PVC tool works just fine, I've always made my own seal installer.

Can you tell if seal is leaking on the OD or at the cam shaft? My last TB service I used aftermarket seals and they worked fine. I just set seal flush with cap, but you may have a groove worn in shaft or a nick from getting the seal out.

I have used 400-600 grit emery to smooth seal surfaces.

92 Montero LS 3.0L V6 Auto, Stock, Original owner, 185,800K miles