waste outlet for bath

[tdog]

Help!
Have been trying to fix a leaky bath waste outlet. Replaced the old one with a brand new unit from Plumb Centre - but it still leaks!
When fitting the new unit, I bedded it in with plumbers mait between the underside of the lip on the plug hole section where it fits into the hole in the bath, and also used the white ptfe tape on the threaded lower section of the unit where the big plastic nut screws on underneath the bath. It is the type of unit that has the overflow connected to the waste outlet by a plastic tube which in turn connects to a loop which goes around the waste outflow pipe on the underside of the bath This loop fits between the plastic nut mentioned above and the underside of the bath, with large plastic washers at the top and bottom of it.
The leak only occurs when the bath is emptying, not when full. As far as I can see the leak seems to be coming from the points (top and bottom) where the large plastic washers meet with the loop on the overflow hose. Everything is screwed up tight.
Any ideas why this should be? Am I missing out using some other sort of sealing stuff? I think it must be someting fairly simple that I am missing as I can't believe that what I thought would be a fairly straighforward job would cause so much bother to get sorted.
Cheers
S

 

[Goodman]

Please make sure you have fitted the right washers for the top(inside bath) and the bottom, supplied with the pack, you do not need to use any additional stuff , i prefer the screwey one, much easier.

 

[tdog]

Thanks for this, Goodman.
This is the thing that puzzles me (being a novice) - there were no washers of the type you say in the pack, only the big plastic washers I mentioned that fit top and bottom of the overflow loop, which are hard plastic and don't strike me as being ideal for making a watertight seal. I had kind of assumed that there would be some sort of durable rubber type sealing washers with the kit. This is why I had to use the plumbers mait to bed the unit into the bath.
I had originally went to the Plumb Centre to get new washers etc only but the guy recommended a complete new unit.
This whole thing looks unpromising since now that I think about it, the waste unit I took out (some as the replacement) was liberally coated all over it with plumbers mait or something similar, which might suggest that the unit that was in place in the first place never really managed to achieve a proper watertight seal by itself.
What is the screwey one you mention - I like the description of this as "much easier".
S

 

[bster]

the waste that you have fitted are a pain in the ar*e !!, i usually 'plumbers mait' the chrome\brass bit to the bath (no washers) then silicon a washer to the underside of bath then silicone the overflow bit then use another washer (silicone between washer and overflow bit) then the nut.

it is a sh*ie design though IMHO.

 

[ChrisR]

Like a lot of plumbing fittings, the design and manufacture are awful.

Plumbers mait is also one of my pet hates. Water, age and movement all affect it badly.
Others who have done far more than me may disagree, but the only way I'm happy to use some of these appalling devices is to put silicone sealant everywhere!

 

[Nige F]

I`m with Chris........the only use for plumbers mait is "initiation" for apprentices........watch out b.ster

 

[tdog]

Ok folks thanks for all of this, which is useful information.
From what you say I can either stick with the unit I've got and plaster it with silicone - in which case presumably this isn't the silicone sealing stuff you get out of b&q for sealing round the bath (or is it? Duh.), or to get the different "screwey" unit - in which case what is this exactly?
Cheers guys.
S

 

[tomovhalifax]

just use normal silicone on all washers, thats what we do