Mercruiser Alpha 1 upper gearcase repair (oil seals) and tools

Repair help and drawings from www.sterndrive.info for any Mercruiser outdrive. Over 100 videos and sterndrive drawing of bell housing and upper-lower gear case. Tec service rep phone number for repair help ordering parts, tools and compounds contact Brian 416-751-7326.

[@gordondills2773]

My outdrive was leaking oil from the shifter shaft and also out the water inlet to the impeller. The oil was leaking down the drive shaft through the two seals above the impeller going into the upper gear box. The oil was so thick it clung to the housing and dripped down the gear shaft and out through its bottom seal. The oil also ran down the drive shaft and puddled up around the impeller housing and after a while seeped through it as well. I watched your video and repaired it myself! Thank you!!! The marine shop was going to charge me at least $700 dollars to repair the seals. It has been almost a week and no leaks!!! Thank you for posting.

[@leandroschauvinhold1557]

Thanks so much!!

[@baghdadmarine]

good work

[@sheldonking1743]

Very helpful to supplement the manual I ordered. Will I only need the 1 size of aluminum oil/grease seal installer or are there 2 different sizes and if so what are the sizes?

[@paxan200618]

Hello i am looking to do exactly the same service as you did i need those upper and lower seal and o rings also i need gasket for outdrive where is the best place to buy them ?

[@christopherwatson283]

You forgot to install the Input Yoke Seal. It came with the Kit.

[@vitahawkins261]

Would this be similar instructions for gen 2?

[@Arcturian1111]

The Spring is down in the lower oil seal on alpha gen one.

[@devildogae]

Same tools for the MC-1?

[@fstarockaburns425]

Hi - bit of a hack but is it possible to remove the brass spanner without the tool? In a pinch that is -

[@kevinzimmerman557]

where can I get one of those 600/800 grid sanding disks I cant find them anywhere

[@stwicks77]

9:14 why did you install with lips of lower seal toward you? I have replaced quite a few of these myself and both upper seal and lower seal are always installed (meaning before I remove them, you can tell it was this way from the factory) with lips facing top of drive unit. In your video, I can see who ever did install the upper seal did put it in upside down, but I can't tell how the lower seal was installed. I dug out my service manual and it says "Apply Loctite 27131 or Type “A” to outside diameter of drive shaft housing lower oil seal and install oil seal with lips facing up (toward top of housing)" Have you found this to be a problem? Thanks

[@toddxhadandl8083]

Was the housing turned upside down? Isn't how you would install the seal? Flip housing and install? Then the seal would be facing up.

[@stevecorona1720]

Is this a gen.1are2??

[@DCWPFLHTP]

Can you tell me how many shims there are and in what size-order they were installed??? Thanks.

[@kubaSWAT]

3:41 how to change oil seal in this unit?? thanks

[@moneymikeslickwill8749]

Where can i get that retainer wrench??

[@jd-wn8xo]

How much would this cost to do

[@captianeddie4554]

why would you not replace the input shaft seal?

[@kdknitro]

its alot of work, you have to redo the preload on the bearing pack.

[@thebenny6785]

You are only doing 90% of the job...why are you not changing the shaft itself? It's not a big deal as long as you have a inch pound torque wrench. Doing this half way is a HUGE waste of time

[@willytv275]

Are you talking about the yoke piece on the drive gear assembly or what? I know on the GEN 2 models you use the inch-pound torque wrench when setting preload. However, on GEN 1 units you just torque the assembly to 80 ft-lbs and you’re set. Please reply because I don’t understand what you mean.

[@mrmichael112002]

This video skips so many steps

[@OneJustGuy]

This video is quite disappointing to me. I’ve rebuilt hundreds of these drives and in this video, he’s focussing on things that don’t matter and completely forgot to change the number one reason for oil leaking out of these drives; the large seal behind the U joints (CV joint) is what most often leaks. Replacing that seal is quite often all that needs to be done as well as changing the washer seal behind the vent screw. I’m not saying replacing the other seals isn’t a good idea, but in most cases it’s quite unnecessary. In addition, some upper drives have a one to one ratio and then those drives it is very important to mark the gears to ensure identical engagement on assembly.

[@HudsoniteJessie]

So much wrong with this video. You only did half the job - I'm not sure why you would neglect to replace any of the driveshaft seals. That lower seal is 100% installed upside down, as per the OEM service manual. The retainer nut should have sealant on it and be torqued to 200ft-lbs. The top cover should have sealant on it, not grease. The top cover bolts need sealant, not anti-seize, and are torqued to 20ftlbs with a torque wrench rather and impact gun and chrome socket.

[@mabhmoob5136]

Terrible with no voice explanation

[@dhrarend-janvanbulzen8468]

Bad work do not like this