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  #1  
Old 02-21-2021, 04:28 PM
BH1166 BH1166 is offline
 
Join Date: Nov 2017
Location: Eatonton Georgia
Posts: 376
Default Consuming Brake Fluid ?

Is it normal to add to the firewall reservoir, say 2-3 ounces every 12 months or so? No leaks, drips etc. inside or out.

Cleveland brakes, Royco 782 fluid, pilot side only brake.

Thanks
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  #2  
Old 02-21-2021, 04:51 PM
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Mel Mel is offline
 
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Quote:
Originally Posted by BH1166 View Post
Is it normal to add to the firewall reservoir, say 2-3 ounces every 12 months or so? No leaks, drips etc. inside or out.
Cleveland brakes, Royco 782 fluid, pilot side only brake.
Thanks
As the pucks wear, more fluid will transfer from the reservoir to the caliper. Be careful not to have the reservoir full when you replace the pucks as the new pucks will push the piston back into the caliper, thereby pushing the fluid back up into the reservoir.
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  #3  
Old 02-21-2021, 05:14 PM
Taltruda Taltruda is offline
 
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Default

Iíve noticed most planes seem to use fluid.. I donít understand it, but yes, itís pretty normal.
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  #4  
Old 02-21-2021, 06:18 PM
gasman gasman is offline
 
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Quote:
Originally Posted by Taltruda View Post
Iíve noticed most planes seem to use fluid.. I donít understand it, but yes, itís pretty normal.
When you apply the brakes, the pads are pressed against the rotating disc and causes friction to slow down the airplane. Each time this happens, a small amount of the pad wears off causing the PUCK to move further towards the disc to press the pad to the disc. The amount of fluid needed between the brake pedal and the PUCK increases and is supplied by the fluid in the brake reservoir causing the level to drop.

If you take good readings of the fluid level, you can tell how your pad are wearing....... you still need to take a look the pads over time.
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  #5  
Old 02-21-2021, 06:34 PM
BH1166 BH1166 is offline
 
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Location: Eatonton Georgia
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Default Oops

I added / topped off the Rez and now replacing pads. One side complete. Iíll pull a couple oz out before finishing other! Break in, then check Rez again. Never gave it a thought, more travel more fluid. Thanks
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  #6  
Old 02-21-2021, 06:39 PM
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Default consuming brake fluid

I've heard of some weird cocktails before, but this takes the cake.
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  #7  
Old 02-22-2021, 08:11 AM
lr172 lr172 is offline
 
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It is a closed system and fluid level should remain constant, relative to the piston resting position. As mentioned, as pads wear, the piston rests further and further out and this movement must be made up with additional fluid from the reservior. If you replace pads and the fluid level does not go back up to where you started, then you have lost fluid somewhere, which means a leak.

If you add 1-2 oz a year and do not have fluid overflowing out of the reservoir after a brake pad change, that is a good indication you have a leak somewhere. The system does not consume fluid during normal course of operations and it doesn't evaporate.

Larry
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Last edited by lr172 : 02-22-2021 at 08:25 AM.
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  #8  
Old 02-22-2021, 09:33 AM
abwaldal@gmail.com abwaldal@gmail.com is offline
 
Join Date: Jan 2017
Location: Battle Ground WA
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Same problem here (RV-6A) for a the last three years. Well I found it. I am in the process of new panel, SDS install etc. Was under panel pulling out carpet, padding, firewall foam etc. And had an ""OH ^#^% moment! what is that liquid looking stuff on the back of the firewall???
Yup brake fluid!!! Seems the T-fitting in the back of the reservoir was loose and weeping. Loss of fluid solved.
Yes, I agree puck movement uses fluid. I have not done the math, But I think the reservoir is big enough v/s puck movement volume that you are going to have to wear most of the pads off to actually need fluid for displacement.
Oh ya when under there I also seen an air bubble in the lines. Gonna bleed those brakes before it hits the air again. Never fly the plane from the right seat so never experienced the soft brakes.
My problem is solved, Hope yours is as easy Art
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