Parking Brake Locked Up in Flight??

[RLCarter]

55 minutes ago, Marauder said:

 

The only time I really needed mine was parking at a nearby airport for some avionics work. The ramp was sloped and I knew I needed the parking brake which didn’t work.

There was one reward. I now hold the world’s speed record for exiting a Mooney.


Sent from my iPad using Tapatalk Pro

 

Should have parked it facing uphill.........

[Skates97]

Ok, as I had said, I hadn't heard from the shop but ran out to the airport yesterday to see if they had gotten the tires on and put the plane back in the hangar. Opened the hangar and there was the plane with new tires. Drove over to their hangar to see if anyone happened to be there and one of the mechanics was so I talked to him for a bit. The valve works fine (cable disconnected), but the cable is locked up.

I'm going to file this in the "You don't know what you don't know" category. The parking brake knob has always been a little hard to pull, and as I think I mentioned previously when pushing it in it would stick a little halfway before going in all the way and releasing. It has been like that since I got the plane two years ago so I didn't know that wasn't normal, I thought that is just the way it felt when actuating and releasing the parking brake. The mechanic said that the valve should operate smoothly and so should the cable. My plane was trying to tell me something with the difficulty in pulling/pushing the knob but I didn't realize it. 

This is what I think happened, which is in line with what @Shadrach posted previously. I stopped to get fuel and set the brake. I pushed the knob to release the parking brake but it only went about halfway or so in before the cable finally gave up the ghost which was not far enough to actually release the brake. I thought it was in all the way because it stopped moving but I did not visually check that it was all the way in (I've never done that before but you can be sure I will now). I am thinking that perhaps I didn't have full pressure on the pedals when I set it which is why I was able to taxi and take off without it releasing, or maybe because it was so cold. As is my usual checklist for taking off after a fuel stop I did not stop and set the brake and do a full run-up, I only used the toe brakes for a quick mag check prior to departure. Had I actually done a full run-up, setting the parking brake as normal, I should have noticed that something was wrong when I couldn't pull the knob out all the way. (It is still stuck in the position I left it, can't pull it out and can't push it in). Landing lighter three hours later the wheels skidded as they touched down and continued to skid until I came to a stop. I'm glad it was both that were locked up and not just one.

So, two new tires and tubes, and I still need a new parking brake cable. Considering putting in a push button locking cable like my new Carb Heat cable. It would prevent pulling it instead of the heat next to it, would also require deliberate effort to pull on and push off.

https://www.aircraftspruce.com/catalog/appages/a700.php

@takair, I checked the invoice for the part number from Aircraft Spruce for the tubes with the 90 degree bend, apparently the only ones they sell. It is the Goodyears, Part #06-05305.

https://www.aircraftspruce.com/catalog/lgpages/gy_tires3.php

[carusoam]

Great follow-up Richard!

Yes, There shouldn't be any push back from the control when you push it in...

It should be smooth all the way in, and smooth all the way back.  Stop to stop....

As for what needs to be replaced... there is a wire and a sheath... both are probably replaceable independently...

Probably cheapest and longest lasting to swap out both parts...

While you are looking, there are a few cables that suffer the same wear... cowl flaps, outside air, heater air.... might review them all while you are in there...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Shadrach]

@Skates97 Is the cable covered in a plastic sheath? It’s not uncommon to see a small access hole made in the cover exposing the wire wound around the cable. A little bit of Kroil or mouse milk will creep down the length of the cable. Should free up easily.

Edited December 3, 2018 by Shadrach

[Skates97]

59 minutes ago, Shadrach said:

@Skates97 Is the cable covered in a plastic sheath? It’s not uncommon to see a small access hole made in the cover exposing the wire wound around the cable. A little bit of Kroil or mouse milk will creep down the length of the cable. Should free up easily.

I don't know. They are going to try to lube the cable before replacing it, but I'm thinking that I may just have it replaced. I think it's the original cable and probably wouldn't hurt to have something from this century. 

He said Thursday they just wanted to get the tires done so they could put it back in the hangar and get to the cable this week. I appreciate them getting it back inside, it rained hard most of the day Thursday. 

[Skates97]

1 hour ago, carusoam said:

Great follow-up Richard!

Yes, There shouldn't be any push back from the control when you push it in...

It should be smooth all the way in, and smooth all the way back.  Stop to stop....

As for what needs to be replaced... there is a wire and a sheath... both are probably replaceable independently...

Probably cheapest and longest lasting to swap out both parts...

While you are looking, there are a few cables that suffer the same wear... cowl flaps, outside air, heater air.... might review them all while you are in there...

PP thoughts only, not a mechanic...

Best regards,

-a-

Yes, those three have a similar feel to the way the parking brake felt, just not as stiff. Was already thinking about replacing them too. 

When they are replaced it will be the whole assembly, no sense in replacing either the cable or sheath with something new and leaving the other half of it as something 50+ years old. 

[Hank]

McFarlane makes replacement cables of all sorts.

[Shadrach]

6 hours ago, Skates97 said:

I don't know. They are going to try to lube the cable before replacing it, but I'm thinking that I may just have it replaced. I think it's the original cable and probably wouldn't hurt to have something from this century. 

He said Thursday they just wanted to get the tires done so they could put it back in the hangar and get to the cable this week. I appreciate them getting it back inside, it rained hard most of the day Thursday. 

It’s not that I’m such a CB that I won’t have a cable replaced. Certainly nothing wrong with replacing it. I’m just a fan of doing what’s easy and least invasive first. Lubing a cable is pretty easy. This one doesn’t live in a harsh environment nor does it get used very much.  It  just hasn’t been lubricated in 53 years.  Any low viscosity,  “creeping” lubricant will likely yield almost identical results to removing, fabricating and replacing for a fraction of the effort.

[David Lloyd]

8 hours ago, Shadrach said:

@Skates97 Is the cable covered in a plastic sheath? It’s not uncommon to see a small access hole made in the cover exposing the wire wound around the cable. A little bit of Kroil or mouse milk will creep down the length of the cable. Should free up easily.

Exactly what I did in a Bonanza with the same problem in 1984.  Was working fine without another lube when I sold it 24 years later.

[bob865]

9 hours ago, Shadrach said:

@Skates97 Is the cable covered in a plastic sheath? It’s not uncommon to see a small access hole made in the cover exposing the wire wound around the cable. A little bit of Kroil or mouse milk will creep down the length of the cable. Should free up easily.

Used these on motocycles to lube control cables.  I wonder it this would work for the cables on the plane?

https://www.amazon.com/Motion-Pro-08-0182-Cable-Luber/dp/B0012TYX9W/ref=asc_df_B0012TYX9W/

[Shadrach]

3 minutes ago, bob865 said:

Used these on motocycles to lube control cables.  I wonder it this would work for the cables on the plane?

https://www.amazon.com/Motion-Pro-08-0182-Cable-Luber/dp/B0012TYX9W/ref=asc_df_B0012TYX9W/

That's a cool product.  My tool box will have one shortly!  It may very well be a good solution for sheathed cables. However, I went back and looked at the pics Richard posted and his appears to be "nekid",  so no need for an access point as the conduit can be flexed to create lube entry points along the whole of the cable.   

[Marauder]

3 hours ago, Shadrach said:

It’s not that I’m such a CB that I won’t have a cable replaced. Certainly nothing wrong with replacing it. I’m just a fan of doing what’s easy and least invasive first. Lubing a cable is pretty easy. This one doesn’t live in a harsh environment nor does it get used very much.  It  just hasn’t been lubricated in 53 years.  Any low viscosity,  “creeping” lubricant will likely yield almost identical results to removing, fabricating and replacing for a fraction of the effort.

I've become a BIG fan of Sea Foam's Deep Creep penetrating lubricant. Everything I have used it on has stayed lubricated.

[Marauder]

2 hours ago, Shadrach said:

That's a cool product.  My tool box will have one shortly!  It may very well be a good solution for sheathed cables. However, I went back and looked at the pics Richard posted and his appears to be "nekid",  so no need for an access point as the conduit can be flexed to create lube entry points along the whole of the cable.   

Mine has a tightly wound metal sheath and not one with some sort of plastic covering found on bike cables.

 

[Skates97]

3 hours ago, Shadrach said:

That's a cool product.  My tool box will have one shortly!  It may very well be a good solution for sheathed cables. However, I went back and looked at the pics Richard posted and his appears to be "nekid",  so no need for an access point as the conduit can be flexed to create lube entry points along the whole of the cable.   

Looks like it has a metal sheath around it, not sure if there is a plastic liner inside between the sheath and the cable, but my guess is there isn't. The conduit flexes but it is coiled so tight I don't know that you could get lube through it? Could possibly get some lube up in there with that adapter that @bob865 linked above. 

[MARZ]

35 minutes ago, Skates97 said:

Looks like it has a metal sheath around it, not sure if there is a plastic liner inside between the sheath and the cable, but my guess is there isn't. The conduit flexes but it is coiled so tight I don't know that you could get lube through it? Could possibly get some lube up in there with that adapter that @bob865 linked above. 

Given that the end isn't frayed or otherwise disfigured - the best way would be to extract the inside cable - put a pan or other container at the end of the outer cable and spay in your favorite creeping lubricant till it comes out relatively clean into your catch basin

Next de-grease in solvent lube and reinsert the inner cable in the housing - repeat as necessary then reattach to the parking brake valve.

And now that I've put it here I have a to-do this weekend!!!

   

Edited December 3, 2018 by Mike Ropers

[orionflt]

use some 5606 hydraulic fluid from a pump style oil can on the out side of the brake cable. just put on enough to cover the cable but not drip. let it sit overnight. the fluid will penetrate thru the cable housing down to the cable. I have freed up cables that hadn't moved in years with this method. be sure not to get any on your paint or carpet. it will remove paint if it sits on it too long. 

Brian

[Shadrach]

1 hour ago, Skates97 said:

Looks like it has a metal sheath around it, not sure if there is a plastic liner inside between the sheath and the cable, but my guess is there isn't. The conduit flexes but it is coiled so tight I don't know that you could get lube through it? Could possibly get some lube up in there with that adapter that @bob865 linked above. 

Mouse milk or Kroil will penetrate rusted bolt threads with a nut in place. Either will make it through that conduit.

[Marauder]

41 minutes ago, orionflt said:

use some 5606 hydraulic fluid from a pump style oil can on the out side of the brake cable. just put on enough to cover the cable but not drip. let it sit overnight. the fluid will penetrate thru the cable housing down to the cable. I have freed up cables that hadn't moved in years with this method. be sure not to get any on your paint or carpet. it will remove paint if it sits on it too long. 

Brian

Brian -- question for you on 5606. When I pulled my parking brake valve to have Terry rebuild it, I needed to remove the two bolts that it was mounted to. I realized after attempting to remove the second bolt that the nut was not attached mechanically to the bracket but rather was literally stuck on the bracket because of a build up of dried up hydraulic fluid. The first nut was so stuck that I didn't even need to use a wrench to hold it. I also found a lot of sticking red goop around the area where the valve leaked. Does this stuff dry out after time?

[orionflt]

yes it can, one of the reasons for not putting too much on. once everything is freed up normal lubrication with an approved lubricant as listed in the service manual will keep it free and will eventually wash out the hydraulic fluid before it gums up.

Brian 

[Yetti]

5606 is mineral oil.  it can catch on fire.   This cable is the same as the roof vent. lots of threads on replacing those.   Tri flow is your friend.

[orionflt]

47 minutes ago, Yetti said:

5606 is mineral oil.  it can catch on fire.   This cable is the same as the roof vent. lots of threads on replacing those.   Tri flow is your friend.

as much as i love triflow, it doesn't breakup the rust and dirt like hydraulic fluid, once everything is freed up that is my preferred lube to keep it free.

Brian

[Shadrach]

On 12/3/2018 at 12:11 PM, orionflt said:

use some 5606 hydraulic fluid from a pump style oil can on the out side of the brake cable. just put on enough to cover the cable but not drip. let it sit overnight. the fluid will penetrate thru the cable housing down to the cable. I have freed up cables that hadn't moved in years with this method. be sure not to get any on your paint or carpet. it will remove paint if it sits on it too long. 

Brian

I find that dot 3 or 5606 are good creepers but work even better if mixed with acetone. I think a 70/30 hydraulic fluid/acetone mix works well.   Given the condition of the conduit an the exposed cable, I don’t think there’s a lot of rust to contend with. I think it’s just dry as a bone.

[orionflt]

2 hours ago, Shadrach said:

I find that dot 3 or 5606 are good creepers but work even better if mixed with acetone. I think a 70/30 hydraulic fluid/acetone mix works well.   Given the condition of the conduit an the exposed cable, I don’t think there’s a lot of rust to contend with. I think it’s just dry as a bone.

never tried that, will keep it in mind .

[Andy95W]

4 hours ago, orionflt said:

as much as i love triflow, it doesn't breakup the rust and dirt like hydraulic fluid, once everything is freed up that is my preferred lube to keep it free.

Brian

5606 also does a great job of collecting dust and getting gummy.  After breaking up the rust and dirt, I think I'd follow it with Tri-Flow or LPS-2, for that reason.

[Shiny moose]

On 12/3/2018 at 11:38 AM, Shadrach said:

Mouse milk or Kroil will penetrate rusted bolt threads with a nut in place. Either will make it through that conduit.

Areokroil is the best I have found to penetrate and free up rusted/ corroded / stuck / stuff. Use a rag to cover cable overspray and spray that cable, move it and spray it again.