Grove Gear Brake line to caliper

[Bryan]

Ok guys I would like to know how all of you are hooking the caliper line to the bottom of the Grove Gear. I have the gun drilled line that comes out the bottom of the gear. Are you installing the caliper with the bleeder valve up or down, and how are you routing the line. What type of line? Plastic or aluminum? Pics would be great. Thanks for any help.

[HansLab]

Hi, I'm installing them right now. As you can see I put the valve as low as I could. I used nylon lines, the hose around it is to prevent problems with rocks and so on.
I'm not sure yet how to make the pass-through in the bottom side of the fuse, but perhaps somebody has a great idea...
I intend to tie-wrap the lines to the top-side of the gear. The nylon lines can make a pretty sharp edge (even in cold conditions, as it is here, now).

[flybymike]

I used the stainless braided teflon lines. I have used these lines for years on Lancair aircraft. I get them from Henry's Engineering and they are custom made to your lengths. Surprisingly enough, they are very inexpensive.
I installed the parking brake in the center console and ran aluminum lines from there back to the gear legs.

Mike

[cap01]

bryan , on my model IV the bleeder is on the bottom of the caliper , like hans with the gear leg fitting pointing aft . the brake system was installed when i acquired the kit and is using the nylon brake line . if i were to do it , i think i would use the braided hoses . not that i have had a problem , the nylon appears to be really tough stuff , but the braided just has more of an aircraft look to them . also the 90 degree fittings at the top of the gear are pointing up and the brake lines go down thru grommets in the fabric to connect to the fitting.

hans , you may want to do away with the big vertical loops , may be a bigger job to get the air out of the system when you bleed the brakes .

[Dave S]

Hi Bryan & All,

Lot of good ideas in this thread.

1) Since the brakes are bled from the bottom up - having the valve on the bottom and the brake fluid supply line on top of the caliper works best.

2) I had some reservations about using an exposed nylon line between the gundrilled gear and the caliper - (meaning, I know what kind of places and crud I drag my wheels through). The nylon is tough; and, I think those who have put a protective hose over the nylon line are doing a lot to protect the line from whatever we drag our wheels through is a great idea. I became aware of the stainless braided line after my build - however, I elected to use the Aeroquip 303 (3/16") aircraft hose (braided covering) for the connections between caliper and lower gear leg - drawback on this is the cost. Fabricating your own hoses causes you to get an assembly mandrel but the positive side is the you can reuse the fittings and make and assemble a new hose if you need to at a later date. Another suggestion a friend provided is to use aluminum tubing designed for the purpose - much more economical but a person will have to open the line in order to remove the caliper for inspection and pad replacement.

3) I waited till after the covering and paint was on before running the nylon line from the upper gear port through the fuselage - a simple soldering iron burn hole through the fabric in the right place and a person is ready to go. Also used a dollop of red RTV (the fireseal stuff) to stick the tubing and seal where the tubing went through the fabric.

I have attached a photo (not the best for the purpose - but what I have) where you can see the aeroquip hose on the far side wheel - I stayed with the nylon for all other brake plumbing.
Sincerely,

Dave S
KF7 Trigear
192ULS Warp

[Bryan]

Dave, Chuck, Mike, and Hans. Thanks all of you for the pics and advice. I am not sure just which way I will go but at least I have a better idea of what I want to do. Thanks again.

[jtpitkin06]

Folks, I seriously do not know the answer to this one:

Dave S says brakes are bled from the bottom up. That's the way it's plumbed on automobiles.It makes sense that the bubbles work their way into the caliper cylinder and rise to the top where it is easy to bleed them off. But aircraft are different.


My Cessna, the Kitfox instructions, and most of the other aircraft I looked at today are plumbed with the supply line at the top and the bleeder at the bottom. Air in the calipers is supposed to work its way back to the master cylinders and get bled off in the cockpit. Er... maybe that's how it works. Does anyone have the answer as to why they are opposite?

John Pitkin
Greenville, TX

[Dave S]

HI John,

You're right - the engineering between cars and aircraft is different on this issue - as to the reason why they are different - I don't know if it is possible in the larger realm of how things got this way to figure out why that is; but, it seems to be the case that, for whatever reason - on cars - the brake fluid is always added at the master cylinder and either pumped with the foot pedal or pressurized cap at the master cylinder to drive the fluid to the wheel cylinders leaving the only escape route for the air at the wheel cylinders to be the top of the wheel cylinders which is where you find the bleeder screw on cars. On airplanes - we add fluid by pumping it up from the bottom which also means the plumbing has to enter the wheel cylinder at the top if we can hope to drive the air out of the system back up through the lines, master cylinders and finally back to.

I would speculate that the reason cars and airplanes are different is simply because there is more than one way to engineer this and the respective engineers of each simply came to their separate conclusions as to how to build and service each.

If you try to bleed car brakes the way airplane brakes are done and v-vs - both systems will have air left in them.

Now - could a person assemble an aircraft brake system the way a car system is done - Sure! but then you would have to remember to bleed them from the top down rather than the bottom up.

The simplest answer - convention, convention and convention - that is the way someone did it at one time and we still do it that way. One way for one discipline and another way for the other....Neither is wrong and neither is right - they both work.

Sincerely,

Dave S