Brakes, the continuing saga

[Slyfox]

also on this. I would not only look into the ends of the lines, but also stick a drill bit up the line. the area where the crush is located is the area of question. how big, don't know. maybe take the line off on the other side and stick a bit up there to get the size. it's important that both sides are the same, so measuring the good side and making sure you have the opening the same on the other. I personally have a drill bit set that goes .03 on drill bits from .040 to .250. I love this set.

that's why I love the inserts in my lines, I know that the opening is good throughout.

[HighWing]

I had concern about the lack of inserts for the tubing with my Kitfox. I was told a couple of different times that the tubing (Nylaflow Type 3/16" T) & fittings supplied by Kitfox do not require the inserts..

For the record, I had Nylaflow tubing with the Poly-Flow fittings on both of my Model IVs. In 900 hours on the original, I had no issues with the brakes. I would suspect the six or eight guys I regularly flew with would say the same thing. Then, I don't recall discussions on the original email lists and wonder if there are any Service Letters in the Kitfox archives. Over the years, Kitfox has been pretty up front on issues that have popped up. My new airplane has had some brake issues, but totally relating to locking brakes. I have concluded that it is a pedal design issue as the "old" plane was ca. 1993 whereas the "new" one is ca. 1992. The difference being the original E type pedals and the new on the C type which under my feet tend to be a brake always pressurized and overheating. I have since modified the pedals.

Regarding Nylaflow tubing. In both of the kits I built, I was supplied with the Poly Flow fittings along with the tubing. I am really curious where the "hardware store" (add the compression ring) fittings are coming from. I have used them on the fuel vent line and did use the inserts there as the tubing was much softer than Nylaflow. The Aircraft Spruce Catalog and website have been like a Bible to me. Do a search on Nylaflow on ACS and two items pop up - A link to the Nylaflow tubing and a link to the Poly-Flow fittings.

Finally, I was surprised that the Lancair IV I helped with came kitted with Nylaflow tubing for the brakes. This puppy has a 100 kn. approach speed and I was thinking heat. But so far so good there - 7 years.

[jrevens]

That's good to know, Lowell... gives me a little more confidence in the Nylaflow and lack of inserts (although I think I will still add inserts if I can get the correct size. I think Wicks may carry them. I sometimes think I'm kind of a belt AND suspenders type of guy when it comes to airplanes. I also think that the plastic has gotten a bad rap in certain circles, sometimes due to poor assembly technique and other factors.

Steve (Slyfox) - no apology necessary. I appreciate the give & take, and you sharing your experience.

Cgruby - I don't recall if you said what size your plastic lines are (1/8", 3/16", or 1/4" OD). They're not 1/4", are they?

[jiott]

After reading this thread, I got to thinking that Kitfox factory really deserves kudos for this sort of thing. When I got ready to install my brake kit, I just opened the box and everything was there-nice brass compression fittings, plastic tubing, and properly sized inserts for the tubing. It all went together without a hitch in the proper way. I didn't have to know about inserts or no inserts or try to determine proper type and size, or try to figure out where to get them. I would be the first to agree that figuring out this stuff for yourself is a good thing and a valuable part of the building/learning experience.

After participating in this forum for over 4 years now I continually see many guys beat themselves to death trying to figure out the best way to do something when a simple call to the Kitfox factory usually gets you the right stuff that is going to work just fine. I have had them gladly send me onesy twosey items. My suggestion would be to start with the factory first and then if you want to learn more and maybe improve the item to a somewhat higher quality, fine. But if you start with the factory recommended items you won't go wrong and end up later spending many hours troubleshooting a problem that you didn't even know you had.

I fully realize that some folks may have added or modified things to such an extent that the factory can't help them so they are on their own, and forums like this can be a great help. Believe me I am not trying to put anyone down, I actually admire those adventurous ones who figure it all out themselves. I am just trying to say that we have a great kit, well engineered and documented, supported by good people that makes life easy for most of us that are willing to go by the book. We also need to support them by purchasing from them whenever possible so their company stays around for many years.

[jrevens]

I for one agree with you Jim, 100%. The particular issue of inserts or no inserts in plastic brake lines has been confusing though, and I've asked someone from the factory if they're needed. The answer - no. That will be good enough for many (or most), but I find it interesting that you say you received inserts. Some other very smart people disagree with the answer I got. So there you have it. It may take a little more time, but sometimes it's smart to research questions that crop up... I'm not saying it's the case here, but people sometimes make mistakes, and sometimes there is a better, & more importantly safer way to skin a cat.

[Slyfox]

I have to agree, John and Deb is a great team. When I got my new engine back in 2009 I got everything from them firewall forward. It was a nice feeling knowing that there was someone that new just what I needed and everything went together nice.

[Slyfox]

That's good to know, Lowell... gives me a little more confidence in the Nylaflow and lack of inserts (although I think I will still add inserts if I can get the correct size. I think Wicks may carry them?....

Steve (Slyfox) - no apology necessary. I appreciate the give & take, and you sharing your experience.

Thanks John, I never know how I'm taken, this is print after all. I know what happened on my plastic lines, and to add I think mine went south over a period of time. I think I had a small leak, I tightened the line, than gradually the brake got less, I kept tightening the line cus the leak came back. finally I said this is bad. than I got to the brakes on the rv and said, hmmmm inserts. I took my line off and sure nuf, no inserts and also closed off, or close to it.

anyway have a nice day.

[Peteohms]

On the plastic brake line issue, how often should you replace the lines?

[HighWing]

... I know what happened on my plastic lines, and to add I think mine went south over a period of time......

In my experience - recent and previous IVs, I think if you are having leaking, it is because of riding the brakes and overheating the brake assembly at the wheel. As mentioned previously, I never had any issues at all on my first Model IV with the E pedals. On the other hand, I have had no end of problems with the new IV and I attribute it to the C pedals with my foot holding constant low braking pressure. Long taxi's would result in extreme heat at the calipers and deformed Nylaflow and leaks. right now, I have a very small leak that I am trying to source, but it is likely a seal at the caliper. It appears as a drop or smear at the low point which is the bleed fitting - no moisture at the brake line fitting.

[Slyfox]

as mentioned, I had a leak at a fitting, to much tightening over time collapsed the line at the compression.

anyway, I have the matco set up. I had brake problems also because of the hardware on the brakes itself, this resulted in severe burn up of the brake pads. what I did was buy all the little hardware parts and polished up everything and reinstalled with new pads and NO lube. it's been over 6 years and over 1000 hrs and am still on the same pads. I'm a guy that hardly uses his brakes. the only time I use brakes is if I want to land real short and do a 180 back to the beginning of the runway. most the time I don't use brakes at all when landing.