V12 exhaust backbox

[Ex Boy Racer]

Flaps have seized open on my exhaust. Not the end of the world and certainly not worth £thousands for new backbox. I wonder though whether it’s possible to free them up to make them work again. Anyone tried this?
Thanks

[AdamV12V]

Absolutely no reason to replace the whole exhaust if one or both valves have seized as they can be cut out and relplaced with new ones. They will occasionally free up if bathed in pentrating oil, but as often as not once seized its the end. Also check that your vaccum pump hasnt failed - easy to mistake for siezed valves as the result is the same.

If it is the valves then replacing them is a lot cheaper than a whole exhaust.

https://www.davidapplebyengineering.com/Shop/Produ...

You might be able source them elsewhere even cheaper if you google a bit.

[tom-4hcey]

I had the valves replaced on my v8 vantage s. Previous owner had removed fuse and the arms had sheared off the butterfly valve where they had sized. Ended up with an annoying rattle at times. I removed the back back and had an exhaust fabricator cut out welds either side of the valves and replace with new helical butterfly valves.

[vpr]

It’s why it makes sense to have the remote fuse as it keeps the flaps working

[Mustang Baz]

If you get really stuck, I've got a full original exhaust system from a '67 V12VS 7-speed manual which was removed very early on in the cars life to make way for the Performance pack. This includes the back box from memory.