From the United States of America? - Checkout our specific plumbing forum for you:USA Plumbing Forum

Discuss Leaky tap connector to toilet cistern in the Plumbing Forum | Plumbing Advice area at

Test4Less - Sponsor
This official sponsor may provide discounts for members

I recently noticed a minor leak coming from the tap connector that feeds my toilet cistern fill valve. Once i'd isolated the water i unscrewed the connector and found that the fibre washer was completely disintegrated. I bought a pack of replacement 1/2" fibre washers from B&Q and reconnected the fill valve. Unfortunately the leak persists. Since then i've tried the following:

Replaced the valve - Fluidmaster, Brass Shank - same result
Used 2 washers! - It appears the leak is coming from the bottom of the connector - same result
Added PTFE to the brass shank - same result (I realise if the leak is coming through the bottom this wouldn't have any affect, but i'm now clutching at straws...)

Any advice would be appreciated here. I could be using the wrong washers maybe? I had to soak it before it fitted over the pipe end. Would that affect it's integrity?




Advent Win
The pipe doesn't look square with the connector. Loosen inlet valve nut, connect up cold water to inlet valve then tighten plastic nut on inlet valve.
Shower Power Booster | Official Sponsor
This official sponsor may provide discounts for members


Staff member
S. Mod
Gas Engineer
Wet / soak the fibre washer first then tighten eg leave it in a bowl for a couple of mins and then tighten down with a spanner

or you could use a hep rubber tap connector washer


If it's not almost perfectly square on to the spigot it won't seal. The simplest solution might be a rubber 1/2" seal. John guest do them for their tap connectors as a spare. You'll probably have to buy a pack of five or ten though.

Ideally the pipe should be bent or replaced so it does fit perfectly but the rubber washer would have a good chance of sealing that I reckon.

Another thing to note, overtightening anything is not good in most types of plumbing fittings but in this case, with fibre washers and brass nut on to brass shank, you'd be surprised how tight you sometimes need to get these to seal.

It can be hard to get these done up tight enough without the valve turning inside the toilet. Some brass shanks have flats cut in to them so you can hold it with a spanner but yours doesn't. I would grab that shank higher up with my pump pliers and use a piece of leather or a couple of layers of cloth under the plier jaws to not mar the thread though.

Reply to Leaky tap connector to toilet cistern in the Plumbing Forum | Plumbing Advice area at Plumbing questions, answers, tips and tricks.

Bulk Workwear - Workmans Clothing and Protective Gear
This official sponsor may provide discounts for members

Plumbing and Plumbers

Plumbing Workwear

Shower Power Booster

Plumbase Spares - Plumbing Supplies and Spare Parts

Water Underfloor Heating

CORGI Direct for Plumbers

The Wetroom Store

Plumbase Spares

New Posts Threads Members