![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
|
![]() |
#1 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
What size brake lines?
So I'm doing a manual to power brake conversion with hydroboost, as well as front disc conversion, on a '68 C10. I'm also replacing all the brake lines, front and rear. I did a search on here to see what size brake lines to use, and the results are just about every conceivable combination of 3/16 and 1/4 inch. Is there any consensus as to what size lines to use from the mc to the junction, from the junction to the front discs, along the frame rail to the rear flex line, and from the rear flex line to the rear drums? Thanks.
|
![]() |
![]() |
![]() |
#2 |
Senior Member
![]() ![]() Join Date: Oct 2014
Location: Eagle, ID
Posts: 3,004
|
Re: What size brake lines?
My truck is four wheel disc and all the lines are 3/16". I don't know if that helps you or not.
|
![]() |
![]() |
![]() |
#3 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
Re: What size brake lines?
Leaning toward 3/16 at the ends, front and rear, with everything else 1/4. Not sure if it makes a difference, really.
|
![]() |
![]() |
![]() |
#4 |
Registered User
Join Date: Apr 2016
Location: saginaw Mi.
Posts: 70
|
Re: What size brake lines?
It depends on the bore on the master cylinder, You need to start first with knowing that then go from there. I would call tech line at someplace like Wilwood. Most lines are 3/16 BUT
|
![]() |
![]() |
![]() |
#6 |
Senior Member
![]() Join Date: Oct 2009
Location: Godley, TX
Posts: 17,963
|
Re: What size brake lines?
No need to look any further than how GM did it. Stock GM disk/drum setup is 3/16 for disk circuit, 1/4 for drum circuit.
Same logic holds true for 4-wheel disk (all 3/16 lines) or all drum (all 1/4 lines). |
![]() |
![]() |
![]() |
#7 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
Re: What size brake lines?
|
![]() |
![]() |
![]() |
#8 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
Re: What size brake lines?
Ok, so went to install some 1/4" brake line on the rear, but the fittings are 7/16" and the wheel cylinder threads are 3/8"! Not sure how I'm supposed to make that work. So unless i'm missing something, it looks like it's going to have to be 3/16" line (with 3/8" fittings) all around.
|
![]() |
![]() |
![]() |
#9 | |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,110
|
Re: What size brake lines?
Quote:
The end at the tee uses a fitting that is larger on the od (7/16-24) and the center ID is drilled for 3/16 tube. https://www.jegs.com/i/RPC/707/R3590/10002/-1 Here is a link to my repair thread scroll to post starting at 194 for my brake line replacement. You may find some information to help you. https://67-72chevytrucks.com/vboard/...=698377&page=8 If you are using the common replacement Corvette master cylinder you will need to obtain several other GM only sized tube fittings to hook the lines up. If you post a photo of the master cylinder you are using we should be able to help you get the lines there sorted out.
__________________
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 |
|
![]() |
![]() |
![]() |
#10 |
Senior Member
![]() Join Date: Oct 2009
Location: Godley, TX
Posts: 17,963
|
Re: What size brake lines?
Did you replace your 68's master cylinder with a disk/drum mc (either stock 71 GM truck or newer or an aftermarket one)? You do sometimes need to get line adapters at the mc (or at least I've had to in the past when buying a new mc)
|
![]() |
![]() |
![]() |
#11 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
Re: What size brake lines?
I'm installing front discs, plus adding a hydro-boost (stock brakes were manual drums all around) with a Corvette-style master cylinder that has a 1-1/8" bore. Mc is Delco part number 18030333.
|
![]() |
![]() |
![]() |
#12 |
Senior Member
![]() Join Date: Oct 2009
Location: Godley, TX
Posts: 17,963
|
Re: What size brake lines?
Not sure what vette style mc means - but most vettes were 4-wheel disk. You need a disk/drum mc if you are still running rear drums. That delco mc may work, but I don't know if it's a disk/disk or disk/drum mc.
|
![]() |
![]() |
![]() |
#13 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
Re: What size brake lines?
Thanks for the info. Very helpfull. The t-fitting I have is also 3/8-24 thread on two sides, so it fits the 3/16 lines with the standard ends. Came from LMC. Here's a photo of the mc.
|
![]() |
![]() |
![]() |
#14 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,110
|
Re: What size brake lines?
This thread has several ways shown of how to hook up the master cylinder to the junction block. I have installed these several ways (1st and 2nd photos for examples) depending on how the different components lined up and or needed to mounted. So there is no one correct way to do it. Just commonly used setups that all achieve the same result.
https://67-72chevytrucks.com/vboard/...d.php?t=711288 Hard to be sure from the photo are the two ports the same size or is the back one larger?
__________________
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 Last edited by HO455; 07-16-2020 at 10:53 AM. Reason: -2 spelling |
![]() |
![]() |
![]() |
#15 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
Re: What size brake lines?
Not sure if they're the same size or not. I'll check.
|
![]() |
![]() |
![]() |
#16 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
Re: What size brake lines?
Checked the mc and the front reservoir is significantly larger capacity than the rear. So I guess that means it's disc/drum.
|
![]() |
![]() |
![]() |
#17 |
Registered User
Join Date: Jun 2012
Location: Portland
Posts: 1,330
|
Re: What size brake lines?
Since you're doing new lines anyways you might consider plumbing in an adjustable proportioning valve below the m/c.
|
![]() |
![]() |
![]() |
#18 |
Registered User
Join Date: Jul 2016
Location: Deerfield IL
Posts: 108
|
Re: What size brake lines?
I'm using this one from Wilwood.
|
![]() |
![]() |
![]() |
#19 |
Registered User
Join Date: Jun 2012
Location: Portland
Posts: 1,330
|
Re: What size brake lines?
Perfect!
|
![]() |
![]() |
![]() |
Bookmarks |
|
|