Mercruiser 888 lower unit assembly

[wrench77]

Okay, I'll start from the beginning and try to paraphrase. Lost my prop, took out pinion, foreward and reverse gears. Got a deal on some used gears and replacing all bearings and seals in lower gearcase. Never set gearlash or preload on a lower unit before. I am a mechanic for a living. Got (some) know how. But not sure what tooling I should have or need to have. Looks like I need the backlash tool and the pinion gear shimming tool. Think I can do it without these tools. Or maybe take it to the boat shop and ask them to do it for me????? This is already exspensive enough let alone doing it wrong and trashing out another set of gears and bearings. Any advice/help is much appreciated. Thank you !!!!!!!!!!!!!

 

[mkast]

Re: Mercruiser 888 lower unit assembly

Have you looked at the maintenance manual?

 

[wrench77]

Re: Mercruiser 888 lower unit assembly

Yes, thouroughly, and of course they say to use all the tooling required. I was just hoping someone had a trick way of doing it without that stuff. I've found through the years there's quite often another way of doing things!

 

[ziggy]

Re: Mercruiser 888 lower unit assembly

i've never worked on the lower. but i've worked a little on the upper. shimmed my drive gear and driven gear. with the proper tool. as you know from being a mech. there are some jobs that plain and simple require you to use the proper tool. usually a oem specialty tool. best i've found, there is no other way than the proper way. anything else would leave question as to weather it's proper or not. if not. best i get it. ya might as well buy a new drive, cause there will be catastrophic events when the parts in question self destruct. even what little i did i think catastrophic failur would be eminent if it was done improper.
dollars and cents wise. unless you just want to have the tools, which i might. the cost effective way of doing it is to R&R the lower with a sei lower. all new, properly put together. when i did what little i did to my upper. i came real close to the cost of an upper from sei. parts and tools wise. only reason i came out under dollars of a new upper was because i was able to borrow the proper tools to do the shimming. without them. i'm quite sure i would have destroyed my drive by now. also. if you have internal failure of the gears from the lower. the upper must be totally serviced too as all the metal fragments will travel thoughout the drive and effect the upper too. probably not what ya wanted to hear. but i do believe dons' sig.

Why is there never enough time to do it right the first time,
But always enough time to do it again?

he's used that statement against me more than once. and more than once he was right... think about it.. i have...

 

[Bt Doctur]

Re: Mercruiser 888 lower unit assembly

If you have ever done rear diffs then you know what I mean when I say
Heel and Toe.I did my very first drive with out the tools.Reused the shims as a starting point,Dytek the teeth, assemble and spin.
Examine the pattern.Almost the same as a ring and pinion install.
Guess at the shim thickness, Dytek, install and spin.
Once the heel and toe in there, your done.
driveshaft with a preload pin: push shaft in while turning
driveshaft without pin: pull shaft up