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MG MGB Technical - Captive nuts

Hi, When I removed the seats in my 76 B to put some new covers on, I found two of the captive nuts were stripped. The floor is in good solid condition so I thought about buying a set of taps to cut new threads.
Any recommendations as to what size and thread to use please.
c cummins

Are the nuts still there? On my car they actually parted company with the floor and languished inside the box section. I was forced to buy long bolts and drill right through the box section so that I could bolt up underneath.
Mike Howlett

The original size is 1/4-28. Since they are stripped I think you would have to go larger such as 5/16-24. The problem is you will have to drill you seat rails larger too.

From memory the two rear nuts you have unfettered access from the bottom. As indicated above the ones in the box section could be more of a challenge.

Shareef Hassan

There are no nuts inside the box section. It is a short steel bar with 2 tapped holes held roughly in position by a pressed steel cover spot welded to the box section. When I took the floors out of mine I found that one end of the cover had come adrift. Have the threads really stripped or has the bar moved to one side?
John Tampkins

Sorry, ignore what I said earlier. I was thinking of the cross member bolts. That will teach me to engage brain before releasing typing finger!
John Tampkins

You can restore the threads back to the original size by installng Recoils in the stripped nuts. Recoil kits are available from Uni-Thread at: http://www.uni-thread.com/
Cheers - Dave
David DuBois

In the UK you would be better looking for Helicoil rather than Recoils. From David DuBois's description I assume they are the same thing.
David Witham

Thanks for the help, I've now bought a set of UNF 5/16 taps, what size drill should I use?
c cummins

c c

why dont try revetable nuts? Simply done, fast and easy and nearly every diy store has them on offer.

Ralph
Ralph

CC, the drill size required should be engraved on the shank of the tap.
John H

7.0mm tapping drill will be fine. The core diameter is .267", that equates to 6.78mm.
Martin Layton

I normally find a nut that fits the tap, then a drill which fits snugly inside the nut.

Liam
Liam H

This thread was discussed between 20/03/2007 and 22/03/2007

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