K

kcameron

Well Known Member
A few weeks ago, I noticed that the left brake pedal on my RV-4 was going down farther than the right one. This last weekend, I installed new seal kits into both master cylinders. After a fair bit of work, I was able to get the right side bled to the point where it holds pressure and without appreciable sponginess.

I wasn't as lucky with the left side. Even after hours of trying to bleed the system, there's not much pedal resistance and the brake barely holds at all. The plane is unflyable now. Argh! One issue is that the builder routed the brake lines such that there are three high spots where air could be trapped. In hopes that a quicker and more volumous bleed will take care of it, I've ordered a pressurized brake bleeder:
http://www.motiveproducts.com

I've been looking around for a replacement brake cylinder in case the power bleeder doesn't do the trick. My plane has Cleveland "10-30" cylinders in each side. The numbering system seems odd since the right one is different from the left. Anyway, so far I've hit two surprises:

1) No one (ACS, Chief, Wicks, etc) seems to carry that model
2) The other roughly similar cylinders I've found are more expensive than I expected ($200-$300). Oh well.

Anyone know where I can find a replacement cylinder?

Thanks,
 
It was probably salvage off some certified aircraft. I highly doubt that the cylinder is the problem. Have you resealed the calipers too? There could be a leak there, but even more likely is that the system might be sucking air from the resevor to the master cylinders (assuming a seperate resevour, with a hose attaching).
 
Bleeding procedure

A hint on bleeding aircraft brakes. First you need to forget what you know about automobile brakes. My system is to do it "backwards," that is put a hose on the bleed screw at the caliper, hook it to a simple pump oil can filled with hydraulic fluid, loosen the bleeder and pump fluid gently into the system. Start with the reservoir empty and keep an eye on it as it fills so you don't make a mess.

John Clark
RV8 N18U "Sunshine"
KSBA
 
kcameron said:
SNIP

I've been looking around for a replacement brake cylinder in case the power bleeder doesn't do the trick. My plane has Cleveland "10-30" cylinders in each side. The numbering system seems odd since the right one is different from the left. Anyway, so far I've hit two surprises:

1) No one (ACS, Chief, Wicks, etc) seems to carry that model
2) The other roughly similar cylinders I've found are more expensive than I expected ($200-$300). Oh well.

Anyone know where I can find a replacement cylinder?

Thanks,
Click to expand...
The 10-30 is the master cylinder that VAN use to supply. They now supply MATCO cylinders. Parts are availabe to fix the 10-30. I just special ordered a piston rod to fix a leak from Spruce.

If you want to replace the master cylinders with what Van presently supplies, see the LIST that is on Van's Web Store.
http://www.vansaircraft.com/public/parts.txt

Search for brake. I found:
BRAKE MAST.CYL.LEFT-1 MATCO 4/6/6A/7/7A/9A $78.00
BRAKE MAST.CYL.RGHT-1 MATCO 4/6/6A/7/7A/9A $78.00


The MATCO are a LOT less than the Cleveland.
 
If you get the bleeder tank from ACS, get the 06-11414 adapter, too. It fits over the bleeder screw and makes the connection very easy. I put a fitting and hose in the reservoir to route and catch the excess fluid in a bottle.

Roberta
 
robertahegy said:
If you get the bleeder tank from ACS, get the 06-11414 adapter, too. It fits over the bleeder screw and makes the connection very easy. I put a fitting and hose in the reservoir to route and catch the excess fluid in a bottle.

Roberta
Click to expand...
I agree as I purchased it also.

Was looking for photos on Spruce's Web Site but did not find any. Here are links to what the stuff looks like that I purchased from Spruce.

http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=225DX-C&ReturnPage=/shop/flyer.aspx?PageNo=1

http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=1246&ReturnPage=/shop/flyer.aspx?PageNo=1
 
RV4 Brakes

I built an RV6 & rebuilt an older RV4 wreck which required a new motor mount and some other sheet metal work. The brake cylinders on the RV4 were mounted upside down due to the lack of room in such a small airframe. We had difficulty in bleeding them from the bottom and could not get the air out of the system until we started bleeding the lines in sections. We just backed off the B nuts and pumped away until fuid came out, tightened the nut and moved up and did this over farther up line. Alot of spilled fluid but it worked.
In contrast, the RV6 was merely pump fluid from the bottom until all air was displaced and it was finished. The only difference in the two systems is the mounting of the brake cylinders. All we had for tools in either case was a "Plews" pump oil can, some vinyl tubing, a jar for overflow, and some AN fittings which I have used for years...it's a jury rig affair made for a few $$$! Hope this helps.

Dick DeCramer
RV6 N500DD flying
RV4 N149KC flying
RV8 Nameless..building Wings
Northfield, MN
 
Success!

I got the power bleeder Wednesday and took it to the hangar Thursday. I had to cut off the "euro" master cylinder adapter they provided. I hooked the hose to a hardware store fitting which I screwed into the top of my brake reservoir. The bleeder is easy to use. It holds up to two quarts of fluid and 30 seconds of pumping gives me 15 PSI or so. It was pushing out about 1 cup per minute. I didn't have a large, clean container handy. I had to keep returning the fluid from my two small cups back into the bleeder which slowed me down a bit.

I got a fair bit of air out but, after several attempts, the pedal was still too soft. I was on the verge of giving up when it occurred to me to try pumping the pedal while bleeding. I used a small length of tubing from the caliper fitting into the cup, got it started until the level was above the bottom of the tube, and started pumping the pedal. Voila! The fluid that came out was frothy with air. When I tightened the fitting, the pedal was good and firm. I repeated this until the "squishing" sound inside the master cylinder stopped. The pedal is now rock-solid.

I know there are a lot of ways to do it but this one worked for me. Thanks for all the help gang.
 
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