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Matco PVD parking brake problem

oren_rokach

Well Known Member
Hello
I have installed the parking break and when screwing the AN3-12 bolts into the firewall bracket, the arm stops moving!
Have anyone encountered such issue?
We are suspecting that it is caused by a manufacturing tolerance between the two parts, so when pressed together creates a bend in the shaft which stops the arm.
see picture below:
https://photos.app.goo.gl/yfv3oWXeMSfDytTo9
See below the 0.02" gap between the two?

I was thinking of installing a shim behind one of them, to close the gap.

Ideas?

Thanks
Oren
 
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I have that same valve. I don't like the design much since pretty much any clamping force is too much. I ended up enlarging the bolt holes to 1/4" (just a hair) and making spacers out of 1/4" stainless tube. I made the tube just a little longer and used the rubber washer to provide the light clamping force on the valve. You still have to be careful not to over torque the bolts with that thin-wall tube, but it got the job done. Doing it all over, I would probably use a different valve, but it is working fine so far.

Here is a link to that entry in my build log:
http://www.mykitlog.com/users/display_log.php?user=ccpeterson@y&project=754&category=5724&log=154965&row=67

FP26082012A0001Y.jpg
 
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That split valve design is prone to problems if not installed right. It almost has to "float". Use the rubber mounting washers under the bolt heads and on the RV-10, I also added a rubber pad under the backside. Use care when tightening. I hated that thing and found the old style single block valve for the -9A. Hopefully I can find another one for my next RV-10.
 
The Matco valve is used on alot of planes---guess its an installation issue. Oren, back off the bolts slightly until the lever moves freely and see how things operate then.
Tom
 
Thank you guys,
Yes, lightening the screws helps, but it is not a good practice.
We installed a shim under the "higher" valve which evened the heights so its better now. I guess indeed only spacers would give a perfect fit.

Thanks!!
Oren
 
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