Filling the Brake Lines/master cylinders through Matco parking brake

rodsmith

rodsmith

Well-known member
This is something I will be doing soon, but I am asking at the moment because a visitor to our airpark had a serious brake fluid leak on his Just Highlander. A couple of us have been trying to help him refill the cylinders. We have been trying to fill from the brake calipers up through the Matco parking brake without luck. With the parking brake off, we can't get fluid through the parking brake. It acts like there is a check valve which doesn't make sense. The brakes wouldn't release if that was the case. That is the procedure I was going to use to fill my brake calipers to remove bubbles that would be entrapped while filling from the top. Hope to hear from someone that has a Matco parking brake and successfully filled the brake system. The Highlander was built by a previous owner so he didn't do the initial fill.
 
I have the Matco parking brake. I filled it from the caliper up with no issues. I used a big plastic syringe and a piece of tubing that fit over the nipple fairly tightly. Drug store stuff, no purpose built tools involved. I had to push pretty hard on the syringe but it went.

I've filled from the top down on other planes, and lots of other vehicles, and had no major issues chasing the bubbles out so that is an option. I always prefer bottom up but sometimes it can be tough to get a good seal at the nipple. If anyone has a part number for a caliper-up pressure bleeder I'd love to know about it. I always end up making my own.
 
Good to know Tim, this is a real head scratcher. I flew in the plane the day before the leak, the parking brake was working fine.
 
Really dumb question, was the parking brake valve actually in the proper position and against the stroke stop…….?

Kevin D
 
I built a highlander with matco brakes and parking brake and had no problem getting flow when bottom up purging from the calipers. An aside, but the bottom elbow of the matco master cylinder holds air. I had to lift the tail up 2-3 feet to get that bubble to clear and get solid pedals.
 
Not a dumb question, but yes we verified that. Eventually got the brakes filled. Took a Mytyvac with lots of pressure on the plunger. Doesn't seem like it should have been that difficult.
 
Tried to bleed the brakes yesterday. I did get the fluid through the matco parking brake but otherwise it was an epic failure. Part of the reason was my equipments wasn't good and I will try again geared up.

For anybody interested, I did find the bleed valve connectors (Grove/Cleveland) so I can apply proper pressure at the bottom without the hose slipping off constantly.
ACS 06-11414
https://www.aircraftspruce.com/catalog/lgpages/ats1246.php

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Another problem I ran into. I appears one of my master cylinders is leaking. What's the best course of action here? Service the O-rings?


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