Speed brake doesn’t close all the way

[amekler]

My 2000 Bravo speed brakes have worked fine til today 

the pilots side won’t close all the way

if you pull the breaker it closes

any one else have this happen?

alan

[LANCECASPER]

18 minutes ago, amekler said:

My 2000 Bravo speed brakes have worked fine til today 

the pilots side won’t close all the way

if you pull the breaker it closes

any one else have this happen?

alan

Look through the log books to see when the last time the maintenance was done. It's supposed to be done once a year but very few shops do it during the annuals. If you don't it turns into thousands in having them serviced. The yearly maintenance can be performed by the owner as well.

 

Search is your friend on Mooneyspace . . . .  if it's happened to you, it's happened to someone before you.

 

[amillet]

Yes. Send them to Precise Flight for overhaul

 

[LANCECASPER]

This may also be helpful:

 

 

[Fritz1]

Cleaning and servicing can't hurt, however this sounds like one of the microswitches is worn or out of alignment, if last overhaul is more than 10 years ago best to send to precise flight for IRAN

[LANCECASPER]

10 hours ago, Fritz1 said:

Cleaning and servicing can't hurt, however this sounds like one of the microswitches is worn or out of alignment, if last overhaul is more than 10 years ago best to send to precise flight for IRAN

Which can also be replaced or adjusted as mentioned in the above references. These are not that complicated. Absolute last resort, send them in. If they can be pulled out and examined, cleaned lubricated and adjusted it helps to learn the device and understand why yearly maintenance will keep them going for decades.

[Fix]

My A&P removed one at last annual, just to check and lubricate.
They are easy to remove by yourself.
Check the Youtube video above first.

There are not many parts that should interfere why they don't close fully.
There are no switch or something else that normally blocks.

Check for a loose cable or similar... 
 

[donkaye, MCFI]

Before you do anything have the retract springs replaced.  They used to be fairly inexpensive, but have since increased in price.  I replace mine yearly preemptively.  That is likely your problem.

[amekler]

Don,

when I pull the breaker it rapidly closes all the way

alan

[Jeff Uphoff]

4 minutes ago, donkaye, MCFI said:

Before you do anything have the retract springs replaced.  They used to be fairly inexpensive, but have since increased in price.  I replace mine yearly preemptively.  That is likely your problem.

I had this trouble at one point last year, and it turned out at reinstallation after routine servicing my shop had inadvertently located a canon plug for the brake's wiring such that it got in the way and blocked complete retraction. Something like a zip tie was apparently all that was needed in the end.

--Up.

[dkkim73]

I had the same problem. They'd had the specified lube service from the Mooney Factory Svc Center, were overdue by pure hrs for a factory refurb. The problem became less frequent. Lubed/serviced again at annual this year. They seem to retract fully these days, esp. in warmer weather. So some of this might be exercise. 

I get the sense that limit switches need adjusting/cleaning, springs might become weak, etc. Pulling the breakers pulls them in unless the springs are broken. 

To be clear, if you want them "greened up", a factory refurbishment is the official way to go. Again, I wish Precise Flight offered some nuance in this regard. 

 

[Jeff Uphoff]

8 hours ago, dkkim73 said:

I had the same problem. They'd had the specified lube service from the Mooney Factory Svc Center, were overdue by pure hrs for a factory refurb. The problem became less frequent. Lubed/serviced again at annual this year. They seem to retract fully these days, esp. in warmer weather. So some of this might be exercise. 

I get the sense that limit switches need adjusting/cleaning, springs might become weak, etc. Pulling the breakers pulls them in unless the springs are broken. 

To be clear, if you want them "greened up", a factory refurbishment is the official way to go. Again, I wish Precise Flight offered some nuance in this regard. 

 

The aforementioned zip-tie fix notwithstanding, mine did require an overhaul last year due to the pilot-side one eventually deciding to quit working, and even afterward, it still intermittently refused to retract normally in cold weather--forcing a breaker pull to disengage the clutch so the springs could slam it down. Apparently, the problem was a bad microswitch, which Precise Flight fixed as a warranty repair after their overhaul.

It's still summer now, so I guess we'll see if that completely fixes the problem come winter again....

--Up.

[PT20J]

Precise Flight charges a lot for overhaul so it is worth checking a few things before sending them in. These work pretty simply. There is a motor geared to one blade through a  clutch. The motor drives the blade up and down. The other blade follows because there is a linkage that connects it to the driven blade. There are two microswitches operated by cams on the slave blade. One stops the motor when the blades are fully extended and the other stops the motor when the blades are fully retracted. The clutch is electrically energized to connect the motor to the driven blade when electrically extending or retracting the blades. When you pull the breaker, power is removed from the motor and the clutch and a spring causes the blades to retract. 

So, if they retract fully when power is removed, the spring is good.

I would take the unit out of the airplane and look it over. See if anything is loose or binding. Without power, you should be able to move the blades freely without any binding. You can check the microswitches with an ohm meter to make sure that they operate at the appropriate blade positions.

[amekler]

My A&P lubed and cleaned. Adjusted the down microswitch. Very sensitive. Working fine for now. Will probably get the $4000 overhaul at the upcoming annual.

Alan

[PT20J]

3 hours ago, amekler said:

My A&P lubed and cleaned. Adjusted the down microswitch. Very sensitive. Working fine for now. Will probably get the $4000 overhaul at the upcoming annual.

Alan

If it is working, I would not pay for an overhaul. The thing is really simple and the only things that can fail are the motor, clutch and micro switches. Just do the annual service and wait until something actually fails to send them in because Precise Flight won’t sell parts so you can’t fix it yourself. 

[amekler]

My A&P would like to replace the microswitch

does anyone have a part #?

[N201MKTurbo]

1 hour ago, amekler said:

My A&P would like to replace the microswitch

does anyone have a part #?

The part number is printed on the side of the switch.

[skykrawler]

I seen this happen if one of the two units is slower than the other.  The new units (fully enclosed) seem to have some electrical interlock between them such that if one is not driving the motor, the other will not either.  Usually cleaning and lubing them up resolves the problem.

The screws on the covers of the enclosed seem to get galvanic corrosion with aluminum which is why they are so difficult to extract.   Especially the ones with the TKS systems since the TKS fluid seem to migrate into the speed brake cartridge.   I might help to apply some penetrating oil and let them sit overnight before trying to remove them.  Its also a good idea to replace any mounting screws that show corrosion - and not overtighten any of the screws.

 

[amekler]

Thanks

 Since  cleaned and lubed they are working fine for now

[PBones]

I have a similar problem with an older Precise flight brake that has the friction clutch not the electric clutch. Precise Flight is not sure they will fix my unit since they are sunsetting it because of parts not being available. Does anyone have a source for the friction disc that my AP can use to replace the existing if Precise flight does not repair the unit? The brakes are in good condition and would hate to have to spend 10K to put in a complete new system over a 5 dollar part!

[LANCECASPER]

2 hours ago, PBones said:

I have a similar problem with an older Precise flight brake that has the friction clutch not the electric clutch. Precise Flight is not sure they will fix my unit since they are sunsetting it because of parts not being available. Does anyone have a source for the friction disc that my AP can use to replace the existing if Precise flight does not repair the unit? The brakes are in good condition and would hate to have to spend 10K to put in a complete new system over a 5 dollar part!

If you haven't done this, do this before anything else. It should be done every year at annual: