Question / Info Request - UL/LSA Brake System Hardware

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

Victor Bravo

Well-Known Member
HBA Supporter
Joined
Jul 30, 2014
Messages
9,569
Location
KWHP, Los Angeles CA, USA
Question for UL and LSA (and E-AB) brake system folk:

I'm now putting the brake system together on a 900 pound gross STOL LSA. I managed to get some imported small motorcycle/pit bike/quad hydraulic brake cylinders mounted to the heel brake pedals, just barely.

The high pressure output from the cylinders is a "banjo bolt" and its associated "banjo fitting". The banjo fitting was purchased from a motorcycle shop near the airport. The banjo fitting's attachment for the brake line was reported (by the Harley-biker-looking guy at the bike shop) to be "AN-3". I took this to mean it is a 37 degree AN style hydraulic nipple fitting for "size 3" aluminum flared brake lines, AN style ferrules and "B-nuts". The B-nuts I had in the drawer fit, so I believe the reference to AN fitting size is correct.

So first I need to get a brake line attached to the banjo... no problem. But only an aluminum or nylon line will fit onto the banjo, because the !(#*$ banjo is very very close to the side wall of the !(#*$ brake cylinder, and there's no room to put an Aeroquip, or rubber, or flexible hose on it. The difference in OD between an aluminum tube and a proper hose is too much. So I can attach a flared aluminum line to the banjo... no problem.

But THEN I need to go from the aluminum line to (hopefully) nylon for the rest of the way, passing through the area where the main gear swings up and down (bungee movement), and down the gear leg to the caliper.

So my big question is... is there an elegant, clean, and low-parts count way to go from an AN aluminum brake line to a nylo-seal "compression fitting" type of nylon brake line? What I am hoping to avoid is the typical stack-up of wonky brass adapters with pipe threads,, three or four components screwed together that look overcomplicated and a little too "hardware store". The nylo-seal is lighter, cheaper, and more elegant up to the point where there's a pound of big clunky square brass parts all screwed together.

Thanks in advance for the brain cells...
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
6,201
Try an industrial; supplier that stocks Weatherhead or Fairview. This is from the Fairview catalog:

1627764360296.png

Their air brake stuff would be better, having the longer nuts, but they don't make them in 3/16".

Brass compression fittings like this will take plenty of pressure. Use an insert inside the nylon tube, though, to get max grip. I used them for years on the Jodel with no problems.
 

Hot Wings

Grumpy Cynic
HBA Supporter
Log Member
Joined
Nov 14, 2009
Messages
7,947
Location
Rocky Mountains
is there an elegant, clean, and low-parts count way to go from an AN aluminum brake line to a nylo-seal "compression fitting" type of nylon brake line?
Read this again, now that I'm awake in the daylight........
All you need now is to connect 2 3/16" lines of dissimilar materials together? If so the part #62-3 👆 , or the local hardware store equal, should do the job with just one fitting.
Even push to connect fittings should be up the pressure that Nylo-seal will tolerate. Don't know about the chemical resistance of the o-rings?
 
Top