Brake lines?

Discussion in 'General Experimental Aviation Questions' started by Dana, Aug 28, 2017.

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1. Aug 28, 2017

Dana

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With the new landing gear on my Starduster being longer, I need to extend the brake lines. Never having owned a plane with "real" aircraft hydraulic brakes before, I'm a little uncertain on how to proceed.

The new gear is air about 4" longer than the old. As it's a royal PITA to access where the existing brake lines attach to the parking brake valve, I'd like to extend the existing lines with a short (4-8") additional piece. Ideally I'd like to get a length of braided hose with a male fitting on one end and a female on the other. What I have now, I presume, are AN fittings in -4 size (judging by the 4-4 stamped on the hose end)?

It would also make sense to change the 90° elbow on the caliper to a 45° one (the other side already has a 45° elbow).

Dana

2. Aug 28, 2017

Dan Thomas

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You could make up a couple of 1/4" aluminum lines from 5052-O .035" wall tubing and run them between the park brake valve and the flex hose. Four nuts and sleeves and two flare unions.

3. Aug 28, 2017

Dana

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If I could easily access the upper end of the hoses at the parking brake valve I'd just replace the entire hose. As it is, any extension needs to go on the lower end. A hard line would be fine, but I don't have a 37° flaring tool, just the standard 45° automotive one.

Dana

4. Aug 28, 2017

Hot Wings

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Double check with the local auto parts store. They may not stock the cheepe 37 deg tool but they should be able to order one. For $25 it will be a single flare type, not the double. If your comfortable with a single flare then this might be an option? 5. Aug 28, 2017 lathropdad lathropdad Well-Known Member Joined: Sep 13, 2007 Messages: 47 Likes Received: 18 Location: Indiana I would advise against using an aluminum tube to extend the brake line. I think the risk of the tube failing over time is much too high. I would suggest that you get short -4 braided lines made with male and female ends. I also would recommend that you use crimped fittings instead of reusable fittings because the crimped are less bulky. Here is one shop that you can get these extensions made; http://www.earlsindy.com 6. Aug 28, 2017 BBerson BBerson Well-Known MemberHBA Supporter Joined: Dec 16, 2007 Messages: 11,424 Likes Received: 2,099 Location: Port Townsend WA Terminate the existing hose to a nice clamp on the back of the steel tube. Then run a 12" flex hose to the caliper. A 1/4" X 4" black pipe or brass nipple in the caliper would work temporarily. 7. Aug 28, 2017 Hot Wings Hot Wings Well-Known MemberHBA Supporter Joined: Nov 14, 2009 Messages: 5,998 Likes Received: 2,001 Location: Rocky Mountains Good thought! Most any equipment hydraulics shop should be able to fabricate the hoses while you wait. Just let them know what kind of fluid so they can pick a hose material that is chemically compatible. They should also have 45 deg and 90 deg fittings in their stock. 8. Aug 28, 2017 Dana Dana Moderator Joined: Apr 4, 2007 Messages: 8,457 Likes Received: 2,855 Location: CT, USA Yes, that's the direction I'm leaning in now. I was thinking hard line because I don't need 12" (the shortest premade flex line I can get), but it just looks easier. And Summit Racing has 12" Aeroquip hoses with -4 AN ends in stock for only$8.00... just need to verify the size before ordering.

Dana

9. Aug 28, 2017

BJC

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FWIW: A friend built an award winning Pitts Model 12 with "Aeroquip fuel hose and fittings" from Summit Racing. After the first flight, he replaced them all due to leaks. That was his fifth or sixth homebuilt, and he had previously restored / rebuilt a dozen or so certificated airplanes.

BJC

10. Aug 28, 2017

Pops

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There is an Aeroquip dealer about 25 miles away from me. They will make about anything you want. I even bought about 20' of Aeroquip SS hose at a surplus military place at \$1 a foot and took the hose to the Aeroquip dealer to make up hoses that I needed, no problem. Really nice people. One Sat after store hours a hose broke on the Backhoe/endloader and they opened the store to make me a new hose.
Any local dealers in your area?

11. Aug 28, 2017

rv6ejguy

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Earls makes prefabbed -3 and -4 lines in a variety of lengths starting at 6 inches and with different ends. Inexpensive and pressure tested to 4000 psi.

12. Aug 28, 2017

Dana

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Well Brian, I hope your friend's case was an isolated incident, I already ordered them from Summit. We'll see how it goes.

Dana

13. Aug 28, 2017

BJC

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He used them for the cost savings. They were recommended by another builder who, apparently, had no problems. Hope yours are in the "no problems" category.

BJC

14. Aug 29, 2017

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