PA-20 Brake Hoses

[CantFindMind]

This is my first post and of course, I need help...

I'm flying a 1953 PA-20, 135hp and found my left brake getting soft. After topping off the cylinder a few times I decided to see where that fluid was going. Long story short, the brake hose near the cylinder was leaking and both of them looked poor. I called Aircraft Spruce, Univair and Spencer and had to pick myself off the floor from sticker shock. Someone told me that a lot of guys were switching over to AN style fittings for these hoses.

My questions are: Does anyone have a good source for making up these hoses? What is your experience with getting them replaced?

(Even though I just joined I have been reading your forum for a little while. You guys are great! Thanks for all the good information!)

[Vagabondblues]

That high price for a complete flexible hose assembly probably includes the cost of a identification tag required under TSO C75, proof testing, regulatory oversight and liabilty. I believe that AC43.13 section 9 details the replacement of flexible "low pressuure" hoses with reusable fittings like the Aeroquip fittings. Your best bet maybe to find a mechanic who has the mandrels and is comfortable building up hose assemblies and making a logbook enty. If I remeber correctly the fittings on my 50 pacer were crimped on.

Do you have the original expander tube brakes? If you do you probably still have the 45 degree flare weatherhead fittings off of the brake master cylinders and maybe even copper lines in the landing gear. I think that they are also 1/8 NPT so you could install a AN 816 union (37 degree flare to 1/8 NPT) to fit the Aeroquip fittings.

[Steve Pierce]

I get the braided steel hoses Aeroquip 666 hose from Varga http://vargaair.com/ but the use regular AN fittings rather than the inverted weatherhead stuff Piper used. We used Aeroquip 303 or Stratoflex 111 on my Dad's Clipper but it is much stiffer than the original hose and doesn't allow the rudder pedals to move correctly if clamped like the original soft hoses Piper used.

[CantFindMind]

The master cylinders do still have the 45º weatherhead fittings and it does look to be 1/8" NPT. I am going to try to find a mechanic here in the Seattle area that can help me make these up. If I can't find one, I will just buy the pre-made hoses. It sure would be nice to get AN fittings in there instead of the weatherhead stuff though.

Thanks again!

[Steve Pierce]

Call Jason Gerard 206-930-2332. He can help you.

[CantFindMind]

Will do. Thanks Steve!

[Stephen]

I just replaced the flex brake lines on a PA-20, making all new flex lines. I got my parts from Spencer in Tacoma. Does your Pacer have both side brakes or just left side?

[CantFindMind]

On the left side only.

[Stephen]

Then, replacing them is no big deal...glad to help if needed.

Are you based at Harvey??

Jason is local and is excellent with Pipers.

[CantFindMind]

Yep good old S43 - Harvey Field. Started out there last fall with Arnold Ebneter as my CFI. Have done all my firsts there in the Pacer. If the weather had cooperated a little more I would have my Private by now but I am very close.

Having a lot of fun!

[BrettL]

I just found the same exact problem with my PA-17 Vagabond. I have a replacement hose on order. I've not been able to get the fitting loose from the master cylinder. So far I've been trying to do this without removing the master cylinder from the airplane. I'm using a 9/16" line wrench, and some liquid wrench. Any suggestions before I resort to removing the master cylinder?

[Stephen]

I just found the same exact problem with my PA-17 Vagabond. I have a replacement hose on order. I've not been able to get the fitting loose from the master cylinder. So far I've been trying to do this without removing the master cylinder from the airplane. I'm using a 9/16" line wrench, and some liquid wrench. Any suggestions before I resort to removing the master cylinder?

If you can fit an actual tubbing box style wrench on the fitting, you might be able to aply more force. You need more leverage. If the nut surface gets rounded off, you may have to go to vise grips.

CFM...I'm into Harvey couple of times a month, do you know Dave Riffle??

Jason is only a few minutes east of Harvey.

You'll have to fly out to Lopez for a visit. Steve

[CantFindMind]

Something that helped me was to attack the problem from the bottom. Unscrew the metal from the bottom of the plane far enough to get access to the bottom of the cylinder. I took both of them out to clean them up an replace the o-rings. Its a little more comfortable than laying across the door frame on the inside.


I know a Dave Riffle that is a Siemens controls guy in the area, not sure if he flies though. I'll have to ask.

I met up with Jason and he made up the brake hoses for me. Nice guy. Watched him lay down a landing that is about the same rolling distance that it takes me to push the throttle all the way in the pacer!

Would love to come out for a visit. Just have to take care of a couple of items first. (Check ride, annual)

[Stephen]

Dave of Siemens is not only a pilot, but owens a Pacer based at....Harvey. We get together occasionally. Glad, you connected with Jason....good man, even though he flies one of those slow cluncky "long wing" cub type planes.

[CantFindMind]

Small world! Formation practice anyone?

Wonder if this wind will ever stop...

[BrettL]

Thanks. I'll probably have to open up the fuselage cowl anyway. It was closed up before I bought it, evidently by someone who didn't want to deal with those pesky screws, by a "new and improved" method that will require a drill to reopen it.

[BrettL]

Well, everything is almost done and I've run into a bit of an issue putting in the new brake line. I bought the Univair hose in hopes of expediency. The section where fitting attaches to the hose is considerably larger to the point that the clamp on the underside of the diagonal tube (under the floorboard) wont bend around it enough to secure the hose in place. It all looks good until I move the rudder pedal, at which point the fitting slips out of the clamp.

Any ideas or suggestions on how to secure the brake line in the clamp?

[Steve Pierce]

Bret, Can you get a picture?

[BrettL]

Steve,

I don't think I can get a picture that would adequately show the issue. Basically there are two strips of metal welded onto the airframe tubing, that originally were curved around the sides of the original brake hose where the fitting is crimped on the hose to form a clamp. This kept this end of the brake hose from moving around. Also because the sleeve was larger before and after the crimp, it kept it the line from sliding back and forth in the clamp. The new hose uses a non-crimped fitting attachment. The two strips of metal that form the clamp only go about a quarter of the way around the new fitting sleeve, so at their ends they are parallel to each other when crimped down as hard as I can get them, rather than curved back toward each other at the ends. Ultimately this allows the fitting sleeve to slide both back and forth, as well as down and out of the clamp.

If you have access to the drawings, the clamp I'm referring to is shown in "Section F-F" on both of the "Controls - Cockpit Installation" drawings, numbers 11600 and 11810.

Brett

[CantFindMind]

BrettL,

I think you are talking about the more forward of two clamps that has two strips of metal welded on about a 2" vertical tube. This would be the first attach point if you follow the hose from the cylinder back.
My old brake hoses were wrapped in electrical tape and then the tape was wrapped around the forward clamp. (Probably "fixed up" this way after the floats were removed) Anyway, the hoses were secured and not allowed to move from this point back but there was enough length to allow the hoses to travel and twist just a bit when the brakes were applied. This was the same for both sides. The metal strips were pointing straight down, parallel with each other and not "crimping" the hoses. They were just acting as a guide.

When I replaced the hoses I put a small section of thin wall hose over the brake hose (to protect the new hose from rubbing on the metal strips) and used a criss-cross pattern of tie wraps to hold it up in place.
Now I don't know if they are supposed to be mounted this way but it works fine and there is plenty of room for the hose to move to allow smooth pedal movement.

Allen

[BrettL]

Allen,

On my Vagabond, this is the only place the brake lines are clamped. According to the drawings, friction tape is supposed to be used where the brake line secures in the clamp. On the old lines the clamp didn't need to be super tight, because it encircled it enough to keep it from dropping out of the clamp. Since the clamp encircled the crimped portion of the sleeve attaching the fitting to the hose it also kept the hose from moving more than just a small fraction of an inch back and forth.

I looked closer today and found that the fitting attach on the hose isn't pushing all the way into the clamp. The two tabs are too close together for the larger hose fitting attach, and only will bend back to the area where they are welded to the tube. This leaves the fitting sitting in the clamp with about 3/16 of an inch space between it and the tube.

I do have it now where I can move the pedals full travel without the hose dropping out, but it's no where near as secure as the other brake line. I was thinking either tie wraps or safety wire to secure. I'm not sure about the implications of the hose dropping out of the clamp onto the inside of the bottom of the boot cowl.

Does anybody make the resistoflex hoses with the original style fittings that would actually fit in the clamps?

Evidently there is still such a thing as "resistoflex".

http://www.resistoflex.com/ (http://www.resistoflex.com/index_b.html)

Brett

[Steve Pierce]

I bet it had the soft rubber, more flexible hoses and the replacements are Stratoflex steel braided under the fabric weave which is not near as flexible and a fatter. My Dad's Clipper was that way and we had to leave them un-clamped because when the brake pedal was pushed the line restricted movement.

[BrettL]

Yes Steve. Both were definetly softer, more flexible brake hoses than the FAA/PMA replacement from Univair (which appears to use Aeroquip 303-4 hose, and fittings). I'm only replacing one at this time. The other hose seems to be in good shape.

[CantFindMind]

Just be careful with the brake pedal pressure you use while braking. My old hoses were pretty "spongy" but the new ones put more pressure to the calipers. I'm guessing that your brakes will be more effective on the side with the new hose.

[redbarron55]

Back in 1975 when I first rebuilt my Pacer I installed Cleveland wheels and brakes to replace the original expander tubes. I used the same type of hose that was originally used. The brakes were very spongy and not effective.
The original setup was designed for the very much lower pressure of the expander tubes.
When I figured out the problem and the solution I had to deal with the routing of the brake lines. In my case I installed dual toe brakes with master slave cylinders. I used Gerdes cylinders with the mounting tabs cut off and welded at 90 degrees to the original so that the lines would exit the side instead of the rear. Right angle fittings allowed the lines to loop up to provide for proper flex and inter connection between sides.
This change gave firm brakes and good braking action. The onlu change I would make now is that I would finish copying the Piper Cherokee system and have slave cylinders on both sides with a hand parking brake and reservior on the firewall.

Good luck with your system.

JDB

[BrettL]

Ok. Brake hose installed, system filled with 5606. Both brake pedals feel exactly the same. The "Electrol" master cylinder has a screw on the side facing the back of the rudder pedal bar, about a half inch from the top, as well as a screw in the very top of the cylinder. Does anyone have any documentation on these? I'm having fluid leak out at the lower screw so I'm unable to fill above it. I'm unsure if the cylinder is supposed to be filled above it. Is the screw there as a max level port, or for some other purpose?

Thanks!

[BrettL]

Well, I now have another brake hose leak. This time its one of the flexible hoses between the fuselage and the gear leg. Piper part number 72101. Is Jason Gerard still a good contact for getting a replacement? The Univair replacements are very expensive, and appear to use the rather rigid Aeroquip 303-4 hose and large end fittings.

[Stephen]

Jason is a good contact...but you apparently do not live in his neighborhood. I removed Electrol master cylinders from a PA-20 recently and installed some Gerdes...which I would switch to Cleveland's any day. Very much improved braking force and better all around cylinder. I made all my own brake flex brake lines which are easy and much cheaper.

[Gilbert Pierce]

The screw in the back of the cylinder was where the little lever that clamped the cylinder shaft when you applied the brakes and pulled the parking brake cable. The cable pulled this little tab up and jammed the cylinder in the depressed posting. Lots of folks removed all of this as it didn't work very well. I removed mine and put the screw back in the hole. Then I had a slight seep of fluid. I took the screw out, put a small "o" ring on the screw and reinstalled it. End of problem. The screw in the top of the cylinder on the plate held in by the clip ring is for adding fluid from the top.

[Vagabondblues]

You may want to use a Stat-O-Seal instead of the O-ring. They are designed to fit under the screw head.
http://www.gen-aircraft-hardware.com/stat-o-seal.asp

[BrettL]

I bet it had the soft rubber, more flexible hoses and the replacements are Stratoflex steel braided under the fabric weave which is not near as flexible and a fatter. My Dad's Clipper was that way and we had to leave them un-clamped because when the brake pedal was pushed the line restricted movement.

I finally found that the aerospace division of Resistoflex was purchased by Parker Hannifin in 2006 and was integrated into the Stratoflex division. Stratoflex 193-4 appears to be the currently available equivalent, and adheres to all the original Piper specifications for the original Resistoflex hose (drawing 71061).

[BrettL]

The screw in the back of the cylinder was where the little lever that clamped the cylinder shaft when you applied the brakes and pulled the parking brake cable. The cable pulled this little tab up and jammed the cylinder in the depressed posting. Lots of folks removed all of this as it didn't work very well. I removed mine and put the screw back in the hole. Then I had a slight seep of fluid. I took the screw out, put a small "o" ring on the screw and reinstalled it. End of problem. The screw in the top of the cylinder on the plate held in by the clip ring is for adding fluid from the top.

I've seen this type of parking brake arrangement on other brands of brake cylinder, but can't picture how the screw half way down the side of the cylinder would be involved in this. Either way, I don't believe the Vagabond ever had a parking brake provision. I'll look into the Stat-O-Seal.

[Bob Mac]

There are very few, if any, things in which I consider myself skilled but I have fabricated hundreds of Aeroquip or similar hoses for a whole bunch of people.
Today I am fabricating some hoses with Aeroquip 303 and find that the nipples from a new batch of fittings will not fit over the mandrel of the tool I've had for 30 years. I had a couple of older fittings in my stash and they still fit perfectly.
Has anybody else experienced this or has something changed that I have missed?