Repairing the Master Mark IV Ballcock

My toilet began making a loud vibration after flushing. It was coming from the fill valve in the tank, which goes by the very masculine term "ballcock". It was labeled "1B1 Master Mark IV" and "Coast Foundry and Mfg." Setting out to repair it, I was easily able to unscrew the float and disconnect the tank fill tube. The white cover pulls up and off, but I could not figure out how to disassemble the valve. I pried and rotated, but nothing moved. I removed the whole unit with stem from the base of the tank, but that is not necessary.

In this photo, see the little red tab. The trick is to pull this tab straight up with pliers. Then the top can be rotated to the left and removed. That's it! It's embarassingly simple. Now you know the secret, without having to find out the hard way.

Replacement parts are available online. In my case all it needed was a good cleaning. Good luck to you.

This page was last updated on 20 Feb 2010.

Written by Charles R. Landau. Copyright (c) 2008, 2010. All rights reserved.

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