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Rudder Pedals: Long Bolt Trick

Phil

Well Known Member
I'm installing the rudder pedals and I ordered the AN3-56 bolts for the standard long-bolt modification.

I was in the process of installing the bolts and found that the holes are not aligned.

Is the other half of the 'trick' bending the pedal flanges in to make the holes align and then filling the gap with AN960-10 washers?

Thanks,
Phil


IMG00036.jpg
 
I'm installing the rudder pedals and I ordered the AN3-56 bolts for the standard long-bolt modification.

I was in the process of installing the bolts and found that the holes are not aligned.

Is the other half of the 'trick' bending the pedal flanges in to make the holes align and then filling the gap with AN960-10 washers?

Thanks,
Phil

That's how I did mine. Removes all the bind.
 
Phil

I would do as you suggested, bend the flanges in to make the holes align. Luckily, mine were aligned so no bending required. Good luck.
 
An alternative

Yup - it's sheet metal, bend to align. :rolleyes:
Being frugal (those long bolts are expensive), I took a piece of aluminum rod - don't recall where it came from or exact diameter, but it was big enough to drill and tap for the AN bolts. I cut it to fit inside the flanges - one really long nut for both bolts, with washers under the head and 'nut'. A drop of locktite on the bolt threads and you are good to go.
 
I bent it to shape and everything looks fine....

but................

AN3-56's are too short for the RV-10 pedals. :(

I just bought $45 worth of bolts and now I am going to have to reorder if I want the mod.

Anyone need a good deal on four AN3-56's?

I might just scrap the long bolt idea and go with the standard factory setup. It stupid to spend $90 on 8 bolts.
 
For what it's worth I just did the long bolt and return spring mod on my RV6.

I did the bolts first and they didn't make much difference. Adding the return springs was like going from night to day.

Jim Sharkey
RV-6
 
I saw in a previous thread on this subject that a long drill bit should be used to drill through to the other side, drilling both sides at once. This insures a straight hole for the long bolt and both sides will line up without any binding. That's what I did on my 7A and it works great. By the way, the AN3-56's were just the right size for my 7A, if anyone else is wondering.
 
I did the bolts first and they didn't make much difference. Adding the return springs was like going from night to day.

Hey Jim,

I'm having a hard time finding a source for AN3-58's, so I'm kinda excited that the bolts didn't make that much difference. :)

One of the lessons I think I learned in this exercise is that the bolt axis on each side of the pedal are clearly misaligned. This creates binding. I think you could bend them so they are aligned and then use the standard hardware and be fine.

Do you have any photos of your return spring mod? That sounds like a pretty cools option and affordable too.
 
You don't have to use bolts/fasteners. I used 1/4 dia spring steel (piano wire). Ground a flat on each end and used set screw collars. Loctite'd in place. No problem for almost 10 years. Total cost - nothing to me. I had this stuff laying around the shop. Maybe $8-10 if you had to go buy it.
 
Hey Jim,

I'm having a hard time finding a source for AN3-58's, so I'm kinda excited that the bolts didn't make that much difference. :)

One of the lessons I think I learned in this exercise is that the bolt axis on each side of the pedal are clearly misaligned. This creates binding. I think you could bend them so they are aligned and then use the standard hardware and be fine.

Do you have any photos of your return spring mod? That sounds like a pretty cools option and affordable too.

brakesprings.jpg


McMaster-Carr part numbers below

6389K625 Nylon Bearing - 5 pack $2.26
9657K115 Steel Spring - 12 pack $6.00
9946K13 Aluminum Set Crew Collar - each $1.91

Less than 15 bucks with spares - Priceless!
For everything else there is ..............

PS - when I did the original installation with two short bolts per pedal I used some McMaster-Carr 95630A460 7/8" dia PTFE washers between the brake pedal and the rudder bar. This reduced binding considerably and perhaps accounted for the negligible effect of the long bolts when I eventually fitted them.

PPS - Did I say that the springs work really well? :)

Jim Sharkey
RV-6
 
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One of the most useful tools during my build was a 3/16" chainsaw sharpening file- craftsman. Anytime I had a tightly fitting AN-3 bolt, a few quick passes with the file made a perfect fit. I used this on my brake peddle assemblies to get a straight axis. Just pass it through both ends of each assembly at the same time and it will then pass the bolt smoothly. Instead of the AN bolts, I used 3/16" brass rod cut to length and then threaded on each end using a die. I installed castellated nuts and cotter pins to capture them and not put any compression on the assembly. This worked very smoothly. The local hardware store had the brass rod at 3' for a few dollars. These also made great alignment pins for the wing spar when fitting it up!
 
very little rotation

i don't think that there is much potential for binding from rotation here... when the brakes are filled and free of air the total movement of the pedal is around a quarter of an inch... pretty much an imperceptible amount of rotation at the bolt. if there is brake drag additional spring force on the brake cylinder arm to fully close the valve is likely a more effective solution.
 
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i don't think that there is much potential for binding from rotation here... when the brakes are filled and free of air the total movement of the pedal is around a quarter of an inch... pretty much an imperceptible amount of rotation at the bolt. if there is brake drag additional spring force to on the brake cylinder arm to fully close the valve is likely a more effective solution.

Yup - Bingo - Bravo - etc

That's my experience - you just need to pull the master cylinder back a smidge to relieve the pressure on the brake rotor. It relaxes on it's own over time but the springs sure do help.

Jim Sharkey
RV-6
 
I'm going to add the springs and you caught me just in time as I'm currently installing the master cylinders...

BTW: I can't fit an AN-3 bolt through the hole in the shaft of the Matco cylinders. I'm assuming you should ream the hole out.... Anyone else run into that problem?

I'm headed to Lowes at the second to see if I can find some springs and collars.. :)

Phil
 
I'm going to add the springs and you caught me just in time as I'm currently installing the master cylinders...

BTW: I can't fit an AN-3 bolt through the hole in the shaft of the Matco cylinders. I'm assuming you should ream the hole out.... Anyone else run into that problem?

I'm headed to Lowes at the second to see if I can find some springs and collars.. :)

Phil

That surprises me - so open it up as little as needed.

PS - Google McMaster-Carr on line - they market way more than Lowes or Home Depot
 
Yeah you can fit the threads through, but when you get to the grip segment of the bolt it's a solid fit. You can't squeeze it through.

Unless someone else has an idea, I'm going to open them up with a #12 reamer and see how that works.
 
I had the same problem with getting the bolt thru the master cylinder. Like I mentioned, the 3/16" chainsaw files works wonders! I used it to get the bolt to fit.
 
dumb question time

How do you get the spring on an already flying plane? My brakes drag a bit. Not so much that I can't get it in and out of the hangar.

Jeremy Constant
 
How do you get the spring on an already flying plane? My brakes drag a bit. Not so much that I can't get it in and out of the hangar.

Jeremy Constant

My guess would be that you lie on your back in an unflattering position while removing the master cylinders, installing the springs & collars, then reinstalling the master cylinders. But that's only a guess :)

BTW, I sent you a PM.
 
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My guess would be that you lie on your back in an unflattering position while removing the master cylinders, installing the springs & collars, then reinstalling the master cylinders. But that's only a guess :)

BTW, I sent you a PM.

I "assumed the position" just recently to un-install and then re-install my auto pilot. I view it at one of the more advanced RV yoga postures, but the real masters know all of the appropriate words for the RV yoga chants and mantras:D

Jeremy
 
AN3-58's Best Wishes!

Hey Jim,

I'm having a hard time finding a source for AN3-58's, so I'm kinda excited that the bolts didn't make that much difference. :)

One of the lessons I think I learned in this exercise is that the bolt axis on each side of the pedal are clearly misaligned. This creates binding. I think you could bend them so they are aligned and then use the standard hardware and be fine.

Do you have any photos of your return spring mod? That sounds like a pretty cools option and affordable too.

AN3-58's Best Wishes!;)

An AN3-57 is nominally 5 and 7/8" long plus a little for the washer. So the next length is 6 and 0/8ths long, correctly called out as an AN3-60.

The last number in your basic AN bolt never ends in 8 or 9, since the lengths are octal based. Just a lil info.:D
 
I learn something everyday.

AN3-58's Best Wishes!;)

An AN3-57 is nominally 5 and 7/8" long plus a little for the washer. So the next length is 6 and 0/8ths long, correctly called out as an AN3-60.

The last number in your basic AN bolt never ends in 8 or 9, since the lengths are octal based. Just a lil info.:D

Thanks Tom for that reminder lesson......!

Bob
 
Not trying to hi-jack a thread but I had a quick question that's pertinent here: Rather than spend $90 on bolts, would it be feasible to cut an appropriate length from an appropriate diameter rod and cut threads to accept nuts (locknuts or cottered) on both ends? Seems a simple matter to fabricate something more suitable ourselves after all the other stuff we've built.

<standing by...>
 
Each option has it's cost.

Not trying to hi-jack a thread but I had a quick question that's pertinent here: Rather than spend $90 on bolts, would it be feasible to cut an appropriate length from an appropriate diameter rod and cut threads to accept nuts (locknuts or cottered) on both ends? Seems a simple matter to fabricate something more suitable ourselves after all the other stuff we've built.

<standing by...>

We are airplane builders, with the right tools and materials we can fix anything. How well depends on skill and materials, and oh yeh, time too.

Somethings I do the long way for the challenge and it beats being at real work.

Other things are great to just install right out of the factory package.
Each option has it's cost.;)
 
Fred,

Read the earlier post on the top of pg 2 for this thread. That's exactly what I did.:cool:
 
Fred,

Read the earlier post on the top of pg 2 for this thread. That's exactly what I did.:cool:

Thanks! I should have spent more time reading all the posts. :eek: Any problems with your fabrication and setup? Has the brass rod held up well?
 
Ref post #10 from Jim in this thread

I am still building a RV-8. I put some half round aluminum brake extensions (like the long bolt idea) on the bottom of my brake pedals. Was wondering if the spring thing would be worth while (or even works) on the 8? Does anybody know by chance? Thanks. Dave
 
Thanks Jim, you made it easy. I googled McMaster as you suggested and cut and pasted the part numbers and presto, compiled an order. Total current price $15.90. I think I'll try the springs and then see if I can thread 3/16" brass rod.
 
Thanks Jim, you made it easy. I googled McMaster as you suggested and cut and pasted the part numbers and presto, compiled an order. Total current price $15.90. I think I'll try the springs and then see if I can thread 3/16" brass rod.

Pleased to help :)
Jim Sharkey
 
I tested the bolt mod alone.

I just used the long bolts on my 7. I tested with 1 psi air pressure at the inlet to the master cylinders and ensured that it always flowed when returned. The pedals were worked until floppy loose then tested. The plunger always returned no matter how slowly it was pressed and/or released.

Maybe with age the springs will be needed. They are in my stock now, along with the collars. I don't like the fact that the springs will rub the shaft.
 
Bill,
If you spend some time correcting some of the deficiencies in all of the pivot locations, the springs are not needed.

1) The long bolt mod for the pedals.
2) Get rid of the washers called out in the design for use as spacers for the master cylinders. Fabricate some one piece bosses and permanently mount them to the pedals so that the lower pivot bolt has plenty of bearing surface and can't tilt sideways if left loose enough to act like a pivot.

I had some aluminum body nylock nutplates that worked perfect as material to make the bosses. Drilled them out, filed them a bit shorter and riveted to the rudder pedal.

600 hrs, Never a problem with cylinder return. No springs.

6708485864a0238f7c484f.jpg
 
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Still looking for pics of the spring installation. Thanks!

Measure the shank diameter of the master cylinder.

Measure the space from the body to the lowest spot a spring could fit and deduct 1/2 to 3/4 of an inch.

Go to your ACE hardware or any other hardware store and look at springs that will fit over the shaft. They do not need to be very strong..... easy squeeze with your fingers.

Get (still at the hardware store) allan screw locking collars with the ID to fit the shank.

Disconnect the master cyl. from the pedal, slide on the spring, slide on the collar, compress the spring the thickness of the collar and tighten the set screw.

Replace bolt.....Done.
 
Still looking for pics of the spring installation. Thanks!

Here you go.

IMG_1462-M.jpg


You can't see the nylon washer at the bottom of the springs, but there is one there. Then the springs go over the push rods, and are held down with a shaft collar and set screw.

I sourced all of these parts at the local hardware store.

I used stainless steel drill rod to make the "long bolts". Cut to size, used a die to thread the ends, then drilled a hole for a cotter pin and used castellated nuts.

IMG_0232-M.jpg
 
Bill,
If you spend some time correcting some of the deficiencies in all of the pivot locations, the springs are not needed.
[/IMG]

Thanks, Bill, love the boss implementation!

I just used the washers and it worked, but will look for some boss material. Maybe some left over bar stock will work, just turn it on the lathe.

Great idea, Thanks!
 
I just finished this step in my build. I did use a 12" #12 bit to make sure the pedals rotated freely on the long bolt.

I noticed that the tabs for the master cylinders may need to be adjusted a little so that the are aligned properly. Otherwise there was some additional resistance.

I went ahead and ordered the springs and etc. from McMaster. Cheap insurance in my mind. PM me and I can send you 4 springs. They are sold in bags of ten. Oh and if you want nylon washers I have those too. I didn't like the shoulder bushing setup called out in a related thread where the 0.5" diameter spring rested on the end of the shoulder bushing.
 
My only issue with the parts from McMaster that were listed, and that I ordered, is the ID of the spring is basically the same as the OD of the sleeve so the spring doesn't fit over the sleeve. Are people unwinding the spring a bit to fit it over the sleeve? or did I order this wrong? I just copied earlier posts but the spring and sleeve are the same diameter.

AF1QipMmWIgIA5b80SJYbhV_J3GluaE6I6Dvzcr3IyOQ
 
Yeah I didn't like the way that fit either. Unfortunately I just blindly ordered the parts listed and didn't check any of the dimensions first. I did subsequently order slightly larger diameter spring and I found some other sleeves that had a slightly smaller OD. I'll see how those parts look and fit tomorrow.
 
I did the long bolt and springs mod on my RV-8A. However, one of the master cylinders developed a leak on top that required a rebuild. The rebuilt cylinders had enough "return" / recovery to eliminate the need for the springs. Kept the long bolts though. Note that the spring installation was not the cause of the leak; the shaft had deformed which allowed fluid to escape under heavy braking. Hopefully the long bolts will prevent the master cylinder from twisting, and reduce wear on the shaft.
 
I did the long bolt and springs mod on my 7 and I still hear the brakes drag on occasion when I'm on a paved runway. But I just inspected the brakes and after 2 years and close to 300 landings, found very little wear on the shoes!
 
After playing with the brake springs way too long I've finally settled on my spring configuration. I ended up just using nylon washers and the 0.5" OD spring. The slightly larger spring actually looked bigger so I decided against it even though I had tracked down sleeves that would fit inside. Now I have a ton of parts I'm not going to use but at least I got to evaluate all the options. My configuration now looks like Bruce's.

If you are interested in any of these extra parts PM me.
 
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I did the long bolt and springs mod on my 7 and I still hear the brakes drag on occasion when I'm on a paved runway. But I just inspected the brakes and after 2 years and close to 300 landings, found very little wear on the shoes!

All disc brakes drag a little by design. There is no return spring on the caliper piston. This keeps the discs clean.
 
Spring OD

If you just order the parts listed, they either changed part numbers or something happened because the formula in this thread doesn't work. The sleeves are perfect, they slip right inside the M/C. You need a spring with an ID of 5/8" of an inch. I got the bag of springs and basically have a bag of springs I'll never use now. OSH had some long ones that worked great, cut in half and tweaked at the ends. The wire thickness of .50 gauge wire spring seemed a lot more appropriate to me than the .41 or the .6?
Good middle of the road type.
 
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I just finished this step in my build. I did use a 12" #12 bit to make sure the pedals rotated freely on the long bolt.

I noticed that the tabs for the master cylinders may need to be adjusted a little so that the are aligned properly. Otherwise there was some additional resistance.

I went ahead and ordered the springs and etc. from McMaster. Cheap insurance in my mind. PM me and I can send you 4 springs. They are sold in bags of ten. Oh and if you want nylon washers I have those too. I didn't like the shoulder bushing setup called out in a related thread where the 0.5" diameter spring rested on the end of the shoulder bushing.

Ray,

I sure would like some of your extra springs and washers. I'm at the point where I'm building my rudder/brake pedals right now. My mailing address is below:

8563 W ILIFF AVE
LAKEWOOD, CO 80227
 
Mike, I'll take a look and try to find those parts. PM me if you don't hear from me and I forget about it.
 
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