Toilet flush pipe problems

[AP77]

Hi,

Our toilet flush pipe is leaking. The cistern is built in behind the toilet and access is limited. The rubber push fit bung was not fitting completely snuggly so I have been trying to refit the flush pipe.

After many attempts, I just cannot not seem to make the compression joint on the cistern and/or the rubber bung completely water tight.

It appears that the alignment of the toilet and the cistern is slight out which means when I tighten the compression joint the rubber bungs comes out slightly. If I hold the rubber bung in place while tightening the compression joint it seems like the compression nut is not completely in line with the tail pipe from the cistern and does not do up sufficiently.

I am using a one piece 1.5 inch (38mm)diameter pipe which is about 32. I can see there are some flexible pipes available on the market but most seem to be 32mm or 40mm. Also these flexible pipes do not get very good reviews.

I have run out of ideas.

Can anyone please give me any suggestions as to the best way to solve my problems?

Many thanks.

 

[alan333]

I'm not a plumber but had the same problem, cured by silicon around the silicon washer and pipe and allowed to cure.

 

[terryplumb]

Remove the flush pipe seal ( the one going into back of pan ) connect flush pipe to cistern making sure the rubber seal is correct way up ( most are cone shaped ,but not all are ). Then mark with a pencil ,on the flush pipe ,at the point it is level with the back outer surface of the pan.this is to establish how much of the flush pipe is entering the inlet hole in the pan. It needs to be approx 1 inch ( 25 mm) in order to make a good joint. The seal should be rubber ,if its nylon they are not very good. If the seal is old or deformed buy a new one. If the pipe does not enter 1 inch ,its been cut too short .replace it. If the pipe is slightly mis aligned ,from left to right between cistern and pan it will usually seal anyway. If its at a severe angle you will need to move the cistern.

 

[AP77]

Many thanks for taking the time to reply.

I will keep the silicone option as my last resort.

I have tried many times to connect the flush pipe to the cistern with different rubber seals. If I use as cone shaped one, which way round should this go?

I have also tried pushing the pipe into the pan first with the bung in place, then connecting the flush pipe into the cistern.

I will check to see how much of the pipe goes into the cistern tail pipe. I think it is a little over 1 inch.

Tomorrow I will buy another flush pipe and cut it to size.

I have been looking for a flexible pipe, approx 30cm long when fully compressed as I think this may work but have struggled to find one suitable.

Thanks again, any suggestions much appreciated.......I have lost count how many times I have tried to make a good seal over the last 2 days!

 

[AP77]

Sorry one more question.

Why are flush pipes 38mm diameter? I hoped to make a new 90 degree flush pipe by joining to straight pieces of flush pipe using a 90 degree compression elbow but could only find 32mm and 40mm compression elbows.

 

[terryplumb]

Unfortunately there are many imported cisterns / valves etc coming into the UK that are of questionable quality. As we don't know exactly what you have ,and you seem to be using " various seals" to make the compression joint ,it may be a good idea if you can post pics of the flush cone ( you called it a bung ) and the seals for the cistern end. You need to examine the end of the thread on the cistern outlet .most are slightly tapered inside so the seal you use should be tapered to suit ,hence you only need to tighten the nut by hand to get a good seal. At the flush cone end ,the pipe should be a very tight fit into flush cone and likewise flush cone very tight Into the pan.

 

[AP77]

Hi Terryplumb, many thanks for your guidance with this.

I persevered this morning and I finally seem to have achieved a good seal on the cistern tail pipe. It was making sure the cistern end was correctly tightened before pushing the flush cone fully home that solved my problem.....so far at least!

I find these forums so helpful with DIY challenges, it is really great that help is never far away. Very much appreciated.