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No Brakes!

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czech6(at)mesanetworks.ne
Guest

Posted: Wed Aug 20, 2008 4:54 pm Post subject: No Brakes!

I have a Yak 52. My brakes work great for a few minutes during landing, then

the right one (only) disappears almost completely. Pads are good. Left one

is perfect.

Do they fade that fast, or could it be something more expensive then fading?



Thanks.

Jetj01(at)aol.com
Guest

Posted: Wed Aug 20, 2008 5:35 pm Post subject: No Brakes!

They fade fast....but usually only when you really need them!

  

 Jj

 YAK 50

  

  In a message dated 8/20/2008 7:55:23 P.M. Central Daylight Time,  czech6(at)mesanetworks.net writes:

  	  Quote: 	
		  -->    Yak-List message posted by: "Bill Geipel"    <czech6(at)mesanetworks.net>



I have a Yak 52. My brakes work great    for a few minutes during landing, then

the right one (only) disappears    almost completely. Pads are good. Left one

is perfect.

Do they fade that    fast, or could it be something more expensive then  ========================

es  y       -->                 - MATRONICS WEB FORUMS  nbsp;               - List Contribution Web Site  ;                             =========================



	




It's only a deal if it's where you want to go. Find your travel deal here.

  [quote][b]

f4ffm2(at)adelphia.net
Guest

Posted: Wed Aug 20, 2008 6:33 pm Post subject: No Brakes!

I have flown Yak 52's (about 20 different airplanes) over a thousand hours...and have not had any meaningful brake fade incidents...even in long taxiis with crosswind.  Brakes are good if one manages them properly.



Any drum brake will eventually fade if ridden heavily without opportunity to cool between applications.

Roger_________________________________________________________________________

On Aug 20, 2008, at 6:35 PM, Jetj01(at)aol.com (Jetj01(at)aol.com) wrote:

 	  Quote: 	
		    They fade fast....but usually only when you really need them!

  

 Jj

 YAK 50

  

  In a message dated 8/20/2008 7:55:23 P.M. Central Daylight Time, czech6(at)mesanetworks.net (czech6(at)mesanetworks.net) writes:

  	  Quote: 	
		   href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics.com/Navigator?Yak-List href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/contribution  [/b] 	
	




 [quote][b]

viperdoc(at)mindspring.co
Guest

Posted: Wed Aug 20, 2008 6:33 pm Post subject: No Brakes!

Do not know what your technique is but I just squeeze and release intermitently. I also let the aircraft roll out on the runway to the end not trying to stop it for the short  turn off (fox trot).  If you have a downhill taxi, take it real slow with the idle back at the stops or they will fade on you real quick there too. Heating up the brakes and having them fade is common with the YAK. They do not get ventilation to cool the pads. Some people have drilled the rivets out of the dust and  mud covers to get better ventilation to the brake shoes. If that is done, the center section of the dust cover needs to be trimmed to make a center disc to keep the felt for the wheel bearing covered. I have not done that so I do not know how that works for keeping the shoes cooler.  

The times I have heated up my brakes with them fading out, after that  I pulled the wheels and scrubbed the pads with emery cloth to remove the glaze. I also roughed up the inside of the brake drum too for the same reason. It seemed to improve my braking after doing that.  

Doc   

       

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Jetj01(at)aol.com

 Sent: Wednesday, August 20, 2008 8:35 PM

 To: yak-list(at)matronics.com

 Subject: Re: No Brakes!  

  

  

     

They fade fast....but usually only when you really need them!  

    

   

    

Jj  

    

YAK 50  

    

   

      

In a message dated 8/20/2008 7:55:23 P.M. Central Daylight Time, czech6(at)mesanetworks.net writes:  

   	  Quote: 	
		    

--> Yak-List message posted by: "Bill Geipel" <czech6(at)mesanetworks.net>

 

 I have a Yak 52. My brakes work great for a few minutes during landing, then

 the right one (only) disappears almost completely. Pads are good. Left one

 is perfect.

 Do they fade that fast, or could it be something more expensive then ========================

 es y   -->              - MATRONICS WEB FORUMS nbsp;            - List Contribution Web Site ;                         

 

 

   	
  

  



 

         

  

It's only a deal if it's where you want to go. Find your travel deal here.  

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       [quote][b]

MarkWDavis

Joined: 03 Jan 2007
Posts: 104
Location: Syracuse, KS

Posted: Wed Aug 20, 2008 8:32 pm Post subject: No Brakes!

Hey Dawg, you wanna buy a good used tailhook?  Only used a hundred times by 

a little Scooter.



Fly Navy!  :  )

---

dsavarese0812(at)bellsout
Guest

Posted: Thu Aug 21, 2008 3:56 am Post subject: No Brakes!

Mike is correct about the brake differential  valve.  Most importantly, the pressure should be the same on both sides  with the applicable rudder pedal fully depressed.  The pressure is directly  proportional to the pressure in the main air tank.  The ratio is  approximate 8 to 1 reduction through the brake reducing valve which feeds the  brake differential valve.  As long as you hold the brake handle, the  pressure should remain constant and proportional to the pressure in the main air  tank.  The brake differential valve can be rebuilt pretty easily.   Doug Sapp has the rebuild kits for them.  Yes, they are identical to the  CJ6 brake differential valve.  So is the brake reducing valve.  Doug  has the kits for them as well.

 Dennis

  

 [quote]   ---

dougsappllc(at)gmail.com
Guest

Posted: Thu Aug 21, 2008 5:23 am Post subject: No Brakes!

Bill, 

 It is most likley that your brake distribution valve is going TU.  I have the parts to overhaul them, I also have parts to overhaul the brake pressure reducing valve.  Give me a call if I can help.

  

 



 

 On Wed, Aug 20, 2008 at 5:55 PM, Bill Geipel <czech6(at)mesanetworks.net (czech6(at)mesanetworks.net)> wrote:

 [quote]--> Yak-List message posted by: "Bill Geipel" <czech6(at)mesanetworks.net (czech6(at)mesanetworks.net)>

 

I have a Yak 52. My brakes work great for a few minutes during landing, then

the right one (only) disappears almost completely. Pads are good. Left one

is perfect.

Do they fade that fast, or could it be something more expensive then fading?

 

-- 

Always Yakin,

Doug Sapp

Phone 509-826-4610

Fax 509-826-3644



  [quote][b]

MarkWDavis

Joined: 03 Jan 2007
Posts: 104
Location: Syracuse, KS

Posted: Thu Aug 21, 2008 6:37 am Post subject: No Brakes!

Dennis,

       Just trying to understand  the system.  If it is the proportioning valve, why would Bill have good  brakes when cold, then only lose one side after rollout?  Just enough  difference in the condition of the two brakes to make one fade but not the  other?  Or is it maybe just enough difference in the  proportioning valve to make two similarly warmed up brakes act  differently?

  

 Thanks,

 Mark Davis

 N44YK

  

 [quote]   ---

dougsappllc(at)gmail.com
Guest

Posted: Thu Aug 21, 2008 7:39 am Post subject: No Brakes!

Bill,

 Not suggesting that this is your problem but I have noticed that at annual when the wheel bearing are repacked some folks are using the wrong (to light) grease, and the felt wheel seals are not getting replaced.  In hot weather this lighter body grease is slinging out of the bearing.  If the felt seals are old or missing this will allow the grease to migrate into the brake drum.  Seals are cheap and normally always in stock.

   

 



 

 On Wed, Aug 20, 2008 at 5:55 PM, Bill Geipel <czech6(at)mesanetworks.net (czech6(at)mesanetworks.net)> wrote:

 [quote]--> Yak-List message posted by: "Bill Geipel" <czech6(at)mesanetworks.net (czech6(at)mesanetworks.net)>

 

I have a Yak 52. My brakes work great for a few minutes during landing, then

the right one (only) disappears almost completely. Pads are good. Left one

is perfect.

Do they fade that fast, or could it be something more expensive then fading?

 

-- 

Always Yakin,

Doug Sapp

Phone 509-826-4610

Fax 509-826-3644



  [quote][b]

dsavarese0812(at)bellsout
Guest

Posted: Thu Aug 21, 2008 7:49 am Post subject: No Brakes!

I'm not sure Mark.  It could also be caused by  a bad or missing rear felt grease seal which caused the grease from the  rear bearing area to migrate outward toward the brake pads and all over the rear  dust cover.  The easiest and least expensive fix would be to pull the wheel  assembly and inspect the rear seal and the area around the rear dust cover for  grease.  It will be obvious because the grease will be covered with brake  dust.  If the felt seal is broken or missing, then I would focus  on this being the possible cause.  Replace the grease seals in the hub,  front and rear; remove the brake pads and wash thoroughly with avgas as this  will remove most all of the grease and not leave a residue on the pads; DO NOT  TURN THE DRUMS under any circumstances, regardless of how scored they will be.  Only replace drums, which Doug has in stock; using 60 grit Emory cloth, sand the  inner surface of the drum to break the glaze; using mineral spirits or similar  solvent, thoroughly pressure wash all of the excess grease from around the brake  surface area and the spindle paying particular attention to the area on and  around the rear dust cover behind the rear bearing and the dust cover around  behind the brake pucks; clean and repack the wheel bearing; reassemble and  test.

  

 If this doesn't fix the problem, overhaul the brake  differential valve.  It's less than a $100 for the parts.

 Dennis

  

 [quote]   ---

dsavarese0812(at)bellsout
Guest

Posted: Thu Aug 21, 2008 7:49 am Post subject: No Brakes!

Great minds think alike Doug.

 Dennis

 [quote]   ---

mikspin

Joined: 12 Aug 2007
Posts: 66

Posted: Thu Aug 21, 2008 10:39 pm Post subject: Re: No Brakes!

I have replaced a set of drums on two Yak 52's where fade was a problem.  It turns out that the wall thickness (suprisingly worn despite several annuals) of the drum was reduced to the point that the normal rate of heat absorption/dissipation couldn't take place during anything more than light braking and low power, level surface taxiing.

Fresh drums (and pads) resulted in no fade during the typical scenarios such as downwind/crosswind taxi, short turnoff (I agree about letting the airplane roll out if you can).  

In both cases, the pilots commented that it felt like a completely different airplane after the drum and pad change, even after a period of use where you would think a glaze would set up on the drums.

czech6(at)mesanetworks.ne
Guest

Posted: Fri Aug 22, 2008 5:59 am Post subject: No Brakes!

Thank you. I am on my way to the flyin' yard to pull the wheels off. We'll

see. Are drums available?



--

dsavarese0812(at)bellsout
Guest

Posted: Fri Aug 22, 2008 6:03 am Post subject: No Brakes!

Most definitely drums are available.  Contact Doug Sapp.  He typically has 

them on the shelf.

Dennis



---

viperdoc(at)mindspring.co
Guest

Posted: Fri Aug 22, 2008 7:12 am Post subject: No Brakes!

Yes, Contact Doug Sapp. 

Doc



--

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