Front brake line connector - The 1947 - Present Chevrolet & GMC Truck Message Board Network

pwdcougar · 06-17-2025, 08:53 AM

Can someone share a picture of what the front brake line connection looks like? Im swapping in a 84 and up axle into my 70 K 10 suburban. The 70 uses a brass junction block to divert the brake line coming from the master cylinder to the right and left side. Of course the older body style trucks use what looks like a 3/824 brake line fitting and the 84 and up is 7/16. Im having trouble coming up with the parts to get it to match up.

**kwmech** · 06-17-2025, 11:21 AM

Not exactly sure where you're talking about. Earlier trucks had the lines from the prop valve going to their respective sides. Square bodies moved the prop valve to the front x-member and went side to side from there. Now the 1970 being drum brake had a single line that came out of the prop valve and split down on the frame, so which fitting exactly. Going from the drum to disc, you'll have to swap out the proportioning valve anyways, so my guess is to get some long pieces of brake line and learn how to double flare or purchase the brake line kit for a 71 or 72 from Inline Tube and go from there

pwdcougar · 06-17-2025, 11:28 AM

There is a single line coming from the proportion valve that goes down to the inside of the left frame rail. There is a brass block that has 2 3/8 brake line fittings and also a hole in the middle of it with a banjo bolt that goes into the left brake line to the caliper. Does the later year proportioning valves have three fittings? One going to the rear and then one for each front wheel? I am pretty good at flaring, especially with the nickel copper stuff.

pwdcougar · 06-17-2025, 01:08 PM

Quote:

Originally Posted by kwmech

Not exactly sure where you're talking about. Earlier trucks had the lines from the prop valve going to their respective sides. Square bodies moved the prop valve to the front x-member and went side to side from there. Now the 1970 being drum brake had a single line that came out of the prop valve and split down on the frame, so which fitting exactly. Going from the drum to disc, you'll have to swap out the proportioning valve anyways, so my guess is to get some long pieces of brake line and learn how to double flare or purchase the brake line kit for a 71 or 72 from Inline Tube and go from there

Which proportioning valve do you think would work best? One from a 71-72 with disks or a 84 and up?

https://www.jegs.com/i/JEGS/555/6313...SABEgIM6fD_BwE

I found this one at Jegs

**kwmech** · 06-19-2025, 04:47 PM

It would depend on which master cylinder you are going to run. Different years ran the front brakes off the front section of the master and vice/verse

06-17-2025, 08:53 AM	#1
pwdcougar Registered User Join Date: Oct 2013 Location: New Jersey Posts: 1,332	Front brake line connector Can someone share a picture of what the front brake line connection looks like? Im swapping in a 84 and up axle into my 70 K 10 suburban. The 70 uses a brass junction block to divert the brake line coming from the master cylinder to the right and left side. Of course the older body style trucks use what looks like a 3/824 brake line fitting and the 84 and up is 7/16. Im having trouble coming up with the parts to get it to match up. __________________ "You know that little thing in your head that keeps you from saying things you shouldn't? Yeah well, I don't have one of those" 1969 Mercury Cougar Standard 4 speed 1969 Mercury Cougar XR7 convertible 1970 4WD Chevrolet Suburban 1997 4WD Chevrolet Silverado Extended Cab Short Bed (purchased new January 1997)

06-17-2025, 11:21 AM	#2
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,941	Re: Front brake line connector Not exactly sure where you're talking about. Earlier trucks had the lines from the prop valve going to their respective sides. Square bodies moved the prop valve to the front x-member and went side to side from there. Now the 1970 being drum brake had a single line that came out of the prop valve and split down on the frame, so which fitting exactly. Going from the drum to disc, you'll have to swap out the proportioning valve anyways, so my guess is to get some long pieces of brake line and learn how to double flare or purchase the brake line kit for a 71 or 72 from Inline Tube and go from there

06-17-2025, 11:28 AM	#3
pwdcougar Registered User Join Date: Oct 2013 Location: New Jersey Posts: 1,332	Re: Front brake line connector There is a single line coming from the proportion valve that goes down to the inside of the left frame rail. There is a brass block that has 2 3/8 brake line fittings and also a hole in the middle of it with a banjo bolt that goes into the left brake line to the caliper. Does the later year proportioning valves have three fittings? One going to the rear and then one for each front wheel? I am pretty good at flaring, especially with the nickel copper stuff. __________________ "You know that little thing in your head that keeps you from saying things you shouldn't? Yeah well, I don't have one of those" 1969 Mercury Cougar Standard 4 speed 1969 Mercury Cougar XR7 convertible 1970 4WD Chevrolet Suburban 1997 4WD Chevrolet Silverado Extended Cab Short Bed (purchased new January 1997)

06-19-2025, 04:47 PM	#5
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,941	Re: Front brake line connector It would depend on which master cylinder you are going to run. Different years ran the front brakes off the front section of the master and vice/verse



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