Author Topic: how does water get into inner sills on convertible?  (Read 1366 times)

Offline 2V8s

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how does water get into inner sills on convertible?
« on: February 06, 2011, 04:00:18 PM »
Just wondering (sorry didnt know the best place for this thread), how and why my inner sills towards the rear seem to have suffered from corrosion where everything else is in good condition.

I am assuming, from looking at sheet metal parts, that the extra inner sill strengtheing on a convertible is a reverse C-section and open to the main closed sills found on all cars, or is it also closed it'self? Has anyone a photo or diagram of the cross section of a convertible sill arrangment?

I cant understand how water would get into this section to rust it out from the inside, whilst the outer sills, which im 99% sure have never been replaced, are all very solid, and so are the floors etc.

It seems to have affected the area just rear of the front seat belt anchor bolts and forward of the rear seats. will attach some photos shortly.

1967 Mustang Convertible C code auto - San Jose 30th Jan 1967
1974 Corvette convertible 350 L48 Auto
2004 Mg ZT 260 SE (Ford V8)
1994 Rover 214 Si 16v
2005 Renault Grand Espace 2.2 DCi

Offline T Lea

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Re: how does water get into inner sills on convertible?
« Reply #1 on: February 06, 2011, 08:54:02 PM »
First of all outer sills are galvanized inners are not. Verts are prone to leaking at the rear of the top at the back of the rear window. From there it travels down the back of the inner 1/4 and the area behind the back of the front seat. Thats why a lot of otherwise rust free verts have weak back floors and rockers

Offline 2V8s

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Re: how does water get into inner sills on convertible?
« Reply #2 on: February 07, 2011, 08:03:13 PM »
Thanks, that explains it a bit - and I never knew any parts were gavanised (other than the 4 floor plate covers). were the sills the only structural places on the body that were galvanized?
1967 Mustang Convertible C code auto - San Jose 30th Jan 1967
1974 Corvette convertible 350 L48 Auto
2004 Mg ZT 260 SE (Ford V8)
1994 Rover 214 Si 16v
2005 Renault Grand Espace 2.2 DCi

Offline J_Speegle

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Re: how does water get into inner sills on convertible?
« Reply #3 on: February 07, 2011, 09:31:49 PM »
Thanks, that explains it a bit - and I never knew any parts were gavanised (other than the 4 floor plate covers). were the sills the only structural places on the body that were galvanized?

Nope  - thing most if not all of the "frame" (frame rails, trans, front and rear cross members)  was
Jeff Speegle

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Offline 2V8s

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Re: how does water get into inner sills on convertible?
« Reply #4 on: February 08, 2011, 09:41:45 AM »
Thanks thats  very interesting - you learn something knew everyday!

Im still going to inject Dinitrol wax protection in all those areas though.

Here's some pics of the areas in question......
1967 Mustang Convertible C code auto - San Jose 30th Jan 1967
1974 Corvette convertible 350 L48 Auto
2004 Mg ZT 260 SE (Ford V8)
1994 Rover 214 Si 16v
2005 Renault Grand Espace 2.2 DCi