Why Is My Thetford Aqua-Magic Style Plus Toilet Leaking After Replacing the Seals?

Updated 10/20/2026 | Published 10/17/2026

Question:

I have a thetford aqua magic style plus toilet I just replaced the seals and when I took off the porcelain top I dont remember how many plastic spacers are needed before putting the porcelain back on? 1? 2? And how tight do I need to tighten down the bolts I notice the seal is letting water go through, than I loosen the bolts and it seems to seal What should I do?

asked by: Randy S

Expert Reply:

Hey Randy, thanks for reaching out. Based on what you're describing, I think you're overtightening the bolts and putting too much pressure on the new seal. The fact that the toilet holds water better when you loosen them is a pretty good indication that something is getting compressed or pulled out of alignment. The porcelain bowl needs to sit evenly on the base, and those plastic spacers help maintain the proper spacing. I wouldn't add or remove spacers just to stop the leak, though.

I'd loosen the bolts, check that the new seal is seated correctly and that the bowl is sitting level, then tighten the bolts evenly, a little at a time, just until everything is snug. Be careful not to over-tighten.

If the seal still leaks, I'd inspect the seal track and flush-ball alignment before tightening anything further.

Are you talking about the plastic spacers between the porcelain bowl and the base, or the spacers underneath the toilet at the floor flange?

expert reply by: Jesse M

Randy S.

10/19/2026

Thank you Jesse I loosened the bolts and realigned the porcelian bowl at it worked Thank you RandyS

Jesse M.

10/19/2026

@RandyS Awesome! Glad to hear you got it sorted out. Don't hesitate to reach out if you ever need anything else!

Jon

10/20/2026

Hello. I started my first RV renovation in around 1996. Since then I've learned a lot about toilets plumbing systems electrical AC units refrigerators engine chassis And so on. Around 2005 I started RV service and repair in the San Francisco Bay area. You can imagine how many toilets I've rebuilt and replaced in that time. Your problem is common amongst RV owners who try to rebuild their toilets. And the wisdom I have is from that experience that I don't rebuild toilets. You may be successful and you may not. And looking at aquamagics I've never liked the poorest quality materials they've used. If I were able to actually do the toilet rebuild for you I might be able to find a reason that you're having this problem. If you have found the problem and it's working since this email I'd be very happy for you. Maybe you could return the parts and the same company would be willing to sell you a completely new dometic. Which is now the one I use but unfortunately I have to constantly grease the pedal mechanism because it gets very rough and That's why all the toilets under $600 are gonna need to be replaced often. I like e trailer and buy lots of Parts from them so I highly recommend this company. And that's the only reason I responded.