Beringer Disc Brake Kit for Schemm-Hirth gliders - experience and effectiveness?

At 07:51 19 October 2017, Craig Lowrie wrote:
The HPH Shark gliders have a Berringer tubeless wheel
with Disc brake.
Until recently, I was the UK agent and have imported ~30
gliders. None
have suffered from problems with the tubeless wheel over
6 years. I'm
not sure that gliders with tubes could post such a good
record. Only one
glider which landed very heavily in soft ground had mud
between the
tyre and the Rim and would slowly go down. I stripped the
wheel and
cleaned it and it has been fine ever since. I have the
special jig but hav

to say that there is really no problem reassembling the
wheel if you are
a practical type. If the O-Ring is undamaged, I think it can
be lightly
greased and used again... I keep a spare just in case...

The Brake system is very good but must be free from air. I
also suspect
that the overpressure regulator in the system can be
responsible for
braking which is OK but not stunning.

I have fitted a Beringer system to a Pegase and that went
really well and
provided a really good soluition... I have photos if anybody
wants to
upgrade their glider... I don't know about the Tost
solution...

Craig Lowrie, UK

At 03:53 19 October 2017, wrote:
On Wednesday, October 18, 2017 at 6:30:06 PM UTC-7,
Michael Opitz
wrote:
At 20:32 18 October 2017, wrote:
Has anyone ever got a hydraulic Tost disk brake to
work WELL on
a
Ventus
2C=
M? I'm convinced I've bled my brakes as well as they
can be bled,
and
STILL=
the braking is very weak. I get some small braking
action, but
nowhere
ne=
ar being able to put the glider on its nose, or flat-spot
the tire. I
can
s=
low down for a taxiway turn off, so long as its well
ahead, but not
enough
=
to help on a short runway, or enough for a real
emergency stop. I
suspect
=
the wire cable between the control stick and the
cylinder under the
seat
mu=
st be stretching. I may try a thicker cable (I'm
experimental).


I have a Discus-2b with the factory Tost 5" wheel also.
We had real
problems bleeding all of the air out of the line. Biggo
at the factor

even sent me a pdf file with pictures in order to do it
correctly from
the bottom. It was a real bear to get all of the air out.
Also,
adjusting the cable/brake handle so that there is no
play helps a lot.

Finally, get a new brake pad even if the old one looks
OK. The new
one will be thicker, so the caliper won't have to squeeze
over as
great a distance to apply pressure. All of these items
add up.

RO

michael, can you post the pdf? I'm convinced I've done
everything
possible
regarding bleeding, but still don't have good braking. So I
don't expect
it
will help, but I'm desperate now. thanks.

There's plenty of stuff on the internet about motorcycle guys
having trouble bleeding brake hydraulics (including
Behringer). In some cases they recommend physically
disconnecting the calliper and/or master cylinder and tipping
it (rotating it) so the the bleed nipple(s) is physically at the
highest part - then bleeding the system; then re-attaching.
Also if the hydraulic line between the cylinder and calliper
has even the slightest 'high point' a bubble can lodge there
and won't be removed by conventional bleeding methods.
Some systems need pressure bleeding. Even the smallest
bubble will be a problem! If you really have got rid of all the
bubbles then your cable/housing is the problem (see Dave
Nadler's post).
Dave Walsh

After installing my system, I was also desperate, having bled the system multiple times. I talked to S-H to get a new braking cable (wich anyway is just about 30 cm long), with no result. I also talked to Tost who insisted that I must take the right procedure to bleed.

And at some point during the next bleeding operations, I got rid of the bubble.

At 03:53 19 October 2017, wrote:
On Wednesday, October 18, 2017 at 6:30:06 PM UTC-7, Michael
Opitz wrote:
At 20:32 18 October 2017, wrote:
Has anyone ever got a hydraulic Tost disk brake to work WELL
on a
Ventus
2C=
M? I'm convinced I've bled my brakes as well as they can be
bled,
and
STILL=
the braking is very weak. I get some small braking action, but
nowhere
ne=
ar being able to put the glider on its nose, or flat-spot the tire.
I
can
s=
low down for a taxiway turn off, so long as its well ahead, but
not
enough
=
to help on a short runway, or enough for a real emergency
stop. I
suspect
=
the wire cable between the control stick and the cylinder under
the
seat
mu=
st be stretching. I may try a thicker cable (I'm experimental).


I have a Discus-2b with the factory Tost 5" wheel also. We had
real
problems bleeding all of the air out of the line. Biggo at the
factory
even sent me a pdf file with pictures in order to do it correctly
from
the bottom. It was a real bear to get all of the air out. Also,
adjusting the cable/brake handle so that there is no play helps a
lot.
Finally, get a new brake pad even if the old one looks OK. The
new
one will be thicker, so the caliper won't have to squeeze over as
great a distance to apply pressure. All of these items add up.

RO

michael, can you post the pdf? I'm convinced I've done everything
possible
regarding bleeding, but still don't have good braking. So I don't
expect it
will help, but I'm desperate now. thanks.

Email posted to your email address listed on this thread. Also,
we had to unbolt the reservoir / master cylinder from the fuselage
mount and hold it maybe 8" above the floor pan while tapping on
the line in order to get all of the air bubbles to rise up and out.
Hope it helps.
RO

On Wednesday, October 18, 2017 at 1:32:29 PM UTC-7, wrote:
Has anyone ever got a hydraulic Tost disk brake to work WELL on a Ventus 2CM? I'm convinced I've bled my brakes as well as they can be bled, and STILL the braking is very weak. I get some small braking action, but nowhere near being able to put the glider on its nose, or flat-spot the tire. I can slow down for a taxiway turn off, so long as its well ahead, but not enough to help on a short runway, or enough for a real emergency stop. I suspect the wire cable between the control stick and the cylinder under the seat must be stretching. I may try a thicker cable (I'm experimental).

We, the owner of a Discus2b and I, found the hydraulic line between the master cylinder and the caliper had failed inside, expanding just enough to not give adequate pressure to the caliper! Replaced the line and voila, good braking but alas, that glider now rests in pieces on the Whites.

Paul Gaines and I did my ventus B with tost factory kit and had to do a lot of retrofitting as nothing was quite as simple as they led to believe. But after making some shims and other small bits, it came together quite well. We installed the master cylinder on the front bulkhead under the seat pan. This kept the brake cable very short and very little stretch. Braking is quite good while I cant lock up the tire on hard surfaces it does take complete back stick to keep from putting it on the nose. And bleeding is a pain but I managed it after a few messy trys.
CH

What Dave Walsh said about disconnecting the caliper and rotate it so the hose is at the top. Also make sure to clamp the piston so it can't pop out and make a mess in the next step.

That next step being to POWER bleed the system! I use a small modified pump up garden sprayer, but a pressure like this would work too: https://www.amazon.com/Motive-Produc...4HD4ZPCTR0A800

On some gliders, with a small reservoir, I've installed a Schrader valve,
drilling out the vent hole (remove the valve and drill a small hole in the cap for the vent). A tube is connected to that and run to a glass container so you can monitor the results.

To avoid a mess make sure all connections are secure (you can wrap a couple of turns of safety wire around the caliper bleed screw to make sure that doesn't pop off. While bleeding, operate the master cylinder a few times.

When the problem is with the cable, it's often the outer sleeve of the Bowden cable. If there's a too sharp bend in it, the windings can tend to climb over each other effectively shortening the housing length and putting slack in the inner cable.