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Tost Disk Brake rebuild?



 
 
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  #1  
Old April 14th 08, 06:29 PM posted to rec.aviation.soaring
Paul Cordell
external usenet poster
 
Posts: 70
Default Tost Disk Brake rebuild?

I discovered that my Nimbus 3D had lost it's wheel brake Saturday.
Fortunately, I still fly with the assumption that it, like many
gliders of the past don't have wheel brakes. No damage done other
than a Long push back to the tiedown area.

Upon examination of the system, (and the puddle) it appears that it's
time for a rebuild of the caliper. Who's got some advice on the
process? Any tricks??

Thanks for the advice in advance

Paul
Ephrata, WA
  #2  
Old April 14th 08, 10:33 PM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 50
Default Tost Disk Brake rebuild?

On Apr 14, 10:29*am, Paul Cordell wrote:
I discovered that my Nimbus 3D had lost it's wheel brake Saturday.
Fortunately, I still fly with the assumption that it, like many
gliders of the past don't have wheel brakes. * No damage done other
than a Long push back to the tiedown area.

Upon examination of the system, (and the puddle) it appears that it's
time for a rebuild of the caliper. * Who's got some advice on the
process? * *Any tricks??

Thanks for the advice in advance

Paul
Ephrata, WA


Tost calipers on DG's and I assume many sailplanes are made by
Cleveland and parts are available through AircraftSpruce.com.
The only differance is that Cleveland uses an O-ring compatable with
hydraulic oil and DG uses one compatable with brake fluid. The O-ring
shown on the Aircraft Spruce parts list is the one for use with
hydraulic oil but the correct O-ring material (EPDM) for poly-glycol
brake fluid can be purchased from mscdirect.com.
The size of the O-ring used on current DG's is 1/8 diameter, 1 I.D
and 1 O.D. and it is available as part# 31953284 for $8.76 (box of
50). Your Nimbus may use a differant size.
  #3  
Old April 15th 08, 01:38 AM posted to rec.aviation.soaring
Paul Cordell
external usenet poster
 
Posts: 70
Default Tost Disk Brake rebuild?

It's Done!

Thanks Dave Nadler and Uncle Hank for the off-line notes.


This Soaring community is always surprising. I talked to Monty@ M &
H Soaring this morning about the spec's for the Pads and O-ring.
Then went over to Aircraft Spruce to get the parts. After I looked
at their web site, I still had some questions about the rivets. I
called a buddy that is an ex '20 owner and RV-7 builder to ask about
the rivets. He lives about 100 miles away. As we talked, he
walked out to his Hanger and went thru some stuff on his work
bench. He had exactly the parts I needed. When would you like to
do this he asked?? I told him that if he wanted to "help", it would
be on his schedule........He responded, I'll be there in an Hour. He
was and did the whole job as I "supervised". Cleaned and polished,
pads and ring with a full bleed and new fluid. The system in general
was in good shape. Just slight corrosion and some gunk. I
supplied him with 1 soda for all the trouble. He'll be back next
weekend for a test flight.

Paul


  #4  
Old April 16th 08, 06:55 AM posted to rec.aviation.soaring
bumper
external usenet poster
 
Posts: 322
Default Tost Disk Brake rebuild?

Paul,

As Gary Evans mentioned, there are basically two brake fluids used in
gliders. The "red stuff" Mil Spec 5606 oil (which most GA aircraft use) and
DOT # automotive type fluid. 5605 wants to have Buna-N seals and O-rings
while the DOT fluid uses EPDM rubber.

You mentioned corrosion and this raises some flags. Cleveland parts, that
Tost uses - changing the rubber parts to EPDM, were never really intended
for use with DOT fluid. The problem is that DOT fluid is hygroscopic and
whatever moisture gets into the fluid can corrode the bare aluminum surfaces
of the caliper and piston (later pistons were anodized and this helps some).
To find out if the piston is anodized, see if it conducts when touched with
the leads of an ohm meter as the anodize surface is an insulator.

If you have corrosion in the caliper bore or in the O-ring groove of the
piston, you will likely have leakage again, probably sooner than later. One
fix is to have the caliper bore machined and brass sleeved along with
anodizing the piston.

If anyone needs a free EPDM O-ring (for DOT fluid) for the Cleveland 300
series caliper, contact me via email (bumperm at att dot fish net) - remove
the scaley thing) to get the address to send a self-addressed stamped
envelope.

bumper
Quiet Vent - reduces vent noise by 10 dba


"Paul Cordell" wrote in message
...
It's Done!

Thanks Dave Nadler and Uncle Hank for the off-line notes.


This Soaring community is always surprising. I talked to Monty@ M &
H Soaring this morning about the spec's for the Pads and O-ring.
Then went over to Aircraft Spruce to get the parts. After I looked
at their web site, I still had some questions about the rivets. I
called a buddy that is an ex '20 owner and RV-7 builder to ask about
the rivets. He lives about 100 miles away. As we talked, he
walked out to his Hanger and went thru some stuff on his work
bench. He had exactly the parts I needed. When would you like to
do this he asked?? I told him that if he wanted to "help", it would
be on his schedule........He responded, I'll be there in an Hour. He
was and did the whole job as I "supervised". Cleaned and polished,
pads and ring with a full bleed and new fluid. The system in general
was in good shape. Just slight corrosion and some gunk. I
supplied him with 1 soda for all the trouble. He'll be back next
weekend for a test flight.

Paul




  #5  
Old April 16th 08, 07:46 AM posted to rec.aviation.soaring
Greg Arnold
external usenet poster
 
Posts: 251
Default Tost Disk Brake rebuild?

Why does Tost change the parts to use DOT fluid?

Which glider manufactures use brakes that take the red stuff, and which
use DOT fluid?


bumper wrote:
Paul,

As Gary Evans mentioned, there are basically two brake fluids used in
gliders. The "red stuff" Mil Spec 5606 oil (which most GA aircraft use) and
DOT # automotive type fluid. 5605 wants to have Buna-N seals and O-rings
while the DOT fluid uses EPDM rubber.

You mentioned corrosion and this raises some flags. Cleveland parts, that
Tost uses - changing the rubber parts to EPDM, were never really intended
for use with DOT fluid. The problem is that DOT fluid is hygroscopic and
whatever moisture gets into the fluid can corrode the bare aluminum surfaces
of the caliper and piston (later pistons were anodized and this helps some).
To find out if the piston is anodized, see if it conducts when touched with
the leads of an ohm meter as the anodize surface is an insulator.

If you have corrosion in the caliper bore or in the O-ring groove of the
piston, you will likely have leakage again, probably sooner than later. One
fix is to have the caliper bore machined and brass sleeved along with
anodizing the piston.

If anyone needs a free EPDM O-ring (for DOT fluid) for the Cleveland 300
series caliper, contact me via email (bumperm at att dot fish net) - remove
the scaley thing) to get the address to send a self-addressed stamped
envelope.

bumper
Quiet Vent - reduces vent noise by 10 dba


"Paul Cordell" wrote in message
...
It's Done!

Thanks Dave Nadler and Uncle Hank for the off-line notes.


This Soaring community is always surprising. I talked to Monty@ M &
H Soaring this morning about the spec's for the Pads and O-ring.
Then went over to Aircraft Spruce to get the parts. After I looked
at their web site, I still had some questions about the rivets. I
called a buddy that is an ex '20 owner and RV-7 builder to ask about
the rivets. He lives about 100 miles away. As we talked, he
walked out to his Hanger and went thru some stuff on his work
bench. He had exactly the parts I needed. When would you like to
do this he asked?? I told him that if he wanted to "help", it would
be on his schedule........He responded, I'll be there in an Hour. He
was and did the whole job as I "supervised". Cleaned and polished,
pads and ring with a full bleed and new fluid. The system in general
was in good shape. Just slight corrosion and some gunk. I
supplied him with 1 soda for all the trouble. He'll be back next
weekend for a test flight.

Paul




  #6  
Old April 16th 08, 07:54 AM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 194
Default Tost Disk Brake rebuild?

On Apr 16, 8:46 am, Greg Arnold wrote:
Why does Tost change the parts to use DOT fluid?

Which glider manufactures use brakes that take the red stuff, and which
use DOT fluid?

bumper wrote:
Paul,


As Gary Evans mentioned, there are basically two brake fluids used in
gliders. The "red stuff" Mil Spec 5606 oil (which most GA aircraft use) and
DOT # automotive type fluid. 5605 wants to have Buna-N seals and O-rings
while the DOT fluid uses EPDM rubber.


You mentioned corrosion and this raises some flags. Cleveland parts, that
Tost uses - changing the rubber parts to EPDM, were never really intended
for use with DOT fluid. The problem is that DOT fluid is hygroscopic and
whatever moisture gets into the fluid can corrode the bare aluminum surfaces
of the caliper and piston (later pistons were anodized and this helps some).
To find out if the piston is anodized, see if it conducts when touched with
the leads of an ohm meter as the anodize surface is an insulator.


If you have corrosion in the caliper bore or in the O-ring groove of the
piston, you will likely have leakage again, probably sooner than later. One
fix is to have the caliper bore machined and brass sleeved along with
anodizing the piston.


If anyone needs a free EPDM O-ring (for DOT fluid) for the Cleveland 300
series caliper, contact me via email (bumperm at att dot fish net) - remove
the scaley thing) to get the address to send a self-addressed stamped
envelope.


bumper
Quiet Vent - reduces vent noise by 10 dba


"Paul Cordell" wrote in message
...
It's Done!


Thanks Dave Nadler and Uncle Hank for the off-line notes.


This Soaring community is always surprising. I talked to Monty@ M &
H Soaring this morning about the spec's for the Pads and O-ring.
Then went over to Aircraft Spruce to get the parts. After I looked
at their web site, I still had some questions about the rivets. I
called a buddy that is an ex '20 owner and RV-7 builder to ask about
the rivets. He lives about 100 miles away. As we talked, he
walked out to his Hanger and went thru some stuff on his work
bench. He had exactly the parts I needed. When would you like to
do this he asked?? I told him that if he wanted to "help", it would
be on his schedule........He responded, I'll be there in an Hour. He
was and did the whole job as I "supervised". Cleaned and polished,
pads and ring with a full bleed and new fluid. The system in general
was in good shape. Just slight corrosion and some gunk. I
supplied him with 1 soda for all the trouble. He'll be back next
weekend for a test flight.


Paul


I've wondered myself - Possibly for compatibility with the master
cylinder components scavenged from motorcycles ?

Beringer systems use DOT fluid (and work extremely well,
and are light). I had an HP that used the red stuff. I don't know
about other glider hydraulic brakes out there.
The Cleveland adaptations are, um, a bit problematic...

See ya, Dave
  #7  
Old April 16th 08, 02:11 PM posted to rec.aviation.soaring
JJ Sinclair
external usenet poster
 
Posts: 388
Default Tost Disk Brake rebuild?

Uses the red stuff (5606).......Schleicher, Genesis, others?

Uses the clear stuff (DOT 3)......Grob, Schempp-Hirth, DG

Look at your master cylinder, if its got red stuff in
it............use the red stuff, if its got clear stuff............

BTW, you can replace a chewed up disk & pads for just over $100 bucks,
see Aircraft Spruce & Specialty p/n 164-01700. Faster than trying to
get Midas to turn your scored disk, it bolts on using the 3 hub bolts.
JJ

wrote:
On Apr 16, 8:46 am, Greg Arnold wrote:
Why does Tost change the parts to use DOT fluid?

Which glider manufactures use brakes that take the red stuff, and which
use DOT fluid?

bumper wrote:
Paul,


As Gary Evans mentioned, there are basically two brake fluids used in
gliders. The "red stuff" Mil Spec 5606 oil (which most GA aircraft use) and
DOT # automotive type fluid. 5605 wants to have Buna-N seals and O-rings
while the DOT fluid uses EPDM rubber.


You mentioned corrosion and this raises some flags. Cleveland parts, that
Tost uses - changing the rubber parts to EPDM, were never really intended
for use with DOT fluid. The problem is that DOT fluid is hygroscopic and
whatever moisture gets into the fluid can corrode the bare aluminum surfaces
of the caliper and piston (later pistons were anodized and this helps some).
To find out if the piston is anodized, see if it conducts when touched with
the leads of an ohm meter as the anodize surface is an insulator.


If you have corrosion in the caliper bore or in the O-ring groove of the
piston, you will likely have leakage again, probably sooner than later. One
fix is to have the caliper bore machined and brass sleeved along with
anodizing the piston.


If anyone needs a free EPDM O-ring (for DOT fluid) for the Cleveland 300
series caliper, contact me via email (bumperm at att dot fish net) - remove
the scaley thing) to get the address to send a self-addressed stamped
envelope.


bumper
Quiet Vent - reduces vent noise by 10 dba


"Paul Cordell" wrote in message
...
It's Done!


Thanks Dave Nadler and Uncle Hank for the off-line notes.


This Soaring community is always surprising. I talked to Monty@ M &
H Soaring this morning about the spec's for the Pads and O-ring.
Then went over to Aircraft Spruce to get the parts. After I looked
at their web site, I still had some questions about the rivets. I
called a buddy that is an ex '20 owner and RV-7 builder to ask about
the rivets. He lives about 100 miles away. As we talked, he
walked out to his Hanger and went thru some stuff on his work
bench. He had exactly the parts I needed. When would you like to
do this he asked?? I told him that if he wanted to "help", it would
be on his schedule........He responded, I'll be there in an Hour. He
was and did the whole job as I "supervised". Cleaned and polished,
pads and ring with a full bleed and new fluid. The system in general
was in good shape. Just slight corrosion and some gunk. I
supplied him with 1 soda for all the trouble. He'll be back next
weekend for a test flight.


Paul


I've wondered myself - Possibly for compatibility with the master
cylinder components scavenged from motorcycles ?

Beringer systems use DOT fluid (and work extremely well,
and are light). I had an HP that used the red stuff. I don't know
about other glider hydraulic brakes out there.
The Cleveland adaptations are, um, a bit problematic...

See ya, Dave

  #8  
Old April 16th 08, 03:59 PM posted to rec.aviation.soaring
Bob Kuykendall
external usenet poster
 
Posts: 1,345
Default Tost Disk Brake rebuild?

On Apr 15, 10:55 pm, "bumper" wrote:
Paul,

As Gary Evans mentioned, there are basically two brake fluids used in
gliders...


Well, pretty much. But:

When I was cobbling together a brake for my HP-18 a few years ago, I
found it really convenient to use a Yamaha TZ250 master cylinder (left
over from my misspent youth) with a Cleveland wheel and brake. The
motorcycle parts like the DOT 3 fluid, and the Cleveland stuff likes
the 5056.

I ended up using a silicone-based brake fluid, similar to what they
now sell as DOT 5 (also left over from the roadracing days) that
worked fine with both ends of the system. It also had enough color
that I could see it through the walls of the 1/8" OD Nylaflow tubing
that connected the two.

The whole system worked great, never leaked, and was trouble-free. And
since the master cylinder is diaphragm-vented as motorcycle brakes so
tend, it didn't drip at all when I turned the fuselage upside-down.

Thanks, Bob K.
  #9  
Old April 16th 08, 03:59 PM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 172
Default Tost Disk Brake rebuild?

On Apr 16, 6:11*am, JJ Sinclair wrote:
Uses the red stuff (5606).......Schleicher, Genesis, others?

Uses the clear stuff (DOT 3)......Grob, Schempp-Hirth, DG

Look at your master cylinder, if its got red stuff in
it............use the red stuff, if its got clear stuff............

BTW, you can replace a chewed up disk & pads for just over $100 bucks,
see Aircraft Spruce & Specialty p/n 164-01700. Faster than trying to
get Midas to turn your scored disk, it bolts on using the 3 hub bolts.
JJ



wrote:
On Apr 16, 8:46 am, Greg Arnold wrote:
Why does Tost change the parts to use DOT fluid?


Which glider manufactures use brakes that take the red stuff, and which
use DOT fluid?


bumper wrote:
Paul,


As Gary Evans mentioned, there are basically two brake fluids used in
gliders. The "red stuff" Mil Spec 5606 oil (which most GA aircraft use) and
DOT # automotive type fluid. 5605 wants to have Buna-N seals and O-rings
while the DOT fluid uses EPDM rubber.


You mentioned corrosion and this raises some flags. Cleveland parts, that
Tost uses - changing the rubber parts to EPDM, were never really intended
for use with DOT fluid. The problem is that DOT fluid is hygroscopic and
whatever moisture gets into the fluid can corrode the bare aluminum surfaces
of the caliper and piston (later pistons were anodized and this helps some).
To find out if the piston is anodized, see if it conducts when touched with
the leads of an ohm meter as the anodize surface is an insulator.


If you have corrosion in the caliper bore or in the O-ring groove of the
piston, you will likely have leakage again, probably sooner than later. One
fix is to have the caliper bore machined and brass sleeved along with
anodizing the piston.


If anyone needs a free EPDM O-ring (for DOT fluid) for the Cleveland 300
series caliper, contact me via email (bumperm at att dot fish net) - remove
the scaley thing) to get the address to send a self-addressed stamped
envelope.


bumper
Quiet Vent - reduces vent noise by 10 dba


"Paul Cordell" wrote in message
...
It's Done!


Thanks Dave Nadler and Uncle Hank for the off-line notes.


This Soaring community is always surprising. * I talked to Monty@ M &
H Soaring this morning about the spec's for the Pads and O-ring.
Then went over to Aircraft Spruce to get the parts. * *After I looked
at their web site, I still had some questions about the rivets. *I
called a buddy that is an ex '20 owner and RV-7 builder to ask about
the rivets. * He lives about 100 miles away. * * As we talked, he
walked out to his Hanger and *went thru some stuff on his work
bench. * He had exactly the parts I needed. * *When would you like to
do this he asked?? * I told him that if he wanted to "help", it would
be on his schedule........He responded, I'll be there in an Hour. * He
was and did the whole job as I "supervised". * * Cleaned and polished,
pads and ring with a full bleed and new fluid. * The system in general
was in good shape. * *Just slight corrosion and some gunk. * *I
supplied him with 1 soda for all the trouble. * *He'll be back next
weekend for a test flight.


Paul


I've wondered myself - Possibly for compatibility with the master
cylinder components scavenged from motorcycles ?


Beringer systems use DOT fluid (and work extremely well,
and are light). I had an HP that used the red stuff. I don't know
about other glider hydraulic brakes out there.
The Cleveland adaptations are, um, a bit problematic...


See ya, Dave- Hide quoted text -


- Show quoted text -


Paul,
Glad to hear your glider brake is back in service.
As a general question to all those really knowledgeable folks out
there, What are the advantages/disadvantages of 5606?
One disadvantage I know of is that it really has strong smell that's
hard to get out of stuff. Others?
Dot 3 will rip the paint off nearly anything (I've used it to strip
small painted parts), is hydroscopic - not a problem in the SW desert
if you do a full bleed annually, and is available just about
everywhere. Any reason NOT to convert? (Aside from the paint
thing...)
In my limited experience with glider brakes it appears that all the
'seals' used are off-the-shelf o-rings, as opposed to specially formed
seals found in automotive and motorycle braking systems. This would
seem to make conversion to DOT 3 a snap. Am I missing something here?
TIA
Jim
  #10  
Old April 16th 08, 09:20 PM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 172
Default Tost Disk Brake rebuild?

On Apr 16, 7:59*am, Bob Kuykendall wrote:
On Apr 15, 10:55 pm, "bumper" wrote:

Paul,


As Gary Evans mentioned, there are basically two brake fluids used in
gliders...


Well, pretty much. But:

When I was cobbling together a brake for my HP-18 a few years ago, I
found it really convenient to use a Yamaha TZ250 master cylinder (left
over from my misspent youth) with a Cleveland wheel and brake. The
motorcycle parts like the DOT 3 fluid, and the Cleveland stuff likes
the 5056.

I ended up using a silicone-based brake fluid, similar to what they
now sell as DOT 5 (also left over from the roadracing days) that
worked fine with both ends of the system. It also had enough color
that I could see it through the walls of the 1/8" OD Nylaflow tubing
that connected the two.

The whole system worked great, never leaked, and was trouble-free. And
since the master cylinder is diaphragm-vented as motorcycle brakes so
tend, it didn't drip at all when I turned the fuselage upside-down.

Thanks, Bob K.


That's a good solution except for my extreme (and possibly mistaken)
paranoia when 'silicone' and composites are allowed close proximity.
 




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