I replaced the fill valve on a toilet and the connection stem on the replacement sticks out much farther than the original. The toilet was installed 12 years ago using a solid supply line, so I need to replace that to reconnect it. The nut holding the supply line to the shutoff valve won't budge. There's probably some minerals in there, but I suspect the original installer used some serious torque to ensure it wouldn't leak.

The metal shutoff valve connects to a PVC feed pipe. I can't figure out a way to secure the valve and leverage against that to loosen the nut. I'm worried about damaging the PVC connection to the valve.

Any suggestions for how to solidly grab the valve in a way that I can put torque on the nut in relation to the valve, without stressing the valve connection to the PVC pipe?

I considered heating the nut with a torch to expand it, but I'm worried about plastic internal parts. I also couldn't figure out a way to get Liquid Wrench into the threads, so I assume brute force is the solution. If there's a better way, ideas are welcome.

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2 Answers 2


I usually use an adjustable spanner to hold the body of the valve when tightening, or loosening, any valve.

This saves so much hassle as the supply pipe does not get kinked or its joint disturbed.

A good tip from the OP in the comments is to remove the knob as this permits a better purchase.

I use the type of adjustable spanner with flat parallel jaws adjusted by a rotating screw: monkey wrench

Borrowed image from https://www.ebay.co.uk/itm/142846365301

  • That's typically what I do, also. In this case, the knob is in the way, so the wrench is at enough of an angle that it doesn't buy me much. Maybe I'll try removing the knob.
    – fixer1234
    Sep 15, 2019 at 4:07
  • Good luck then, did not meant to preach to the converted, but will leave the answer for others. Cheers.
    – Solar Mike
    Sep 15, 2019 at 4:09
  • OK. I was already doing essentially that, but your answer made me realize the problem was the knob. I removed that and then it worked (I grabbed the valve with big vise-grips). So close enough. :-)
    – fixer1234
    Sep 15, 2019 at 4:20
  • 1
    @fixer1234 added your tip to my answer. Hope the rest of the day goes well :)
    – Solar Mike
    Sep 15, 2019 at 4:25
  • Keep a close eye on that plastic nut at the bottom of the toilet/top of the supply line. They're notorious for cracking. (Notorious enough that I'd replace the entire supply line, but that's just me.) Sep 15, 2019 at 20:05

Couldn't you just

  1. Shut off the supply valve (verify by flushing toilet)

  2. Hacksaw the solid supply line midway between supply valve and toilet

  3. Using an exact open or closed box wrench, remove the nut that retains the solid fill line

  4. Remove the solid fill line

  5. Find a threaded connector flexible fill line and connect it between toilet and fill valve.

  • That's essentially my plan. I can get a wrench solidly on the nut without needing to cut the supply line. The trouble is that I have nothing to torque against to loosen it.
    – fixer1234
    Sep 15, 2019 at 3:59
  • Usually I just hold the supply line and twist with the wrench. Usually isn't stuck so badly..
    – gbronner
    Sep 16, 2019 at 13:48

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