Brake Line fitting size? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72SB · 05-06-2022, 12:27 AM

72 manual disc/drum

what is the thread/pitch of the front & rear brake line fittings that goes to distribution block?

**HO455** · 05-07-2022, 06:19 PM

Please post a picture. Otherwise we are just guessing.

72SB · 05-07-2022, 11:44 PM

The front & Rear brake line on proportioning valve (yellow arrow), what size are those line fittings?

**Steeveedee** · 05-07-2022, 11:48 PM

The one on the left of the pic is 3/16" tube, so should be a 3/8" nut. The other line is 1/4", which I believe has a 7/16" nut. Are you looking to buy line wrenches? I have some you can use. You're only a few miles from me.

72SB · 05-07-2022, 11:55 PM

I want to know the thread size to see if I need adapters for the new MC/Booster/PV I am installing

front 3/16-18?...or?
rear 7/16-24?

72SB · 05-08-2022, 12:00 AM

Quote:

Originally Posted by Steeveedee

Are you looking to buy line wrenches? I have some you can use. You're only a few miles from me.

I have flare wrenches......and this set that is the Snap On clone, only $200 less

**Steeveedee** · 05-08-2022, 12:10 AM

I don't remember the thread pitch, but a b-nut is a b-nut. They only have one pitch. I think I have some in my parts stash. I'll take a look.

ETA- both have 24 pitch threads.

72SB · 05-09-2022, 11:14 AM

No one knows the thread size & pitch of the stock front & rear brake lines connection to proportioning valve??

Using the CPP disc/drum proportioning valve. In other swaps I have done on other cars I needed a few adapters to connect existing brake lines to aftermarket PV, was hoping to find out before swap so I have them.

**pjmoreland** · 05-09-2022, 11:25 AM

The CPP PVK installation instructions list the sizes of the ports on the CPP combination valve.

conoco · 05-09-2022, 11:40 AM

I just completed this job a couple days ago on my 1972 k20. I put a new proportional valve on and converted my rear drum to disc. However, the same fitting sized were used. I made about 5 trips to napa because I was trying to find the right fittings.

You will need
3/8-24 inverted flare nut (7/16th wrench) for the front brakes

9/16-18 inverted flare nut for the rear brakes

1/2-20 and 7/16-24 connection for the master cylinder

Mine was all stock that I replaced. Hope this helps.

72SB · 05-10-2022, 10:04 AM

Thanks guys, I do have the 411 info in the CPP kit....are the stock lines the same size fitting as the CPP kit?

05-06-2022, 12:27 AM	#1
72SB Registered User Join Date: Apr 2022 Location: Moorpark, CA Posts: 737	Brake Line fitting size? 72 manual disc/drum what is the thread/pitch of the front & rear brake line fittings that goes to distribution block?

05-07-2022, 06:19 PM	#2
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 10,953	Re: Brake Line fitting size? Please post a picture. Otherwise we are just guessing. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

05-07-2022, 11:44 PM	#3
72SB Registered User Join Date: Apr 2022 Location: Moorpark, CA Posts: 737	Re: Brake Line fitting size? The front & Rear brake line on proportioning valve (yellow arrow), what size are those line fittings? Attached Images

05-07-2022, 11:48 PM	#4
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,261	Re: Brake Line fitting size? The one on the left of the pic is 3/16" tube, so should be a 3/8" nut. The other line is 1/4", which I believe has a 7/16" nut. Are you looking to buy line wrenches? I have some you can use. You're only a few miles from me. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

05-07-2022, 11:55 PM	#5
72SB Registered User Join Date: Apr 2022 Location: Moorpark, CA Posts: 737	Re: Brake Line fitting size? I want to know the thread size to see if I need adapters for the new MC/Booster/PV I am installing front 3/16-18?...or? rear 7/16-24?

05-08-2022, 12:10 AM	#7
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,261	Re: Brake Line fitting size? I don't remember the thread pitch, but a b-nut is a b-nut. They only have one pitch. I think I have some in my parts stash. I'll take a look. ETA- both have 24 pitch threads. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA Last edited by Steeveedee; 05-08-2022 at 11:25 AM.

05-09-2022, 11:14 AM	#8
72SB Registered User Join Date: Apr 2022 Location: Moorpark, CA Posts: 737	Re: Brake Line fitting size? No one knows the thread size & pitch of the stock front & rear brake lines connection to proportioning valve?? Using the CPP disc/drum proportioning valve. In other swaps I have done on other cars I needed a few adapters to connect existing brake lines to aftermarket PV, was hoping to find out before swap so I have them.

05-09-2022, 11:25 AM	#9
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,388	Re: Brake Line fitting size? The CPP PVK installation instructions list the sizes of the ports on the CPP combination valve. Attached Images

05-09-2022, 11:40 AM	#10
conoco Registered User Join Date: Nov 2019 Location: Eagle River Alaska Posts: 320	Re: Brake Line fitting size? I just completed this job a couple days ago on my 1972 k20. I put a new proportional valve on and converted my rear drum to disc. However, the same fitting sized were used. I made about 5 trips to napa because I was trying to find the right fittings. You will need 3/8-24 inverted flare nut (7/16th wrench) for the front brakes 9/16-18 inverted flare nut for the rear brakes 1/2-20 and 7/16-24 connection for the master cylinder Mine was all stock that I replaced. Hope this helps. Attached Images __________________ 1972/Sierra Grande k2500 / 383 / th350 with Gear Vendors / 4.11 / 4" lift with 35s / Eaton Rear Axle

05-10-2022, 10:04 AM	#11
72SB Registered User Join Date: Apr 2022 Location: Moorpark, CA Posts: 737	Re: Brake Line fitting size? Thanks guys, I do have the 411 info in the CPP kit....are the stock lines the same size fitting as the CPP kit?



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