Drum Brake adjuster nut

[DerekJ]

Anybody know what size the nuts are that are used to adjust the front drum brakes, I couldm't get a good fit with 11/16.

 

[Dave Russell]

Hi Derek,
I don't know for sure on your car. My BN2 uses a 3/8 Whitworth, between 11/16" & 3/4", wrench on the adjusters.
D

 

[DerekJ]

Thanks Dave,

I'm pretty sure the brakes on my 100-Six are the same as the BN2

 

[DerekJ]

Dave

I'm sure you know this but I was just doing some research myself on Whitworth threads which have always confused me.

The 3/8" Whitworth you mention of course does not refer to the diameter across the hex nut but to the thread itself. Apparantly no one really knows how the diameter of the hex nuts for Whitworth threads was arrived at. It is not fractions of an inch or milimeters and neither does it follow any discernable pattern. You just have to have the correct Whitworth wrench. If you don't have one (and i don't -yet) its worth trying a metric wrench which can supposedly provide a better fit than the SAE's.

 

[Ed_K]

DerekJ,

Just use your Whitworth adjustable wrench. If you don't have one of those, try your metric adjustable. /ubbthreads/images/graemlins/devilgrin.gif .... sorry, I couldn't control myself !

 

[Dave Russell]

Derek,
The 3/8 W bolt head measures .710" across the flats. the closest metric wrench is 19mm which measures .765 across the flats. The closest US wrench is 3/4" which measures .755 across the flats. Neither substitute is very close to fitting the Whitworth.

You're right, it's a mess. I just keep a variety of wrenches & can usually find a fit. If not, I have to go buy another wrench.
D