Author Topic: 71-78 brake line thread size?  (Read 3532 times)

Offline Catrik

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71-78 brake line thread size?
« on: October 15, 2015, 09:11:52 AM »
Guys from Rough Country said their 71-78 front brake line http://www.roughcountry.com/extended-front-brake-lines-89340s.html will fit an 86, even though it doesnt say so.. Well it does fit but the way it attaches to the brake line bracket is different. I thought I just put a nut on the outside thread, but what is the size?

Offline Catrik

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Re: 71-78 brake line thread size?
« Reply #1 on: October 17, 2015, 08:51:01 AM »
I mean the thread pointed in the picture

Offline bd

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Re: 71-78 brake line thread size?
« Reply #2 on: October 17, 2015, 11:55:00 AM »
Did you ask Rough Country (1-800-222-7023 or email) or post your question under FAQ - ASK A QUESTION on their website?  If you already have the hoses, take them to a local hardware store and use their thread diameter and pitch gauges to determine the size.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline enaberif

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Re: 71-78 brake line thread size?
« Reply #3 on: October 17, 2015, 12:59:09 PM »
The issue is that from 73-78? They used a 7/8 banjo bolt then in 79 then changed to the 10mm standard banjo. There are differences in the hoses.

Offline VileZambonie

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Re: 71-78 brake line thread size?
« Reply #4 on: October 17, 2015, 01:25:51 PM »
It is retained by a stamped nut

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Offline VileZambonie

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Re: 71-78 brake line thread size?
« Reply #5 on: October 17, 2015, 01:37:30 PM »
Also referred to as a pal nut.
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Offline bd

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Re: 71-78 brake line thread size?
« Reply #6 on: October 17, 2015, 04:19:09 PM »
Although PAL nuts were used by the factory and are somewhat self-locking, they easily distort when square engagement with the nut using a fixed size wrench is not possible.  If access to tighten the nut inside the frame is limited I recommend an internal star washer and plated steel nut to retain the bulkhead fitting.  For easier disassembly in the future smear a little anti-seize on the external threads of the bulkhead fitting before inserting it through the frame.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline enaberif

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Re: 71-78 brake line thread size?
« Reply #7 on: October 17, 2015, 04:58:25 PM »
When I did mine I had to use a large fender washer to keep the hose from going through the frame hole then I just used the pal washer on the backside.

Offline Catrik

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Re: 71-78 brake line thread size?
« Reply #8 on: October 18, 2015, 06:05:36 AM »
I did ask Rough Country, they didn't know. They just get them in a box and ship them forward.
The local bolt store probably doesnt have so special nuts (I live in a world of metrics), I'm thinking of making one from brass, I just need to know the thread and wouldn't like to take it off just to measure it.

I tried going through Rockauto but didnt see any of those pal nuts, only the hold down clips.

Offline VileZambonie

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Re: 71-78 brake line thread size?
« Reply #9 on: October 18, 2015, 02:14:08 PM »
If I have spare in the garage I'll measure one
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Offline enaberif

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Re: 71-78 brake line thread size?
« Reply #10 on: October 18, 2015, 03:24:08 PM »
Use napas website or rockauto to get the fitting size. It is what I did.

Offline Catrik

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Re: 71-78 brake line thread size?
« Reply #11 on: October 19, 2015, 10:06:26 AM »
Use napas website or rockauto to get the fitting size. It is what I did.
I feel silly now.. That's what I always do first but I just didnt look hard enough. Looks like it is 5/8"-18 and it sounds about right http://www.rockauto.com/catalog/moreinfo.php?pk=1362386&cc=1294938&jnid=511&jpid=3

I hope we have that sized tap at work!