Brakes - Before I take the time?

[RICK MARTIN]

I've just read through all the AC thread titles and info I can find here on the forum regarding AC hydraulic brakes. I didn't find one mention of problems, need to rebuild, poor performance etc.

I have and old AC with what I believe to be the original hydraulic brake system (although I only have one master feeding both main wheel brakes). After filling and bleeding the system, I'm getting almost no braking effect, and I have no leaks. Because I'm suspicious that the machine spent some time out in the weather, I am getting ready to tear into the calipers to see if their funtion is being inhibited in any way by pitting, corrosion etc.

I have enclosed a photo of the type of calipers I have. Before I start this, if anyone has any advice like:

1. Don't bother, trash 'em
2. Yes, of course they can be serviced and should be fine
3. Or any special knowledge/tricks to share

Please let it fly!

Thanks,

Well......................I thought I was going to post a photo. Where has the the "go advanced" function gone?

[Doug Riley]

Rick, my AC also came with the original Matco hydraulic brakes. I could create more braking power bracing my feet right on the ground, so I took them off to save weight. They also make it a hassle to remove the wheels.

I had problems bleeding them. The shade-tree method (put a short hose on the wheel valve, stick the other end of the hose in a jar of fluid, open the wheel valve and pump the pedal 'til no more bubbles come out) can't work because (unlike a car) there's no reservoir at the master to replace the fluid lost. I tried making a bleeder out of an oil squirt can -- that was better but still not great. I think air got trapped because the bleeder valve was on the very bottom of the wheel caliper. It ought to be on top to gather the air.

[gyromike]

Rick of you click the EDIT button on your post you should see the button to GO ADVANCED.

[RICK MARTIN]

Hey Doug!

Thanks for the input on this. With a little ingenuity, I think I can work around the "bleeding & elevation" issues. I'm hoping for input about how well the brakes work and issues related to anyone actually having them apart. Jake just called and gave me his fifty cents. He pretty much agreed with you about the braking ability of the system. Right now, it almost gets away from me if I'm on pavement (which I am most of the time). I'm going to make sure my idle is as low as possible. But I really think they should be doing better than they are right now.

I hope all is well with you and yours way up there in the north country.

[GyroRon]

What kind of fluid are you using? I think you should be using automatic transmission fluid

[bones]

Another thing is to make sure the plastic tube for the fluid is of the right rating, had a sportcopter here early this year and nothing we done would make the brakes work, then out of frustation, i held onto the tubing with 2 hands while the brakes were operated, and you could feel the tube swell and stretch, so what was happening was, the brake calipers would move in and touch the disk, take up pressure to certain piont, then the tubing would just absorb any more pressure that was applied, replaced with very thick walled tubing problem fixed. 5000lb/inch i think it was.
The bleeding is not hard to do, as Doug said, do it from the wheel back to the master cylinder, we ended up deliberately leaving a couple of small bubbles, in each line so the brakes werent so touchy.

[Rick Whittridge]

If you have the Old Posi-stop Brakes It`s best you scrap them? Heres is what I have to offer you if needed.

Advanced Rotor Designs
937-878-2598

If you dont need tires I can save you some money?

[RICK MARTIN]

Ron, Yes I'm using ATF
Mark, thanks for the info on the line. I'll check it.
Rick, I've been admiring your set up for a while. I'll certainly let you know if I decide to make the investment.

This is the set up I have. Are these the old ones which did not work very well?

Thanks,

[cgmg]

Rick,

On my AC single, the brakes worked ok on grass, but not on pavement, so yours sound typical to my experience. Fortunately for me, I hardly ever fly off pavement, so it wasn't that big a deal for me.

You'll have to spend some money to get brakes that work better. I wouldn't invest a lot of time trying to improve the hold of your current ones.

[Timchick]

I got some Hegar brakes from Rick W. for my KB-2. Once bled correctly they worked great. I used both methods Doug mentioned for bleeding and they both worked pretty good. Sticking the tube from the master cylinder nipple into a bottle of fluid and pumping the pedal worked a little better for me. The master cylinder has a spring on the shaft and when the spring returns the pedal after pushing it will suck fluid into the master cylinder.

[Doug Riley]

Rick, those look like the Matcos that came with the early Air Command. I tried pushing fluid in both directions; no great luck. Hegars may be better.

OTOH, with just a 447 and grass surfaces, foot-power was all I needed, with any amount of planning. I could wind up to just about full power with the Wunderlich engaged, and still hold her just by bracing my legs. The prerotator loaded the engine RPM to about 4300.

It's nice to able to remove the mian wheels without fussing with the calipers and the brake rotor.

[Earthboundmisft]

Rick, on some aircraft I have had to remove the caliper with the line still attached,
and put a shim inbetween the pads to simulate the brake rotor. Then turn the bleeder UP,
and bleed them that way. Make sure the pads are de-glazed, and 'buff' the rotor with
a mild abrasive. My 2 cents...

[Rick Whittridge]

It's nice to able to remove the mian wheels without fussing with the calipers and the brake rotor.





Your Right Doug, My wheels are easy to remove (One Nut) with the floating Disc Design. The Matco`s were a PAIN to deal with!

[brs]

What kind of fluid are you using? I think you should be using automatic transmission fluid

If you have MATCO don't use ATF! They specifically say not to. They use skydrol (6106?). Anyway, I've called their office in UT several times and they are very helpful.

I just installed a set on the SHredo but have not yet hydrated them. My reading suggestes that poor braking is due to poor pedal geometry. Also, they make an insert for their cylinders which increases the braking efficiency.

[RICK MARTIN]

Thanks guys. Knowledge is power. I'm storing away all this info. I'll take anything you can give me.

[gyroplanes]

I may be wrong, but I'm fairly certain the original Air Command brakes, like Ricky has, are Azusa or Hegar and not Matco. A friend need a new master cylinder and couldn't readily locate one. It turns out LEAF still had some parts and has discounted them dramatically.
Dennis Fetters would know, if he chimes in here.

[CLS447]

Yeah Tom ! Mine still work good too !

I bought extra tires & wheels with the adapter plates. I remove the 3 shoulder bolts that the disc rides on & pull the pull pin on the axle & the wheel comes right off.

They have always done the job for me.....Don't try steep hills with the engine running !

[DennisFetters]

I may be wrong, but I'm fairly certain the original Air Command brakes, like Ricky has, are Azusa or Hegar and not Matco. A friend need a new master cylinder and couldn't readily locate one. It turns out LEAF still had some parts and has discounted them dramatically.
Dennis Fetters would know, if he chimes in here.

I used Hegar-4 products brakes on the Commander. You can contact Terry and he still has parts available for them. I don't have his contact information.

[CLS447]

Dennis, are you talking about the brakes that were used with the Azusa plastic wheels ???

The master cylinder looks like Hegar but what about the thin discs & calipers that worked with the plastic Azusa wheels ??

[RICK MARTIN]

Right Chris. I have the Asuza plastic wheels. I'll try to take a better picture of the caliper.

[DennisFetters]

Dennis, are you talking about the brakes that were used with the Azusa plastic wheels ???

The master cylinder looks like Hegar but what about the thin discs & calipers that worked with the plastic Azusa wheels ??

All supplied by Hegar-4.

[RICK MARTIN]

Thanks Dennis. Any other advice on making them work as well as possible?

[DennisFetters]

Thanks Dennis. Any other advice on making them work as well as possible?

The big thing is to make sure to get all of the air out of the system. I used a large syringe with a small tube at the master cylinder and push large amounts of oil to one wheel-brake at a time, while pushing in and out on the piston, and catch the run-off into a cup and re-use it. It takes some help with a guy running from one wheel and then to the other a few time to make sure all the air is out.

The Hegar-4 brakes worked just "OK" for the Commander, but in time I learned that it's really a Micky-mouse set-up that I would never use again on a new aircraft. Hegar-$ has some much better stuff out now, but I don't think it will fit as easily on the Commander.

[RICK MARTIN]

I appreciate the feedback.

[Rick Whittridge]

Dennis is right the Old Brakes you have where Not Good, However the new designs that I sell do work well & is not found on any web site because they our exclusive to Advanced Rotor Designs product lineup! They will fit the Air Command easily. No More Plastic Tube Pinching Azusa Wheels!

[RICK MARTIN]

Thanks Rick. I have a few more issues to straighten out before the machine is back in the air. Then I'll give the brake upgrade some serious thought.

[robsat61]

hey rick,could not help but jump on this....check jake on this but....whoever heard of a hydraulic brake system without a master cylinder!!!!!.the matco system just needs a master cylinder to be effective and allow proper bleeding..damn,even my '58 willys had a master cylinder....rob.

[scottessex]

Rick do you have the old air command style brake caliper that goes around the axle tube?
i just picked up a set I thought they would be good.??/?

[Rick Whittridge]

Rob, My brake kits do come with a Mcly? It is a closed system so a reservoir is not needed? Reservoirs are for cars not aircraft. This kit is easy to bleed with the suppied fluid & pump. 10 minutes, two people & your done.


Scott, I`m not sure what you have, I`ve not seen those before, how about a photo please?

[RICK MARTIN]

Scott,

I know it's hard to tell from the lousy photo I provided. But yes, I believe the caliper mount goes around the entire axle tube. The plunger appears to be like the one Rick posted. Jake did mention that it might help to provided a lever arm like in Rick's system. Again, I will try to take some better shots this weekend.

[scottessex]

Like these?

http://i568.photobucket.com/albums/ss122/scottessex/IMG_2013-1.jpg

http://i568.photobucket.com/albums/ss122/scottessex/IMG_2011-1.jpg

http://i568.photobucket.com/albums/ss122/scottessex/IMG_2014-1.jpg

http://i568.photobucket.com/albums/ss122/scottessex/IMG_2012-1.jpg

[Rick Whittridge]

Scott, I have never seen that style before? That is probably what Rick M. has? I don`t have any parts for them.

The 5" Lever Mcyl is preferred & is a upgrade with my kits.

I would guess that dual bleeders would be for mounting the caliper in the up or down position to help bleed the system, Only the highest bleeder would be used because they both come from the piston area.

Those appear to be Cast, My stuff is Solid Billet!

[RICK MARTIN]

Yes Scott. I will not be at the airport until Thursday, but I believe that is what I have. Mine definitely have the double bleeders.

Dennis, are these the Hegar-4s you were referring to?

[gyroplanes]

Those are the original Air Command Hegar brakes.

[carls]

why not use bicycle disk brakes. Don't mess with hydraulic fluid, use a cable. I been using them for years. Weighs eight ounces per wheel.

Carl

[scottessex]

I also have a set of bicycle hyd brakes, but I am not sure how strong they would be for a 2 place.

[DennisFetters]

Yes Scott. I will not be at the airport until Thursday, but I believe that is what I have. Mine definitely have the double bleeders.

Dennis, are these the Hegar-4s you were referring to?

Those are them. It's what I have on my 582 Commander Elite that I'm flying here in China, except mine are the older ones that only have one bleder... on the bottom! Pain in the a$$ setup. I had Terry Hegar change it to the double bleeder.

[RICK MARTIN]

Dennis, Scott, Carl, Tom,

You guys are great! Now I know exactly what I have, and what to expect from them. Thanks again to everyone who took the time to give their opinions. I love this forum!