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Dual Brakes and Parking Valve Install on a KF4-1200

13 posts in this topic

Posted (edited)

Since I had no idea how old the brake fluid was, I decided to flush and add some fresh fluid during the off season...

 

Uh oh... :unsure:

 

In the process I found a little fluid weep at one brake, so it made sense to remove the fitting and replace with some fresh thread sealant at the time. Then I found some moron buggered up the vent bolt on one of the MC-1 cylinders so that needed to be rebuilt. Matco didnt have the parts, too old! Got to thinking about how hard and brittle the old brake lines were from the gun-drilled Hammerhead spring gear to the brake pucks. Probably a good idea to replace them, as they are hanging in the breeze just waiting to get whacked. That led to the decision to replace all brake lines and reseal all fittings in the system. At that point, I figured if I was going to do all that and spring for new integrated reservior master cylinders, I might as well add those passenger side brakes I wanted while I was at it. Poached parts from the Avid+ kit (again!), however, I still needed to buy (4) new MC-4a master cylinders. When I had Matco on the line, for some reason at that very instant I somehow decided I could't live without installing a parking valve too. Holy crap... my quick brake flush suddenly turned into $500+ out of pocket and several afternoons!

 

Here's the obligatory 'before' pic...

 

post-53-0-32903400-1366141115_thumb.jpg

 

I used the dual brake plumbing schematic on Matco's website along with a pic I found in the member gallery on the TKF forum to get organized and plan before hitting the hanger...

 

post-53-0-18556800-1366141158_thumb.jpg

 

Here I've replaced the original pilot side MC-1 master cylinders and added the (4) new MC-4a master cylinders on both sides. Special thanks to Larry (Av8R3400) for supplying the right side toe brake pieces! Of course, I had to do my $1.50 rudder pedal mod to the right side pedals too. (Hint: if you are the only other Kitfox owner with an orange powder coated frame, I had some Kubota tractor touchup paint that proved a dead nuts match for the new toe pieces)...

 

post-53-0-35114000-1366141247_thumb.jpg

 

For the brake line I used Parker Parflex Nylon Tubing, High Strength, Semi-Rigid, Inside Dia .180 In, Outside Dia 1/4 In, Wall Thickness .035 In, Temp Range -60 To 200 F, Max Pressure 425 PSI, Burst Pressure 1700 PSI, Vacuum Rating 28 Inches Hg, ~$0.50/ft @Grainger. Definitely more rigid than the stuff it replaced, but it was easy to heat and form fairly tight bends when heated. I used some old Bing blue fuel line for chafe protection and routed back along the left kick panel to accomodate the new parking valve...

 

post-53-0-22657900-1366141855_thumb.jpg

 

The parking valve is from Matco, and it ain't exactly cheap. Kinda wish I'd seen Leni's tip to look in the sand rail parts catalogs before ordering but it is what it is. I made up a valve mounting plate and did a test install. Was conderned about clearance with the control stick aileron horn Heim end bearing with the original location I posted here so I moved it over some on the mounting plate. I also flipped it so the handle was down and tucked in nicely to prevent inadvertant operation...

 

post-53-0-23009000-1366142458_thumb.jpg

 

You can see the brake line routing aft of the parking valve that I chose in this pic. I would have preferred to run them further aft to the next side-to-side tube before going under the aileron push/pull tube and then up to the fittings in the spring gear, but I was just that much short on my new brake line supply. Once heated and bent, they are very stiff but I added a bit more cheap chafe protection in case...

 

post-53-0-16007100-1366142955_thumb.jpg

 

At first I was going to route a single supply line from the remote reservior, then mount a line splitter fitting someplace near the floor. This made for not enough flexibility and slack in the supply lines that enter the top of the pilot side master cylinders when moving through the full pedal operating travel. The reservior and mount didn't seem strudy enough to plum the splitter directly to the reservior, so I made up a mounting plate to put the splitter up under the panel and ran separate supply lines all the way to the master cylinders...

 

post-53-0-95224100-1366143556_thumb.jpg

 

I also used a couple adel clamps as a flexible standoff for the supply lines to ensure some movement give with no chafing on the footwell edge. Reloaded with 5606 and tried to work the air through before taking a test taxi. Grrr, still soft on the right side so it's about to get messy rebleeding the system. For some reason I was wondering if moving a Lady's 'lil pocket rocket along the lines would help chase any air bubbles up first? :P

 

post-53-0-47953200-1366144183_thumb.jpg

 

Time will tell if it's worth it but, after a few weekends futzing around, I'm just happy to have this right side brake job [almost] DONE.

 

:BC:   

 

 

 

[edit] add Matco schematic

 

DualBrakeInstall.pdf

 

 

 

Edited by dholly

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Posted

Great Post Doug - Glad to hear that I am not the only one who makes a mountain out of a molehill!

Just like scratchbuilding or modifying - "Gosh, this looked so simple - if I had just followed the original instructions"!

Ed in MO

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Posted

Nice write up Doug!  hmmm.. you must be kin to my wife... anytime I am working on something and get all greasy she comes down to the garage and um.. takes my mind off work for awhile!  Did you (or can you) fill from the calipers to flush the air out the system?  I use an old oil pump can to fill from the caliper and it assures you can have no air in the system and thereby leave the toys in the bedroom.  Something tells me the better half would prefer a different lubricant than 5606!  :lmao:

 

:BC:

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Posted

Now that you have all that done, I see you still have the killer unreinforced rudder peddle arms. You need to do something about that.

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Posted

Step lightly? :)

 

Actually, I have the mangy fox torque tube undergoing renovations as we speak. You were correct warning it was Smitty ugly. More work but less potential downtime since I have to farm out that welding job and 'no rush' = le$$ cost. Will do a quick swap out when done.

 

 

@ Leni - I shitcanned the oilcan and went to Plan B, a plastic ketchup squeeze bottle. Works pretty good filling from the caliper up, particularly since it's flexible enough to roll up like a toothpaste tube. I just invert the squeeze bottle and fill the attached hose, then zip tie the hose to the caliper zerk. It kept most of the air out but not all. Now the problem is bleeding the system further to remove all the air without another set of hands. I think if I unscrew the reservior, let it dangle with a catch can directly under and just keep pushing fluid through it, I might waste $5 of 5606 but hopefully won't make too big a mess.

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Posted

Matco said DOT 5, not DOT 5.1, 3, or 4 is a approved replacement for H-5606 fluid.  I got some from auto parts store, it works the same as 5606.  Name brand is AGS DOT5.   Russ.

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Posted

What kind of tubing did you use?  When I tried using poly tube on my set up, it expanded too much and the brakes were mushy.  Is that poly tubing or a more rigid type?

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Posted

What kind of tubing did you use?  When I tried using poly tube on my set up, it expanded too much and the brakes were mushy.  Is that poly tubing or a more rigid type?

I think the tubing Doug used was the same stuff that Matco sends out with the kits.  We had a local guy try and use the poly tubing that is used on Semi truck air brakes.  That stuff is only good for 160 PSI max and it lasted one or two flights before it blew apart and dumped 5606 all over the cockpit.  I use the black tubing because it has a higher rating and is a little bit stiffer and does not give me that spongy feel in the brakes.

 

:BC:

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Posted

What kind of tubing did you use?  When I tried using poly tube on my set up, it expanded too much and the brakes were mushy.  Is that poly tubing or a more rigid type?

I used Nylon tubing, but I don't know if Matco supplies the same as Leni suggests. From the original post:

For the brake line I used Parker Parflex Nylon Tubing, High Strength, Semi-Rigid, Inside Dia .180 In, Outside Dia 1/4 In, Wall Thickness .035 In, Temp Range -60 To 200 F, Max Pressure 425 PSI, Burst Pressure 1700 PSI, Vacuum Rating 28 Inches Hg, ~$0.50/ft @Grainger. Definitely more rigid than the stuff it replaced, but it was easy to heat and form fairly tight bends when heated.

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Posted

You mean I didn't have to go to alaska rubber and have brake line made up special?

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Posted

166Nflyer,

 

No you didn't.  I've been fighting my brakes on the Avid Plus and after much bleeding, of my fingers and hands, and trying three different strengths of tubing, I settled on the stuff, .035 wall, that MATCO recommends.  Just received 35 ft., cost $.96 per foot.  I tried the heavier wall, but it was  so stiff that when I tried to bend it to fit between the cylinder and the firewall, it would sometimes pull itself out of the fitting.  Also, with the heavier wall tubing you have to heat it to get it over the inner sleeve of the fitting.  With the .o35 wall tubing, it slides right over the sleeve and is much easier to route, I still have to heat it a bit, just 'til it relaxes, to route the tubing to the parking brake.  Mine is in the center of the fuselage under the seat.  I operate it with a cable from the panel.  The biggest expense has been the brass fittings, but still cheaaper than having the hoses made up by one of the local shops.  Some of those can run $50.00 each.  

 

I'm glad Doug posted his pictures, it gives you some options on how the lines can be routed and protected when you wonder if you're doing it the most efficient way.

 

Jackak

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Posted

My routing was definitely not the most efficient use of tubing and I ended up using more tubing than expected to route the way I did. Coming off the right side master cylinders directly towards the back under the right side door would have saved my having to 'double-back' across the front and then back towards the rear under the pilot side door. Ultimately it was all about the park brake location really, and the K.I.S.S. principle. Don't have (or want) a console in this plane to route stuff down the center, and my original plan of locating the valve under seat with a Bowden cable actuator and knob located on the seat truss ran into clearance problems. I was also concerned about the cable operation with a remote valve location as the valve lever does have a noticable amount of resistance to movement. Lotsa ways to skin this cat of course (so to speak) and your hands in the process! :)

 

@ Jack- I used the tubing from my Avid+ kit for the Kifox. Is the tubing you sourced from Matco the same Parker Parflex? Also curious if you have a pic of your park valve install and remote reservoir location in the Avid+, I'll be installing a center console in that plane. Thanks!

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Posted

Doug,

 

Yes, the tubing is the Parker Parflex .035 wall.  I was a little concerned using the .035 walll, but the tech at MATCO said it was up to the task, so I ordered it.  No one I talked to would stick their neck out and recommend heating the tubing to help shape it, but acknowledged that I was doing it and never said that it would weaken the tubing in any way.  I don't have any pics of the parking brake install, but it's in the center of the fuselage on the right side of the elevator push-pull tube, about mid-seat.  I just put a piece of aluminum on top of the belly tubes and used some angle to provide a spot to clamp the cable housing.  The lever on my valve moves very smoothly and have no problem positioning it with the cable.  To provide a stop for the valve arm, I just put a short piece of plastic tubing on the wire and when you pull the parking brake on, the arm bumps against the tubing when it's in the park position.  The remote reservior is centered on the firewall, probably not the best spot, that location had me routing the lines through the pilots left pedal and the copilots right pedal first, to prevent kinking the tubing.  Your mounting position on the KF looks like it might be a better place.  I don't know if there is a best place under the panel, I've debated moving the reservior to th engine side to make servicing easier, or to reopen the acess panel I cut in the boot cowl to get to the Rotax oil tank when I was considering the use of my old 582.  I could have pretty easy access that way, but don't like the idea of possible water leaks when it rains.

 

I'll see if I can get a few picture soon and post them.

 

Jack 

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