How good do your brakes work?

[Zwaustin]

Glad to know its not just mine!! 

 

[jetdriven]

How many of you have pedal extensions. Because since we installed those the brakes suck. After new pads twice, installed dual brakes, NO KIDDING bled brakes for 15 hours and rebuilt the parking brake, new master cylinders, etc the pilot side sucks. The copilot side is rock hard and tight.  

[Shadrach]

9 hours ago, jetdriven said:

How many of you have pedal extensions. Because since we installed those the brakes suck. After new pads twice, installed dual brakes, NO KIDDING bled brakes for 15 hours and rebuilt the parking brake, new master cylinders, etc the pilot side sucks. The copilot side is rock hard and tight.  

Did you bleed from the bottom up with a pressure pot? Whether it's hydraulic flaps or brakes, this is the only way I have been able to ensure no air is in the system. Even with the P Pot it took 2 people to clear all air from the system.

[jetdriven]

1 hour ago, Shadrach said:

Did you bleed from the bottom up with a pressure pot? Whether it's hydraulic flaps or brakes, this is the only way I have been able to ensure no air is in the system. Even with the P Pot it took 2 people to clear all air from the system.

Yes even both sides at the same time with two pressure pots.

[Shadrach]

19 minutes ago, jetdriven said:

Yes even both sides at the same time with two pressure pots.

 That sucks, I remember having trouble as well and I don't have pedal extenders. The only way for me to get the pedal to firm up was to sit in the plane and repeatedly actuate the brakes on the pilot side while the pressure pot was forcing fluid into the system at the caliper.  We had rigged overflow on the reservoir before we started. I would say that we bled close to the full capacity of the system at least two times over before the brakes felt as they should.

[Guitarmaster]

There is a article or a thread somewhere about this very problem. I have not tried it myself, but I have the same issue with weak brakes. The procedure is to separate the hard line from the soft line in the wheel well just enough to let fluid (and air) out since that is a high point in the system. Then slowly depress the brakes. Whoever posted the article called it a, old motorcycle trick. Apparently, his results were night and day.

I plan on trying this at the annual in February.

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[Shadrach]

On November 23, 2015 at 11:11 AM, Marauder said:

 

Owning the same plane for the past 24 years, I have done my fair share of landings with brakes & tires in various conditions. It's all about the same.

I found by trying to use as much aerodynamic braking as I can muster, it helps a bit. In extreme cases, heaven forbid (I know I am going to the Mooney penalty box for saying this), I do retract the flaps to get more weight on the wheels on the roll out.

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No penalty box as long as you don't retract before touchdown. Retracting before touchdown is poor technique in my opinion. 

[Seth]

I had to replace/rebuild my brakes on the Missile, and it took a while to get all the air out of the system when bleeding the brakes.  I still feel however that my stopping power is not as good as it was prior to redoing the brakes.

That being said, I've been in other Mooneys and the brakes are similar to my current setup.  The setup before I think just had better brakes though I can't find anything in the logs about it.  I don't want to flat spot a tire, but I would have to work pretty hard to do so right now in my opinion.

 

-Seth

[Releew]

Look at the surface area of the pad and rotor.  No way this design is made to stop you fast at a high speed.....  Its enough to slow the aircraft down and stop at a slow speed or allow for tight turns via. differential braking.  Sure you can easily lock them up but it won't stop you any faster.....just skid and spend more money!  

Rick

[DonMuncy]

8 minutes ago, Releew said:

Look at the surface area of the pad and rotor.  No way this design is made to stop you fast at a high speed.....  Its enough to slow the aircraft down and stop at a slow speed or allow for tight turns via. differential braking.  Sure you can easily lock them up but it won't stop you any faster.....just skid and spend more money!  

Rick

Rick,

I agree as to the last sentence, but respectfully disagree as to the first. If they had a bigger rotor or pad, they would just lock up easier. It appears to me if one wanted to stop faster they would have to have more rubber on the ground. Ie. more tires or bigger tires.

[Shadrach]

The brakes on these planes are adequate. There are plenty of folks on this board going in and out of sub 2000' runways. I've never flown an aircraft that would throw you forward in your seat under braking.

[jackn]

Just replaced my pads & rotors with Cleveland and broke them in as instructed. They work much better then the old ones. The ridges and valleys really cut down on the surface area being contacted. The 172 is much lighter and stalls 20 knots slower. 

[RLCarter]

You should be able to lock the brakes up with moderate to hard pressure. Several things come to mind on spongy brakes, most common is air trapped in the system. I’m going to assume that they were spongy before, hence all the parts & labor. Check to make sure there are no external (visual) leaks anywhere (including the belly area) in the system, if all is dry re-bleed the system. Air will migrate to the highest area(s), you have to move enough fluid thru the system to fully replace what is in the line to insure all the air has been pushed out. I personally use the conventional method of bleeding but with a twist. I connect a clear piece of hose to the wheel cylinder bleeder valve, then route the clear hose up at least 12 inches then loop back down into a catch can. On an aircraft this will take a minimum of 2 but 3 people would be best. Make sure the reservoir is full and the person in the cockpit has the stamina to operate the brake pedal numerous times, have them apply slight pressure to the pedal while the person below slowly opens the bleeder and checks to see if any air comes out, the pedal will go soft but they need to keep pushing the full stroke of the pedal. Here is the twist, leave the bleeder valve open, the loop in the clear line will fill with fluid and not allow air back in the system. The brake needs to be continuously pumped to keep the fluid and trapped air moving out, they can switch legs if they need to but do not stop pumping until all the fluid has been replaced in the line and/or no more air bubbles are visible and the bleeder is closed off. Make sure the reservoir does not run dry (3^rd person) during the process, if a 3^rd person is not available the one outside will pull double duty keeping the fluid full and operating the bleeder. If no air was visible the next thing I would check is the brake wheel cylinder alignment with the brake disk, they must be square with each other. The torque plate (mounting bracket) is easily flexed or bent if the wheel cylinder binds on the pins instead of floating on them, this is generally visible by an uneven gap between pads and the disk. This will also cause a soft pedal due to the hydraulic energy being used to flex everything back into alignment rather than squeezing on the pads. It seems like a lot of work but in reality it shouldn’t take that long to bleed both brakes and check the alignment of the wheel cylinders if bleeding didn’t correct the issue.

 

 

[Mooneymite]

6 hours ago, RLCarter said:

You should be able to lock the brakes up with moderate to hard pressure. 

 

I agree.

My Mooney, like most aircraft I've flown will lock the brakes at any speed if enough pressure is applied.  I have no experience with the bigger, heavier Mooneys, but I can flat-spot most any other heavy aircraft if I want to (I don't).  I suspect there's an air bubble somewhere if you can't.

[gsxrpilot]

I can certainly lock the breaks up on my C. And if I forget to retract the flaps, they lock just touching them. So put me in with Marauder as I also retract flaps as soon as the wheels touch down. That's assuming I'd even bothered to extend the flaps for landing.

[DXB]

On 12/12/2015 at 2:19 PM, gsxrpilot said:

I can certainly lock the breaks up on my C. And if I forget to retract the flaps, they lock just touching them. So put me in with Marauder as I also retract flaps as soon as the wheels touch down. That's assuming I'd even bothered to extend the flaps for landing.

+1      

[Shadrach]

Flaps up or down, brake lock from just touching the pedal likely means the plane is still flying and the touchdown was too fast. We turned off in 1000ft of runway yesterday with moderate braking and full flaps down. The "only chirps" were from imperfections/bumps in the runway surface. 

[gsxrpilot]

The only turn off at my home field is 800 ft from the edge of the grass. I make the turn easily almost every time. Speed control is not a problem.

[cnoe]

 

On 12/13/2015 at 5:02 PM, gsxrpilot said:

The only turn off at my home field is 800 ft from the edge of the grass.

It looks like you've got another 300' of taxiway beyond the turn-off that simply dead-ends. If you had tundra tires you could just cut across when landing a bit long.

FWIW, my J's brakes will lock up on a quick turn-off if I don't retract the flaps. Depending on who's flying with me I've been chastised for either "retracting" or "not retracting" on the roll-out.

I knocked out my night currency last night and made the mid-field turn off every time following the PAPI down so I figure mine are working well enough.

[Mooneymite]

 

Quote

Depending on who's flying with me I've been chastised for either "retracting" or "not retracting" on the roll-out.

You're the PIC....you gotta do what you think is best.

Having said that, in the commercial world, the FAA inspectors were pretty adamant about not touching anything during the landing roll that wasn't in the SOP's.  We weren't supposed to touch a thing until off the runway.  I presume that the FAA had statistics to support this policy.  There have been a few Bo's that ended up on their bellies because the pilot thought he was retracting the flaps.

The B-727 ops called for retracting landing flaps back to the 25 position, but other than that specific airplane, touching flaps while on the runway was a no-no.

[Hank]

I generally retract my flaps on the roll out. While holding the throttle to idle, I just reach my finger over and down and push the switch towards Up, while braking gently. Raising the gear after departure requires letting go of the throttle and lifting my entire hand to the top of the panel to grasp the switch with my thumb and fingers. Hard to make this mistake in a Mooney if you don't let go of the throttle.

Besides, the extra weight on the gear gives the brakes more authority. No, I have never locked up the brakes on my Mooney.

When landing on grass, the soil and grass provide extra braking power, too. You'll know how much by the amount of throttle it requires to taxi.

[Mcstealth]

On ‎11‎/‎23‎/‎2015 at 10:58 AM, Joe Larussa said:

I have about 100 hours on this Mooney in the last three months. Coming in at 75-80 MPH depending on runway length. The A&P that I was working

with did the break in process. Just seems like I can stand on the brakes and couldn't lock them up if I tried. 

This to me sounds like a master cylinder issue. Yes you can have glazed over pads, but even then if you stand on the brakes, you should be able to lock them up. If you have good firm pressure, with no squishy air in the lines feeling, the master cylinder would be one of my prime suspects.

Yes again about the glazed over brakes pads. They can feel the same as a partially working master cylinder. On organic pads, a glazed pad is recognizable enough. I cannot say for metallic pads but would assume they are easily spotted.

Anyone know the specs for the brake system?

[FloridaMan]

Bringing this thread back. At 2500 lbs, I cannot lock the brakes up on the rocket. I tried and couldn’t do it. I can still stop in 1500ft when landing at 2900lbs, but I had a close call the other day where I needed to apply maximum braking and the wheels did not lock. I have flat-spotted both mains to the cords in my m20f aborting a max gross takeoff. 

[Yetti]

Does the rocket have the dual piston calipers like the longer bodies.    Your pads may also be glazed over from doing lazy landings

[FloridaMan]

45 minutes ago, Yetti said:

Does the rocket have the dual piston calipers like the longer bodies.    Your pads may also be glazed over from doing lazy landings

I have the single piston calipers.