Cleveland's On Cruisaire... forget the club book.

Now the question is how much of the flexible brake line to replace..?

Easy to say All of It.. and that maybe the right answer.

Is the old stuff gonna hold up at 450-500 psi ?

Having experienced what can happen if you experience a simple brake failure..
not anxious to go there again.

Not at all sure why my brake lines are not all 1 piece between the metal tubing section inside the wing,
and the brake ?? Mine are two pieces spliced near the top of the gear leg.

Options are:

1. make an approx. 1 ft U shaped extension.. to extend the existing brake line to the clevelands.

2. Replace the lower section with a longer new hose.

4. Replace all the flexible hose.

I'm guessing that the biggest cost in having new hoses made is fittings and the cost of installing them.

>>So a couple of longer 1 piece hoses( one on each side) might be the safest and still economical way to go??<<

comments ? Advice ??

woeful tales of neglect and destruction ?
 
Blimby, my brake lines are one piece from the master cylinder to the brakes and I do not like it. I'm considering making a junction joint at the upper end of the gear strut. The reason is that the brake line geometry changes as the landing gear is retracted and extended and from full strut extension to gear-on-ground. There's a lot of flexing and stretching going on, which I got to witness during my first annual gear swing. In fact, my brake lines were being strangled by the 1/16" retract cable at the upper end of the strut when the gear was retracted. You would never see that in a walk around. I like the idea of a junction at the upper end of the strut because the geometry of the brake line from the strut to master cylinder never changes and should last a very long time. The lower half of the brake line could be easily changed if required.

artL
 
I dont have my books anymore (damn that fire) but I seem to remember a diagram in the parts manual that shows where the lines should be pipe, and where it should be hose. I agree with Art that a single flex line is not a good idea. There should be a joint where the wing and the fuselage come together, so that you dont have to cut lines or snake lines out, for a simple wing removal. I am not sure exactly where it goes back to flex near the top of the landing gear. Replacing any older flex line is a good idea. Just my 2 cents worth. _____Grant.
 
If you want a copy of the Bellanca Cruisair Senior 14-13 Brake System Diagram, I can send a .jpg file to your email - just let me know. It shows the hard lines and flex hoses from the original installation. It is too large to upload here.

ArtL
 
Art.. interesting comments, as I am just now contemplating ordering new aeroquip lines from A/C Spruce.

The original configuration has a flex line at the master cylinder.
metal line in the wing.
flex line from inside the wing to the upper 1/3 of the landing gear
a splice coupling
flex line extending about 2/3rds of the gear leg length to the brake assy. ( now about 8 " too short)

I agree that the lower section takes the most wear.. from flex, brackets, dirt, service, sun
you name it.
so, there was wisdom in the original designs making this section replaceable.

of course every fitting adds to the price of a fabricated hose.

my hoses appear to be like aeroquip 603 ... cotton and rubber.
the newer 606... Teflon and stainless looks a lot sturdier.... and the 5606 I am using is so nasty
that Teflon has a good ring to it.

$2 a foot more.. not enough to matter. if the fittings aren't too dear.

----

assuming I connect at the BOTTOM of the disc brake assy. the new line has to curve around the casting
which makes it look like a 90 degree fitting screwed into the brake assy.. would give the best routing for the hose... I see on cessnas they use a curved metal line to do this.

Not being an aircraft designer or A&P... I am not sure what the best practice would be here.
Maybe AC repair practices will help. ??
 
Blimby, I doubt if I'd be much help here, but one thing I would suggest is that you have the bird on jacks and cycle the gear to check clearances before you purchase parts. As I recall from your earlier pictures you might have some interference problems if you choose the wrong connection mode.

I know on mine, when the gear is retracted the flex lines do some strange things and are different on the left and right gear. I am in the process of researching all of the old 'Contact' issues for pointers.

And of course any sharp bends in routing are best served with hard fittings - you want to bend the flex hose itself as little as possible. AC 43.13-1B (Accept. Methods, insp & repair) has some flex hose installation parameters. Available on-line, it is almost 700 pages long, but you can search for keywords such as 'flex hose' to zero in on what you need. Check out page 494 for examples of proper routings.

Heck of a project you have going there - good luck - surely it has been done before?

art
 
Blimby, another thing I forgot to suggest is to stick with the original flex hose specifications. Teflon hoses can take a 'set' when subjected to high temps or pressures. I don't know what the limits are, but the 'methods' caution against straightening a bent hose that has been in service. This may be one of those instances where 'better' isn't.

art
 
Art, thank you for the kind offer to email me PDFs, but at this point I dont have a working printer, so I will deal with things after I finish cleaning up from the fire. Even though I lost far less than many people in this fire, the aftermath is taking much longer than I expected. Life goes on! _____ Grant.
 
Art and Grant, Thank You !

The "POH" shows the brake lines.. and I have the parts manual somewhere also.

Art, it helps to remember that mine is a flying airplane, that goes through gear retraction inspection at each annual. So, I have no worries that the current installation is somehow "wrong".

... I have AC 42-13 or whatever it is.. thanks.

I am not going to forego the Teflon / Stainless because of "imagined problems"... but I will ask Dan Torrey,
who works on Bellanca's all day every day.. see what is preferred.

My "imagined problem" is a suspicion that the rubber lining of the 603 aeroquip ( or similar) hose may Degrade With Time And Contaminate The Brake Fluid. Suspicion confirmed with an old timer today..
as in he also "suspects " that this happens.

Thus.. I am strongly considering replacing ALL the flexible lines.. since I do know my brake fluid has/is being ( been) contaminated, and I don't know by what.
 
Art.. I measured 150 psi max (SCOTT 4000).. but with a leak . so the numbers I quoted previously should be correct.

you will start busting metal parts trying to get 200 psi... and Godzilla himself couldn't get 300 not even with Faye Wray in his arms.

BTW the bore is 13/16th inch.. and they are single stage... one effective O-ring. ( 4300 in urpcup are two stage.)
( wheeler dealers are 5/8" with twin plungers and 2 effective O-rings.)

---

Got out the Wheeler Dealer Masters ( from cruismaster ).. to begin cleaning them up and overhauling them.
I took one look at the wimpy size of the plunger rods... and the 1949 date stamp...
brought them home to work on the rubber covered work bench, and went to sleep on it.

Woke up at 5 am worrying about the things and said. "THIS IS STUPID... YOU PAY ALMOST $2000 FOR NEW Brakes, AND THEN YOU ARE GONNA USE 66 YEAR OLD MASTER CYLINDERS ? WTF! " We know the scotts break at or near the clevis on top of the plunger.. why do I want to use these Old masters built with half the plunger beef ?

I Don't !

So, today I ordered up a pair of new Grove 675-2 master cylinders. right fit, right pressure, right displacement, right stroke. AND the plunger diameter is just as stout as the scotts. These guys make STC'd brake kits for cubs and super cubs... so it aint cheap experimental crap. fingers crossed.
 
Blimby - this will be a great exercise. Now that we 'know' that the piston dia. on the Scott 4000 is 13/16" and not 7/8", I calculate that with 140 lbs. brake pedal pressure - which should be easily achieved according to previous research - then the system pressure should be around 270 psi. More than adequate for the Bodell brakes. I will continue and report. However, I now have a lot of repair and modification to do on my main landing gear due to previous installation errors. Old airplanes are so much fun if you prefer to tinker rather than fly! Thanks for your continue input. Well appreciated. art
 
Oh, BTW Blimpy, if the Wheeler Dealer masters have a 5/8" dia. piston, then they should be able to put out about 460 psi with 140 lbs. brake pedal input. I know there is some system loss due to friction, etc., but this should be adequate for your new brakes. Just saying - if you are not getting near that system pressure then you might consider there is something else wrong.

here's the basic formula - piston area in square inches divided by brake pedal pressure equals system pressure. So with a 5/8" dia. piston (dia/2 = radius (r) and r squared times pi = area then A=πr^2 then a 5/8" dia piston has about 0.306 sq in area. Take the 140 lb brake pedal pressure and divide it by the area and you get (140 / 0.306 = 456 psi). You earlier suggested that the Clevelands required 400 - 500 psi., so there you go.

Personally, I'd use the Wheeler Dealer masters and save the $$$. But that is a personal preference.

art
 
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