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M8 Servo nut ?
Posted: Fri Nov 05, 2021 7:59 am
by RichardHyde
Morning all,
Are the nuts that secure the brake servo to the bulkhead (NH108041) really M8 ?!
Isn’t that a metric size ? Is this the only Dolomite metric component ?
Thanks, Richard
Re: M8 Servo nut ?
Posted: Fri Nov 05, 2021 8:31 am
by cliftyhanger
I discovered a metric machine screw on my spitfire, OE. Holds the chrome hood handle to the spindle. Little m4 thing, but that was a surprise. (fell out somewhere on the way to Goodwood. Only stayed in place 50 years.... shoddy workmanship)
Re: M8 Servo nut ?
Posted: Fri Nov 05, 2021 9:51 am
by Mad Mart
Yes they are 8mm. Richard. It's not the only metric fastener but I can't remember any others off the top of my head.
Re: M8 Servo nut ?
Posted: Fri Nov 05, 2021 3:57 pm
by Carledo
It actually depends on age, early car's servos had imperial threads on both ends of the servo, later cars had M8 on the body end and M10 on the M/cyl fitting. Dual circuit master cylinders also have metric unions, M10x1 on the rear circuit and M12x1 on the front. They are the only metric fittings i'm aware of on Dolomites.
Steve
Re: M8 Servo nut ?
Posted: Fri Nov 05, 2021 5:23 pm
by xvivalve
Battery connection bolt.
Re: M8 Servo nut ?
Posted: Tue Nov 09, 2021 11:14 pm
by Carledo
xvivalve wrote: ↑Fri Nov 05, 2021 5:23 pm
Battery connection bolt.
And there I was, convinced that was 1/4" Whitworth!
Steve
Re: M8 Servo nut ?
Posted: Wed Nov 10, 2021 9:12 am
by xvivalve
Carledo wrote: ↑Tue Nov 09, 2021 11:14 pm
xvivalve wrote: ↑Fri Nov 05, 2021 5:23 pm
Battery connection bolt.
And there I was, convinced that was 1/4" Whitworth!
Steve
Depends on the age of the car; I've found metric to be common on later cars.
Re: M8 Servo nut ?
Posted: Wed Nov 10, 2021 3:44 pm
by soe8m
Never had a dolomite with metric battery clamp bolts. Alway's that 'no spanner does actually fit' bolt and nut on the clamp.
Jeroen
Re: M8 Servo nut ?
Posted: Thu Nov 11, 2021 10:10 am
by geeksteve
soe8m wrote: ↑Wed Nov 10, 2021 3:44 pm
Alway's that 'no spanner does actually fit' bolt and nut on the clamp.
I've got one of them

Tried Imperial, Metric and Whitworth and none of them are a very convincing fit. I'm sure it's probably one of them but with a sloppy tolerance, or it's somehow worn..
Re: M8 Servo nut ?
Posted: Thu Nov 11, 2021 2:33 pm
by yorkshire_spam
Currently working on the BW65 from our 1850... that's a right mix of metric and imperial, anything that's Borg Warner generic (internals, main casing) that's metric. Anything that's BL/Triumph specific (tail shaft housing, bell fixings, etc.) that's UNF/UNC. What a PITA.
Re: M8 Servo nut ?
Posted: Sun Nov 14, 2021 10:22 pm
by Carledo
soe8m wrote: ↑Wed Nov 10, 2021 3:44 pm
Never had a dolomite with metric battery clamp bolts. Alway's that 'no spanner does actually fit' bolt and nut on the clamp.
Jeroen
That's the 1/4" Whitworth! it's a few thou bigger than 13mm and smaller than 9/16" Ever since I started my apprenticeship in 1970, Lucas battery clamps had this odd throwback size bolt and it lasted till the early 80s when everything finally went metric. I still have a 1/4 Whit spanner left in my toolbox from those old apprentice days, think it originally belonged to my grandad!
Steve