Disk brake line help, please

When I did my disc brake conversion I decided to do my own lines rather than use the pre-made that came with the kit. The ones in the kit where way longer than needed and were a mix of rubberflex and solid.

If had to do it all over again I would have just stuck with the stock kit. Half the double flair kits are pure junk. I went through three of them, then there is the brake lines, the stock steel lines you get from the auto parts store are impossible to bend and flare properly. Spend the extra money and get the premium nickle/copper lines, they are easy to flare, easy to bend and resist corrosion.

Good luck.

Ron W.

When I converted my boat trailer from surge drum to surge disk, I decided it was way easier to just go with the premade lines, Etrailer or Eastern Trailer have several lengths, the double flares are pretty tricky unless you do it a lot.

If you have to make up your metal brake lines be sure you use a double flaring tool to make the flares.

A really boring answer for the loops is because at least with boat trailers, which use either surge drum or disk or electric over hydraulic disk; its really difficult to make a proper flare so a lot of boat trailer manufactures use premade sections of brake line that come in standard lengths, add a few coils to take up the slack, and your brake lines are run.

OP here...

Thanks for the input and getting me straight on loops in brake line. I thought the loops were for stress which made me wonder why not all brake installs didn't have them?

This install is going on a 8,000 pound trailer as upgrade/replacement for existing elec drum brakes. Going to get complete kit. I'll have to replace my mid 90's brake controller and going with Hydrastar brake actuator. Sort of sold on a Kodiak kit at the moment but I could be easily persuaded to another brand.

(hint to all the guys) :) Score another one for Escapees magazine. The final "go ahead" was result of only 3 blocks from our house. A bicyclist drove off the sidewalk into street right in front of us, we barley missed him. Got home, parked trailer, wife checks the mail and there's the latest Escapees magazine. My wife is probably like most other women and doesn't read many technical articles on anything mechanical. But she reads Escapees magazine cover to cover. Article is written by a women and discusses the benefits of disk brakes.

Thanks Escapees

The loops minimize stress fractures due to vibrations.

Matt is correct, the loops are only there to facilitate connection. Without them the lines are too stiff to maneuver and it was hard to build them to exact enough tolerances so that they just mated up. Got this straight from a retired Ford engineer.
You will note that on newer cars where production tolerances are much tighter and those same lines no longer have the loop.

It's for vibration damping.

If you have a straight piece of tubing and wiggle it up and down at the fitting, much like a can wiggled back and forth the fitting will stress crack at the nut.

If you put a pig tail in the tubing the pig tail will take the vibration and be a lot less prone to stress crack at the tubing nut. I see this a lot on high vibration things like airplanes and race cars.

Put the pig tail in it. It's just good mechanical practice. :)

azdryheat wrote:
My gut reaction is you don't know enough about the process to do it by yourself. Hire a mechanic to do the job properly and safely.

My gut reaction is you are jumping to too many conclusions way too fast.

Path,

While employed in Detroit, I only worked 2 years in foundation brakes. But I have done a lot else before I went back to the water only to get wiped out by the depression.

You have neglected to say what you plan to put disk brakes on and if they are a new addition or a replacement for existing drum brakes. Either way, if this is complete kit and all you have to do in bolt on parts and bend lines, do it your self. You will ruin at least one piece of line, so don't be stupid, just get and bend another.

The reason for loop in older vehicles was to facilitate assembly. It makes it easier to get the lines lined up right in the connections. In modern times and with modern design systems, this is no longer required. You may see a piece of line with a wrap. That looks like a spring on the line. That is because it was discovered that the line as routed had a natural frequency that could cause it to fatigue and fail, so they added that to change it.

Matt