Brake System Education

[Marauder]

Last week I noticed my right brake pedal extended a little further back than the left and didn’t return. The braking on the right side was slightly softer than the left side.

 

I thought I understood the brake system, but I am perplexed on whether I am dealing with an air in the line situation or perhaps something like a seal leaking internally in the master or elsewhere.

 

Looking at this picture you can tell the right pedal is further depressed than the left. When I pull on the pedal, it returns to the correct position but I can feel a little detent or bump when I pull. Ignore the rug, Santa promised me new ones for Christmas (I promised him I would be less naughty this year).

 

 

Terry H will be coming over this week to implement the “solution” but I decided to troubleshoot what I could.

 

I checked over the calibers and did not see any evidence of leaks. Terry and I replaced the pads last year.

 

 

Looking at the reservoir, the level is about 1.5” from the top of the tank. What a pain to get to it. Not sure if the level should be higher than where it is.

 

 

I did notice a little bit of fluid in the area where the parking brake valve is. I would think if it was leaking here, both brakes would be affected.

 

 

Finally, I pulled the access panel to check on the master cylinders and found them bone dry.

 

 

 

Anyone have any ideas whether what I am seeing is an air in the line situation or something else?

 

 

 

 

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[RLCarter]

Sounds like it's binding, disconnect at the master cylinder and see if it's in the pedal/linkage or the master cylinder itself

[Marauder]

Sounds like it's binding, disconnect at the master cylinder and see if it's in the pedal/linkage or the master cylinder itself

I did follow the linkage down through the floor and looked over the linkages. Nothing obvious. I couldn’t observe the movement when it was being pushed and pulled. Terry and I will look at that. Thanks.




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[Shadrach]

Is that side dragging?  Part of a damaged o-ring can "roll" out of its seat and create problems.  Internal leaks don't manifest them selves externally.  My guess is that cylinder will need to come apart.  The pedal/cylinder linkage is pretty simple. Making sure it's free and well lubed is low hanging fruit.

Edited November 19, 2018 by Shadrach

[Marauder]

Is that side dragging?  A damaged o-ring can "roll" out of its seat and create problems.  Internal leaks don't manifest them selves externally.  My guess is the cylinder is coming apart.

 

I have heard a little bit of dragging a couple of times. Wasn’t enough to be able to say which side was doing it. Just that rubbing sound.

 

As for the master cylinder, is there a rebuild kit for them? Or is there a company out there that rebuilds them? Thanks for the reply.

 

 

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[Shadrach]

12 minutes ago, Marauder said:

 

I have heard a little bit of dragging a couple of times. Wasn’t enough to be able to say which side was doing it. Just that rubbing sound.

 

As for the master cylinder, is there a rebuild kit for them? Or is there a company out there that rebuilds them? Thanks for the reply.

 

 

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LASAR has them I am sure.

[kortopates]

If you your parking brake had signs of leaking then for sure you should rebuild it with new o-rings. You'll be able to get a kit from LASAR for that and the MC if you want to do that one too.
Incidently, leakage in the parking brake will not effect both brakes. There are of course 2 separate lines going through it that don't connect except for the external valve mechanism.

If you haven't already, when you bleed and flush, you can switch to the synthetic equivalent of 5606H.


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[kortopates]

BTW, when the MC is re-installed, be sure to remove that gap between the bracket and the MC fitting with a washer or 2 so that it can't move side to side to prevent any side loading. Probably just one standard -08 washer, plus the thin one behind the cotter pin.


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[Shadrach]

6 minutes ago, kortopates said:

If you your parking brake had signs of leaking then for sure you should rebuild it with new o-rings. You'll be able to get a kit from LASAR for that and the MC if you want to do that one too.
Incidentally, leakage in the parking brake will not effect both brakes. There are of course 2 separate lines going through it that don't connect except for the external valve mechanism.

If you haven't already, when you bleed and flush, you can switch to the synthetic equivalent of 5606H.


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Paul,

I am a little confused by your statement.  It could be read to imply that a leaking parking brake will effect one brake but not the other.  I am assuming you mean that it will not effect either brake.  

[kortopates]

Paul,
I am a little confused by your statement.  It could be read to imply that a leaking parking brake will effect one brake but not the other.  I am assuming you mean that it will not effect either brake.  

The 2 independent lines through the parking brake don't interconnect except through a valve mechanism. Depending on which O-rings are leaking it could very well only leak out from one side - not necessarily both sides. I forget exactly, but I recall at least 4 O-rings. Hope that clarifies.


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[Shadrach]

28 minutes ago, kortopates said:

The 2 independent lines through the parking brake don't interconnect except through a valve mechanism. Depending on which O-rings are leaking it could very well only leak out from one side - not necessarily both sides. I forget exactly, but I recall at least 4 O-rings. Hope that clarifies.


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I'm not sure if the newer birds are set up differently, but the divider is after and below the parking brake on the F models. A leak in the parking brake should not effect anything below the parking brake.  Even though Chris's bird is newer, I am pretty sure the system is the same as my 67.

Edited November 19, 2018 by Shadrach

[Marauder]

I'm not sure if the newer birds are set up differently, but the divider is after and below the parking brake on the F models. A leak in the parking brake should not effect anything below the parking brake.  Even though Chris's bird is newer, I am pretty sure the system is the same as my 67.

I’ll snap a picture of mine tonight and post.


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[Marauder]

If you your parking brake had signs of leaking then for sure you should rebuild it with new o-rings. You'll be able to get a kit from LASAR for that and the MC if you want to do that one too.
Incidently, leakage in the parking brake will not effect both brakes. There are of course 2 separate lines going through it that don't connect except for the external valve mechanism.

If you haven't already, when you bleed and flush, you can switch to the synthetic equivalent of 5606H.


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Any preference between these 2?





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[Marauder]

Does anyone know which master cylinder I have?

This is the kit will overhaul a 10-30, 10-30A, 10-30C, or 10-300 Master Cylinder Assembly.




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[kortopates]

I'm not sure if the newer birds are set up differently, but the divider is after and below the parking brake on the F models. A leak in the parking brake should not effect anything below the parking brake.  Even though Chris's bird is newer, I am pretty sure the system is the same as my 67.

I see what you mean! The mid body's went too a different parking brake valve that is downstream past the master cylinders, about under the rear seat.
Your earlier one looks like it prevents fluid from going back into the reservoir? No idea when they changed, but more the J so I expect your right about which one Chris has.


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[kortopates]

Any preference between these 2?





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Neither actually. Those are identical. There is a synthetic that is fully compatible to 5606H you show above. Has some improved properties in addition to not burning. Here is a link to the Royco brand https://www.skygeek.com/royco-782-synthetic-fire-resistant-hydraulic-fluid.html


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[Shadrach]

2 hours ago, kortopates said:

I see what you mean! The mid body's went too a different parking brake valve that is downstream past the master cylinders, about under the rear seat.
Your earlier one looks like it prevents fluid from going back into the reservoir? No idea when they changed, but more the J so I expect your right about which one Chris has.


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I am betting that the elimination on the external panels that gave access to the aft side of the fire wall (starting with the raked windshield of the J) are what necessitated the change to the braking system.  It looks like Chris's plane has a SWTA  201 windshield mod which utilized small triangular access panels just above each side wall of the aft fire wall.  You'd never be able to get the pictures he has with some of the other windshield mods.  Indeed the older set up locks fluid in the system and will not allow it back into the reservoir.  

Edited November 20, 2018 by Shadrach

[Shadrach]

5 hours ago, Marauder said:

 

I’ll snap a picture of mine tonight and post.


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Don't need a picture, I can see that you have a similar system to mine from the existing photos. It's obvious to me that the parking brake actuator is mounted under the reservoir on the firewall.

[Yetti]

Since you are making a mess with the brake fluid.  Change out the hose between the resivoir and the parking brake.  Brake fluid will degrade the rubber.  It's a small ID hose like 1/4 or 3/16 found at your local National Aircraft Parts Association.  Ask for oil, not gas hose.

[Marauder]

The black Master require 3 o-rings from the grumpy IA inventory.   Yours are different.   The manual is on the manufacturers site.  http://www.csobeech.com/files/Bonanza-Deb-MC-Overhaul.pdf
http://www.parker.com/portal/site/PARKER/menuitem.223a4a3cce02eb6315731910237ad1ca/?vgnextoid=0ed66d8a0465e210VgnVCM10000048021dacRCRD&vgnextfmt=EN

Dave at Lasar said there two different cylinder types. Mine are the Cleveland version. Looks like you have the other version.




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[Shadrach]

8 hours ago, Marauder said:

Does anyone know which master cylinder I have?

This is the kit will overhaul a 10-30, 10-30A, 10-30C, or 10-300 Master Cylinder Assembly.




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Pull the panel behind the left cowl flap and take a look.  They could be Gerdes, Cleveland or paramount cylinders. Best to verify.

 

Edit: I see Dave beat me to it!

Edited November 20, 2018 by Shadrach

[Marauder]

I am betting that the elimination on the external panels that gave access to the aft side of the fire wall (starting with the raked windshield of the J) are what necessitated the change to the braking system.  It looks like Chris's plane has a SWTA  201 windshield mod which utilized small triangular access panels just above each side wall of the aft fire wall.  You'd never be able to get the pictures he has with some of the other windshield mods.  Indeed the older set up locks fluid in the system and will not allow it back into the reservoir.  

That’s exactly what I have and there would be no way I could gain access to the reservoir without it. I think a buddy’s 79!J has the reservoir in the avionics bay.


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[Ron]

Anyone have a Paramount B47G master cylinder (used on early model M20 Mooneys) for sale. If so, contact me at:

Ron Stapleton

615-838-5685

ronstapleton@bellsouth.net

[Shadrach]

2 minutes ago, Marauder said:

That’s exactly what I have and there would be no way I could gain access to the reservoir without it. I think a buddy’s 79!J has the reservoir in the avionics bay.

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I wish it was still being made. It's the best of the windshield mods for the older birds.

[Marauder]

So people often ask me my philosophy on maintenance. I could say, I fix stuff, and only that stuff that breaks. That ain’t me...

I decided that I’m going to rebuild both master cylinders and the parking while I have everything apart. I noticed my brake lines (the flexible ones in the gear bays) look a bit shoddy. So where do you buy replacement sets?


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