Pipe sizes and tube nut sizes

[Pahs59]

Can someone confirm the steel pipe sizes for an FC Holden plus the tube nut sizes and threads
Brake lines...
Clutch line...
Fuel lines...
Carb to dizzy line...
Vacuum line from fuel pump to manifold

[ardiesse]

Brake pipes, clutch pipe, manifold-to-vacuum-pump and wiper motor to vacuum pump pipes: 7/16" AF, 1/4" dia.
Fuel pipes: 1/2" AF, 5/16" dia.
Vacuum advance pipe: 3/8" AF, 3/8"-24 TPI, 3/16" dia.

Rob

[Errol62]

Just watch out for metric size hex heads as that is what you may get now when you buy new ones. From memory 3/8” replaced with 10mm. I also had a metric clutch slave bleed nipple recently. Threads and pipe diameters are still imperial, just the heads.


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[Harv]

Just watch out for metric size hex heads as that is what you may get now when you buy new ones. From memory 3/8” replaced with 10mm. I also had a metric clutch slave bleed nipple recently. Threads and pipe diameters are still imperial, just the heads.

The "metric flats on imperial threads" fittings make me grind my teeth, like using pliers to undo nuts.

Thread sizes:
3/16" pipe uses 3/8-24UNF thread.
1/4" pipe uses 7/16-20UNF thread.
5/16" pipe uses 1/2-20UNF thread.
3/8" pipe uses 5/8-18UNF thread.

Cheers,
Harv

[Dr_Terry]

The "metric flats on imperial threads" fittings make me grind my teeth, like using pliers to undo nuts.

Thread sizes:
3/16" pipe uses 3/8-24UNF thread.
1/4" pipe uses 7/16-20UNF thread.
5/16" pipe uses 1/2-20UNF thread.
3/8" pipe uses 5/8-18UNF thread.

Cheers,
Harv

I'm with you Harv, metric A/F with imperial threads can be annoying, but there is a simple reason it exists.

The guys that manufacture the pipe nuts, can only purchase metric bar, i.e. nowadays in the case of 3/8" UNF pipe nuts, they are made from 10mm hex bar.

The cost of machining the bar to become 3/8" hex would be prohibitive compared to the cost of the actual nut. So 10mm A/F with a 3/8" thread it is !!

Dr Terry

[my8thholden]

come on fellas ,its easy fixed ,just stamp your 10mm spanner 3/8 !!!!!!!Vern

[ardiesse]

. . . actually it works the other way.  When your 3/8" AF spanner wears out, it magically becomes 10 mm.  And when your 1/2" spanner wears out, it becomes 13 mm.

Rob

[Harv]

Sadly, for me it works out worse. I go to tackle a fitting, and am too stupid to clean it off properly. I try the 3/8", and because of the grease/rust/dirt it doesn't fit. I curse the 10mm hex bar issue and whip out the 10mm flare nut spanner. I then proceed to round off the corners on the 3/8 bleed screw  .

Cheers,
Harv

[my8thholden]

AAAH,HUH..so its you Harv ,you must have worked on LHR wheel cylinder of my car somewhere last century ,spose you change light globes with a stillson wrench too ,gotta keep larfin ...Vern

[Pahs59]

Thanks to everyone for all the information..I’m ok with pipe sizes and can look at the head of a bolt or nut and know the size but have never been able to work out threads or thread sizes,It’s helped a lot and maybe helped others as well
Thanks again

[Harv]

AAAH,HUH..so its you Harv ,you must have worked on LHR wheel cylinder of my car somewhere last century ,spose you change light globes with a stillson wrench too ,gotta keep larfin ...Vern

Harv's School of Tool Abuse. If you can't fix it with a hammer, you've obviously got an electrical problem 

Cheers,
Harv

[59wagon]

The guys that manufacture the pipe nuts, can only purchase metric bar,

Imperial bar stock is still readily available - it’d be interesting to know why they don’t use it.
Cheers, John


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[Harv]

I’m guessing there is a big factory somewhere, making pipe fittings. They would make lots of metric stuff, and a little bit of imperial. Easier to buy just one bar stock, and just roll the threads different for metric/imperial.

Cheers,
Harv

[Errol62]

I got a big surprise when I went to bleed my original looking clutch slave. Wound up pulling it off the mount, hose intact, as I didn’t want to butcher the bleed screw. It was then I discovered it was 10mm hex fitting size. Then when I went to buy wheel cylinder tube nuts they were 10mm.

Bought a nutsert gun and guess what, imperial thread sizes sorry what??! So now my car is a mix of metric, imperial, oh yes and whitworth!


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[my8thholden]

Gents  ..Westinghouse Air and Brake at Rydlemere make heaps of tube and tube fittings ,or used to ,its been a while 15yrs since I had any contact ,now known as Wabtec  ..new German owners ,you probably cant deal direct with factory but would steer you to an outlet I imagine ..Vern .

[NES304]

. . . actually it works the other way.  When your 3/8" AF spanner wears out, it magically becomes 10 mm.  And when your 1/2" spanner wears out, it becomes 13 mm.

Rob

Hahahha soooooo true


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[DnD]

Relay great information. Can anyone advise me of much pipe I need to replace both the fuel and brake lines?  Dermot