Cannot get outdrive installed to the last 1/2 inch - need your advice!

I posted this on a thread I found that was similar to the problem I'm having but it was an old thread that no one has responed to for years so I'm posting again here. Apologies if this is not the correct way to do this.
1998 Alpha 1 Gen 2. Torn shift bellows so decided to do a lot of other work while in there, including replacing the gimbal bearing since it came with my kit (now I wish I had not since I believe this is where I'm having problems). NO problem with most of the job with the exception of the oil resevoir nipple breaking off and being impossible to get to in this boat. No sweat, we will simply check the gear oil much more frequently. The real problem is that I simply cannot get the outdrive back on. I have read the manual and looked at a ton of videos and I'm certain I have the setup correct. Forward gear, prop shaft fully counterclockwise, shift linkage line up, everything greased. I even built a small dolly to help position the outdrive. My son and I can get it to the point that we have to turn the prop very slightly so that the splines line up and it goes in another 2 to 3 inches. I'm certain the shift arm is in the right position. I just cannot get the outdrive to go in the last 1/2 inch. Now I'm wondering if I got the new gimbal bearing fully seated. I used the alignment shaft and the special "puck" that is use to push the bearing in. However, I did not drill the hole in the tool. Instead I used a piece of 2x4 and a 4 pound hammer to tap the bearing into place. It went in fine and looks great. My alingment is still good. I believe the splines are mated since, as I mentioned earlier, an 1/8 of a counterclock wise turn let us move the drive in - just not the last 1/2 inch.
So, am I correct in thinking the bearing may just not be seated far enough in and is blocking my driveshaft from going fully into place? Is there any measurement out there from the bearing out to the edge of the housing (or somewhere else) to verify it is in far enough. I wish I had measured it before I removed the old one but I failed to do so.
I sure could use some advice on this. I've been fighting this for two days now and it is about to whip me.

Grease the o rings on the shaft and give it a kick. Also be sure the shift linkage is position properly.

I appreciate the reply. I did grease the o-rings as well as the splines and the housing (both on the outdrive and the female end on the transom. I'll admit I'm hesitant to force the issue since it feels like I'm hitting something more solid than rubber o-rings. I'm going to pound on the bearing a little more tomorrow. I saw another thread where the fellow inserted the alignment tool, put the bearing seating puck on, and then used a piece of galvanized pipe with inside diameter fitting over the alignment too.. This allowed him to drive the bearing in without having to try to drill a hole in the alignment tool. I'm off to Lowe's in the morning to try to find the right size pipe. Do you have any comment regarding the possibility that the bearing is not in far enough? Does this sound feasible to you?
Thanks again

Before you do all that)…,Instead of just grease to the 3 o-rings on the shaft, add oil to them too as it aids to the slid in process immensely there at the end…
Grease alone seems to help create a hydraulic affect and makes it pretty challenging to get the drive all the way in…worse case, try no grease and oil only to see if it helps better…

Additionally, oil the gimbal bearing hole where the shaft slides through…

I will definitely do this. I'm now reasonably certain I have the bearing all the way seated. I'm now thinking it is either the o-rings or my bearing alignment is a little off. I'm going to try the oil and run the engine a bit with the alignment tool pushed all the way in to try to better position the bearing. The unit came off easily so I don't believe the engine alignment is off. I have watched quite a few videos saying that a new bearing can be slightly off making it hard to get the outdrive back on. I noticed last night that I was not getting the alignment tool all the way in so today I'm going to lightly hammer it until it bottoms out and then run the engine a bit.

I know this is a Merc and not an OMC but the driveshafts are very similar and in my OMC Cobra shop manual it says NOT to grease the o-rings, clean the grooves for them out and just oil them. Grease in the grooves that they fit in can cause the o-ring to not sit like it should and also grease can cause the rubber o-ring to expand slightly. On the OMC the other thing that really helped was to use a long thin screwdriver to slightly turn the u-joints which helps the splines to align. With the Merc since it's in gear for the install turning the prop just a bit might be all it takes, like 1/8th of an inch.

gonna have to get under it with a flashlight to see exactly if the shift arm is seated properly into the shift shoe.Once you have confirmed that it is (and both should be well greased) then put the 2 middle mounting nuts on and gently gently tighten them down a little at a time. Use a short rachet so you can feel any resistance.they should tighten pretty easily and close the gap; Any resistance will tell you that something aint right so proceed gently. Charlie

I finally got it. I don't know if it was the oil on the o-rings, leaving the alignment tool inserted while I turned over the engine (to "force" the gimbal bearing into better alignment) or just finally kicking the damn thing hard enough to get it in, or most likely the combination of all the above, but it finally went in. I think I'm just a little too hesitant to beat and kick on stuff. Probably left over from working on B-52's from 69-75. Some of you old techs might remember "brogan maintenance" which was used pretty often on some systems but not the stuff I worked on (radar bombing and navigation systems). Or, it might just be that I have gotten really old.
Anyway, thanks a ton for all y'alls help. Hope I can help someone else on this forum in the future.

eh..
On the Mu-2 I flew, if there was an issue with the fuel control unit on initial start up, the manual said to "malletize" it.

JFCMoore said:

or just finally kicking the damn thing hard enough to get it in,

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I'm going to go with that...

I would NEVER recommend bashing an outdrive to get it installed. I have installed my own outdrives for over 30 years and the most force I have ever had to use was hitting it with my shoulder to get it moving. Bashing it might get it in however just as high a chance that you are forcing something that has a legit reason for not going on smoothly and you F something up with bashing it. Charlie

JFCMoore said:

I noticed last night that I was not getting the alignment tool all the way in so today I'm going to lightly hammer it until it bottoms out and then run the engine a bit.

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If you need to hammer your alignment tool to get it to bottom after the gimbal is aligned then your engine is out of alignment. Hopefully it inserted/removed easily after the initial go round

Thanks for the replies. I understand the engine alignment issue - or maybe I don't. I don't see how the engine alignment changes when you remove the outdrive. If it comes off easily, doesn't that indicate the engine is in alignment with the existing bearing? It was only after I removed and replaced the gimbal bearing that I ran into the problem of not being able to easily get my alignment tool pushed in all the way to the engine. It seems to me that this is a clear indication that the bearing needs alignment - not the engine.

JFCMoore said:

Thanks for the replies. I understand the engine alignment issue - or maybe I don't. I don't see how the engine alignment changes when you remove the outdrive. If it comes off easily, doesn't that indicate the engine is in alignment with the existing bearing? It was only after I removed and replaced the gimbal bearing that I ran into the problem of not being able to easily get my alignment tool pushed in all the way to the engine. It seems to me that this is a clear indication that the bearing needs alignment - not the engine.

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The bearing is in alignment with the engine. The bearing "gimbals" in the bore, so it should rotate as needed to align with the engine. This should happen when you insert the alignment tool, but a new bearing might be a bit tight. Inserting the alignment tool and whacking it up/down/side/side will encourage the bearing axis to get parallel to the coupler. After that the alignment tool should come in and out easily. The alignment tool has tighter tolerences than the drive shaft, so coming off (or even going on) easily could still mean that your engine is not sitting quite in line with the bearing. Engine can shift over time, which is why the alignment is checked ever year. Again, you didn't say if you still needed a lot of force with the alignment tool after trying to align the bearing. If it's me, I remove the outdrive, check the alignment properly and try again. 15 minutes vs wiping out your engine coupler.