Taifun Brake saga continues..

Abstract:    Please be informed that the gaskets/o-rings in the master brake cylinder MAGURA are not for use with Fluid 41 (former Fluid 4)! It needs DOT 3 or 4.

Subject: Re: Taifun Brake saga continues..
From: "cloudsipper" <amelendy@yahoo.com>
Date: 10/7/08 2:54 PM
To: Taifun17E@yahoogroups.com

--- In Taifun17E@yahoogroups.com, "KORFF LUFTFAHRT DB"
<cornelia.korff@...> wrote:
"> Please be informed that the gaskets/o-rings in the master brake
cylinder
> > MAGURA are not for use with Fluid 41 (former Fluid 4)! It needs DOT
3 or 4.
> > With Fluid 41 it will be damaged!
> > The o-rings you can buy from Spruce for the calliper are normally
for the
> > use with Fluid 41 and will not be stable with DOT 3 or 4 and will
dissolve
> > after a short time.
> >
> > You need o-rings for DOT 3 or 4 maybe from TOST.
> > www.tost.de <http://www.tost.de/>
> > Part-No.: 075835 O-ring for 30-9, for brake fluid DOT 4
> >
> > Best Regards,
> >
> > Cornelia Korff
> >
> > (Technischer Leiter)
> >
=======

My answer.....

The proper O-ring material is epdm and is a standard size (218), the
O-rings are available from several suppliers in the US. I believe Tost
charges 3.80 euro ($5.18 each!) ..plus shipping from Germany!!  Mine
cost $0.50 each and envelope postage.
Where is the brake reservoir?
When you open up the flat, horizontal  baggage section, the large
reservoir is *not* the brake reservoir, but rather the hydraulic
landing gear reservoir. This fluid appears to be mil-spec 6036
(mineral oil). The brake reservoir is located further aft under the
sloping part of the baggage compartment and is buried below all the
control linkages there. There appears to be a drain (I hope it's a
bleeder type.. Korff can you confirm this?)
BTW if you really need the parts from Tost...Here is an excerpt from
the 2008 Tost catalog..excuse the alignment, it was cut and paste
==========
Brake assembly 30-9 and spare parts
075818 Brake assembly 30-9, for Tost wheels, for hydraulic fluid
356,00 423,64
075820 359,00 427,21
075873 4,10 4,88
075825 45,00 53,55
075834 8,50 10,12
>>>>>> >>>>>>
075835 O-ring for 30-9, for brake fluid DOT 4 3,80 4,52
>>>>>> >>>>>>
075862 Brake lining for 30-9, non-asbestos pc 14,20 16,90
075861 Rivet for brake lining 075862 pc 0,32 0,38
075865 Service set brake linings for brake 30-9 set 30,00 35,70
set consists from 2 ea. brake lining and 6 ea. brass rivet 0,00
075870 20,20 24,04
075881 Nut for anchor bolt 075870 2,50 2,98
075882 Washer for anchor bolt 075870 1,65 1,96
075871 Back plate assembly for 30-9 99,50 118,41
075872 Pressure plate assembly for 30-9 78,00 92,82
075891 Torque plate assembly for 30-9, original equipment for brake
disk 162 mm dia. 133,00 158,27
075892 Special torque plate, for Tost disk brake wheels 141,00 167,79

Taifun17E] Brake dis-assembly & pad replacement
> >
> > 
> >
> > Caliper assy removal was pretty easy, the o-ring shows some
> > wear/roughness maybe even some deterioration (heat?), the
> > cross-section is almost square! Some corrosion outboard of the o-ring,
> > cleaned up OK with scotchbrite. O-rings are $0.39 at Aircraft Spruce,
> > but most FBO's seem to carry a few. The oil pump dispenser seems like
> > the common way to push fluid up into the reservoir. The reservoir is
> > under a removable panel under the baggage section upholstery.
> > So far, so good..
> > I went ahead and replaced brake pads since I had the unit apart
> > (besides, the pads were oil soaked). The only uncertainty now is the
> > "burning -in" of the new pads. (I guess if the pads don't glaze up
> > well, I'll be doing circles on run-up.)
> > I believe all of this can be done by an owner, even if the ship is
> > certified. Correct me if I'm wrong.
> >
> > --- In Taifun17E@yahoogrou <mailto:Taifun17E%40yahoogroups.com> ps.com,
> > "Fred Bonar" <fbonar@> wrote:
>> > >
>> > > Al
>> > >
>> > > Mine are coming up, pads are 80% but since its only been flown 15
> > hours in 9
>> > > years, all seals are suspect, the 105 to 110 heat didn't help either.
>> > > Already replaced the compass and fuel seals and rings.
>> > >
>> > > Bob had some great tips on bleeding..
>> > >
>> > > Fred
>> > >
>> > >
>> > >
>> > > From: Taifun17E@yahoogrou <mailto:Taifun17E%40yahoogroups.com> ps.com
> > [mailto:Taifun17E@yahoogrou <mailto:Taifun17E%40yahoogroups.com> ps.com]
> > On Behalf
>> > > Of cloudsipper
>> > > Sent: Saturday, September 27, 2008 3:31 PM
>> > > To: Taifun17E@yahoogrou <mailto:Taifun17E%40yahoogroups.com> ps.com
>> > > Subject: [Taifun17E] Re: Brake failure at end of taxiing !
>> > >
>> > >
>> > >
>> > > Yup.. looks like "30-9" a standard Cleveland assy.
>> > > I'm leaning toward just ordering an O-ring.. any thoughts?
>> > > The whole assy is ~$380 so it's not catastrophic.
>> > >
>> > > I guess the tricky part is bleeding the assy after the fix .. everyone
>> > > says to pump fluid up from the bleeder valve and watch for overflow at
>> > > the master reservoir.. I think I can do that.. will try a turkey
>> > > baster and some tubing. wish me luck.
>> > > Al
>> > >
>> > > --- In Taifun17E@yahoogrou <mailto:Taifun17E%40yahoogroups.com> ps.com
> > <mailto:Taifun17E%40yahoogroups.com> ,
>> > > "Fred Bonar" <fbonar@> wrote:
>>> > > >
>>> > > > # is on the brake cliper, should be Cleveland and parts
available from
>>> > > > Aircraft spruce, don't know about cost but mine are due.
>>> > > >
>>> > > >
>>> > > >
>>> > > > From: Taifun17E@yahoogrou <mailto:Taifun17E%40yahoogroups.com>
ps.com
> > <mailto:Taifun17E%40yahoogroups.com>
>> > > [mailto:Taifun17E@yahoogrou <mailto:Taifun17E%40yahoogroups.com>
ps.com
> > <mailto:Taifun17E%40yahoogroups.com> ]
>> > > On Behalf
>>> > > > Of cloudsipper
>>> > > > Sent: Saturday, September 27, 2008 1:26 PM
>>> > > > To: Taifun17E@yahoogrou <mailto:Taifun17E%40yahoogroups.com> ps.com
> > <mailto:Taifun17E%40yahoogroups.com>
>>> > > > Subject: [Taifun17E] Brake failure at end of taxiing !
>>> > > >
>>> > > >
>>> > > >
>>> > > > Last flight of a Young Eagles day, taxiing to fuel pump and brakes
>>> > > > failed (spoiler lever went all the way to the stop) Brake fluid
>>> > > > noticeable on left main. On a scale of 1 to 10 where 10 means get a
>>> > > > ($$ A&P mechanic to fix it) how difficult is this going to be to
> > repair?
>>> > > > Is the brake system from Cleveland? any part numbers? I'm
thinking an
>>> > > > O-ring failure, but I guess it could be more serious... HELP !!
>>> > > >
>>> > > > Fortunately it was the last flight of the day and the failure wasn't
>>> > > > on the runway at high speed..
>>> > > >
>> > >
> >

Subject: RE: [Taifun17E] Re: Taifun Brake saga continues..
From: "Fred Bonar" <fbonar@yahoo.com>
Date: 10/9/08 7:47 AM
To: <Taifun17E@yahoogroups.com>

Al

Where did you ultimately get your seals and o-rings, Aircraft Spruce?  How did you identify the fluid as to being Fluid 41 or DOT 3 or 4.
Fred

Subject: Re: Taifun Brake saga continues.. (long answer)
From: "cloudsipper" <amelendy@yahoo.mail>
Date: 10/9/08 8:56 AM
To: Taifun17E@yahoogroups.com

Fluid 41 or MilSpec 5606( the correct designation, I used the wrong number earlier) is a mineral oil (and in the gallon I bought, colored  red). I determined that the red fluid in the hydraulic reservoir was oil by absorbing a bit on a piece of paper towel and putting the paper towel on the surface of a clean bowl of water..there was an immediate
"oil slick". This technique was suggested (only using a q-tip) for checking the fittings in an oxygen system for oil traces.  The brake reservoir Dot4 question is a tougher one.. the same test showed no "slick", and the fluid (amber colored) was either absorbed or evaporated from my hands.. it felt (and smelled) different, kind of oily at first and then nothing. I remember handling glycerine and it was similar. Remember rubber powered airplanes? green soap & glycerine?  As to whether it was dot3 or dot4, I can't answer. All the relevant reading indicates that Dot4 is an acceptable substitute for Dot3, but the reverse is not true, (Jim Leedy talks about seals being destroyed after replacing Dot4 with Dot3.) NAPA auto parts has Dot4 at a very reasonable price. Dot5 is silicone based and a *completely* different product, don't even mess with it!

The o-rings came from an outfit in Denver who only wishes to deal with businesses ( I guess the sales tax issue?) Email me directly if you need more info. (allan.melendy@yahoo.com) *Note* I found a reference in the 17E type 1 maintenance manual showing the master cylinder and reservoir under the left seat...Different from mine (I apologize for these constant references to having a different airplane, I'm not suggesting the type 2 is superior, just different

The Magura reference by Cornelia Korff threw me a little, but they(Magura) do make master cylinders for motorcycles and trail bikes, so I guess it's not a stretch to see them in airplanes. To be honest, I haven't really located the master cylinder under the tangle of control rods (type2 alert) since my concern was only with the brake
reservoir.
Hope all this helps..Most automotive literature suggests changing Dot4 every year because it absorbs moisture so rapidly. There doesn't seem to be the same level of concern for the small reservoirs for motorcycles & trail bikes. By all accounts Dot4 is incredibly hygroscopic and can cause brake failures when the adsorbed water vaporizes or when it drops the boiling point of the brake fluid sufficiently. The good news: it doesn't burn! ... there have been several cases recently of oil based hydraulic
brake fires, particularly in enclosed wheel pants. Off topic..
I noticed Powergliders.de published my article.. if you haven't visited the site, it's a real treat. The Taifun get-together must have
been a special experience. Maybe we could do something like that in this country. A lot farther to fly..:(
Best regards.
Al Melendy

Subject: Re: Taifun Brake saga continues..>nightmare !
From: "cloudsipper" <amelendy@yahoo.com>
Date: 10/10/08 7:46 AM
To: Taifun17E@yahoogroups.com

Installed new O-rings in caliper assemblies, pumped fresh Dot4 fluid through the bleed valves ... drips out the bottom of the airplane under the master cylinder. Oh, I discovered the master cylinder..it's buried below all the control bellcranks on the rear of the bulkhead below the sloping part of the baggage compartment. The actuating piston protrudes forward through the bulkhead and is pushed to the rear when the airbrake assembly reaches the end of its rearward travel. Thats what's *supposed to happen*, but for some reason the actuating rod is not coming forward!  I suspect that the piston inside the master cylinder has gotten jammed (bad o-ring?) at the end of its travel and can't reset. Not the least of the problem is the terrible access in that part of the ship. The master cylinder( with built-in reservoir) is inches above the bottom of the fuselage. I may have to dis-assemble the aileron and flap bellcranks and remove them to get access to the #@%$# master cylinder. I've even considered cutting a
hole for access, but more than a bit concerned about weakining the structure. Other master cylinders for aircraft seem to have a cylinder travel of 1 to 2 inches, am I missing something? There is a drain on the bottom of the cylinder, perhaps the piston can be forced forward by pressurizing that connection. Anyone have any suggestions?

Subject: Re: Taifun Brake saga continues..>nightmare !
From: "John" <johncallahan@yahoo.com>
Date: 10/10/08 5:04 PM
To: Taifun17E@yahoogroups.com

I see that yours is a 17E II so you had better have a look at this link.  http://www.powerglidertaifun.de/technics/crack/cracked.htm Lots of other good info here also. Hope this is not your problem.
Regards, John.

Subject: Re: Taifun Brake saga continues..>nightmare !
From: "John" <johncallahan@yahoo.com>
Date: 10/10/08 6:34 PM
To: Taifun17E@yahoogroups.com

I just tested that link and it's out of date. Instead go to www.powerglidertaifun.de then technics then "cracked not crashed".
John