Hot Rods Brake Line and Fitting Sizes

I've been getting a lot of calls recently about how to identify what size fittings to use with aftermarket parts, so I thought I'd share this video that lays out everything. The biggest misconception that seems to be going around right now is that the size of a port (in a master cylinder or proportioning valve) determines the size of the tube you have to use. This is not the case. If a prop valve has a very large 9/16 port for instance, you can still just put a large 9/16 fitting on the smaller 3/16 tube. Have a look at the video at the bottom of this post.

Also wanted to share that we are offering a free disposable car cover and 10% off our products right now to H.A.M.B members with code "2018" . www.thestopshop.com Excludes disc brake conversion kits.



Todd
614-557-3442

 

yes, i agree with you that there is a lot of misunderstanding of brake lines and fittings.... working part time at an auto parts store i see it everyday

 

You probably get a lot of the same questions we do then! We usually get "I just need a 3/16 fitting". We have to explain that 3/16 is the size of the tube and we have more than a dozen different size fittings that will go on a 3/16 tube!

 

I completely disagree with using a 9/16" fitting on a 3/16" line - even though that fitting is manufactured. People need to consider what happens when you screw these different sized flares together. Not only does the style of flare need to match, the SIZE of the two flares coming together should be at least close in size - they are nowhere near close if you use the 9/16" fitting on a 3/16" line. Another thing to consider beyond the material of the brake line tubing is the material that the components themselves are made out of. There's a huge difference between a (steel) wheel cylinder and (br***) proportioning valve. Here's a photo of what happens when a 3/16" steel line is plumbed into a 9/16" proportioning valve. There is a tremendous amount of unused surface area on the proportioning valves flare / that's where the seal takes place, in case you didn't know. And, where the (too small) 3/16" line flare came in contact with the proportioning valve's flare, there appears to be damage. The damage would not have occurred, if the flare sizes where closer in size to each other. Flared fittings are meant to be able to be installed and taken apart repeatedly, without destroying the tubing or the components. The damage had little to do with over tightness, or even the difference in materials (steel into br***). The damage was caused by severe flare size difference.

 

Here's the pictures. On the right is the fitting in question 9/16" fitting X 3/16" line. The fitting on the left is a 9/16" fitting X 1/4" line. Which would you feel better about screwing into your proportioning valve? Or maybe you don't mind turning your new proportioning valve into a leaking, non-reusable, piece of junk.

 

That's over tightening damage.

I have done this exact installation more than 100 times, including on my own daily driver.

Zero defects.

The only other time I have seen this is when the flare was made improperly, resulting in improper overall diameter when complete.

Neither of these two scenarios is a defect in the fitting design or configuration.

The flare featured on the 3/16 line on the right has an unacceptable ridge on it, which should not be there in the first place, and must be removed before installation, or it alone will cause damage to the br*** cone.

 

@gimpyshotrods - Fair enough. I agree with your statement, but I agree more with my statement. I am just not a fan of any product that falls in the category of "one size fits all", especially when the product relates to a brake system. Damage, or how, or why it occurred was not my main point. Maybe because I'm a licensed plumber and a licensed A&P mechanic, I pay a little more attention when connecting tubes, pipes, or lines to components. I'm sure you've seen plumbing components at your local hardware / home supply store that "solve" problems, but if a professional was actually consulted, rather than the cashier, the purchaser would be informed that the item in question does not meet code / is illegal. In the plumbing world, I have seen 100's of NPT ******s connected to braided stainless flexible supply tubes. The supply tubes are not NPT threads, they are straight threads that seal with a rubber gasket similar to a garden hose. Point being, they don't leak when joined, but that doesn't make it right.

I respect your opinion regardless if it differs from mine - you contribute to the HAMB on a regular basis. What also bothered me was the fact that this newbie @Todd McClure joins the HAMB with a sales pitch, and promotes a plumbing practice that I don't agree with. An "unlike" ****on would have been much easier.

 

I respect your opinion, as well. We all come from different places, and have had different experiences. Adding those all together is what any good community does. The sum total of all of that builds a huge knowledge base. I hope that is what we are doing here.

As for blatant self promotion, I wholeheartedly agree with you. Opening threads for the sake of advertising belongs in the Hamb-O-Dex, not on the main board.

I do realize that I have a listing for my services in my signature. I am doing those for basically sandwich and gas money, to prevent headaches, and to the streamline registration process.