Jump to content

1/4" or 3/16" Brake Line?


epix1718

Recommended Posts

Bought the Kanter kit to completely replace my brake system.. new wheel cylinders, master cylinder, etc...  While at it going to replace the brake lines and they appear to be 1/4" originally and know that 3/16" is the modern standard.  Thinking about picking up this kit on Amazon that is 25' of NiCu 3/16" with all all the normal SAE fittings.  

 

Would this work?  (I've never replaced brake lines before so it's a learning opportunity)

 

https://www.amazon.com/gp/product/B01801G45A/

Link to comment
Share on other sites

Whatever  size  your wheel cylinders and master cylinder accept. That what I would use. 

Link to comment
Share on other sites

The lines on my '37 were all 1/4".  I bought a 50' roll and separate fittings at my local NAPA.  Ended up with a bit left over.   The price on that Amazon listing is really good especially if it's 1/4".    I paid a bit under $1/foot for the line only. 

Edited by thebeebe5
Link to comment
Share on other sites

From the standpoint of brake performance the size of the line makes no difference.  Use what ever was stock if you are restoring the brakes to stock, that will make finding the correct fittings easier.

Link to comment
Share on other sites

Many cars and trucks I have worked on had 3/16" lines from the master (or the proportioning  valve-newer vehicles) to brake cylinders and the rear lines were 1/4" diameter.

 

Why? Do not know.

I am not any kind of hydraulic engineer, must be some reason? 

Any engineers out there with a answer??

DJ

Link to comment
Share on other sites

3 minutes ago, DJ194950 said:

Many cars and trucks I have worked on had 3/16" lines from the master (or the proportioning  valve-newer vehicles) to brake cylinders and the rear lines were 1/4" diameter.

 

Why? Do not know.

I am not any kind of hydraulic engineer, must be some reason? 

Any engineers out there with a answer??

DJ

I am not a hydraulic engineer but I did service Uncle Sam's Naval Air for over 12 years as a hydraulic specialist.....but I do know that line diameter doesn't matter with hyd pressure, all that does is dictate how much fluid needs to be in the system to operate properly. All I can think of is savings on the smaller line weight and monetary........Are all M/C s 3/16 standard issue? Who knows....lol.

Link to comment
Share on other sites

the 1/4 line was a work around instead of going with a proportioning valve..you get a delay with the 1/4 line plus the expansion rate of the tube itself (yes it does expand)  Pascal is a theory, not an absolute science...as the components of the system work within their own mechanical limits...

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Also has to to do with fluid volume. Larger wheel cylinder pistons that need a lot fluid to move the shoes need the larger line to deliver the volume of fluid required for the same push of the pedal.

 

Rick

  • Confused 1
Link to comment
Share on other sites

The volume of fluid that moves is based on the displacement in the master cylinder, nothing to do with the lines. The lines, regardless of the size will always be full of fluid. Unless there is air in there IMO.

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

I'm pretty sure  factory line size was 1/4" up through 42 then 1946 on was 3/16".

Link to comment
Share on other sites

I worked on both a 1936 P2 Plymouth and a 42 S10 DeSoto that had original 1/4" steel lines.

now a 31 CD 8 Chrysler I did had the factory Copper 1/4" lines on it.

  • Like 1
Link to comment
Share on other sites

  • 2 weeks later...
On 5/4/2018 at 10:18 AM, maok said:

The volume of fluid that moves is based on the displacement in the master cylinder, nothing to do with the lines. The lines, regardless of the size will always be full of fluid. Unless there is air in there IMO.

Yes and no. In theory with the right master cylinder you could push the right amount of fluid through a hypodermic needle, or use a 1/2" tube. It's an engineered solution based on cost, ease of manufacture, material availability, and at the time probably common sense.

 

Rick

Link to comment
Share on other sites

3 hours ago, MackTheFinger said:

This stuff really works to prevent rust. i have had to repair lines on several cars over the years and have always found good metal under the armor

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use