Upper Unit lower Oil Seal

[TXS V20]

Allright guys, I was trying to remove the lower oil seal on the upper unit (lots of oil in the lower unit cavities and the rubber seal was gone) without removing the upper unit from the gimbal/transom. After tugging and prying on it (with a gear puller/screwdriver/hammer) decided that the water tube cover needed to come off. Dang, broke the first screw/bolt that I came to. Does the water tube cover need to come off to replace that seal? Any ideas, ? Anyone wanna buy a 78 I/O with busted sterndrive ?:cry:

[spareparts]

if I'm understanding you correct, you are replaceing the lower seal in the upper unit of a mercruisers outdrive(MC1, MR1, ALhps 1 gen 1). If so, you don't have to remove the water tube cover(you usually break the screws offf). The very bottom seal(of the upper unit) usually comes out with a seal puller or a curver hook type tool. But thats not the seal that holds the lube in, its only there to hold grease up in the splines(only place you'll see two seals facing the same way in a mercruiser), teh seal under the driven gear must be installed by removing the gear set, which requires dissasembling the upper unit

[TXS V20]

Well, you're definitley correct about breaking the screws off and I'd been told by folks that have done this before that the lower oil seal of the upper unit (correct as you described it) could be removed by a half of a gear puller with some leverage (without removing the upper unit). I couldn't/didn't mangae to accomplish this. So looking for impediments, i broke the dang screw off the water tube cover. Question is; what's next ? and, it should be obivous by now I ain't a mechanic

[TXS V20]

If that seal is only there to hold grease in, why is it called the oil seal, and if it doesn't tend to separate oil from the upper and lower units then what does? I may have fubared the wrong seal - have the entire kit AND I guess tomorrow I'll take the upper off. At this point I'm inclined to chalk it up to a learing process and order one of the new Jap version outdrives. Only problem with that is I don't know if the original 470 will take it. if I have to repla:sad:ce the power I'd rather go with a 4.3 V6 which would require an alpha. ALL of a sudden this Lil pig is getting awfully expensive!!!

[spareparts]

first of all, its not that hard to reseal the upper, it may take some creativity and or special tools, but its not that hard. Go ahead and pull teh upper off the boat, flip it upside down, use an extra long drill bit and drill out the broken bolt, if you screw it up, you wouldn't have wasted time resealing before hand. After you get the broken scew taken care of, pull the top cap, remove the big spanner nut for the drive shaft(here's where that creativity or special tool comes in), keep the spacers and shims in place( I use a bread tie to keep them together till I'm ready to put them back in). Once you have the upper stripped, knock all teh seals out, take notice of the position of the lip(take pics if you have to). The fun part is driving the new seals in place with out the proper drivers, you can experament with various pieces of tubing or other objects, worse comes to wrose, take it to a shop, cleaned up, with everything ready to go back together, and see what they will charge to reaseal and assemble it.

As far as the aftermarket drives, the uppers are essitially the same from MC1, MR1, and Alpha 1(gen 1), there is only cosmetic external changes on the uppers of these drives. What makes an Alpha, an Alpha( and 7 times stronger than the earlier drives) is all in the lower, so even if you were to upgrade to a high output V8, you would really only need to upgrade the lower. Remember, they used to offer 230 hp(around 200 by todays standards) 351 Fords with the MCI

[TXS V20]

Feel a little better about it this morning - should I plan to replace all three bolts in the water tube cover and replace the gasket or do you think just work on the one ?

[TXS V20]

Thanks Spareparts - btw I could use a few. I've gotten the upper unit separated from the lower and gimbal housing. Got the two damaged oil seals out of the upper. Most everything else inside looks good. Need a new bushing for the shifter and replacement gaskets and she's going back together - screw a broken bolt. I may try it later with some neighbor mechanic assistance, but if I get the parts back in first she's going together without one fourth of the water cover bolts. I'm afraid I'd do more damage by messing with it. Anything else I should be looking for while it's apart ?

[spareparts]

check the gimbal bearing, bellows, shift cable. Take a good look at teh shift shaft bushing in the lower, look at the shaft itself, yours is probably not stainless and will probably have a grove in it. Also look at eh shift shaft in the bell housing, you can update teh bushing/seal arangement with a leter style bushing that has an intergeral seal, most people over look the shift shaft seal in the bell

[TXS V20]

The shift shaft busing is gone as is the washer that (I think) was suppose to be there. It's brass and in good shape. A little loose also where it slides into the housing. I think I can tighten that up a little with pliers. Everything else looks ok for a 30 year old outdrive. You think leaving the bolt head broken will be an issue ?

[spareparts]

it will probably be ok