Brake servo mount bobbin

[TonyA]

One of the four 1/4 inch unf bobbins which secure the brake servo mounting plate to the inner wing has come adrift in what seems to be a shallow void between the inner wing and the wheel srch. What are the dimensions of this type of bobbin..what diameter hole do I have to make to fish it out and glass in a replacement..Thx.

[alan.barker]

Hi Tony,
Are you sure it's unf. I think it would be unc.
Don't forget when you fish it out you can Helicoil the thread.
To rebond you will need a hole much bigger than the Bobbine. So you can enlarge the hole a lot to fish it out.
Alan

[TonyA]

Thx Alan, you are right of course it's 1/4 inch. Pls tell me approximate size of the bobbin.so I have some idea of what I'm trying to fish out .It's my first bobbin excavation and I'm nervous..! Tony

[Bud English]

From r.dent: https://www.rdent.com/
Bobbins
Replacement cast aluminum bobbins in original oblong shape and size. Approximately 1-3/8" long x 13/16" wide x 11/16" high. Blank bobbins can be easily drilled and tapped as needed.
Ref. 36B1999