The Murphy Builders Site

If it is any consolation, Ken, I can confirm that you can successfully land and take-off with one line blown, as I have done it twice now. The problem is taxiing, and luckily, I had a passenger both times that I was able to send outside the plane, and hang onto the rear tail spring to steer. Just make sure you don't get going too fast, or they won't be able to keep up(did that too).

With the wavy washers to dampen the front wheels, they will stay straight even after your rudder loses effectiveness. Just make sure you kill your engine, when it slows down. And of course don't be leaning hard on the good brake once you lose your rudder authority.

The good news is that my lines did not brake due to abrasion in that retainer area. In fact, after 500 + hours, and checking regularly, there is no detectable abrasion. I think I just had a defective or poor quality brake line (original pre-builts installation). One time it broke in the cabin, squirting fluid, and the other time just above where it attached to the brake assembly at the wheel, but not where it could touch anything. When they go, you know right away as you have no pedal pressure, and you need to think fast then about what to do when you slow down (ie shut off your engine).

Also, you want to be sure your brake assembly (and retainer) is on the outside side of your floats, so you can have your axle grease nipple easily accessible.

As for gear joint wear and tear, mine are still solid with no play after 500 hours. Most of my landings are on pavement, but have had a small number on some very rough fields, too. I think the key here is to have very stiff suspension, so you never bottom out. I have seen some others that were loose, but I think it was because they had the wrong pucks, and were not stiff enough. To lubricate, I just smear grease on the joints (very messy), but seems to work. Mine spend time in salt water too. I fully expected my gear and bearings to be worn out by now, but they are all still good.

Walter

----- Original Message -----
From: Ken <klehman@albedo.net>
Date: Friday, December 5, 2008 9:38 am
Subject: [rebel-builders] amphib 1800 brake line
To: rebel-builders@dcsol.com

I've been puzzling over routing the amphib brake line to the
wheel
cylinder to minimize abrasion. At the very least I have to move
the
brake line retainer on the side of the wheel well a bit more
towards the
top of the float than the manual shows. However the line will
still rub
the thick washer at the top of the doughnut/spring assembly with
the
wheels down.

Unless someone has a better idea, my question is how often does
the
plastic line have to be replaced due to abrasion or is it much
of a
concern? Loss of brakes could end badly on the amphibs.

Ken

FWIW I've also used one size longer bolt than spec'd for most of
the
main gear moving joints to get full engagement of the smooth
bolt shanks
in the moving parts. Perhaps I'm too picky but these aluminum
parts
don't have bushings and are not real easy to service or lubricate.




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LOL Walter!
I'm picturing some poor fellow hanging on for his life to a rope tied to
the tail ;)

I put those die springs in the suspension so I'll definitely have more
movement and wear than with the pucks. I was able to drill a 1/16" hole
into some of the joints so that I can squirt grease in with a needle
injector on the grease gun. Wayne suggested cutting back the felt axle
seals a bit so they don't blow out when adding grease to the axle nipple
but I have not done that. Guess I'll find out how good the felt seal is
for myself...

thanks for the reply
Ken

WALTER KLATT wrote:

If it is any consolation, Ken, I can confirm that you can
successfully land and take-off with one line blown, as I have done it
twice now. The problem is taxiing, and luckily, I had a passenger
both times that I was able to send outside the plane, and hang onto
the rear tail spring to steer. Just make sure you don't get going too
fast, or they won't be able to keep up(did that too).

With the wavy washers to dampen the front wheels, they will stay
straight even after your rudder loses effectiveness. Just make sure
you kill your engine, when it slows down. And of course don't be
leaning hard on the good brake once you lose your rudder authority.

The good news is that my lines did not brake due to abrasion in that
retainer area. In fact, after 500 + hours, and checking regularly,
there is no detectable abrasion. I think I just had a defective or
poor quality brake line (original pre-builts installation). One time
it broke in the cabin, squirting fluid, and the other time just above
where it attached to the brake assembly at the wheel, but not where
it could touch anything. When they go, you know right away as you
have no pedal pressure, and you need to think fast then about what
to do when you slow down (ie shut off your engine).

Also, you want to be sure your brake assembly (and retainer) is on
the outside side of your floats, so you can have your axle grease
nipple easily accessible.

As for gear joint wear and tear, mine are still solid with no play
after 500 hours. Most of my landings are on pavement, but have had a
small number on some very rough fields, too. I think the key here is
to have very stiff suspension, so you never bottom out. I have seen
some others that were loose, but I think it was because they had the
wrong pucks, and were not stiff enough. To lubricate, I just smear
grease on the joints (very messy), but seems to work. Mine spend time
in salt water too. I fully expected my gear and bearings to be worn
out by now, but they are all still good.

Walter

----- Original Message ----- From: Ken <klehman@albedo.net> Date:
Friday, December 5, 2008 9:38 am Subject: [rebel-builders] amphib
1800 brake line To: rebel-builders@dcsol.com

I've been puzzling over routing the amphib brake line to the wheel
cylinder to minimize abrasion. At the very least I have to move
the brake line retainer on the side of the wheel well a bit more
towards the top of the float than the manual shows. However the
line will still rub the thick washer at the top of the
doughnut/spring assembly with the wheels down.

Unless someone has a better idea, my question is how often does the
plastic line have to be replaced due to abrasion or is it much of
a concern? Loss of brakes could end badly on the amphibs.

Ken

FWIW I've also used one size longer bolt than spec'd for most of
the main gear moving joints to get full engagement of the smooth
bolt shanks in the moving parts. Perhaps I'm too picky but these
aluminum parts don't have bushings and are not real easy to service
or lubricate.

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Yeah, it was in Manitoba this past summer. Because of wind direction, had to taxi to the end of a 4000+ foot long runway to take off, and with a strong tail wind, was stepping on the brakes pretty hard at the end to stop. Then having to taxi all the way back with no steering, got going too fast, as I knew an ag plane was coming back to land, and didn't want to hold him up. It was my nephew (younger guy), and he was pretty winded by the time we got back.

The other time was with my wife, but that was at home in Langley. She was not too pleased either, though.

I just grease mine until I see a little squeezing by. I do this every time I come back home, before I pull it into the hangar. I also have a cylinder collar inside the wheel to contain the grease and prevent it spreading in the wheel area.

Walter

----- Original Message -----
From: Ken <klehman@albedo.net>
Date: Friday, December 5, 2008 2:37 pm
Subject: Re: [rebel-builders] amphib 1800 brake line
To: rebel-builders@dcsol.com

LOL Walter!
I'm picturing some poor fellow hanging on for his life to a rope
tied to
the tail ;)

I put those die springs in the suspension so I'll definitely
have more
movement and wear than with the pucks. I was able to drill a
1/16" hole
into some of the joints so that I can squirt grease in with a
needle
injector on the grease gun. Wayne suggested cutting back the
felt axle
seals a bit so they don't blow out when adding grease to the
axle nipple
but I have not done that. Guess I'll find out how good the felt
seal is
for myself...

thanks for the reply
Ken

WALTER KLATT wrote:

If it is any consolation, Ken, I can confirm that you can
successfully land and take-off with one line blown, as I have

done it

twice now. The problem is taxiing, and luckily, I had a passenger
both times that I was able to send outside the plane, and hang onto
the rear tail spring to steer. Just make sure you don't get

going too

fast, or they won't be able to keep up(did that too).

With the wavy washers to dampen the front wheels, they will stay
straight even after your rudder loses effectiveness. Just make sure
you kill your engine, when it slows down. And of course don't be
leaning hard on the good brake once you lose your rudder authority.

The good news is that my lines did not brake due to abrasion

in that

retainer area. In fact, after 500 + hours, and checking regularly,
there is no detectable abrasion. I think I just had a

defective or

poor quality brake line (original pre-builts installation).

One time

it broke in the cabin, squirting fluid, and the other time

just above

where it attached to the brake assembly at the wheel, but not where
it could touch anything. When they go, you know right away as you
have no pedal pressure, and you need to think fast then

about what

to do when you slow down (ie shut off your engine).

Also, you want to be sure your brake assembly (and retainer)

is on

the outside side of your floats, so you can have your axle grease
nipple easily accessible.

As for gear joint wear and tear, mine are still solid with no play
after 500 hours. Most of my landings are on pavement, but have

had a

small number on some very rough fields, too. I think the key

here is

to have very stiff suspension, so you never bottom out. I have seen
some others that were loose, but I think it was because they

had the

wrong pucks, and were not stiff enough. To lubricate, I just smear
grease on the joints (very messy), but seems to work. Mine

spend time

in salt water too. I fully expected my gear and bearings to be worn
out by now, but they are all still good.

Walter

----- Original Message ----- From: Ken <klehman@albedo.net> Date:
Friday, December 5, 2008 9:38 am Subject: [rebel-builders] amphib
1800 brake line To: rebel-builders@dcsol.com

I've been puzzling over routing the amphib brake line to the wheel
cylinder to minimize abrasion. At the very least I have

to move

the brake line retainer on the side of the wheel well a bit

more

towards the top of the float than the manual shows. However the
line will still rub the thick washer at the top of the
doughnut/spring assembly with the wheels down.

Unless someone has a better idea, my question is how often

does the

plastic line have to be replaced due to abrasion or is

it much of

a concern? Loss of brakes could end badly on the amphibs.

Ken

FWIW I've also used one size longer bolt than spec'd for most

of

the main gear moving joints to get full engagement of the

smooth

bolt shanks in the moving parts. Perhaps I'm too picky but these
aluminum parts don't have bushings and are not real easy to service
or lubricate.

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At 12:42 PM 05/12/2008 -0500, you wrote:

I've been puzzling over routing the amphib brake line to the wheel
cylinder to minimize abrasion. At the very least I have to move the
brake line retainer on the side of the wheel well a bit more towards the
top of the float than the manual shows. However the line will still rub
the thick washer at the top of the doughnut/spring assembly with the
wheels down.

Unless someone has a better idea, my question is how often does the
plastic line have to be replaced due to abrasion or is it much of a
concern? Loss of brakes could end badly on the amphibs.

Ken

FWIW I've also used one size longer bolt than spec'd for most of the
main gear moving joints to get full engagement of the smooth bolt shanks
in the moving parts. Perhaps I'm too picky but these aluminum parts
don't have bushings and are not real easy to service or lubricate.

Hi Ken I couldn't get the retainer to work with my brake line when I built
the first float. The line tended to kink as the gear was retracted. So I
removed the retainer and now just count on the stiffness of the brake line
and the angle of the brake fitting to keep the line in place. It's worked
well and there's never been any trouble with abrasion. The origional brake
lines went hard and discoloured fairly quickly and I replaced them with
plastic truck air brake line which has worked just fine. I believe that MAM
has sourced plastic line from several sources over the years and some of it
has not been very good quality. I suggest taking a short piece and soaking
it in brake fluid for a few months to see if it is any good.
Drew



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Drew Dalgleish wrote:

At 12:42 PM 05/12/2008 -0500, you wrote:

I've been puzzling over routing the amphib brake line to the wheel
cylinder to minimize abrasion. At the very least I have to move
the brake line retainer on the side of the wheel well a bit more
towards the top of the float than the manual shows. However the
line will still rub the thick washer at the top of the
doughnut/spring assembly with the wheels down.

Unless someone has a better idea, my question is how often does the
plastic line have to be replaced due to abrasion or is it much of
a concern? Loss of brakes could end badly on the amphibs.

Ken

FWIW I've also used one size longer bolt than spec'd for most of
the main gear moving joints to get full engagement of the smooth
bolt shanks in the moving parts. Perhaps I'm too picky but these
aluminum parts don't have bushings and are not real easy to service
or lubricate.

Hi Ken I couldn't get the retainer to work with my brake line when I
built the first float. The line tended to kink as the gear was
retracted. So I removed the retainer and now just count on the
stiffness of the brake line and the angle of the brake fitting to
keep the line in place. It's worked well and there's never been any
trouble with abrasion. The origional brake lines went hard and
discoloured fairly quickly and I replaced them with plastic truck air
brake line which has worked just fine. I believe that MAM has sourced
plastic line from several sources over the years and some of it has
not been very good quality. I suggest taking a short piece and
soaking it in brake fluid for a few months to see if it is any good.
Drew

Thanks Drew

I'm seeing the same bit of "kinking" I guess. That doesn't bother me but
I don't like how the line touches the top of the retainer so I'll do
something there. No retainer might be the way to go.

I did pick up some 3/8" truck brake line for the up/down lines and it
seems much higher quality so that was a great idea of yours. The
fittings are much superior as well. I did not know that stuff was also
available in 1/4" OD as well. The float kit shipped with 1/4" parker
brake line (0.035" wall thickness) similar to what came with my airframe
kit. I haven't heard of any problems with the Parker stuff but I think I
will need more 1/4" line anyway so will check it out.

Ken



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Thanks Drew

I'm seeing the same bit of "kinking" I guess. That doesn't bother me but
I don't like how the line touches the top of the retainer so I'll do
something there. No retainer might be the way to go.

I did pick up some 3/8" truck brake line for the up/down lines and it
seems much higher quality so that was a great idea of yours. The
fittings are much superior as well. I did not know that stuff was also
available in 1/4" OD as well. The float kit shipped with 1/4" parker
brake line (0.035" wall thickness) similar to what came with my airframe
kit. I haven't heard of any problems with the Parker stuff but I think I
will need more 1/4" line anyway so will check it out.

Ken

1/4" is available and there's also push-loc fittings that work great. You
just cut the tube square and shove it into the fitting. It has a ring on
the end that when pushed back releases the tube so it can be pulled out. I
installed these on my master cylinders to speed up changing from wheels to
floats.
Drew



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Ken.. you'll see the dimensions in my Float build CD do not match the MAM
manual for the brake line retainers postion. I've done them with the line to
the top of the caliper and to the bottom of the caliper and have had no
issues with abrasion on the nylon parker brake line plumbed either way.

Wayne

----- Original Message -----
From: "Ken" <klehman@albedo.net>
To: <rebel-builders@dcsol.com>
Sent: Friday, December 05, 2008 12:42 PM
Subject: [rebel-builders] amphib 1800 brake line

I've been puzzling over routing the amphib brake line to the wheel
cylinder to minimize abrasion. At the very least I have to move the
brake line retainer on the side of the wheel well a bit more towards the
top of the float than the manual shows. However the line will still rub
the thick washer at the top of the doughnut/spring assembly with the
wheels down.

Unless someone has a better idea, my question is how often does the
plastic line have to be replaced due to abrasion or is it much of a
concern? Loss of brakes could end badly on the amphibs.

Ken

FWIW I've also used one size longer bolt than spec'd for most of the
main gear moving joints to get full engagement of the smooth bolt shanks
in the moving parts. Perhaps I'm too picky but these aluminum parts
don't have bushings and are not real easy to service or lubricate.




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Thanks Wayne
Guess I missed that 10" back and 3" up pic or didn't realize it was
different than the manual. Occasionally one must hit me over the head
with a 2x4 to get my attention ;)
Ken

Wayne G. O'Shea wrote:

Ken.. you'll see the dimensions in my Float build CD do not match the MAM
manual for the brake line retainers postion. I've done them with the line to
the top of the caliper and to the bottom of the caliper and have had no
issues with abrasion on the nylon parker brake line plumbed either way.

Wayne

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Hi Ken,
I replaced my leaking plastic line in the wheel-well with a length of 1/4"id
braided stainless, no more probs......Angus


----- Original Message -----
From: "Ken" <klehman@albedo.net>
To: <rebel-builders@dcsol.com>
Sent: Friday, December 05, 2008 12:42 PM
Subject: [rebel-builders] amphib 1800 brake line

I've been puzzling over routing the amphib brake line to the wheel
cylinder to minimize abrasion. At the very least I have to move the
brake line retainer on the side of the wheel well a bit more towards the
top of the float than the manual shows. However the line will still rub
the thick washer at the top of the doughnut/spring assembly with the
wheels down.

Unless someone has a better idea, my question is how often does the
plastic line have to be replaced due to abrasion or is it much of a
concern? Loss of brakes could end badly on the amphibs.

Ken

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Thanks Angus, I had considered braided lines but there isn't a lot of
room there.

Walter sent me a pic of his factory builts with the brake line routed
below the hydraulic cylinder instead of above it like the manual shows.
Interestingly that seems to solve most of the problem as long as the
line is tied to the cylinder to stop chafing at that point.

Angus McKenzie wrote:

Hi Ken,
I replaced my leaking plastic line in the wheel-well with a length of 1/4"id
braided stainless, no more probs......Angus


----- Original Message -----
From: "Ken" <klehman@albedo.net>
To: <rebel-builders@dcsol.com>
Sent: Friday, December 05, 2008 12:42 PM
Subject: [rebel-builders] amphib 1800 brake line

I've been puzzling over routing the amphib brake line to the wheel
cylinder to minimize abrasion. At the very least I have to move the
brake line retainer on the side of the wheel well a bit more towards the
top of the float than the manual shows. However the line will still rub
the thick washer at the top of the doughnut/spring assembly with the
wheels down.

Unless someone has a better idea, my question is how often does the
plastic line have to be replaced due to abrasion or is it much of a
concern? Loss of brakes could end badly on the amphibs.

Ken

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