Bendix Drive on Lightweight Starters

[mikefox]

We have a lightweight starter in our 1989 M20J (Magnaflight) and have had numerous issues over the years with the Bendix sticking (turn the key, and the starter motor spins but the gear doesn't engage the ring gear).

 

Anyone else have issues with Bendix drives?  We have called the manufacturer who advised us to use dry silicone lube spray every 25 hours, but sometimes we have sticking anyway.  Usually several attempts makes it work, but it still makes one awfully nervous when at a field with no services!!

 

Anyone have any experience with solenoid-type starters?

 

Thanks,

 

Mike

[Marauder]

My starter does the same periodically and staying current on the silicone re-lubes helps a lot.

[bumper]

When you take a Bendix apart on the bench (carefully laying out all the parts in order on a white towel   ) you come to understand that the *only* really good way to clean a Bendix is to disassemble the bugger. Spraying with silicone spray is good, no question, but it won't clean out, or even reach the gunked up old grease inside,

[yvesg]

Try spraying silicone after every flight for a while. See if this improves it. We did that several years ago when we were in the same situation and it worked fine.

Yves

[Marauder]

Bumper is correct, the best you can do with the silicon is make the gunk inside slippery enough to allow it to move. You definitely don't want to use something like WD40.

[PierceM20F]

I'm starting to have the same issue on my starter (I think). How/where do you apply this silicone to the bendix after every flight? I can see the gear that would connect to the ring for the prop but the rest of the starter is inside of the starter assembly. Maybe you could stick a small tube like WD40 can has and stick it further inside the assembly? Newer guy here so I apologize for not having the correct words for parts...

[A64Pilot]

I would follow this article. I believe the key is clean and dry.

https://www.lycoming.com/content/how-clean-your-direct-drive-engine-starter

I take exception to silicone spray though, I would use either dry film lubricant or graphite or Molybedum powder myself. Graphite can cause some corrosion but I don’t think it’s an issue here. Issue is as I see it is anything wet will attract dirt and stick the thing.

In the Desert I found Molybedum powder to be excellent on the AH-64 ammo system, we had been using Break Free with great success until we got i the desert then you needed a dry lube.

Dri-Slide is a good lube, is kerosene I think with graphite, the kerosene carries the graphite into tight places, then flashes off.

Dupont makes an excellent dry lube, it’s teflon in a carrier, the carrier flashes off and leaves the teflon behind, I even used it on the sails on my boat, great zipper lube etc, it doesn’t even stain, but good heat resistance and some protection from rust, similar to silicone spray but much better in my opinion

 https://www.amazon.com/DuPont-Non-Stick-Dry-Film-Lubricant-Aerosol/dp/B003UTX0R8/ref=pd_bxgy_sccl_1/147-3221661-6971439?pd_rd_w=8VZef&content-id=amzn1.sym.7f0cf323-50c6-49e3-b3f9-63546bb79c92&pf_rd_p=7f0cf323-50c6-49e3-b3f9-63546bb79c92&pf_rd_r=4TK3EVBXEGS0E4EBMFKZ&pd_rd_wg=1JQfW&pd_rd_r=d9e1840d-8581-469b-8bb6-e0d84f84761a&pd_rd_i=B003UTX0R8&th=1

[N201MKTurbo]

Dri-Slide is molybdenum disulphide. 

[EricJ]

14 hours ago, PierceM20F said:

I'm starting to have the same issue on my starter (I think). How/where do you apply this silicone to the bendix after every flight? I can see the gear that would connect to the ring for the prop but the rest of the starter is inside of the starter assembly. Maybe you could stick a small tube like WD40 can has and stick it further inside the assembly? Newer guy here so I apologize for not having the correct words for parts...

Just spray it in behind the gear around a bit on the shaft.   On my J I could only do it if the lower cowl was off, so I sprayed it whenever the cowl was off.   On earlier models if the starter is exposed it should be easier.

Also, this only applies to the original starters with a Bendix drive.   If you have a Sky-Tec or a B&C it doesn't need to be sprayed.

 

[PT20J]

Sky-Tek