Squalling Cleveland Brake

[Bob Axsom]

In the beginning I had a master cylinder O-ring that was damaged in factory assembly (the O-ring was pinched in assembly and a small crescent was cut out of the edge as it was forced into position). The master cylinder leaked back up through the top and bled on the floor. I bought an overhaul kit and installed the new O-ring and all was fine (after I stretched the return springs to get the piston all the way back when released). Then I allowed the right brake pads to wear down sufficiently to allow the slave cylinder O-ring to clear the cylinder and the fluid bled on that side while parked in Florida. I made a improvised repair with some incorrect pads that were available and flew home. Later when landing at Prescott, AZ the right break line broke at the flare during a short turnoff (lot of pressure I'm sure). I borrowed a flare tool, fixed that and continued on to California the next day. Sometime in this scenario (beginning after Prescott I think but Jeanine says after Panama City) the right brake started making an embarrassing sqaulling noise. I attributed it to brake pad contamination. I tried cleaning and resurfacing the pads and I thought I had it but in fact the intermittent squall upon application of the right brake returned. I thought the pads were saturated so I replaced them but the squalling problem remained. I use the rudder to turn and I tap the brakes when necessary to minimize the squall and I'm getting pretty good at it but the squall remains. This year at annual time I went way overboard and replaced the discs as well as the pads thinking that something may have happened to the right disc during this time. Initially everything was blissfully quiet but yesterday the squall was back. I have some more ideas but I would sure welcome a wise (I mean that in a good way) input or two on this nuisance item.

Bob Axsom

[casper]

If you do figure it out would you please let me know.

[gasman]

Beval the leading eadge of the pad.

[Mike S]

Originally Posted by Bob Axsom

the right break line broke at the flare during a short turnoff (lot of pressure I'm sure). I borrowed a flare tool, fixed that--

Check the brake line-----they can make a similar noise.

Since you just worked on it before the noise started, I would suspect it.

http://www.vansairforce.com/communit...ake+line+noise

[John Clark]

Originally Posted by gasman

Beval the leading eadge of the pad.

Putting a slight bevel on the leading edge of the pad (about 1/8 inch at 45 degrees) will help. The issue here is a vibration being created in the brake caliper. Another possible fix is to make sure that the bolts/pins that the caliper slides on are clean and rust free. a small amount of a dry lube like graphite helps. If all else fails, a light coat of dry lube on the back side of the pad where it contacts the piston. Obviously being very careful not to get any on the face of the lining or the disc.

John Clark
RV8 N18U "Sunshine"
KSBA

[Bob Axsom]

This is good input and I will use it all.

Bob Axsom

[Jamie]

Originally Posted by Bob Axsom

This is good input and I will use it all.

Bob...please report back with your findings. I'm having the same problem.

[Bob Axsom]

We are going to Branson in the morning but I will get the fairing off and work this proplem with the recomendations here before next Saturday and I will report the results. One of the fixed recomended by two people involved beveling the leading edge of the pads (the edge facing the incoming rotation of the disc - the bottom) that has a ring of shared experience to it. You might try that while you are waiting - It can't hurt. I will also look for brake fluid seepage around the fitting & piston, spring displacement of the caliper by the aluminum tube, the condition of the guide pins and the piston face and evaluate the need for dry lube.

Bob Axsom

[Christopher Murphy]

Bob,

A few years ago I replaced the plastic brake lines on my RV-4 with Aluminum tubing all the way to the brake caliper. They both squalled like a son of a gun. Had a nice loop for vibration.

Added a short section of hose into the brake caliper, no more noise.

Chris Murphy

I too went through all of the above mentioned fixes before I did what I knew would fix it.

[Bob Axsom]

Thanks Chris.

Bob Axsom