Cleaning out the drain tube
A brief note on an occasional maintenance item which probably should be available only after the 9pm watershed! Here Victor Smith describes how to find this item and clean it out. (Aug 12)

Recently I found my V8 with a pool of water in the driver's legwell after a night out in the elements during the MGLive! weekend. Whilst mopping out I recalled the late Geoff Allen, our former V8 Historian who worked at the MG Plant for 27 years, telling me about the little known part which drains the fresh air vent chamber below the small chrome grille immediately in front of the windscreen. It is AHC321 - Tube-drain and dust valve, which is the polite way of referring to the rubber tube which was there to act as a drain for the fresh air vent chamber. Geoff referred to it as "Ted's Knob" as that was the name of the part on the production line where a fellow with a reputation with ladies was very able at fitting the part!

Well over the years two things happen to Ted's Knob - first it hardens as t
he rubber ages and second the dust, mud and leaves which find their way into the fresh air chamber accumulate at the bottom and with the water that gets in there washes down into the rubber drain tube. When all is working well the sludge passes through but with age there can easily be a blockage. In fact the photo alongside shows a plug of silt and small stone chips in the hardened slit which had blocked the drain.

The caution before you start attempting to clean out the rubber drain is be very careful not to cause the rubber tube to detach from the upper mounting point as it is a real devil to put back or fit a replacement. Removing the sludge needs a long rigid wire inserted from the top through the grille down through a small circular opening on the base of the fresh air chamber. A wire coat hanger carefully straightened can be used. Gradually work your way down through the accumulated gunge until the lower end goes through the tip of the rubber drain. You then need to apply a

Drain tube blocked with a plug of silt and stone chips

careful reaming action. Then with the car on ramps, get underneath and careful squeezing of the hardened rubber slit and prolonged excavation with a screwdriver, you will see an extraordinary variety of material fall by your hands! So it is wise to wear plastic goggles.

The part is shown on page 108-N15 of the MGB Parts Manual AKM0039 February 1977 First Edition

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