Thrust Bearing Replacement

[Peter S]

I am about to replace the thrust bearing on my A4 engine, hopefully without removing the engine from the boat. So far I have I have separated the rear coupling, removed the prop shaft and taken the nut off the back of the reversing gear, pulled off the output flange, and removed the oil seal plate from the back of the reversing gear.

I'm not 100% sure of the next steps, but I can see the thrust bearing, and believe my next step is to remove the output shaft, which will require the use of a puller to get it out, then I will have to get the bearing out. I have the Moyer Marine Manual, which mainly deals with overhaul of the reversing gear after removal of the engine from the boat. It appears I have to remove the pressure plate fingers to get the tail shaft out.

Has anyone replaced a thrust bearing or have any insight on this?

Peter S

[Don Moyer]

Peter, you do NOT need to remove the reversing gear from the engine to replace the rear thrust bearing. From where you are at this point, you only need to pry off the second round cast plate (the one behind the one that was holding the oil seal). This round plate houses the thrust bearing. You can then replace the thrust bearing and reassemble everything just as you took it apart. Don

[Peter S]

Thanks Don,

I got it came off ok. I bought the bearing, seal and the gaskets from you last fall, do you recommend a using sealer with the gaskets or are they ok on their own.

Thanks again,

Peter

[sastanley]

Peter, for the oil seal flange gasket, I used Permatex #3 on both sides...in hopes that I never have to take it apart again. That's as far as I went, so it is the only advice I can give you.

[Don Moyer]

Peter, it's good to use the Permatex on the threads of the six retaining bolts as well, especially on the lower three.

[Peter S]

Don & Shawn,

Thanks,

Best Regards,

Peter

[Peter S]

I'm about to start reassembly my thrust bearing. I have pressed in the thrust bearing into its housing, and the seal into the seal housing plate, however I don't have a tool to reassemble the output flange coupling into the trust bearing and tailshaft. Some instructions say it can be assembled with a rubber mallet, however there are some risks associated with this method. I'm debating if I can assemble the output flange coupling to the thrust bearing and seal housing/plate off the engine. I would need to have the seal plate to thrust bearing gasket in place before I did this, but I was thinking I might be able to press the parts together in a press or a very large vice. I would press it in just far enough to comfortably engage the tailshaft nut. It assumes the whole assembly will slide onto the tailshaft ok afterwards, and the woodruff key aligns ok and nothing binds.

Has anyone else reassembled in this manner, I might be completely out to lunch on this, and have overlooked something very basic. Does it sound feasible?

I will take the parts to the engine/boat before I try and look to see if I have missed something I will also try the output flange/couple on the tailshaft before I attempt this. Space between the hull and the tailshaft may also be a limitation, once everything is assembled.

Any input would be appreciated.

Thanks,

Peter

[hanleyclifford]

I have never had any trouble driving that coupling back onto the shaft. Just make sure everything is super clean and no burrs or edges are protruding any where. When ready to drive make sure the coupling is started "square" and it will go on without a lot of violence. Make sure the key starts into it's slot and does not move forward or rise. If excessive resistance is encountered, back it off and investigate.

[Peter S]

Thanks for the advice. I tapped the output coupling back into place, the output shaft nut is back on and tightened, the washer is tabbed over and I'm ready to reinstall the prop shaft.

Thanks also to Don and Shawn.

Peter