Re-sealing a 1977 MCM 120 drive *More Pics added*

[rbthntr64]

Well,
The pressure check of my 1977 MCM 120 drive failed yesterday, so I am off to the world of finding the leak. I can get it up to 5 psi and that is it. Then it bleeds back to zero. I sprayed the upper/lower seam with soapy water and did not see a leak there. I did the same on the rear seal at the prop shaft nothing there either. I am going to separate it from the gimbal and check the seal at upper unit where the shaft goes in. Just as a precautionary measure, I would like to just replace most of the seals while I have it apart. I am going to order a seal kit. Is there a way to replace the shaft seals without a complete tear-down?
Thanks for the guidance on this guys!

Oh, and wondering if this is considered an Alpha, alpha 1, or ?

 

[achris]

Re: Re-sealing a 1977 MCM 120 drive *More Pics added*

That is an MC-1 drive.... Have a read of this and it lists the possible leak points... Some seals can be replaced very easily, others not so.

http://forums.iboats.com/showthread.php?t=548631&p=3765967&viewfull=1#post3765967

 

[rbthntr64]

Re: Re-sealing a 1977 MCM 120 drive *More Pics added*

OK. applied 15 psi with an airbrush compressor and found the only evidence of a leak was at the shift shaft. The little wafer seal seemed kind of puffy and very soft, and there was gear oil all around the shaft.

 

[achris]

Re: Re-sealing a 1977 MCM 120 drive *More Pics added*

OK. applied 15 psi with an airbrush compressor and found the only evidence of a leak was at the shift shaft. The little wafer seal seemed kind of puffy and very soft, and there was gear oil all around the shaft.

I guess you found the leak... I always replace the bushing and the seal as an assembly... easier and better. You have to pull the bushing out anyway, and replace the 'O' ring too.

Part # (bushing with seal) 23-30617A2
'O' ring 25-25439

Chris......

 

[rbthntr64]

Re: Re-sealing a 1977 MCM 120 drive *More Pics added*

Thanks Chris! Do you have a part number for the little wafer seal that sits under the washer on top of the bushing?, or better yet, can you point me where to find exploded views of the drive with part numbers? Can I get most of this stuff from iBoats? Would like to patronize the site that is helping me out

 

[achris]

Re: Re-sealing a 1977 MCM 120 drive *More Pics added*

I use www.mercruiserparts.com for some parts look-up, others use crowley marine, or baotinfo.

Chris.....

 

[rbthntr64]

Re: Re-sealing a 1977 MCM 120 drive *More Pics added*

Got everything ordered. Hope it gets here quick!