Brake line service loop, is it necessary.

AMURRAY · #1 01-05-2008, 02:34 PM

All of the fixed gear Cessna's I have been around do not have a service loop. I seems that it is extra unsupported brake line that can vibrate around. I know others have had problems with brake lines breaking at the caliper.
Comments please.

Thanks, Aaron

AlexPeterson · #2 01-05-2008, 02:53 PM

Unsupported, a service loop probably would be a problem. I clamped mine with an adel clamp in at least one location. As for the service loop, you need to allow for caliper movement owing to pad wear, so some degree of left/right motion is needed. However, changing pads requires that you move the caliper a fairly long ways inboard, to disengage the large guide pins. If you didn't have a service loop, you'd have to disconnect the hydraulic line. Same thing if you remove a wheel for tire change. I'd put the loop in again. Just watch where the gear fairing can contact the line, I found some chafing there until I readjusted things. The gear fairings like to move.

robertahegy · #3 01-05-2008, 02:55 PM

The service loop will help prevent the vibration from cracking the line near or at the fitting at the caliper. It also allows some flex so the caliper remains able to float and align itself. Lastly, if you should develope a crack, it allows you enough excess to repair the line. Mine's been fine for 4 years.

Roberta

rvbuilder2002 · #4 01-05-2008, 03:14 PM

As already metioned....Without the service loop you will have to disconnect the brake line (and then bleed the brakes after reconnecting) every time you remove a wheel or replace the brake pads.

robertahegy · #5 01-05-2008, 06:26 PM

Oh yah!! I forgot about that. Replaced my brakepads last year at annual time. Would have been tough without that loop.

Roberta

Mel · #6 01-05-2008, 06:38 PM

The loop doesn't have to be a full 360 degrees. I have a sort of half loop on mine. Been working fine for 15 years. No cracks, no problems changing pads.

pierre smith · #7 01-06-2008, 06:28 AM

.....like my Air Tractor has. Some guys run the aluminum lines down to near the bend in the landing gear, then run flexible rubber hose to the caliper and then you don't need a loop.

Regards,

Bob Axsom · #8 01-06-2008, 06:25 PM

It is very easy to include the loop when you build the airplane but if you install permanent fiberglass strut fairings you are pretty much stuck with what ever you put in there to start with. The loop is handy for field repairs. This is kind of a long story but I have to set the context. At Panama City, Florida I wore my pads down too much and allowed the fluid to leak out past the o-ring on the piston. Me and a friend JW Neal were able to make some pads out of some different sized ones that he had. The pads had to be ground down in thickness and maybe some other mods in order to get them to fit (it's been a while). Anyway they were off and on many times to get the repair accomplished. After getting home the brake pads were replaced with the proper part numbers. Later in the year we were on our way to California with a fuel stop at Prescott. On landing I was making a show of getting off the runway at the first taxiway and the the right brake failed. I was pretty easy to cut off the end broken at the flare, reflare the tube and fix the problem.

I use the rudder for turning as much as possible these days but if I have another failure there is no concern about being able to fix it with the excess line provided by the loop.

Bob Axsom