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Fredrik S
Staff Sergeant
Gender: Male
Location: Jönköping, Sweden
Registered: Sep 2014
Status: Offline
Posts: 49
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Posted Tuesday, January 5, 2016 @ 06:30 AM
Hi all.
A friend of mine bought a RF5B last year and is fiddling with the yearly inspection.
I am the technician for his RF5 and we have hit a little snug.
The 5 has the optional disc brake and therefor a hydraulic wheel brake. They had a lot of problems bleeding the air out of the system so we decided to take it apart and inspect it and discovered some really not good looking seals in the master cylinder.
Now to my question, does anyone of you with this system know what brake fluid is used in the RF5B?
Is it standard red (hydraulic propertied) brake fluid as found in pawnees, ASK21:s etc or is it supposed to be filled with DOT4 car brake fluid?
We can´t seem to get the information from the flight manual nor the maintenance manual because the system is not really described apart from the standard mechanically activated drum brake.
-------------------- Best regards
/Fredrik Svanberg
RF4D serial#4104 SE-XSK
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Donald
Command Sergeant Major
Gender: Male
Location: Scotland
Registered: Jan 2007
Status: Offline
Posts: 489
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Posted Tuesday, January 5, 2016 @ 11:50 AM
I have no personal knowledge but does this thread help?
http://sbeaver.com/cgi-bin/fournier/cutecast.pl?session=tUBd7d2mmLCaFL2ZEmXXUl1yS2&forum=11&thread=261
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Fredrik S
Staff Sergeant
Gender: Male
Location: Jönköping, Sweden
Registered: Sep 2014
Status: Offline
Posts: 49
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Posted Thursday, January 7, 2016 @ 02:18 AM
Yhank you Donald!
I tried to do a search in the forum before i posted my question but in my browser that thread didn't pop up, so i thank you for the link
-------------------- Best regards
/Fredrik Svanberg
RF4D serial#4104 SE-XSK
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Donald
Command Sergeant Major
Gender: Male
Location: Scotland
Registered: Jan 2007
Status: Offline
Posts: 489
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Posted Thursday, January 7, 2016 @ 03:11 AM
I didn't search the forum but typed RF5 brake system into google and that thread was the 5th result.
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Collin
General
Gender: Male
Location: McMinnville. Oregon
Registered: Oct 2006
Status: Offline
Posts: 711
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Posted Saturday, January 9, 2016 @ 10:04 PM
Hi,
I also have been doing my annual inspection. My brake lost its bleed last summer. I added fuild 5606 mil spec fuild and the brake got worse. It had some clear fuild that did not mix with the 5606. I am now replacing all the rings. It sure is fun getting to the master cylinder. I am adding a vent hose so future back (reverse) bleeding does not make mess.
Collin
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eugenio
First Sergeant
Gender: Male
Location: Str. Val S. Martino inferiore 133/7 I - 10131 Torino ITALY
Registered: Oct 2006
Status: Offline
Posts: 294
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Posted Tuesday, February 16, 2016 @ 04:54 PM
Normally the disc brake system installed on the RF5 and RF5B is Cleveland and it is supposed to work with petroleum based liquid (the red one, or if you like the clear one used on hydraulic circuits). The orings used on these system are compatible with these kind of fluids. In some gliders (I think also on the K21, for sure on the Grobs) the manufacturer used DOT 3 or DOT 4, that are organic based liquids, not compatible with the material used for the other kind of fluid, for that reason there are specific orings to be used with DOT fluid. The master brake cylinder is fitted with orings for the petroleum based fluid, so the whole system should work with it. The reason why on the gliders they use the DOT is because the master brake cylinder is done with a motorbike one which is suitable only with organic fluid.
Eugenio
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Martin Hill
Sergeant
Gender: Male
Location: UK
Registered: Apr 2010
Status: Offline
Posts: 35
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Posted Friday, February 19, 2016 @ 01:09 PM
For what it is worth Tost lists the wheels fitted to RF5 as Super 6" (drum) and SB 6" (disc). My drum wheel is definitely a Tost. Whether all RF5 disc wheels are Tost I can't say.
In the Tost Wheel Manual (1999) it states:
"For pressure transfer use either hydraulic fluid (MIL H 5606) or DOT 4 brake fluid (in TOG brake callipers and Cleveland callipers identified by Ø)."
I am not sure what "identified by Ø" means - either physically marked on wheel or different wheel diameters have different brakes. There is no information on that.
I would suggest contact Tost for a definitive answer. I have found them helpful in the past. Email: info@tost.de or phone: +49-89-544 599-0.
The manual was available on their website (in pdf) but if anyone wants a copy let me know.
Martin
-------------------- RF5 #5107 G-BEVO
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Martin Hill
Sergeant
Gender: Male
Location: UK
Registered: Apr 2010
Status: Offline
Posts: 35
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Posted Friday, February 19, 2016 @ 01:37 PM
I have found in other Tost documents that the brakes are Cleveland 30-36A (for 6mm disc). However the 30-36A comes in two variants:
p/n 076810 for MIL-H-5606 hydraulic fluid
p/n 076820 for DOT 4 brake fluid
I would suggest look for a p/n or marking or ask Tost.
-------------------- RF5 #5107 G-BEVO
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