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Don't understand brake calipers

dwilson

Well Known Member
Building a 9A. To the point of attaching the brakes/wheels

Instructions state "Remove the inboard brake shoe from the brake caliper, and bolt the caliper to the mounting flange."

1) which is the "inboard" brake shoe? The one that gets pushed on by the hydrolic puck or the other one?

2) "Bolt" the caliper to the mounting flange? It looks to me like the caliper rides loosely on it's metal posts that move in and out with pressure from the hydrolics. I don't see how you can "bolt" the two pieces together.

I can go with my intuition, but I sure would like some advice from those who have gone before me.

Thanks

Duane Wilson
9A
141L (reserved)
 
The "inboard shoe" is the part held on with 2 bolts that is the smaller part. It's the other part besides the larger brake cyl where the brake line goes.

So you take those 2 bolts out, then take the large part you have left and bolt it with 2 bolts to the mounting points on the axle. then the wheel goes on, and then the smaller pad goes back on with the original 2 bolts.

Sorry I don't have any pictures handy.
 
Intuition isn't all bad

You can look at exploded views in Aircraft Spruce catalogs or go on-line through a Cleveland Wheel & Brake Google search and get drawings that may help form an understanding of how the things go together and how they work. If you try to get too picky with Van's word picture it will defeat you. Often I had to study the actual parts and develop as comprehensive an understanding as I could and proceed with the assembly. Basically the piston is the metal puck with an O-ring on its perimeter to seal it in its little cylinder in the housing which sits on the inboard side of the disc that is bolted to the wheel hub. There is a metal part containing the inboard brake pad (riveted on with special brake rivets requiring special tools for installing and removing) which floats on two pins that extend from the aforementioned housing. The other pad is riveted to another metal piece which is inturn bolted to the outer edge of "the housing". When you put on the brake incompressible hydraulic fluid from the master cylinder forces displacement down in the housing (slave cylinder) the housing moves toward the centerline of the airplane pulling the outer pad against the outside of the disc and the piston pushes against the metal part containing the inner pad pushing it against the inner surface of the disc exactly opposite the outer pad. So the two pads are equally pressing against the opposite sides of the disc increasing the coefficient of friction until the kinetic energy of the moving airplane is overcome to the extent that it slows or stops or the wheel stops turning and you damage the tire. Once you put one of these ingenious mechanisms together you probably won't give it a whole lot of worry.

Bob Axsom
 
just to correct Bob,you are right about the rivet breaker,but it is possible to drill the rivet yourself with an 1/8 drill,then clean the shoe and in a brake you
set an punch thats fits the head of the rivet,then with another punch and a hammer you carefully punch the rivet so it splits four ways.
A helper for first timers is good!!!!

j?rn m?ller
RV8 208 hours
 
The brake rivet tool is less than $30, and you will use it every year or so when you replace your brake pads. Worth getting, IMHO.

rv8pilot said:
just to correct Bob,you are right about the rivet breaker,but it is possible to drill the rivet yourself with an 1/8 drill,then clean the shoe and in a brake you
set an punch thats fits the head of the rivet,then with another punch and a hammer you carefully punch the rivet so it splits four ways.
A helper for first timers is good!!!!

j?rn m?ller
RV8 208 hours
 
Gary Bricker

The inboard pad is always the pad next to the hydraulic piston. On a airplane or a car. With exception corvettes which have dual calipers.
 
dwilson said:
Building a 9A. To the point of attaching the brakes/wheels

Instructions state "Remove the inboard brake shoe from the brake caliper, and bolt the caliper to the mounting flange."

1) which is the "inboard" brake shoe? The one that gets pushed on by the hydrolic puck or the other one?

2) "Bolt" the caliper to the mounting flange? It looks to me like the caliper rides loosely on it's metal posts that move in and out with pressure from the hydrolics. I don't see how you can "bolt" the two pieces together.

I can go with my intuition, but I sure would like some advice from those who have gone before me.

Thanks

Duane Wilson
9A
141L (reserved)
Can anyone elaborate on the answers already provided on this thread? I have exactly the same questions that Duane has and the other posts don't really address Duane's 2nd question. How do you bolt the caliper to the flange? Like Duane asks, it seems like it just floats. There doesn't seem to be any way to bolt the caliper to the flange.

I don't know why Van's doesn't provide an exploded view on DWG C2, but it sure would help! :mad:

Any clarification and/or pics would be really appreciated! Thanks.
 
rv8pilot said:
just to correct Bob,you are right about the rivet breaker,but it is possible to drill the rivet yourself with an 1/8 drill,then clean the shoe and in a brake you
set an punch thats fits the head of the rivet,then with another punch and a hammer you carefully punch the rivet so it splits four ways.
A helper for first timers is good!!!!

j?rn m?ller
RV8 208 hours

you should never drill out the rivets.. eventually the holes get enlarged, the rivets swell more than they are supposed to, which then causes your expensive brake pad to crack because of the expansion pressure.

I agree...the proper tool is cheap. Its part of owning and maintaining an RV.
 
Let's clear this up!!!!

alpinelakespilot2000 said:
Can anyone elaborate on the answers already provided on this thread?How do you bolt the caliper to the flange? Like Duane asks, it seems like it just floats. There doesn't seem to be any way to bolt the caliper to the flange.

Any clarification and/or pics would be really appreciated! Thanks.
http://img83.imageshack.us/img83/3863/vafbrakecalbd7.jpg
vafbrakecalbd7.jpg

The part you see on the left is is the only part that gets bolted to the axle.

Then the main body with the piston and the plate with the brake pad on it will slide into the bushings from the back and the pad will fact toward the end of the axle. Now the wheel with the disc will slide onto the axle and push right up to the brake pad on the main body. With that in place, you now take the small part with the pad on it (center in the pic.) and slide it down the other side if the disc, and install the bolts.

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Really not much to it :D :D

You can drill JUST the shop head off of the rivets with an over size drill bit. Drill the brass shop head till it almost drops off...... then with a punch smaller than the new rivet shank, punch out the old rivet. NEVER DRILL INTO THE SHANK!!!!! Like Scott says, you never want to do that. :eek:
 
Last edited:
(2) Yes, the inner pad indeed does ride loosely on those two pins. It's part of the beauty of disk breaks as the pad wears the piston simply push's out. The whole caliper moves as a unit and applies pressure on the outer and inner pads at the same time. You never have to make an adjustment until the pads need to be replaced. When replacing old pads simply use a clamp to gently press the piston back into it's cylinder put the new pads in place and reassemble the caliper. Be gentle when pressing your breaks the first time and watch your fluid level. Takes about five minutes per side.
 
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