Jump to content

Parking Brake


Al Downs

Recommended Posts

Has any had experience with the parking brake refusing to unlock? I first experienced this problem while braking somewhat hard to make a turn off. The brakes locked up. I was able to release it by opening the bleeders.

 

The next time it happened, opening the bleeder did not release it. I then had the brake pads replace, everything cleaned and reassembled. The problem seemed to be fixed.

 

Yesterday, they locked up again and I was able to release them by playing with the brake handle and the parking brake lever.

 

At this point I am unable to identify the problem but would sure like to fix it before I get stuck somewhere..

 

Anyone else had a similar problem?

 

2010 CTLS with Matco brakes

 

Thanks

Al Downs

Link to comment
Share on other sites

Hi Al,

 

 

Who's brakes are these? Matco or the Italian brakes?

Only a couple of things can cause this. First the plunger to the master cylinder is not going back to the full open position. It would only take about 1/4" - 3/8" to affect this. You may have something broken inside the master cyl. Make sure it goes completely forward. Pull the top of the tunnel off and check it. The second would be if the parking brake valve has broken and isn't opening and you just think it is. Check that next. The master cyl. is my first guess. My last thought is. Is it both brakes locking up or just one? If it is just one the it is a caliper problem.

Link to comment
Share on other sites

Al and Roger. I saw a CTLS with Italian brakes experience a locked right brake during hard braking after landing the other day. The CFI got out, smacked the caliper with his clipboard and it released. I looked at the brake and it appeared that the pads were worn enough to allow the caliper piston to come out too far and get cocked in the caliper bore. The brake pads were approx. 1/16" thick but I believe that the recommended minimum is 1/32"? Installation of new pads fixed the concern so I'm wondering about the allowance down to 1/32" Al, what are the thickness of your brake pads on the brake that's hanging up? You might need to install new pads, even if these are above the minimum allowed? Don't quote me on allowed thicknesses and check the specs.

Link to comment
Share on other sites

Al and Roger. I saw a CTLS with Italian brakes experience a locked right brake during hard braking after landing the other day. The CFI got out, smacked the caliper with his clipboard and it released. I looked at the brake and it appeared that the pads were worn enough to allow the caliper piston to come out too far and get cocked in the caliper bore. The brake pads were approx. 1/16" thick but I believe that the recommended minimum is 1/32"? Installation of new pads fixed the concern so I'm wondering about the allowance down to 1/32" Al, what are the thickness of your brake pads on the brake that's hanging up? You might need to install new pads, even if these are above the minimum allowed? Don't quote me on allowed thicknesses and check the specs.

 

These are Matco brakes and the pads were replaced after the second incident. However it has happened again with new pads but I was able to free them by playing with the brake handle and the parking brake lever. So far I am unable to pinpoint the problem.

Link to comment
Share on other sites

Hi Al,

 

This sounds like the push rod to the master cyl. is not releasing all the way forward. You may be sitting on the proverbial edge of locking and unlocking inside the master cyl. If that is the case you need to shorten the master cyl. control rod at the rod end which will allow the push rod on the master cyl. to extend fully. That means you need to remove the screw that holds the master cyl. push rod in the control tube, then loosen the rod end nut and shorten it a one turn. I doubt that you have an issue with the calipers since this happened before the new pads were installed. The pads have a wear point notched into them. You can see it without removing the pads.

Link to comment
Share on other sites

Hi Al,

 

This sounds like the push rod to the master cyl. is not releasing all the way forward. You may be sitting on the proverbial edge of locking and unlocking inside the master cyl. If that is the case you need to shorten the master cyl. control rod at the rod end which will allow the push rod on the master cyl. to extend fully. That means you need to remove the screw that holds the master cyl. push rod in the control tube, then loosen the rod end nut and shorten it a one turn. I doubt that you have an issue with the calipers since this happened before the new pads were installed. The pads have a wear point notched into them. You can see it without removing the pads.

Thanks for the suggestions. I will take a look at those things this weekend.

 

Al

Link to comment
Share on other sites

For a secondary tip incase Roger's doesn't work:

 

I have seen these Matco brakes come slightly loose causing this problem. What happens in some cases is the caliper gets "cock eyed" and won't release. Just take a large straight screwdriver and pop it back in place and it wil release. Then pull the wheel and torque everything back.

Link to comment
Share on other sites

  • 4 months later...

The reason many have gotten away from these people is they rarely respond to emails. I have sent 6 and not one reply. FD had the same issues and so do other aircraft Mfg's. If they do answer it's weeks away usually. They aren't very responsive to orders. If you can find the pads here in the states then your are ahead of the game.

They aren't very good in performance either and that's another reason people have gotten away from them. These brakes would be better suited for a craft much lighter than ours. For the 4-6 years in between replacement it would be easier to just get them in the states even if it cost a little more.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...