Annual speed brake lubrication

[larryb]

After noticing that the ICA for the PreciseFlight speedbrakes specifies annual lubrication of the drive gear I asked my MSC if they did that at annual. They do not. I am sure they would do it if I asked, but if you don't ask... He then tells me that if I do it myself, just lube the gear and don't get anything on the clutch. This makes me wonder about the rest of the fleet, and if they got their annual gear lubrication then perhaps they would avoid some costly overhauls. Of course, you'll pay an hour labor each time they are lubed, so there is that cost. 

So I finally got around to this myself yesterday. It takes about 30 minutes each side. Quite simple, just a lot of screws. It drops out the bottom of the wing through the inspection plate. No disassembly of the speedbrake is required, the sides are open. A little dab of Aeroshell 22, as specified in the manual. The gears did not look worn, but they were dry. I am sure they would have started wearing more rapidly without lube.

[LANCECASPER]

Thanks. Because of your post I just downloaded the maintenance sheet for the speed brakes. I'm going to lube the worm and worm gear the next chance I get.

[kortopates]

Awesome suggestion and exactly the way to do it, by consulting the ICA or Precise Flight documentation. But I just wanted to add the caveat that since there are many generations of speed brakes they aren't all the same. Some of the earlier speed brakes, such as my pneumatic actuated brakes, use sealed bearing. Trying to lubricate these is not recommended (Precise says not too) since it can do more harm by attracting dirt than do good. Consult your documentation first.

[PT20J]

Thanks for pointing this out. I never thought about it. I checked my logbooks and mine have not been out since the previous owner Sent the to Precise Flight for repair in 2012. I’m going to create a new annual checklist that includes all the installed equipment so everything is in one place. 

Skip

[larryb]

One of the reasons I started this thread is because I was surprised that my shop did not automatically perform ICA tasks on installed equipment without being specifically asked. I expected something basic such as lubrication would be performed. This is a well-known MSC. Is this a universal practice? 

[Davidv]

+1 on doing this yourself, I've removed and reinstalled the brakes several times now and have about 0 A&P knowledge or skills.  One of mine stopped working shortly after I purchased my plane so I sent them into PF and they said that they hadn't seen my brakes since they shipped them to Mooney in 1991.  Needless to say it was not a cheap overhaul, but I got back pretty much brand new brakes.  A little preventative maintenance lowers the chance of spending about $2K.

[PT20J]

3 hours ago, larryb said:

One of the reasons I started this thread is because I was surprised that my shop did not automatically perform ICA tasks on installed equipment without being specifically asked. I expected something basic such as lubrication would be performed. This is a well-known MSC. Is this a universal practice? 

Last annual before I purchased it a year ago was at a well known MSC and it wasn’t done. 

[JimK]

There is lots of good info here which is provided by some sharp people but please allow me to add my two cents from personal experience.  I started studying the system after one of my speed brakes would not deploy at the end of a long cross country.  When I learned that annual lubrication is recommended I first tried to take the easy way out by extending the speed brakes on my Ovation 3 so I could reach the gear to lubricate it.  That’s when I realized that I could only access about 90 degrees of the gear and none of the worm drive.  Then it occurred to me that the gear only rotates about 90 degrees during deployment so the grease I applied May never come in contact with the worm drive.  Also his method would not remove the contaminated old grease which is exposed to the environment. That’s when I knew I would have to remove and disassemble the speed brakes in order to do he job right.  I still don’t believe it is necessary to do this every year but the following YouTube video shows how I cleaned, lubricated and inspected my Precise Flight Speed Brakes.  Once I did this maintenance the speed brakes worked great.

 

Edited February 5, 2024 by JimK

[ArtVandelay]

If you’re going to be parking outside, use some painters tape to seal the SB slot, an ounce of prevention…

[natdm]

On 2/5/2024 at 5:14 AM, ArtVandelay said:

If you’re going to be parking outside, use some painters tape to seal the SB slot, an ounce of prevention…

Every single time you fly? Dang. 

Would be nice to have some removable covers. I don't know if I'll break out the tape roll every time I fly. 

[natdm]

@ArtVandelay I might give this a try: https://a.co/d/47dUlCo Just use some permanent marker to put some red stripes on them so they're more visible on preflight.

[ArtVandelay]

Every single time you fly? Dang. 

Would be nice to have some removable covers. I don't know if I'll break out the tape roll every time I fly. 

I’m usually hangared.

[skykrawler]

On 6/27/2019 at 9:02 AM, larryb said:

One of the reasons I started this thread is because I was surprised that my shop did not automatically perform ICA tasks on installed equipment without being specifically asked. I expected something basic such as lubrication would be performed. This is a well-known MSC. Is this a universal practice? 

Technically an annual is an inspection.  Often the oil and filter is changed - the filter must be inspected.   An AD may require some maintenance.  Some folks assume overall maintenance will be performed, but that is a discussion that must be had with the shop.

[Fly Boomer]

24 minutes ago, skykrawler said:

Technically an annual is an inspection.  Often the oil and filter is changed - the filter must be inspected.   An AD may require some maintenance.  Some folks assume overall maintenance will be performed, but that is a discussion that must be had with the shop.

Last comment from @larryb was 5 years ago but, if he was following this topic, I would say I don't think speed brakes are specifically named on the Mooney 100-hour and annual inspection guide, but it does ask "All Applicable (ICA) Instructions for Continued Airworthiness complied with?"  Seems like that should cover it -- especially when an MSC is doing the annual.

https://www.mooney.com/wp-content/uploads/2020/12/100-HOURANNUAL-Inspection-Guide.pdf

[Pinecone]

May not be on the Mooney guide, but it is on the STC/ICA for the speed brakes.

[rickseeman]

JimK: thank you for the video

[moosebreath]

Note that the Mooney maintenance manual for factory speedbrakes calls for inspection every 1000 hours.  Quite different from the ICA.

[natdm]

When doing this, if any screws are stripped.. I asked PF if they were ok emailing me what screws go where, and was able to get a shema for the ones in the video (which I also have).

010S0067-1.pdf