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MG MGB Technical - Fitting A Short SIll

Slowly bringing my dads 1978 BGT back to life after 20 years in the garage. Car was zebarted and wax oiled from new and is completely solid all over apart from where some idiot drilled a hole on top of the drivers sill where water has got in. I have already cut a hole in the outer sill that was rust and need to patch the inner sill small area less than 6" across rest is perfectly sound and still covered in waxoil. Can someone confirm where the short sill piece is welded in? I am in two minds as to buy the whole new outer sill and cut the area I need or replace with the short sill?
C Carter

There seems to be a hole as standard on the top of the outer sill just below the hinges. It's normal to drill a hole in the top of the inner sill in the corresponding position as well as at the back of the door opening where the sill becomes the B-pillar, again inner and outer sills, as part of a comprehensive rust-proofing process. If your sill has rotted through under the door then that was probably missed. Any water getting in there simply drains out of the holes in the bottom of the outer sill and the castle section, some will always get in from underneath from spray from the front wheels, but you can always fit closed grommets in the top.

Not sure what you mean by a short sill, the sill runs from the back of the front wheel arch to the front of the rear wheel arch. If the section under the door has corroded then you need to check what is behind the splash panel in the front arch, and behind the trim panel aft of the B-pillar. There is a very small gap in both those places between the outer sill and the back of the wings, thicker treatments won't run into that gap but just bridge it, and allow condensation and corrosion to develop below it. Having had a car Ziebarted in the past it's my opinion that this falls into the category of 'thicker' unless significantly thinned and sprayed on a very warm day, like Waxoyl which if anything is a little thinner. I dribbled clean engine oil into those two gaps from above then distributed it with a piece of card poked in the gap.
Paul Hunt

Thanks Paul doesnt seem to be a hole on the passengers ide just the drivers side?

I am aware of the sill running front to back and have taken the wing off to check the front section and all is fine.

This is the short sill repair section http://www.ebay.co.uk/itm/MGB-GT-MGC-1962-1981-SILL-R-H-NEW-/350375750887?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Model%3AMGB+GT&hash=item519405ace7
C Carter

I think they used to be popular in the bad old days. AFAIK they were just fitted over a rusty sill.
Dave O'Neill2

That doesn't seem the right shape even just to repair the section under the door, between the wings, which would be considered a bit of a bodge. It's not a standard repair panel.
Paul Hunt

If you've already got the front wing off the best thing to do would be to fit a whole new outer sill. Once the old one is fully removed you will see exactly what needs doing to the centre "castle section". You will need a rear wing lower repair panel & both sill & panel need fitting with the door in place to ensure correct alignment.

My 72 roadster had 3 sills one on top of the other when I bought it. These short repair panels are just bodges.

G Britnell

This thread was discussed between 28/05/2013 and 05/06/2013

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