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  #1  
Old 07-09-2021, 10:32 AM
gggflyer gggflyer is offline
 
Join Date: Jun 2021
Location: Scottsdale
Posts: 43
Default RV4 brakes not effective

I just purchased an RV-4. Been flying it a few hours and keeping in mind that I have nothing to compare it to since its my first RV, I dont think the brakes are working as they should.

I have to apply so much pressure for them to work. On run up they barely hold the plane at 1800 rpm for mag check.

When taxing it takes way too much constant pressure to keep going straight with the right brake. I feel that im going to snap the actual pedal off.

Is this normal and i just have to get used to it or is there a way to adjust the effectiveness of them.

Thanks for the help. Im a newbie to the experimental side. I come from a vtail bonanza and a luscombe so this experimental stuff and what parts were used to build is much different. In the bonanza i would just look at the parts manual.

I think per the seller this has matco cleveland brakes. It was built around 2013 so newer version of rv4

Thanks in advance

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  #2  
Old 07-09-2021, 10:39 AM
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D Weisgerber D Weisgerber is offline
 
Join Date: Sep 2019
Location: Ionia Michigan
Posts: 287
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This isn't normal, I fly an RV6 which has the same brakes as an RV4 and the brakes are very effective. It sounds like maybe the brakes are glazed or there's some contamination on the pads keeping them from biting. If you can find some one in the area that is familiar with them maybe they could look at them for you. The brakes are either Matco or Cleveland those are 2 different brands. Good luck.
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  #3  
Old 07-09-2021, 10:43 AM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
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Any other RV tail draggers on the field? Maybe have one of them taxi your 4 around to have them assess if all is good in the landing gear alignment.

You should not have to (& shouldn't!) stand on a brake pedal to taxi straight. By doing that, you are generating a lot of heat & glazing the pads. Maybe more use of the rudder pedals instead of brakes? Run ups to 1800 is usually normal for these brakes.
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  #4  
Old 07-09-2021, 11:28 AM
swjohnsey swjohnsey is offline
 
Join Date: Nov 2018
Location: Kingsville, TX
Posts: 365
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Yep, not normal. The RV-4 brakes are normally very good. Check the condition of pads. It might need a bleed. Also there should be no need for brakes to taxi.
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  #5  
Old 07-09-2021, 11:41 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 6,537
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First guess is contamination of the pads, like brake fluid or grease. Air in the system just creates extended pedal travel and initial mushy feel; It shouldn't impact the amount of force necessary to achieve fully braking pressure.

Larry
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  #6  
Old 07-09-2021, 11:57 AM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 7,768
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The symptoms you describe are also typical of pads that have not been ‘conditioned’. Figure out what kind of pads you have, read the manufacturer’s instructions. Typically, one or two firm stops from a modest taxi speed. Do not overheat them.
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  #7  
Old 07-09-2021, 12:41 PM
gggflyer gggflyer is offline
 
Join Date: Jun 2021
Location: Scottsdale
Posts: 43
Default Correction to brake manufacturer

Brakes are cleveland and wheels are matco.
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  #8  
Old 07-09-2021, 07:45 PM
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Saber25 Saber25 is offline
 
Join Date: Dec 2010
Location: Colorado
Posts: 261
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With a 1989 RV4 built to plans, I've not experienced these issues. Having to taxi with one brake applied would lead me to believe a complete check of the system is required before the next flight. A hot brake could lead to a ground loop or at least a trip to the woods. Pull the wheel pants and start trouble shooting!
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  #9  
Old 07-09-2021, 07:46 PM
FinnFlyer FinnFlyer is offline
 
Join Date: Aug 2018
Location: Bell, FL
Posts: 571
Default Firewall recess

This is probably silly, but here goes.

The pedals in the RV-4 go into a recess in the firewall.
With big feet you might be pushing on the firewall rather than on the top of the pedal.

Finn
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  #10  
Old 07-10-2021, 03:02 PM
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f14av8r f14av8r is offline
 
Join Date: Apr 2012
Location: Tampa (Wimauma actually)
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if there is air in the brake lines, they won't seem as effective because when you push on the pedals the compressible air "dampens" the input. Bleed your brake lines. Hydraulic fluid is not compressible and will directly transfer the force of the pedal to the brake cylinder.
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