New Tubeless Setup but Leaks from the Valve Stem Base

Hey, all. I‘m converting my ‘21 Trek Checkpoint ALR 5 gravel bike to tubeless tires. I’m using [Bontrager’s 700C x 17.5 mm rim strips](https://www.trekbikes.com/us/en_US/equipment/cycling-components/bike-rims-accessories/bike-rim-strips-tape/bontrager-tlr-rim-strip/p/31426/) and their recommended [55 mm rectangular base valve stems](https://www.trekbikes.com/us/en_US/equipment/cycling-components/bike-tubes-tubeless-bike-tire-accessories/bike-valves-accessories/bontrager-rectangular-base-tlr-valve-stem/p/13521/). The tires are [Panaracer GravelKing SS Plus+](https://www.panaracerusa.com/products/gravelkingss7b?variant=34487905878178) in 700C x 32 both front and rear.

I seated the tires with my AirShot and they don’t leak, even after several hours to reform the tires after being folded for who knows how long. They will deflate after several days, however.

Trouble is, I still get leaks from the base of the valve stems after deflating the AirShot, adding about 2 oz of Orange Seal regular formula, and inserting the Presta valve cores. I tightened the little nut as much as I feel comfortable with (finger tight then 1/2 to 1 full turn with pliers) but the front still leaks at around 30 psi. The back used to leak in the same manner but it’s settled down now to where I can’t hear it but will need to add air every week even with no weight on it.

I verified that the rim strip and rim hole are perfectly aligned. No cockeyed business going on there.

What should I try next? Should I ditch the rectangular base stems for tapered conicals? (I never liked the design of the rectangular bases.) I read somewhere about using contact or rubber cement between the valve base and rim strip. Good idea? I’d like to keep the rim strips if at all possible but I won’t be opposed to pulling them off and just using Gorilla tape or similar as a last resort. Or switching back to tried and true tubes.

Help me, oh wise Redditers. You’re my only hope.

by mtnscp