bleeding brake help

Marchetti Sportster...
.. . . Are there any tricks to bleed the brakes on this homebuilt?
Four master cylinders, one on each pedal, running to two 'T's, where a
single tube continues to each wing. Thinking of using a vacumn pump, to
pull the fluid down to the caliper.
Also, can anyone reccommend a good radio service shop in the Northwest?

On Nov 3, 5:01*pm, "Pintlar" wrote:
Marchetti Sportster...
. . . Are there any tricks to bleed the brakes on this homebuilt?
Four master cylinders, one on each pedal, running to two 'T's, *where a
single tube continues to each wing. *Thinking of *using a vacumn pump, to
pull the fluid down to the caliper.
Also, can anyone reccommend a good radio service shop in the Northwest?

Reverse bleed .... from the brakes into the master cylinders? Works
on lots of brake systems.
=====================
Leon McAtee

On my Kolb (Freebird calipers, Hegar master cylinders, no reservoir),
I attach tubing to the bleeder screw on the caliper which runs up to a
funnel (made from a 1 liter soda bottle). I fill the funnel with
brake fluid and hang it above the level of the master cylinders (let
fluid run down to fill the tubing until it's full before attaching it
to the bleeder screws on the calipers), open the bleeder screws at
both ends, and go do something else until bubbles stop coming out the
cylinder bleeder screws. No pumps required.

-Dana

On Tue, 3 Nov 2009 20:20:54 -0800 (PST), "
wrote:

On Nov 3, 5:01*pm, "Pintlar" wrote:
Marchetti Sportster...
. . . Are there any tricks to bleed the brakes on this homebuilt?
Four master cylinders, one on each pedal, running to two 'T's, *where a
single tube continues to each wing. *Thinking of *using a vacumn pump, to
pull the fluid down to the caliper.
Also, can anyone reccommend a good radio service shop in the Northwest?

Reverse bleed .... from the brakes into the master cylinders? Works
on lots of brake systems.
=====================
Leon McAtee

--
I don't trust a government I can't shoot back at.

In article ,
"Pintlar" wrote:

Marchetti Sportster...
. . . Are there any tricks to bleed the brakes on this homebuilt?
Four master cylinders, one on each pedal, running to two 'T's, where a
single tube continues to each wing. Thinking of using a vacumn pump, to
pull the fluid down to the caliper.
Also, can anyone reccommend a good radio service shop in the Northwest?

I was taught ALWAYS to bleed aircraft brakes from the wheel UP.

A simple pump-type oil can with a length of plastic tubing can serve
well as a bleed tool. Just make sure that it has a big enough reservoir
and that there is no air in the line.

Brake bleeding can be pretty messy and a two-man operation.

1. Pump the fluid into the tubing, leaving no air bubbles.
2. Attach the tubing to the bleed valve on the wheel cylinder.
3. Have assistant at the appropriate rudder pedal ready, with a drip
container, to open the master cylinder.
4. After assistant has opened the master cylinder, open the wheel
cylinder and pump until assistant sees only fluid and no air.
5. Close wheel valve; have assistant close the master cylinder valve.

6. Repeat #3-#5 for any other rudder pedal cylinders on that wheel.

7. Repeat #1-#6 for the opposite gear.

--
Remove _'s from email address to talk to me.

Orval Fairbairn wrote:

I was taught ALWAYS to bleed aircraft brakes from the wheel UP.

A simple pump-type oil can with a length of plastic tubing can serve
well as a bleed tool. Just make sure that it has a big enough reservoir
and that there is no air in the line.

Brake bleeding can be pretty messy and a two-man operation.

1. Pump the fluid into the tubing, leaving no air bubbles.
2. Attach the tubing to the bleed valve on the wheel cylinder.
3. Have assistant at the appropriate rudder pedal ready, with a drip
container, to open the master cylinder.
4. After assistant has opened the master cylinder, open the wheel
cylinder and pump until assistant sees only fluid and no air.
5. Close wheel valve; have assistant close the master cylinder valve.

6. Repeat #3-#5 for any other rudder pedal cylinders on that wheel.

7. Repeat #1-#6 for the opposite gear.


As it happens, I had the day off, so today I headed over to an A&P not
far away with a main tire for fitting. They packed the bearing, replaced
the brake pads, and retracted the slave cylinder.
When it came time to go, I pumped the pedal, but the brake action did
not go hard.
So I taxied back, and they added brake fluid using Orval's recipe.
THEN the pedals came up firm....

Brian W

In article ,
brian whatcott wrote:

Orval Fairbairn wrote:

I was taught ALWAYS to bleed aircraft brakes from the wheel UP.

A simple pump-type oil can with a length of plastic tubing can serve
well as a bleed tool. Just make sure that it has a big enough reservoir
and that there is no air in the line.

Brake bleeding can be pretty messy and a two-man operation.

1. Pump the fluid into the tubing, leaving no air bubbles.
2. Attach the tubing to the bleed valve on the wheel cylinder.
3. Have assistant at the appropriate rudder pedal ready, with a drip
container, to open the master cylinder.
4. After assistant has opened the master cylinder, open the wheel
cylinder and pump until assistant sees only fluid and no air.
5. Close wheel valve; have assistant close the master cylinder valve.

6. Repeat #3-#5 for any other rudder pedal cylinders on that wheel.

7. Repeat #1-#6 for the opposite gear.


As it happens, I had the day off, so today I headed over to an A&P not
far away with a main tire for fitting. They packed the bearing, replaced
the brake pads, and retracted the slave cylinder.
When it came time to go, I pumped the pedal, but the brake action did
not go hard.
So I taxied back, and they added brake fluid using Orval's recipe.
THEN the pedals came up firm....

Brian W

You should not have needed additional fluid. When you remove a main
wheel, part of the process is to expand the calipers physically. When
everything is done, all you should have to do is press the brakes a
couple of times to get a firm pedal, since, theoretically, no fluid has
left the system, unless somebody disconnected a brake line during the
process.

--
Remove _'s from email address to talk to me.

Orval Fairbairn wrote:
In article ,
brian whatcott wrote:

Orval Fairbairn wrote:

I was taught ALWAYS to bleed aircraft brakes from the wheel UP.

A simple pump-type oil can with a length of plastic tubing can serve
well as a bleed tool. Just make sure that it has a big enough reservoir
and that there is no air in the line.

Brake bleeding can be pretty messy and a two-man operation.

1. Pump the fluid into the tubing, leaving no air bubbles.
2. Attach the tubing to the bleed valve on the wheel cylinder.
3. Have assistant at the appropriate rudder pedal ready, with a drip
container, to open the master cylinder.
4. After assistant has opened the master cylinder, open the wheel
cylinder and pump until assistant sees only fluid and no air.
5. Close wheel valve; have assistant close the master cylinder valve.

6. Repeat #3-#5 for any other rudder pedal cylinders on that wheel.

7. Repeat #1-#6 for the opposite gear.

As it happens, I had the day off, so today I headed over to an A&P not
far away with a main tire for fitting. They packed the bearing, replaced
the brake pads, and retracted the slave cylinder.
When it came time to go, I pumped the pedal, but the brake action did
not go hard.
So I taxied back, and they added brake fluid using Orval's recipe.
THEN the pedals came up firm....

Brian W

You should not have needed additional fluid. When you remove a main
wheel, part of the process is to expand the calipers physically. When
everything is done, all you should have to do is press the brakes a
couple of times to get a firm pedal, since, theoretically, no fluid has
left the system, unless somebody disconnected a brake line during the
process.



That's what the A&P said too. But this was a new acquisition, whose
maintenance state was a (comparatively) unknown quantity. In fact, I
had not picked up on the relatively long rudder pedal travel earlier,
until I lost action.

Brian W