installation

[Sailwood]

Don,

The total rebuild had gone quite well until I tried to re-install the reversing gear. I can get it mounted over the gear cluster, but it won't go the last 1/2" or so. The shaft will not enter the pilot bearing. I tried gently tapping with a rubber mallet but no go. Should the tip of the shaft have a chamfer to help guide it in ? I fear the machine shop may have damaged it when they changed out the forward adjusting nut for the new one. They said they had to totally dismantle the gear cluster and pressure plate mechanism to press off the old adjuster. Any sage advice?

Doug Soden

[Don Moyer]

Doug,

I'm a bit fearful that they may have pressed out the tail shaft by pressing directly on the front end of the shaft. If they pressed on the very end of the shaft, they very likely spread the end a bit by "mushrooming" it. I don't know of any way to remove the mushrooming but to disassemble the unit one more time and machine the end of the shaft to conform to the ID of the pilot bearing. Perhaps a long thin Dremel tool could work down the enlarged tip, but unfortunately the entire tip that needs to go inside the bearing is enlarged (yes, I made this mistake myself some years ago). For whatever it's worth, here is the complete disassembly of the reversing gear from the end of Chapter 6 of our service and overhaul manual. See especially step 5 in the first section:

DISASSEMBLY OF REVERSING GEAR CASE

The following procedure would be necessary to repair or replace the operating cone, pressure plate, gear cage bearing, or clutch disks.

REMOVAL OF TAIL SHAFT AND GEAR CAGE BEARING

1) Remove the three fingers from the pressure plate by removing the pins and cotter pins (see Fig 3).

NOTE: Reinstalling these cotter pins can be quite difficult. Observe carefully how they are installed by the factory, and then attempt to procure pins as close to the originals as possible before starting reassembly. It also helps the put a slight bend in the new cotter pins before reinstalling them.

2) Position the adjusting collar until its rearward face is flush with the end of the threads on the tail shaft.

3) Remove the forward pilot bearing (see Fig 2).

4) Position the gear case (pinion gears up) in a press in such a way as to support the adjusting collar between two strong plates. The edges of the plates should be notched so as to form an opening as close to the diameter of the tail shaft as possible.

5) Press the tail shaft out of the propeller gear using a piece of 3/4" round stock (3 1/2" long). The end of the round stock must be recessed (15/32" dia. x 1/2" deep) to prevent damage to the forward (pilot bearing) end of the tail shaft. A press with at least 12 ton capacity is usually required.

6) Remove pressure plate and clutch disks.

7) Remove the retaining ring and gear cage (pilot) bearing (code 12).

REMOVAL OF PINION GEARS

1) Remove the retaining ring on the forward face of the gear case (Code 3).

2) Drive the 4 pinion studs (Code 4) out of the gear case. The studs can only move forward, from the direction of the clutch disks to the forward end of the gear case.

REASSEMBLY

The gear case assembly can be reassembled by reversing the above steps, with only a few precautions:

1) Install the spacers on the pinion studs so that the small gears are positioned against the forward end of the gear case.

2) The forward end of the gear case can be placed directly on the press when pushing the tail shaft back into the propeller gear. However, the coupling nut should be installed on the end of the shaft to prevent damaging the threads.

3) If you are working on a very late model reversing gear (circa 1980 or later), there will only be two plain steel disks in the clutch assembly. Be sure that these two disks are placed - one on either side - of the middle bronze disk. On all other models, the third disk is installed between the pressure plate and the first bronze disk.

Regards,

Don

[Sailwood]

fixed

Don,

The shaft end was, in fact, mushroomed. I returned to the shop with the old pilot bearing. He mounted the whole assembled cluster in his lathe and reached in with his pointed "shaver" (have no clue as to what it is called) and removed the mushroom slick as can be. Fits like a glove.

I'll let you know how the initial startup goes tomorrow. I'm a tad nervous, but since the rebuild has been assisted by my Obsessive Compulsive Disorder on steroids, an easy start is anticipated.

Doug Soden
ASPEN Columbia 29 #131
Great Bay, NJ