i had a +ve/-ve leak with rev’s this is how it went with them:
1) Let all the air from your -ve,, bike upside down
2) pump your spring rate psi into the +ve
3) turn the bike upside down again and pump the -ve until the fork start suck down, no more than a mm or 2.
if the +ve/-ve seal has gone you wont be able to equalise the fork, you’ll also see the psi in pump very, i could actually see the psi in the -ve decrease with the pump left on the valve.
If it’s sucking down on a ride i would suggest that you have more -ve than +ve and possibly not a seal leak, this is something else i suffered with.
Step 3 was advice that came via mtbr and a guy who was given some tips by PUSH’d., I actually end up with just over 5psi more in the –ve and the forks feeling plush.
btw i have 150mm rev’s , i hated them until i actual took the time to read how to set them up properly, there now way better an capable than a set of Van36’s I had, awesome hard hitting forks.