David Warr

15 August 2026 at 10:11 #83628

Hi My 3 Litre tourer has developed a leak on the water pump drain tap.

Ive tried moving the leaver back and forth to no avail.

do i need to replace it

Will the M45 drain tap fit ?

Will I have to drain the system ?

any help will be appreciated

regards

David

Richard Branch

16 August 2026 at 20:50 #83632

Hi David,
As no one has picked this up I’ll give you my thoughts.
I don’t have a 3 Litre, my car is a 16/80 but I would imagine the drain cocks are universal.
To change the cock you will definitely have to drain the system, at least down to the level of the drain cock you’re changing. Just open it and if you want to reuse the coolant put a large container underneath to catch it.
Let us know how you get on.

Richard…

L C Hannam

24 August 2026 at 10:51 #83701

Your existing tap can probably be restored fairly easily. You will need to drain your coolant, but only down to just below the level of the tap … draining from the tap itself would be ideal. Assuming a standard vintage pattern tap, dismantle by straightening and pulling out the split pin, then remove the washer, spring and shaped collar … note this detrmines which way the tap turns, so note/photo its position before removal. The handle can now be withdrawn, revealing that it has a conical seating, which you will probably find a tad scored, hence the leak. Cut a small piece of fine grade emery paper, wrap it around the cone, abrasive inwards, then re-insert it in the tap body and rotate back and forth. Do this until you have a smooth unmarked surface. Now turn the emery and repeat, so that the tap body surface is similarly treated. Now remove the emery paper, and repeat, but using toothpaste as the grinding medium. Rinse clean, and reassemble. Do check the spring, if, perhaps through rust, it has lost tension, it will need retensioning or replacement … the assembly needs to be held together reasonably firmly, otherwise it will still leak. Hope this helps.

Laurence