Alpha 1 forward gear needle bearing working out

[Shortcat]

My 1979 SearRay w/Alpha 1 outdrive would not go into reverse gear.
I bought tools to disassemble and found the Forward Gear needle bearing had moved out of the gear bore about 3/8 ths of and inch or so.
Could not move dog-clutch into reverse gear as needle bearing prevented shift spool from moving rear enough to engage dog clutch.

I found Alpha "2" has a snap ring for the forward gear needle bearing.

Has anyone had this failure issue and how did you fix to prevent re-occurance.

Note that took quite a bit of force to push the bearing into bore to fully seat against the lip on the gear (at the "rear" of the gear) -

I'm thinking I may try staking or hitting it with a TIG weld - just enough to create a bump to stop bearing migration.

Adding: over 500 hours on drive when this occurred

 

[Dieter]

My 1979 SearRay w/Alpha 1 outdrive would not go into reverse gear.
I bought tools to disassemble and found the Forward Gear needle bearing had moved out of the gear bore about 3/8 ths of and inch or so.
Could not move dog-clutch into reverse gear as needle bearing prevented shift spool from moving rear enough to engage dog clutch.

I found Alpha "2" has a snap ring for the forward gear needle bearing.

Has anyone had this failure issue and how did you fix to prevent re-occurance.

Note that took quite a bit of force to push the bearing into bore to fully seat against the lip on the gear (at the "rear" of the gear) -

I'm thinking I may try staking or hitting it with a TIG weld - just enough to create a bump to stop bearing migration.

Adding: over 500 hours on drive when this occurred

Wonder if the bearing is worn and hence why it is walking in the bore. I would either stake (with center punch) the bore for tighter fit or use loctite retaining compound in it

 

[kghost]

I have never seen this issue in over 30+ years. I have worked on drives with well over 1000+ hrs.

Can you post any pics?
One of the needle bearing out as you described
One of prop shaft area/surface that goes into bearing

 

[Droid]

Shortcat:
If that is the original gearcase, it's a #1, not an Alpha. The gears are different but the bearing & its installation is the same.

Kghost:
I'm thinking same as you, the needle bearing inside fwd gear. I've never seen 1 migrate either.

Dieter:
I'm doubtful the inner bore of the bearing can be staked. It's hard as hell and at best he can only get a center punch in diagonally to try.

 

[racerone]

Oil pressure may have moved the bearing.----Install a new bearing.

 

[Droid]

Post 4 above should read: I'm doubtful the inner bore of the GEAR can be staked.

 

[kghost]

Oil pressure may have moved the bearing.----Install a new bearing.

I am using my cell so dont want to look at parts diagram now.

But, the forward gear bearing comes pre-assembled with needle bearing correct?
Its been many years since a bearing, seal only refurb so I forget if that bearing is sold sperately???

 

[Droid]

The FWD gear (both MC1 & Alpha) come with the bearing installed.
Gears can only be bought as a complete set of 3.
Bearings are available individually.

 

[kghost]

The FWD gear (both MC1 & Alpha) come with the bearing installed.
Gears can only be bought as a complete set of 3.
Bearings are available individually.

 

[Shortcat]

Thank you to everyone who replied -
I had a 15 mile or so run w/engine turning 3-4K (28 mph on the two-ton searay) and stopped to walk a beach - when I went to back away - would not go into reverse - gearshift would barely go past detent.

When I pulled it apart - no metal - oil fine - nothing appeared out of order until I got the propshaft out. I could see the clutch would not move enough to engage reverse gear. (The one mounted on the carrier) ???

I took apart the shift spool parts (small cotter pin and a nut of sorts) and slide off the parts. When I looked at the forward gear, i was puzzled by the needle (roller) bearing being partially outside of the gear. Odd as I have never seen or read of such an arrangement. I looked at the rest of the pieces and all in very good condition. I had replaced the water pump and shift cable in late spring and had used the boat another 40 hours or so (at least) and no problems till the last time of use.

I ruminated on the bearing being where it was as that being out of the bore stopped the clutch from being able to move to engage reverse.
??? I looked at the forward gear and saw there is a lip at the end of the bearing bore (at the side next to clutch dog) and !!! - aha! somehow the bearing has worked it's way out of the bore. So, I got a correct size bearing seating tool and pressed the bearing back to seat against the lip.

Took a bit of force I noted, not anywhere near "loose" - Assemble and now clutch moves as it should.

NOTE: This outdrive is a GLM I bought from "Basic Power Industries" at Harkers Island, NC

Boat has never been in salt water since I rebuilt is (bought from almost a junk yard) - I rebuilt the 305 SBC and paid someone to replace water pump and seals in lower unit. Later it totally failed when oil leaked out and I was cruising. The upper gears actually melted!

So - "screw-it" - I bought the GLM. Other than water pump - never had any issues till this bearing issue.

I found another blog where someone had same issue and got a new GLM gear set and poster noted the forward gear needle bearing is held in by a snap ring. Nice eh?

I also read the only way to remove the forward gear needle bearing is totally destructive.

Staking the bearing not possible - the gear is case-hardened/heat treated steel alloy. I could have got a puller on the bearing but didn't think of that while is was part way out of bore. If I had thought of doing that, I could have put loctite on it - which have also read is recommended by Mercury shop manual using Loctite 271.

I don't know how long the bearing has not been fully seated in the forward gear and previous to changing shift cable (boat still had original from factory) - and now think maybe is has been some time as getting shift mechanism set up so gearshift works properly has been near impossible. A lot of time to get out of reverse had to move shifter almost into forward.


GLM notes: Getting the drive pinon nut off was very easy - $$$ painful as the proper tool is $150 or so. I was reticent to try an open end wrench as didn't want to chance rounding off nut and consequent PITA issue! Using proper tool, nut came off very easy.
Getting the pinion off - not so easy!!! using various implements of destruction, (screwdriver mostly) I got the pinion off. And fouled up the process by pulling driveshaft out to far and the lower rollers from bearing fell into gearcase. Mechanical puzzle to get the pinion gear out with rollers in the mix! SO, don't pull the drive shaft any more than necessary to get threads out of way. (I can be taught!)
The issue of getting off the pinion? GLM left some metal shavings on the splines. Cleaned up everything and waiting for new water pump stud (galled thread - gotta love stainless steel) and rear prop-shaft needle bearing. I broke the perfectly good one trying to drive out the seals. It pays to be careful. New bearing about 20 bucks w/shipping.
The bearing carrier "nut" was very easy to remove - no corrosion as never seen salt water. There is a fellow: Michael Borders - who has a great video of rebuild a lower unit - complete with having to destroy the "nut" to get out the carrier. Mine came out almost as easy opening a bottle of beer! (32 oz with screw cap )

If I'm still alive (I'm going on 80) and this bearing works out again - i will get the GLM gear with the retaining ring. I can get the lower gearcase off the boat in about 30 minutes and can get the gearcase apart in less than a couple hours. PITA to spend a day doing but Wife and I *love* boating and we use the boat for overnight camping on the lake (John H. Kerr reservoir/AKA Buggs Island Lake)

Thank "you all" for your comments and suggestions. I hope my info about this fun helps someone.

Cost to do this work - less than $300 due to tools I had to buy. Parts minor part of the bill.

If I had taken to a boat repair place - I figure I would have been out way over 1K $

Plus the activity helps my weight - no beer drinking while using tools! !!! especially a chain saw

Cheers Everyone!

Adding - I note on EBAY one can buy the forward gear and pinion - no reverse hear.

 

[Droid]

The trick to dislodging the pinion gear from the drive shaft is to back the nut off only until flush with threads then (if I recall correctly) with the wrench tool in place, smack the propshaft up (towards the cavitation plate). Tool will pop the drive shaft up. Must remove the upper bearing retainer nut just under the water pump 1st if an Alpha drive. MC1 drive has no retainer.
I assume your GLM drive is an Alpha replacement.
If buying OEM, gears are sold as a 3 piece set.

 

[racerone]

That would be an SEI aftermarket unit I think.

 

[kghost]

SEI is a very affordable replacement drive with a 3 year warranty. I know several who have gone that route.

They are around $1800 ish for a complete drive.

That being said, There is no way to determine who or where the parts come from or the quality of said parts used.

When I said I have never seen a Mercruiser drive have this issue it ONLY refers to Mercruiser. Not aftermarket drives/parts.

 

[Shortcat]

kghost:

regarding "only Mercury" - maybe their instruction to use LOCTITE 271 on the bearing installation is the reason?
Another possibility is bore vs. bearing diameter. Just thinking out loud - maybe Mercury bore is a 10 thousandth smaller bore diameter - hence more of the Interference fit so bearing is more firmly held.

I don't have an inside micrometer to measure if the bearing works out again. However, I have put almost 1300 hours on the drive and ?? before it re-occurs is my thought.

Given GLM has added a retaining ring - makes me think, perhaps, their machining tolerance is not equivalent to Mercury. (or whoever makes for Mercury)

Given the hardness of the gear, I figure the bore is finished with a grinder. Such a process is critical in that keeping the grinding wheel dressed properly. Think $$$ process!!

I did a LOT of reading and bought a few manual too. Most helpful was: https://www.sterndrives.com/rebuild_alphaone_lower.html
and the youtube video. I note that the youtube video never mentions the bearing shimming or how to set clearances. ??? I view the absence as major omission. Hypoid gears do not last if not set up for proper mesh - not the same as "clearance." For rounding out ones knowledge - I would say read a shop manual on how to set up rear-axle gears. I have a Ford factory manual that has about 20 pages of "how-to" on putting a new gearset in an axle housing.

I had to replace upper drive housing gears 15 or so years ago - hit something and broke part of a geartooth. Had to replace upper housing tapered roller bearings and re-ship. That was lots of fun. I bought "Mercrusier" gears and no problem since. I flushed the lower unit with kerosene and then gasoline (while manually turning drive and prop shafts) and found very little metal bits in the lower section. Guessing the small oil passage didn't allow much to migrate into lower gear housing.

Checked bearing races and roller and lower stuff all looks very serviceable.


Thanks again for the comments!

Info:
1. ANSI B4.1 Standard Classes (Inch Units)
For the standard nominal size range of 1.19 to 1.58 inches (which contains a 1.5-inch part), the standard limits are specified in thousandths of an inch: [1, 2, 3]

Fit Class	Description	Min. Negative Clearance (Interference)	Max. Negative Clearance (Interference)
LN1 / LN2	Locational Interference	-0.0001 in	-0.0013 in
FN1	Light Drive Fit	-0.0001 in	-0.0011 in
FN2	Medium Drive Fit	-0.0006 in	-0.0018 in
FN3	Heavy Drive Fit	-0.0010 in	-0.0024 in
FN4	Force Fit	-0.0013 in	-0.0031 in
FN5	Shrink Fit	-0.0020 in	-0.0040 in

 

[kghost]

Most interference dimentions rarely go more then .0015". Fairly standard for interference/press fit.

It would be impossible with a .010" interference.

 

[Droid]

The forward gear is shimmed by way of shims in the housing nose prior to the race being installed.
There is no shimming required with the needle bearing.