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Rudder Pedals And Brake Pedals Questions

mfleming

Well Known Member
Patron
I'm working on my rudder pedals and brake pedals today. (QB -7 fuselage)
I've searched the forum and found some answers to my questions but a lot of the info is old (not necessarily bad) and many of the photos don't show up anymore.

So hopefully this isn't too redundant.


  1. Are the brake return springs on the Matco master cylinders really necessary?
  2. Should I wait to drill the lower master cylinder hole in the horn. (looks pretty good where the drawings show)
  3. Plastic brake lines upgrade? (I don't live in the desert)
  4. My rudder assemblies do not have a bare middle section for the F-6115 center bearing block...is that normal and will I have to to use paint stripper?
  5. How the heck do I drill the F-719 forward skin stiffener for side the bearing blocks? (I don't have an angle drill)
  6. One last question...Extra rudder cable tabs on the inboard pedals...leave or cut off?
 
I used springs, so don't know how they do with out them. I heard of issues, so was proactive.

I used the plastic brake line, as have many others without issue. 500 hours trouble free here.

Drill holes in the blocks on your drill press to keep them straight. Set them up on the angle iron where you want it (clamps will help) and drill from the top with a 1 foot or two foot drill bit (whatever length it requires) through the block. You can gets these at home depot.

I left the extra tabs. Less grinding and painting. They are not objectionable.

Larry
 
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Long bolt option

You didn't ask but worth mentioning. Instead of bolts on either side of each pedal, buy AN3-56 bolts and secure them with castle nut and cotter pin. The pedal moves much smoother.
Make sure the outer two are inserted from onboard to outboard. No way to remove them otherwise.
 
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You didn't ask but worth mentioning. Instead of bolts on either side of each pedal, buy AN3-56 bolts and secure them with castle nut and cotter pin. The pedal moves much smoother.
Make sure the outer two are inserted from onboard to outboard. No way to remove them otherwise.

I did forget to ask about the long bolts...

I have my brake pedals temporarily mounted to the rudder assemblies and the supplied bolts seem adequate.
Do the AN3-56 bolts really make a $30 difference?

What is the consensus on #2 - Should I wait to drill the lower master cylinder hole in the horn?

Also - what about a pedal finish...prime and paint or anodize like Bruce Swayze's beautiful pedals.

100_6566%20(Small).JPG



Here's a photo of my temporary installation.
pedals.jpg
 

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I had my pedals hard anodized at a local shop. I was afraid that any other method would wear too quickly. Some have painted them, some have had them powder coated. Mine came out pretty well I think. If you decide to go down the anodized path let me know and I can give you some hints on the surface prep.

I also installed the return spring. Pretty cheap insurance in my mind.
 
I used springs, so don't know how they do with out them. I heard of issues, so was proactive.

I used the plastic brake line, as have many others without issue. 500 hours trouble free here.

Drill holes in the blocks on your drill press to keep them straight. Set them up on the angle iron where you want it (clamps will help) and drill from the top with a 1 foot or two foot drill bit (whatever length it requires) through the block. You can gets these at home depot.

I left the extra tabs. Less grinding and painting. They are not objectionable.

Larry

Thanks for the tips - I'll be looking for a long 3/16" bit!
 
The standard internal Matco springs are fine as long as your bolt alignment is good, which is helped by using the long bolt setup, and there is no binding elsewhere.
Vans design puts a side load on the piston shaft. Over time, they wear and start to leak at the top seals. Adding springs may or may not contribute to faster, or slower?, wear.
Your center bearing block should have washers installed as spacers to take up what was lost when you cut them. Those spacers also give clearance for the powder coat. If it binds, put in a thicker washer (spacer).
 
Van's brake pedal is one of the few points of really bad design. Drill your pedal assemblies apart and rerivet the angles to the aft side (the side your feet press) to set the pedal surface 7/8" further forward. You're far less likely to inadvertently brake when all you want is rudder/steering with your toes on the bar. Prepunched hole accuracy lets you do this by swapping parts left-right/fore/aft to make the rearrangement. It's worth the trouble now.

John Siebold
 
Just make sure you have the proper tilt to the pedals and you won't have the dragging brake problem. Do not set up the pedals to match the vertical weldment. They must tilt toward the firewall. Your feet don't point straight up sitting in an RV.
 
The standard internal Matco springs are fine as long as your bolt alignment is good, which is helped by using the long bolt setup, and there is no binding elsewhere.
Vans design puts a side load on the piston shaft. Over time, they wear and start to leak at the top seals. Adding springs may or may not contribute to faster, or slower?, wear.
Your center bearing block should have washers installed as spacers to take up what was lost when you cut them. Those spacers also give clearance for the powder coat. If it binds, put in a thicker washer (spacer).

So the center bearing block rides on the powder coat...I would't have expected that.

As far as the long bolt option goes...I can't see how that cures anything?? Maybe I'm being blinded by the $50 for four bolts :eek:
 
Van's brake pedal is one of the few points of really bad design. Drill your pedal assemblies apart and rerivet the angles to the aft side (the side your feet press) to set the pedal surface 7/8" further forward. You're far less likely to inadvertently brake when all you want is rudder/steering with your toes on the bar. Prepunched hole accuracy lets you do this by swapping parts left-right/fore/aft to make the rearrangement. It's worth the trouble now.

John Siebold

I haven't riveted yet so that is an easy option. I'll rearrange the angles and see how it looks.

Being a -7, inadvertent brake application is not on my list of fun experiences :eek:
 
Just make sure you have the proper tilt to the pedals and you won't have the dragging brake problem. Do not set up the pedals to match the vertical weldment. They must tilt toward the firewall. Your feet don't point straight up sitting in an RV.

What's a good tilt? ?" or so?
 
washers

in reading posts about the brakes I never hear any talk about the thickness of the washers that take up the distance between the weldment and the pedal on my 4 and now the 7 the drawing show the washers but I think a note stating as required would eliminate this "binding" as everyone of mine needed different thickness of washers to fill the gap and not bind. most are home made washers of what I had of various thickness.
 
in reading posts about the brakes I never hear any talk about the thickness of the washers that take up the distance between the weldment and the pedal on my 4 and now the 7 the drawing show the washers but I think a note stating as required would eliminate this "binding" as everyone of mine needed different thickness of washers to fill the gap and not bind. most are home made washers of what I had of various thickness.

My -7 plans call for the AN960-10L thin washer to be between the weldment and the pedal. In my case those thin washers barley slipped between the gap...there's definitely no slop.

I don't see how the long bolt prevents any binding. Unless the tabs flex, which I would be surprised they did.
 
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I don't see how the long bolt prevents any binding. Unless the tabs flex, which I would be surprised they did.

The long bolts make sure the two sides are on a common axis for the pivot motion. Two separate bolts can end up being on different axis's and cause binding. Also, best to use a long drill and run it through both sides at the same time.
 
Also, best to use a long drill and run it through both sides at the same time.
Yes. If you don't do this you're likely to get more binding by using one long bolt than if you just used two separate bolts per plans. That's what happened to me when I tried to "upgrade" to a long bolt. That said, in my opinion, the two-bolts per plans will work just fine.
 
...... That said, in my opinion, the two-bolts per plans will work just fine.

Yes, I'm not convinced from an engineering standpoint that $50 worth of bolts is going to cure anything.

The tabs are predrilled, if they are not on the same axis now, all that can be done is enlarge one of the holes and we don't want that.

After reading as much as I can on the long bolts, I'm pretty convinced that the real problem is the week return spring in the Matco master cylinders. So I'll be adding those to my to do list.
 
.......Your center bearing block should have washers installed as spacers to take up what was lost when you cut them. Those spacers also give clearance for the powder coat. If it binds, put in a thicker washer (spacer).

I confirmed with Van's that the powder coat is left on and the center bearing blocks are installed exactly as you describe.
 
I didn't use the $50 bolts. Instead I got a piece of 3/16" SS rod and threaded and drilled each end for a nut and cotter pin. The pedals will work much better with a thru pivot than two separate ones.
 
Yes, I'm not convinced from an engineering standpoint that $50 worth of bolts is going to cure anything.

The tabs are predrilled, if they are not on the same axis now, all that can be done is enlarge one of the holes and we don't want that.

After reading as much as I can on the long bolts, I'm pretty convinced that the real problem is the week return spring in the Matco master cylinders. So I'll be adding those to my to do list.

Since you brought up engineering - look at the moment applied to the short bolts. That shear force and resulting moment rotates the bolts in the sloppy holes and will cause them to bind. Use the long bolts and you won't back here later lamenting about poor pad life and overheating/dragging brakes.

I bought the return springs, but did not install them, the bolts ( I like the stainless shaft idea) resulted in allowing the light internal springs of the master cylinders to return and open the fill hole. I tested them with some air pressure to ensure that the fill ports were uncovered.

One thing that also affects possible hangup - that is the stiffness of the hoses on the pressure side. That stiffness is not trivial and could contribute to the inability of the master plunger to fully return. I am keeping an eye on this as part of phase I. (Validation)
 
I Concede

Since you brought up engineering - look at the moment applied to the short bolts. That shear force and resulting moment rotates the bolts in the sloppy holes and will cause them to bind. Use the long bolts and you won't back here later lamenting about poor pad life and overheating/dragging brakes...... (Validation)

So its not like I didn't believe everybody but I just couldn't visualize what the long bolt did that the two short bolts didn't do.

I went out to the rudder/brake assembly and tightened the castle nut to what I thought they would be in service (not to tight). Sure enough, when I applied enough force on the pedal I could see how the shear force tried to rotate the bolt and it was was levered out of the proper plane, setting up a possible binding action.

Soooo...I was wrong, the collective was right...just don't tell my wife I said that ;)

Van's cost estimator takes another hit :D
 
I found a bag of new an3-56 bolts on ebay, 27 bolts for 30 dollars shipped. Check ebay and give some to your buddies, anyone near Sarasota can stop by and get a free set from me. I like the single axle setup.
 
I found a bag of new an3-56 bolts on ebay, 27 bolts for 30 dollars shipped. Check ebay and give some to your buddies, anyone near Sarasota can stop by and get a free set from me. I like the single axle setup.

I can't find them???
 
What's a good tilt? ¾" or so?
I sat in mine with the bolts snug and string tied to each pedal, pushed on them and pulled the string till I found the perfect fit..... then I drilled for the master.

As far as bolts, look at a longer bolt from ACS that can be cut down.... longer seems to be cheaper.
 
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That has changed since I received my fuselage kit in April of 2012.

http://mykitlog.com/users/display_l...project=2052&category=7420&log=189934&row=158 (bottom photo)

Interesting. My early kit rudder bar was completely powder coated, including the ends, which I had to strip the paint to fit the bearing block.

I have posted before about the Matco spring "issue". They are more than adequate. If they are not returning, your pedals are binding. This needs to be fixed or you might suffer excess wear on the binding surfaces, bolts, whatever. Putting a bigger spring over the shaft just masks the root problem.

The cylinder geometry isn't how Matco engineers want to see the product installed. Vans design introduces a side load. I have spoken to Matco and they are well aware of how Vans set up is. It simply means over time the shafts will wear and the seals will leak. For mine, it was around 700 hours. It was a pretty easy rebuild back to new with readily available rebuild kit, but no reason these wouldn't las much longer if the shaft wasn't side loaded as a result of the design.
 
Interesting. My early kit rudder bar was completely powder coated, including the ends, which I had to strip the paint to fit the bearing block.

I have posted before about the Matco spring "issue". They are more than adequate. If they are not returning, your pedals are binding. This needs to be fixed or you might suffer excess wear on the binding surfaces, bolts, whatever. Putting a bigger spring over the shaft just masks the root problem.

The cylinder geometry isn't how Matco engineers want to see the product installed. Vans design introduces a side load. I have spoken to Matco and they are well aware of how Vans set up is. It simply means over time the shafts will wear and the seals will leak. For mine, it was around 700 hours. It was a pretty easy rebuild back to new with readily available rebuild kit, but no reason these wouldn't las much longer if the shaft wasn't side loaded as a result of the design.

Even after Van's said leave the powder coat on, I'm inclined to strip the coating off.
Do you remember how you stripped the powder coat off?

Besides ensuring that there is no binding in the pedals, was there anything to be done about the side load on the Matco master cylinder?
 
Long bolts installed

Received the long bolts...Whats the consensus for leaving out the thin washers between the pedal and the weldment if it make the brake pedal a little stiff?

pedals2.jpg
 
Even after Van's said leave the powder coat on, I'm inclined to strip the coating off.
Do you remember how you stripped the powder coat off?

Besides ensuring that there is no binding in the pedals, was there anything to be done about the side load on the Matco master cylinder?

Sorry for the delay. Missed this. Most paint strippers take powder coat right off, just mask off where you don't want to remove it.
There is nothing you can do about the side load unless you re-engineer the system.
 
Received the long bolts...Whats the consensus for leaving out the thin washers between the pedal and the weldment if it make the brake pedal a little stiff?

pedals2.jpg

I don't think I used any washers, but I did file down one weld slightly that was interfering with smooth operation of the pedal. Rustoleum gloss white is great for touch up paint...matches the newer powder coat quite well.

I used the long pivot bolts and no extra return springs...works smoothly with no bind.
 
I don't think I used any washers, but I did file down one weld slightly that was interfering with smooth operation of the pedal. Rustoleum gloss white is great for touch up paint...matches the newer powder coat quite well.

I used the long pivot bolts and no extra return springs...works smoothly with no bind.

It does look like the washers are a "as needed" item.
I have the extra springs...not sure if I'll install them yet.
 
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