1962 GMC K1000 front brake hose to cylinder fittings - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ledslinger · 05-15-2023, 03:59 PM

My 1962 GMC K1000 Suburban has an adapter fitting between the brake hose and the wheel cylinders. The female portion is straight thread 7/16" -20, and the male part is straight thread 3/8"-16. It is a plated steel fitting sealed with copper washers on both ends.

Anybody know where to get these?

Ledslinger · 08-03-2023, 09:44 PM

I went to Tompkins Industries, a hydraulic hose supplier today, and showed them a sample 1962 GMC K1000 front brake hose fitting and they said they had 729 of them at their Olathe store. I drove across Kansas City to get them and thought I was in luck, but the male part of the fitting was 1/8" NPT pipe thread instead of straight 3/8"-24. The counter guy looked through all types of catalogs to find one, and was looking at ways to use two fittings to adapt it. I didn't want two fittings.

I bought two of the fittings with the male 1/8" NPT and was thinking I'd drill and tap the male end and thread in a section of a 3/8"-24 bolt and silver solder it in. Then I figured out if I removed the threads on the fitting, it would still be thicker than the major diameter of 3/8"-24 threads: .3667. So I will file off the threads on the male portion while spinning in a drill press, and try to run a die down it. I don't have a lathe.

The fitting part number is 6404-04-02. It has correct 7/16"-20 threads on the female end.

Ledslinger · 08-19-2023, 09:43 PM

My plan to file down the 1/8" NPT steel fitting down to .3667, and thread to 7/16"-20 worked perfect. I cut the head off a 7/16"-20 bolt to screw into the fitting and chucked the non threaded bolt shank into the drill chuck. Laid my small drill press on its side to do the filing, then stood it up and spun it by hand in the die and stock laid on the drill press table.

Some have solved the problem by tapping the wheel cylinder to 7/16"-20 and using no adapter, but I wanted to keep the original setup with the adapter. Nobody cares about this unless you still have drum brakes on a 1960-1963 or so GMC K1000 or K10, but I have seen several discussions in the past seeking this fitting.

05-15-2023, 03:59 PM	#1
Ledslinger Registered User Join Date: Dec 2011 Location: Lee's Summit, MO Posts: 102	1962 GMC K1000 front brake hose to cylinder fittings My 1962 GMC K1000 Suburban has an adapter fitting between the brake hose and the wheel cylinders. The female portion is straight thread 7/16" -20, and the male part is straight thread 3/8"-16. It is a plated steel fitting sealed with copper washers on both ends. Anybody know where to get these?

08-03-2023, 09:44 PM	#2
Ledslinger Registered User Join Date: Dec 2011 Location: Lee's Summit, MO Posts: 102	Re: 1962 GMC K1000 front brake hose to cylinder fittings I went to Tompkins Industries, a hydraulic hose supplier today, and showed them a sample 1962 GMC K1000 front brake hose fitting and they said they had 729 of them at their Olathe store. I drove across Kansas City to get them and thought I was in luck, but the male part of the fitting was 1/8" NPT pipe thread instead of straight 3/8"-24. The counter guy looked through all types of catalogs to find one, and was looking at ways to use two fittings to adapt it. I didn't want two fittings. I bought two of the fittings with the male 1/8" NPT and was thinking I'd drill and tap the male end and thread in a section of a 3/8"-24 bolt and silver solder it in. Then I figured out if I removed the threads on the fitting, it would still be thicker than the major diameter of 3/8"-24 threads: .3667. So I will file off the threads on the male portion while spinning in a drill press, and try to run a die down it. I don't have a lathe. The fitting part number is 6404-04-02. It has correct 7/16"-20 threads on the female end. Last edited by Ledslinger; 08-03-2023 at 09:52 PM.

08-19-2023, 09:43 PM	#3
Ledslinger Registered User Join Date: Dec 2011 Location: Lee's Summit, MO Posts: 102	Re: 1962 GMC K1000 front brake hose to cylinder fittings My plan to file down the 1/8" NPT steel fitting down to .3667, and thread to 7/16"-20 worked perfect. I cut the head off a 7/16"-20 bolt to screw into the fitting and chucked the non threaded bolt shank into the drill chuck. Laid my small drill press on its side to do the filing, then stood it up and spun it by hand in the die and stock laid on the drill press table. Some have solved the problem by tapping the wheel cylinder to 7/16"-20 and using no adapter, but I wanted to keep the original setup with the adapter. Nobody cares about this unless you still have drum brakes on a 1960-1963 or so GMC K1000 or K10, but I have seen several discussions in the past seeking this fitting.



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