The Hummer I uses an ABS modulator, pump made by WABCO. For you Hummer mechanics, I have a few questions for you regarding that modulator:

Is the modulator also used on the Hummer 2 and/or 3, or only on the I ?

Most importantly, regarding the modulator shuttle valve seals (two very small seals, about 1/4" in diameter---not true " O-rings," but actual seals), where is a source supplier for those two seals, only the seals; nothing else, where can I buy them? Jack

 

As far as I know the Wabco modulator shared with RR is only in the H1. None of my trucks are ABS trucks so I haven't had to source those. Check with hummech here on the forum. I know he rebuilds those units semi-regularly.