I'm pressure testing my IM/TB, and sure thing, the TB is leaking from the butterfly shaft ends. There's an o-ring and bearing at work here. I've replaced the o-ring and still leaks. : ( Any one else have this issue or a remedy? I called MP today, and they said its normal, which I can understand, but I'm still questioning it because they didn't know what o-ring size I needed..

Apparently I need to source a better bearing. Ill try that and see if it helps.

Keep us posted on the progress, this will be good information down the road for MP60mmTB users.

I will be fixing mine this weekend. If i remember i will do a small how to.

I had this problem on my Jeep 60mm throttle body. I dont know about the MP throttle body's but on the jeep tb there is a little slit on the edge where the o-ring goes around the tps. that little slit causes it to leak, so what i did was JB Weld the gap.

i replaced the bearings and added neoprene washers. i had to space the bearing out slighly, but now it holds air, so much that it busted my IM gasket lol. 40 psi too much? lol