Siphon for very old toilet cistern

[perdrix]

I have an old (Shanks) cistern with an bottom exit hole that is 2½" in diameter and the flush pipe is about 1 5/8" diameter.

The syphon needs replacing, but I cannot (so far) find anything that will fit.

Please can someone point me to a supplier that will be able help? Or am I going to have to replace the cistern and down pipe?

Thanks
Dave

 

[rpm]

I have an old (Shanks) cistern with an bottom exit hole that is 2½" in diameter and the flush pipe is about 1 5/8" diameter.

The syphon needs replacing, but I cannot (so far) find anything that will fit.

Please can someone point me to a supplier that will be able help? Or am I going to have to replace the cistern and down pipe?

Thanks
Dave

Hi Dave and welcome to the forum, best thing to do is to remove the siphon and look in a plumbers merchants for a repair kit as more often than not the plastic membrane at the bottom has split

 

[perdrix]

Hi Dave and welcome to the forum, best thing to do is to remove the siphon and look in a plumbers merchants for a repair kit as more often than not the plastic membrane at the bottom has split

Thank you but I wish it were that simple! The design is much older - it uses a disc that rides up and down on a shaft which I replaced years back with a new disc cut from the lid of a plastic paint can.

The problem with siphon unit is twofold, the hole the shaft goes through at the top of the bell has worn and the shaft binds as a result, and the threads for the nut at the bottom (that holds the flat disc with holes in onto which the moving disc drops to make a seal) have failed. Not totally beyond repair/re-build with the facilities of a machine shop I would guess, but I don't have that sort of stuff.

So it really is a case of replacing the siphon unit (or the entire cistern which will be costly to match up).

Dave

 

[perdrix]

Hi Dave and welcome to the forum, best thing to do is to remove the siphon and look in a plumbers merchants for a repair kit as more often than not the plastic membrane at the bottom has split

Unfortunately this isn't a simple case of fitting a new diaphragm, this one uses a disc that slides up and down the shaft inside the syphon.

The hole at the top through which the shaft slides up and down has worn over the years and now the shaft catches when its is flushed. The threads for the nut at the bottom of the shaft are full of lime-scale. The nut has partly come off but now won't come any further. Not beyond repair by a fully equipped machine shop, but unfortunately I don't have one.

 

[jtsplumbing]

B & Q do a syphon with adaptor rings :

 

[kirkgas]

When Tamz sees this post he will offer you one from his garage that he has had in there since 1977

 

[kirkgas]

Change the siphon and flush pipe and make a bigger washer for the new smaller syphon, it was easier for us years ago to use a bit of sheet lead to cut two washers but not sure if you can get any lead, maybe try the scrappies and buy a bit from him

 

[shaky]

Change the siphon and flush pipe and make a bigger washer for the new smaller syphon, it was easier for us years ago to use a bit of sheet lead to cut two washers but not sure if you can get any lead, maybe try the scrappies and buy a bit from him

Now you showing your age!!

 

[perdrix]

B & Q do a syphon with adaptor rings :

I went there on your recommendation and found a Fluidmaster push button dual flush unit that said it fitted both 1.5" and 2" outlets.

While the hole in the cistern base is somewhat larger than normal for a 2" unit, it did fit, so I'm a happy bunny, and so is the CFO as it was a whole lot cheaper than a matching cistern 🙂.

Thanks
Dave