Upper Gear Case leak

[wmschenck]

Aloha,
My 1987 Chaparral XLC 200 with Alpha One outdrive is leaking oil at the bottom of the shift shaft in the upper gear housing. I suspect it is coming out of the drive shaft input area at the top of the gear housing and running down the shift shaft. I have not pulled the outdrive off yet. I'm a competent mechanic that just got finished replacing the shift cable and boot from the lower unit to the shift plate and also replaced the shift shaft bushings, plus I rebuilt the 5.7 liter engine. I was wondering if there is an outter seal that I can replace with out tearing the guts of the upper outdrive apart. I imagine if I have to pull to much apart, going back together will involve some serious tools and calibration to retain gear mesh, etc. Thanks in advance for the great advice.

 

[Bt Doctur]

Re: Upper Gear Case leak

when you had it apart , did you remember to replace the quad seal, a flat looking O ring between the halves

 

[wmschenck]

Re: Upper Gear Case leak

I didn't have the upper and lower halves apart. I had the outdrive (complete assembly) removed to replace the engine. The leak can be seen where the upper shift shaft in the upper houseing and the shift shaft on the lower housing match up together. (Remember this is the area that is affected if you don't have the remote in forward gear). Anyway, I suspect it is leaking from the area where the universals and input shaft come out of the housing. Is there a seal in this area that is simple to replace or does it require tearing the entire case and drive line apart?

 

[Bt Doctur]

Re: Upper Gear Case leak

If the gearset does not use "rolling torque" its fairly easy to replace the carrier seal in the upper.
#20 in this link http://www.marinepartsexpress.com/M...7_0D469858/DRIVESHAFT HOUSING-DRIVE GEARS.pdf

 

[wmschenck]

Re: Upper Gear Case leak

How do I know if my gearset uses rolling torque? Thanks.

 

[Bt Doctur]

Re: Upper Gear Case leak

during disassembly, if the gear and bearings just pull off the yoke it uses a inner spacer to set the preload.Remove/replace the seal , reassemble . If the gear must be pulled off ,you do not have the inner spacer and tightening the nut sets the torque. The procedure is outlined in the manual.
3A-19 here http://www.boatfix.com/merc/Servmanl/6/6covr3.pdf

 

[ziggy]

Re: Upper Gear Case leak

have ya pressure tested the drive?
to me, that seems like the next step. your speculating on where the leak is. pressure test and use some soapy water to help see if you can locate the leak, then decide on what is necessary to repair it.

 

[Don S]

Re: Upper Gear Case leak

With any outdrive leak, the first thing you do is drain all the oil, then do a pressure check. Many times it's necessary to split the upper and lower and check each half separately to isolate the leak.

 

[wmschenck]

Re: Upper Gear Case leak

Thanks for the help guys. Yesterday I noticed a new leak coming from the front of the prop. I will plan to drain the outdrive, remove, seperate, and do the leak checks to confirm where they are coming from. Doc, thanks for the link. It only showed the introduction. Where can I get the rest of the manual? I'm interested to see how the rest of the story goes. I'm a retired aircraft mechanic with plenty of tools, but I don't have any of the specialty tools required to work on these outdrives. So the next question for me is do I pay a boat mechanic to do what I can try to do, or do I try this myself. Fortunately, I'm smart enough to know what my limits are! Ha ha.

 

[ziggy]

Re: Upper Gear Case leak

Where can I get the rest of the manual?

this one works for me.. http://www.boatfix.com/merc/Servmanl/srvcovr.pdf ya want #6. scroll to the second page where it says in big letters, sterndrives, r,mr, alpha1, alpha1ss. the curser will turn to a hand. click again to see the contents, click on the contents, a, b c.... etc.

i'm not even an aircraft mech. and i try to fix my own. i've bought a few tools, i've rented some, i've become friends with my local mercruiser techs at the local dealer. they've let me borrow a tool or two that are oem tools. what i can't do. like press brgs. off i've let the local dealer do. i've taken the parts to them in a ready to disassemble state. so far they work with me. i 'think' i have a good relationship with them. and the side benefits are clear.... i also buy many of my parts from them. that helps too i'd think. so imho. read the book alot, ask questions here, and tackle the job. folks here just wanna help out. i know they've helped me a ton... i'm likely a better mechanic for them helping me too. for that i thank them a lot too... they know who they are...

 

[Bt Doctur]

Re: Upper Gear Case leak

The link works, click on the red outlined box. that other link works the same way, you need to click on the center box to open the index

 

[wmschenck]

Re: Upper Gear Case leak

I guess I'm more of a mechanic than an Adobe reader user! Ha ha. Thanks so much Ziggy and Doc! It is AMAZING what you can do when you have the "job guides" in front of you! The Air Force has a job guide for EVERY job imaginable on the aircrafts. You certainly don't want to rely on the mechanics memory on how to install a jet engine!