure how I got it started.
 Didn't have enough sense to change the timing belt before driving it to Arizona,..
 but it wasn't a broken timing belt that stopped me.
 The oil pump let loose of the vacuum pump slot.
 
Didn't know how to fix it then but now I'd remove the pin holding the gear to the vacuum pump shaft(not easy) and swap the bushing from inside the pump to the worn bushing showing on the bottom of the vacuum pump.

 That will push the gear back downward toward the oil pump.
As the gear wears into the bushing it gets farther from the oil pump.
 With the diaphram style vacuum pumps the oil pump shaft wears like a ramp,
 the more it wears the harder it pushes as they get farther apart.

That would have gotten me back on the road but a long term fix would probably require the slot in the vacuum pump to be tig welded and ground back into shape, removing the ramp.
,.. and a new oil pump (shaft).

 Vane style pumps don't have the brass bushing and don't ramp when they wear.