unplanned brake dragging

[woodruff]

I have an ongiong problem with brake dragging on my 1955 C 170 with Clevelands. My size elevens won't easily clear the top/brake section of the rudder pedals. When landing or on the ground, I make a conscious effort to keep my heals back and on the floor, but this barely gets the job done. Are there more user friendly rudder pedals or should I leave a little air in the break cylinder? This problem is more pronounced with winter boots. Funny, but I don't seem to have this issue with skies or floats. Thanks, Myndy Woodruff

[hilltop170]

I wear size 12s and do not have any brake dragging problems. Are you sure it's you or maybe the pistons are sticking in the calipers and not retracting properly causing the dragging? When was the last time the pistons were removed, cleaned, and new o-rings installed? Do not introduce air into the system deliberately.

[Bruce Fenstermacher]

There are a few things that can be checked for proper adjustment and rigging before resorting to a "lower fluid level".

As Richard said the calipers and pucks are the first things to go after for proper operation. Then I'd check the rigging of your pedals from the fire wall. If this is not correct brake application could be introduced with just pedal movement. I don't have the adjustment on at the top of my head right know but it's been discussed here before. (I could find it later)

[jlwild]

Woodruff,

I had same problem last year on the right brake on my '55 170B with Cleveland's. Don't have parts numbers, or corect part names, but the two guide pins on caliper and bracket in which pins slide when brakes applied were worn out. Parts were replaced with new and now all is well on right side. PS: I have size 12 shoes and son size 13. Now left side is starting to drag. Looking back I should have replaced left side parts at same time

[n2582d]

There are a few things that can be checked for proper adjustment and rigging before resorting to a "lower fluid level".

As Richard said the calipers and pucks are the first things to go after for proper operation. Then I'd check the rigging of your pedals from the fire wall. If this is not correct brake application could be introduced with just pedal movement. I don't have the adjustment on at the top of my head right know but it's been discussed here before. (I could find it later)

The Pre-63 Service Manual calls for 6 1/2" from the rudder pedal bar to the firewall. Here's what the '55 C-170B manual says:

Rudder Pedal.jpg

You might try screwing the clevis all the way down to place the top of the rudder pedals as far forward as possible. The threaded ends at the top of the brake master cylinders allows for around .160" of travel. The Pre-63 Service Manual has this table to correct for dragging brakes:

Dragging Brakes.jpg

[woodruff]

Thanks for the great ideas. I'll get on it as soon as the hangar doors thaw out enough to open.Myndy Woodruff

[GAHorn]

That last suggestion in the chart, "Worn or accumulated dirt...." in the caliper guide-pin area can result in the behavior Jim (jwild) offered earlier.

Whenever accessing the area or working on the brakes, look for seepage of brake fluid which will attract dirt and "gum up" the guide pins and guides on the calipers, preventing the calipers from sliding easily on the pins. Use a gun-bore brush to clean out the guides within the calipers, and use a parts brush to clean the pins. (MY old stand-by miracle-juice, WD-40 makes a good brake guide-pin cleaner if you don't already have some.....just don't get it on the brake pads or discs themselves, although it will dissipate with first brake-use....but any/every hangar should have an aerosol can of brake parts cleaner on-hand, along with a can of aerosol eletronics/contact cleaner. Another good product is aerosol "dry" lubricant, whch may be applied to the pins and guides.)

[T. C. Downey]

I don't believe the OP has brake problems, he has big feet. resulting in not being able to keep his feet off the top of the pedal.

I suggest he remove his shoes prior to flight.