brake master cylinder / pedal attach clevis

artL

artL

New member
Taxiing out we suddenly lost left braking and found the clevis attaching the rudder pedal to the brake master cylinder had snapped. Unfortunately it happened when we were planning on going to Triple Tree - fortunately it didn't happen on landing. Looking for a replacement or equivalent part. Anyone have a source or suggestion? Here is a picture of the broken part...

View attachment 1

I could use the original part or a similar threaded clevis such as from a Cleveland installation, however have not located a source of the detail parts. Will replace both left and right.

Thanks, artL
 
Hmm. Is it possible that this clevis broke from repeated side loads which put bending loads on it?
This may point to inspection awareness required on the Cruisair for whatever caused this failure. The normal compression only service load of the part would be nowhere close to fatigue limits and therefore this clevis should never fail.

Could the body of the brake cylinder be forced against something during rudder or brake action? Anyone ever see a bent brake clevis here? Stretched rudder cables putting the pedals too far forward? Dunno.

Maybe type clubs should be generating supplemental maintenance, inspection and ops data in a usable form. Just some thoughts. Lucky this happened at taxi speeds.
r
 
This part probably has it's origin as a turnbuckle fork.
Early in my Cruisair ownership, I broke the welded tab that holds the lower master cylinder mounting point.
This airplane is nearing 70 years of age. Parts will wear out or break. Use common sense in your pre-flights and annual inspections.
Dan
 
This could be a big deal for any of us. The top of your brake cylinder looks the same as the ones on my 14-19. If needed, are there replacements available? Tom Robinson
 
Are your cylinders the original Scotts or are they later Wheeler Dealer, or are they Clevelands? Post a picture of the whole master cylinder, and I might have parts. _____Grant.
 
Brakes... I only use them to run-up..
They're bad juju.. the monster flaps on the bellanca slow the plane down so fast I have to throttle-up to get to the first turn off..

j4crash_zps6b3ed2ae.jpg

That J4 has been on it's back 7 times since it's birth in 1939.. all due to braking.

oops_zpsdb708af8.jpg

one of 6 Buckers at my airport, always going someplace together.. this guy was in a group of 3 on landing. good thing he was last in the group.

you all remember this: http://youtu.be/BoOQ-qPcd-E

lousy brakes on a taildragger are a blessing :)
 
In late '93 or '94, the same clevis broke off the brake cylinder on my Cruisair when I was doing a turn around on the runway getting ready to take off. Pretty interesting ride until the grass/sod field stopped me. Looks like the same break I had.

My plane had been converted to Bodell brakes by a previous owner which are a great brake and during a telephone call they (I forget who) opined that although the STC does not call out changing the master cylinders, that was probably the reason it broke. The reasoning was thus: The original expander tube brakes used a low pressure/high diplacement cylinder but the Bodell (and other newer style) are a high(er) pressure/low(er) displacement system. If you don't change the cylinders at the same time it take pretty good pedal force to get enought brake to hold the plane a much above about 1700 rpm. This results in the stems being overstressed on most flights unless you're on a grass runway or are a "I don't need no stinkin' brakes" sort of guy". I said "Oh, imagine that" and swapped my factory original cylinders to a new style and haven't had troube since.

Just my un-asked for 2 cents worth.
 
I'm sorry that I'm late with this but I had same problem with the Goodrich 87-87 brake master cylinders installed on the crate. I have the parts breakdown from Manual #13 dated 15 July 1959. The rod like yours broke, it is item 10 p/n 38-70. For me it was impossible to find. I contacted my machinist friend and he made me two new ones. He also provided me with the CAD drawing so some other machinist would be able to make them. If you want a copy of the CAD and parts pictorial just e-mail me your FAX and I will send it over ( 2 sheets letter size). I was going through my records and found this and remembered someone had the same problem. Old airplanes like old age can give you problems! Lynn the crate :wink:
 
twheel47 said:
... Looks like the same break I had.

My plane had been converted to Bodell brakes by a previous owner which are a great brake and during a telephone call they (I forget who) opined that although the STC does not call out changing the master cylinders, that was probably the reason it broke. ...
Just my un-asked for 2 cents worth.
Click to expand...

Thanks for the 2 cents...

Mine had been converted to Bodell also; your reply makes sense and I will take that advice.

It has been a long year with no flying - started with a burst water pipe in a (new to me) hangar which took 3 months to repair/dry out (the hangar only - airplane remained dry) which resulted in a timed-out annual. I had purchased it with a fresh annual, however after-the-fact research shows so many things done on the airplane without proper documentation that I may spend the rest of my days trying to sort it all out. My IA is trying to keep me honest and legal.

By any chance would you have copies of STC / 337 for brake cylinder change or any info on an approved replacement?

Thanks, artL
 
In an earlier post I mentioned that I experienced a master brake cylinder piston rod failure last year. Several posts apparently experienced similar failures.

As I have been going through the 2 boxes of paperwork that came with the airplane, I found a Bellanca Service Bulletin #17 which addresses this type failure, and recommends rigging the rudder pedals aft by adjusting the turnbuckles at the rudder post control horn.

It is recommended reading.
 
Re-reading this thread reminds me that Jim Green probably has the proper cylinders for the Bodel conversion. Firestone/Wheeler Dealer/ Bodel are all basically the same, and when the T.C. was owned by Wheeler Dealer, they made cylinders that work great, and physically fit. Scott cylinders on Bodel brakes will give you high pedal pressure which can lead to fatigue breakage. I dont know for sure, but the Wheeler Dealer cylinders might work well with Clevelands also. Give Jim a call He advertises in our news letter. Grant.
 
I have attached the part of the 337 that was used to modify my brakes. Haven't had any trouble with the brakes (other than replacing pads) in the last 24+yrs. Please feel free to use this if you want. I can send you the first two pages of the 337 if necessary.
Larry
 
Many of us will be glad to learn if the wheeler dealer cylinders really are high pressure(or high enough for Clevelands). There are actual Cleveland masters that are a direct replacement (size wise) for the original Scotts. I have them on my plane, but the labels have long ago washed off, and the paperwork doesnt give them a number. If your pocket book can stand the shock, it might be possible to send a Scott to a Cleveland dealer, and see what they come up with. I remember helping on another Cruisair, and fitting Cleveland cylinders, but they didnt work out since the ports came out 90 degrees to the original, and there was physical interference. Life is not easy in Ancient Airplane Land. Grant.
 
Grant.. I have spent a bunch of time trying to research Cleveland master cylinders.
Their website is nearly inscrutable.

I think they may have previously made a 7.5 inch tall master, but currently the 10-35 which is 8.0 inches tall
seems to be the nearest match.

Grove makes a wide variety of master cylinders.. some obvious clones of Cleveland.. and in every height, cylinder diameter ( and hence pressure) and with every port orientation you could ask for.

This would be the absolute no brainer, guaranteed to fit, and work solution, but no faa/pma.
no labels on the scotts, and I doubt if there ever were. I'd become Canadian and skip this nonsense if they'd have me !

It turns out the displacement of the Cleveland brake is only .19 of a cubic inch.
so I guess .38 cu.in for a pair. This is like two thimbles worth of fluid. They want 400-500 psi at full gross weight according to the chart. Scott barely makes 175. Barely.

Based on the diameter of the 8) cylinder.. it would be almost impossible for the wheeler-dealers to not work.

I will measure and report.
 
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