how to retract Prestolite Bendix pinion?

[Bluebeard]

I am reinstalling my former Prestolite starter, after testing it still works by applying 12 volts. It does work, so I am ready to reinstall it. But following the test the Bendix pinion is now in the forward "engaged" position, and I can't figure out how to get it to retract? Is there some knack here?

Normally it would retract after the engine starts and reaches X rpm. Spinning the prop (plugs out) does not work retract the pinion.

Bolting the starter in place with the Bendix pinion in the forward position does not look like a good idea, as the pinion would put unknown stress on the ring gear when you tighten the mounting nuts.

Maybe someone here knows the solution!

[Mike S]

Spin the gear on the shaft.

[JimRice]

I just replaced my Bendix drive on my Presolite/Aero Electric MZ4222. Per manual, it says to install with Bendix drive out so you can check the Bendix teeth meshing with the ring gear teeth. I did so and it worked fine.

I have another identical starter which I picked up for $55. I can spin the Bendix on it back in by hand, but on the new drive unit, I could not. In fact, when I took it out and was trying to determine how to removed the pin which holds the drive to the shaft, I turned it so the Bendix was forward and it took me several tries before I could get it to go back in.

In short, it isn't necessary to have the Bendix retracted to put it on and begin using it. You do want to start it and ensure it is retracting when started before you cowling it up however.

[Bluebeard]

My Prestolite is MZ 4204. I could not find in the manual a reference to the installation procedure but it seemed to me it would be safer for the ring gear to install the starter with the Bendix pinion retracted.

The manual says the pinion retracts when centrifugal force (after starting) forces a detent pin out of a notch in the screw shaft.

But there does not seem to be a way of manually retracting this pin (which must be inside the Bendix assembly) if the engine does not start.

I tried spinning the engine by hand but this is apparently not enough rotation to free the pin ....

[RV7 To Go]

Originally Posted by Bluebeard

My Prestolite is MZ 4204. I could not find in the manual a reference to the installation procedure but it seemed to me it would be safer for the ring gear to install the starter with the Bendix pinion retracted.

The manual says the pinion retracts when centrifugal force (after starting) forces a detent pin out of a notch in the screw shaft.

But there does not seem to be a way of manually retracting this pin (which must be inside the Bendix assembly) if the engine does not start.

I tried spinning the engine by hand but this is apparently not enough rotation to free the pin ....

When I installed my Prestolite the pinion was out and would not retract after testing. I was told it required start RPM on the flywheel to retract the bendix. It worked fine on the first start and a few hundred since.

Al

[JimRice]

Originally Posted by Bluebeard

My Prestolite is MZ 4204. I could not find in the manual a reference to the installation procedure but it seemed to me it would be safer for the ring gear to install the starter with the Bendix pinion retracted.

The manual says the pinion retracts when centrifugal force (after starting) forces a detent pin out of a notch in the screw shaft.

But there does not seem to be a way of manually retracting this pin (which must be inside the Bendix assembly) if the engine does not start.

I tried spinning the engine by hand but this is apparently not enough rotation to free the pin ....

By design, the Bendix will not retract unless the engine starts. It takes much more RPM than you can accomplish by hand.

Installing it with Bendix forward/engaged allows you to see that it is engaging the ring gear teeth properly when extended. Installing it engaged is no different than a failed start on a normal start up where the Bendix remains engaged.

[jeffkersey]

Originally Posted by JimRice

By design, the Bendix will not retract unless the engine starts. It takes much more RPM than you can accomplish by hand.

Installing it with Bendix forward/engaged allows you to see that it is engaging the ring gear teeth properly when extended. Installing it engaged is no different than a failed start on a normal start up where the Bendix remains engaged.

Where did you buy the rebuild kit for your Bendix drive? My starter failed Saturday and I had to leave my plane away from home. I had just installed it in December. I'd say there is only 60 or 70 hours on the airplane since installing it. The gear is still spinning. It just won't push out and engage the ring gear. The bendix gear is a little buggered up in the front half. On the last start, there was a noise that was not right. It cleared in a few seconds. I must not have retracted properly and got chewed up.

The starter that came on the airplane failed at about 350 hours. I guess I need to keep a spare starter on the shelf. Seems like very poor service life considering the way my truck has 175000 miles and still starts....

Thanks for any advice and info you have

JK

[JimRice]

I bought the Bendix drive at Aircraft Spruce.

This is the correct one for my starters. There are a bunch of different models.
https://www.aircraftspruce.com/catal...rterdrives.php

[jeffkersey]

Originally Posted by JimRice

I bought the Bendix drive at Aircraft Spruce.

This is the correct one for my starters. There are a bunch of different models.
https://www.aircraftspruce.com/catal...rterdrives.php

Thanks Jim...

[WingsOnWheels]

A common maintenance mistake is to use oil or grease on the bendix. Over time this will gum it up and cause it to fail. Disassemble and clean it with solvent, the use silicone spray lubricant on reassembly.