brake line sizing

Posted By: Crizila

brake line sizing - 12/10/14 04:10 AM

About to start designing a brake system for my 33. Going with AN stuff for the most part. Also thinking about plumbing it all in -3 ( 3/16" ) line. Any thoughts about using -4 ( 1/4" ) off the master and then down to -3 to the brakes? 4 wheel disc with GM calipers. Thanks, John

Posted By: moparx

Re: brake line sizing - 12/10/14 04:26 AM

are you contemplating using all braided line ? or just for the 3 flex points[both front wheels and the rear end]? or am i just missing the size [an] point ? as for the sizing, 3/16 is really all you need.

Posted By: Crizila

Re: brake line sizing - 12/10/14 04:04 PM

On the line size, just wanna make sure I won't have any "volume" issues. Pretty sure 3/16" will be fine. Except for the flex points, the rest will be hard lined in 3/16".

Posted By: dogdays

Re: brake line sizing - 12/10/14 06:03 PM

If we assume that the brake fluid is incompressible and the lines don't expand with pressure, then the volume you shove into one end of a filled line is the same volume that will come out at the other end, no matter what the size.

I don't believe I've ever seen 1/4" line on brakes.

The above assumptions are not 100% correct but they are close enough to work.

R.

Posted By: Crizila

Re: brake line sizing - 12/10/14 10:49 PM

10-4 on that. Thanks.

Posted By: John_Kunkel

Re: brake line sizing - 12/11/14 07:53 PM

Volume versus velocity. Lots of older cars had 1/4" brake lines.

Posted By: Challenger 1

Re: brake line sizing - 12/11/14 09:05 PM

I have used 3/16 steel line and #3 fittings on many scratch built dragsters that went 265 mph. They always stopped real well. It's all you need, imo.

Posted By: Crizila

Re: brake line sizing - 12/11/14 09:45 PM

Quote:

Volume versus velocity. Lots of older cars had 1/4" brake lines.

Ya, kinda why I asked John. Assume most of them were drum/drum or disc/drum. Since this is a 4 wheel disc application, and I will be using two separate masters with 1" bores each, don't think I am going to have any volume issues. Pedal ratio will be 6.25:1 for this manual system, so pedal pressure shouldn't be to hi.

Posted By: DDodger

Re: brake line sizing - 02/19/15 11:53 PM

Quote:

If we assume that the brake fluid is incompressible and the lines don't expand with pressure, then the volume you shove into one end of a filled line is the same volume that will come out at the other end, no matter what the size.

I don't believe I've ever seen 1/4" line on brakes.

The above assumptions are not 100% correct but they are close enough to work.

R.

All hoses will expand "some" maybe not "much". But the larger they are the more they expand. I'd use no3 and keep hoses as short as possible.