Week Brakes !!

[MKB]

Recently bought my Mooney Acclaim M20TN which is flying very well, I do however find the brakes to be less than effective is this just me or is the braking system a little week?  If so are there any upgraded available.

 

MKB   Bristol UK

[Davidv]

2 hours ago, MKB said:

Recently bought my Mooney Acclaim M20TN which is flying very well, I do however find the brakes to be less than effective is this just me or is the braking system a little week?  If so are there any upgraded available.

 

MKB   Bristol UK

You should change them out for month brakes, I hear they are more effective. 

The braking on my bravo isn't great and I'm told there are upgraded brakes that I can buy.  However, I thought they may have fixed that by the time they started making Acclaims...

[Little Dipper]

You might want to start with the fluid.  Over time the brakes on my 1995 Ovation were very poor and getting worse.   It was due to the fluid starting to gel.    I have been getting my brake fluid changed each year at annual and the brakes are much better.

[EricJ]

Mooney brakes aren't the best in the GA world, that's for certain.   If the pedals don't have long travel and aren't soft (I was going to say "if they're high and hard", but that makes people think of other things), then they probably don't need to be bled or serviced.   Raising flaps early in the rollout allows the brakes to be applied harder earlier with less likelihood of lockup.

 

[PT20J]

Agree with @EricJ . Mooney brakes work fine but it takes a lot more pedal pressure than on many other makes. Raising the flaps after touchdown gets more weight on the wheels and helps. @donkaye suggested deploying the speed brakes after touchdown, which also helps. I move my feet up on the pedals after touch down so that the ball of my foot is on the top of the pedal and that helps get more pressure on the brakes without breaking my toes. Just be careful because there isn't much feel between maximum braking and locked up and it's easy to flat spot a tire. Also, after replacing the linings, be sure to break them in properly.

Skip

[N201MKTurbo]

If the brakes are weak, the airspeed is too high!

[carusoam]

Welcome aboard, MKC!

One way to test the brakes is to press them fairly hard...

But, if you do this above 50kias, they are going to lock, send out a smoke show, and you will have flat spotted a pair of two nice expensive tires...
 

+1 for keeping the fluid fresh...

+1 for using proper technique...

If the brakes don’t lock-up while you are pushing the pedals to the floor... there may be room for improvement...
 

For additional insight on the art and magic of Mooney landing techniques... see the Master... Master CFII.... Don Kaye...  Don has produced a well regarded training for all things Mooney and landing...
 

PP thoughts only, not a mechanic or a CFI...

Best regards,

-a-

[BillC]

12 hours ago, Little Dipper said:

You might want to start with the fluid.  Over time the brakes on my 1995 Ovation were very poor and getting worse.   It was due to the fluid starting to gel.    I have been getting my brake fluid changed each year at annual and the brakes are much better.

  I have had weak brakes after sitting for a while. My IA said the fluid will gel over time.  I have new pads so it wasn’t that. He was right. We flushed and replaced with fresh fluid. My brakes  are now working perfectly.

[Guest]

Gelled and sticky brake fluid is a reality.  

Fill the reservoir full, connect a pressure pot full of Mil H 5606 fluid to the top of the reservoir, raise the pressure to about 10 psi, open the bleeder screw on the caliper until clean red thin fluid comes out.  Repeat for the other caliper.

Clarence

[StevenL757]

2 hours ago, M20Doc said:

Gelled and sticky brake fluid is a reality.  

Fill the reservoir full, connect a pressure pot full of Mil H 5606 fluid to the top of the reservoir, raise the pressure to about 10 psi, open the bleeder screw on the caliper until clean red thin fluid comes out.  Repeat for the other caliper.

Clarence

This....^

[mike_elliott]

5 hours ago, M20Doc said:

Gelled and sticky brake fluid is a reality.  

Fill the reservoir full, connect a pressure pot full of Mil H 5606 fluid to the top of the reservoir, raise the pressure to about 10 psi, open the bleeder screw on the caliper until clean red thin fluid comes out.  Repeat for the other caliper.

Clarence

Clarence, what are your thoughts on Royco 756 or 782? I believe it has received the proper regulatory blessings to be used as a sub for Mil H 5606 and doesnt have the unwanted property of "gelling" over time. I personally havent used it yet, but this change was high on the list for the Bravo prior to selling her.

[EricJ]

2 hours ago, mike_elliott said:

Clarence, what are your thoughts on Royco 756 or 782? I believe it has received the proper regulatory blessings to be used as a sub for Mil H 5606 and doesnt have the unwanted property of "gelling" over time. I personally havent used it yet, but this change was high on the list for the Bravo prior to selling her.

I was wondering about 782 as well, as it is also miscible with 5606, so you wouldn't have to flush the system to start using it.   Aeroshell 31 is another synthetic replacement for 5606 that is compliant.  The synthetic stuff is a little more expensive, though, so I think that's keeping some people in 5606.   I've been thinking about switching but didn't know what experiences people have been having with the synthetic.

Royco 756 is essentially mineral-based 5606, so it's not anything special to my understanding.

[Guest]

6 hours ago, mike_elliott said:

Clarence, what are your thoughts on Royco 756 or 782? I believe it has received the proper regulatory blessings to be used as a sub for Mil H 5606 and doesnt have the unwanted property of "gelling" over time. I personally havent used it yet, but this change was high on the list for the Bravo prior to selling her.

It would be an acceptable alternative to 5606 in my opinion.

Clarence

[RobertGary1]

Same here. The fluid had turned to jello and caused weak braking. A good bleeding ( which is difficult on these planes) fixed it. 

Do not bleed up as you would to eliminate air. You need to bleed down jn this case to avoid pushing thick jello into the valves in your master cylinders. Just crack the valve at the wheel and push out. In my case it was so thick I had to really pump the brakes to move anything. 
 

-Robert 

[Bentonck]

The brakes can be a little frustrating and it is possible that you have jello in there, worth a look.  But I have an Acclaim and I can tell you they just aren't that great.  

I bring the flaps up as soon as the front wheel is down and don't apply brakes above 50kts.... if you do, you'll end up on the side of the runway with a blown out tire at the worst, or flat spotted mains at the best.  

The brakes are *adequate* but they certainly aren't awe-inspiring.  I would love nothing more than to find a way to STC a set of Bimbo's on there with some anti-lock and press everyone forward in their seatbelts upon landing but that ain't happening....so it's airspeed control, get the flaps up when you can, and then apply what little braking action you have.  If you come in at the right speed you don't need a lot of braking anyway but it's terrible to come up to a taxiway at 30kts and miss the damn thing because you waited too long to brake.

[Davidv]

29 minutes ago, Bentonck said:

The brakes can be a little frustrating and it is possible that you have jello in there, worth a look.  But I have an Acclaim and I can tell you they just aren't that great.  

I bring the flaps up as soon as the front wheel is down and don't apply brakes above 50kts.... if you do, you'll end up on the side of the runway with a blown out tire at the worst, or flat spotted mains at the best.  

The brakes are *adequate* but they certainly aren't awe-inspiring.  I would love nothing more than to find a way to STC a set of Bimbo's on there with some anti-lock and press everyone forward in their seatbelts upon landing but that ain't happening....so it's airspeed control, get the flaps up when you can, and then apply what little braking action you have.  If you come in at the right speed you don't need a lot of braking anyway but it's terrible to come up to a taxiway at 30kts and miss the damn thing because you waited too long to brake.

Or maybe we can add one of these?  The Mooney version of CAPS.
 

[Bentonck]

6 hours ago, Davidv said:

Or maybe we can add one of these?  The Mooney version of CAPS.
 

Now *there* is a good idea.

[carusoam]

Do you think they fire off the retro rockets on the nose as they pull the drag chute lever?  

Great details on braking distance, Benton...

50ias is the magic number... above, smoke show... below, pretty good braking... same number for M20C and M20R, just a difference in mias vs kias...  

I watched a video on some new technology brakes for aircraft...  kind of  high end, but not ABS complex or expensive...

https://www.beringer-aero.com/en/wheels-brakes

 

Don’t watch the video... it is easy to get sucked in and have a screen time challenge after that...   

Best regards,

-a-

 

[Bentonck]

/q Don’t watch the video... it is easy to get sucked in and have a screen time challenge after that...    /q

 

...damnit I got sucked in.