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Forum Home > General discussion about the Austin 8 > Drain Tap to Radiator

Posts: 26

The Drain tap to the radiator has always been a bit of a loose fit. I drain the water out every autumn and then in the spring, refit the drain tap, bind the threaded part in hemp and plumber's paste for refitting. Without such it is a very loose fit. In fact it does not fit at all, you could push it in and out if no hemp was bound around.

This is not very satisfactory. I would try and get a new drain tap but the thread does not look bad.In any case what size is it? Standard sizing seems to be 1/4" BSP which gives a measured dia. of about 12mm. This is what the existing tap thread dia is. The next BSP size up is 3/8" which is too large a dia. for the rad.

Anyone have any definitive info on sizes? The workshop manual and other publications give no hint.

April 18, 2017 at 2:55 PM Flag Quote & Reply

Hermann Egges
Site Owner
Posts: 15

The tap has a standard size 1/4" BSP. I will check where I have ordered my taps. Ones fitted they will do, but they are indeed a bit loose fit.

May 2, 2017 at 4:52 AM Flag Quote & Reply

Posts: 26

Dank U Hermann!

in between times I have purchased a butterfly type drain tap meant for a Jaguar but with a 1/4 " BSP thread size - just to see if it fits, ...and it does!! The fit is quite secure and I have not used any plumbers tape on the thread. If it does weep a littel in practice, then I can do this.

May 4, 2017 at 4:50 AM Flag Quote & Reply

Andy Fisk
Posts: 4

I've found that the problem isn't generally with the drain tap, but with the Water Inlet Elbow itself where it attaches. The Elbow itself appears to be made of Aluminium and probably suffers due to electrolytic action. Might be worth seeing whether this has happened on your Elbow and if so contacting a specialist for repair.

May 8, 2017 at 2:05 PM Flag Quote & Reply

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