1984 Mercruiser R/MR upper gear case

[jimn]

Good morning. I finally had a chance to remove the upper bearing carrier- it had worked fine when I took the boat out but leaked gear oil when I tilted it up after trailering it. The retainer ring wasn't really tight- I would have thought it should be tighter, but will check the specs in the manual before claiming it as 'too loose'. It's 41 years old and the pinhead who owned it before me re-defined overheat, so I'll wait until I see what is needed.

I plan to replace seals and O-ring, but as long as the bearings aren't visibly worn and the end-play is minimal, do I really need to replace them? The end nut and tension washer are mandatory, but at first glance, the assembly doesn't seem to be loose to the point that wear seems likely.

I know I need to set the pre-load, too but this is the first time I have dealt with an upper GC- any tips & tricks will be appreciated.

Thanks

 

[Bt Doctur]

if this is on the upper unit of a MC1 or Alpha 1 drive the carrier ring is 200 Ft/Lbs .
The torque you mention is "rolling torque" used only on the Alpha GEN II drive, a regular alpha is 80Ft/Lbs for the nut

 

[makomark]

the spanner nut goes on tight...so, based on the 'pinhead' mention, it wouldn't be a bad idea to check out what you have apart...

If the drive was set up properly, normally, you don't have to shim anything differently when changing the seals.

 

[kghost]

The torque spec with a 18 inch torque wrench and the merc spanner special tool is 123 lb/ft for the upper assembly (ujoints).

get a manual and follow it, take note of the shims and reuse exactly the way they were when taken apart.
Replace the carrier seal and oring and coat the oring and retaining nut only with mercs or other "perfect seal" goop and align bearing assemble to get back in (not always easy) and then tourque spanner nut to 123 lb/ft.

Note: nylar nut on drive shaft is a different spec so having the manual will tell you what is is and based on a spacer or no spacer tells you what and how to do it properly.

If you dont have a manual or the special spanner and a quality tourque wrench not sure what else fo say.

Any questions? Ask..

 

[jimn]

if this is on the upper unit of a MC1 or Alpha 1 drive the carrier ring is 200 Ft/Lbs .
The torque you mention is "rolling torque" used only on the Alpha GEN II drive, a regular alpha is 80Ft/Lbs for the nut

I had seen 80 ft-lb for the nut, 6-10 in-lb rolling torque on an Alpha 1, but it's the ring that I suspected as being too loose and didn't have the spec when I posted. I wouldn't assemble this without reading the manual, first.

 

[jimn]

The torque spec with a 18 inch torque wrench and the merc spanner special tool is 123 lb/ft for the upper assembly (ujoints).

get a manual and follow it, take note of the shims and reuse exactly the way they were when taken apart.
Replace the carrier seal and oring and coat the oring and retaining nut only with mercs or other "perfect seal" goop and align bearing assemble to get back in (not always easy) and then tourque spanner nut to 123 lb/ft.

Note: nylar nut on drive shaft is a different spec so having the manual will tell you what is is and based on a spacer or no spacer tells you what and how to do it properly.

If you dont have a manual or the special spanner and a quality tourque wrench not sure what else fo say.

Any questions? Ask..

Thanks- I had mentioned that I would check the manual, just wanted to remove the assembly to see how it looked before digging deeper. I used the spanner to remove the ring- as I said in our phone conversation last year, I worked for three Merc dealerships and have access to any tools that I don't already have- I bought the outdrive and engine manuals as soon as I got this boat. I have plenty of Perfect Seal, too- needed it for the lower and as soon as it arrived, I found the tubes that I already had.

I would never work on something like this and guess at the procedures or specs. Everything will be laid out in sequence, as it comes apart.

The video I watched showed the guy using a piston ring compressor to hold everything in alignment for reassembly.

Thanks for the specs.

 

[jimn]

the spanner nut goes on tight...so, based on the 'pinhead' mention, it wouldn't be a bad idea to check out what you have apart...

If the drive was set up properly, normally, you don't have to shim anything differently when changing the seals.

I don't know who worked on this before I bought it, but I saw that one of the four bolts holding the cap onto the upper was sticking out- when I removed it, I found that it had a bend of close to 30°- I'm going to guess that someone lost the handle of it and it hit something. I got a replacement when I was working at the last boat dealership.

All of the damage was caused by the impeller in the photo- the main bellows felt like Silicone rubber, but because I didn't find gear oil in/on it, I didn't suspect the seals or loose ring. The valve in Cyl #2 made it run a bit lumpy.

 

[kghost]

I had seen 80 ft-lb for the nut, 6-10 in-lb rolling torque on an Alpha 1, but it's the ring that I suspected as being too loose and didn't have the spec when I posted. I wouldn't assemble this without reading the manual, first.

With out knowing the history on the upper driveshaft bearing stack assembly you have to go by the parts instructions in the manual that describes the torque spec for small spacer or No small spacer. One requires 70 -80 Lb ft and the other is the rolling torque. See attached images Item H

 

[jimn]

I finally had time to check out the yoke assembly- the seal is definitely bad and neglect was the cause- I doubt this boat had much regular service and the spring in the seal had broken at some point, so water did get in, but I haven't seen damage from it, other than where the seal rides. The bearings have a bit more end play than I like, but the gears look fine. I'll have to get new shots of the seal and its carrier- the ones I have didn't load.

It's a good thing I'm not paying someone else to repair everything.......

 

[kghost]

When you replace the seal, wether just the seal or the seal and alum carrier its pressed into. Do a mock assembly taking note of where the seal lip rides and direction seal is installed. Then take apart and you can press the seal within the Alum carrier just far enough to get the seal lip to ride on fresh steel on the yoke.

This saves the need to replace the yoke and will give you quite a few years of normal sealing.

Also if you dont use spacer and have to do a rolling torque, make sure you clean threads and use RED loctite on nut/threads.

 

[jimn]

When you replace the seal, wether just the seal or the seal and alum carrier its pressed into. Do a mock assembly taking note of where the seal lip rides and direction seal is installed. Then take apart and you can press the seal within the Alum carrier just far enough to get the seal lip to ride on fresh steel on the yoke.

This saves the need to replace the yoke and will give you quite a few years of normal sealing.

Also if you dont use spacer and have to do a rolling torque, make sure you clean threads and use RED loctite on nut/threads.

I used the wire wheel on my grinder to clean up the shoulder on the yoke- the lack of sealing and what I assume is the delay between repairing a problem that had existed caused the yoke to rust, that killed the seal, yadda, yadda, yadda. As I had posted, the main bellows felt like Silicone rubber, because of the gear oil- there wasn't much on the rubber and it was also charred from the exhaust, so I didn't suspect an upper GC leak.

The videos about replacing the seal had mentioned pressing it in far enough to land on smooth metala, but I'm not sure that can happen with this one, unless I can find a seal that has the same OD, but slightly smaller ID- I know someone who has a machine shop and they could clean up the surface which, as the photo shows, has a slight groove.

I'm probably going to replace it since I can find them starting around $40. I'll replace the bearings, too- I don't want a catastrophic failure for myself or whoever has the boat after me.

For some reason, the site won't upload the photos of the seal and carrier ring- it didn't work yesterday, either. Mind of I try to send them to you?

 

[Dieter]

I used the wire wheel on my grinder to clean up the shoulder on the yoke- the lack of sealing and what I assume is the delay between repairing a problem that had existed caused the yoke to rust, that killed the seal, yadda, yadda, yadda. As I had posted, the main bellows felt like Silicone rubber, because of the gear oil- there wasn't much on the rubber and it was also charred from the exhaust, so I didn't suspect an upper GC leak.

The videos about replacing the seal had mentioned pressing it in far enough to land on smooth metala, but I'm not sure that can happen with this one, unless I can find a seal that has the same OD, but slightly smaller ID- I know someone who has a machine shop and they could clean up the surface which, as the photo shows, has a slight groove.

I'm probably going to replace it since I can find them starting around $40. I'll replace the bearings, too- I don't want a catastrophic failure for myself or whoever has the boat after me.

For some reason, the site won't upload the photos of the seal and carrier ring- it didn't work yesterday, either. Mind of I try to send them to you?

Normally folks either put a speedi sleeve over it to make a fresh surface, replace the yoke, or position it deeper in the housing as mentioned

 

[jimn]

Normally folks either put a speedi sleeve over it to make a fresh surface, replace the yoke, or position it deeper in the housing as mentioned

Never knew about the Spedy Sleeve because I haven't needed to rebuild an upper but thanks for mentioning it.

 

[Dieter]

Never knew about the Spedy Sleeve because I haven't needed to rebuild an upper but thanks for mentioning it.

commonly available for just this purpose. you have to measure them by shaft size. may not work best here if a yoke is $40. yours must have been wet for a while I would replace the ujoints while you are in there. Moog 315G or equivalent should fit the ones with inside retaining rings. When I used them on my gen 1 years back they were like $15 vs what the "marine" ones are listed as.

I just replaced the perma lube ones on my current boat - it had about 300 hrs on it and had never had water in the bellows = they looked way worse than the much older greaseable ones on my gen one. So much for lubed for life.... also the GKN number on these ones (outside retaining rings) crossed over to RWD Volvos - same ujoint used on every 240/740/940 for like 20 years. Dispelled the myth of marine parts in outside of fuel and electrical components.

 

[jimn]

commonly available for just this purpose. you have to measure them by shaft size. may not work best here if a yoke is $40. yours must have been wet for a while I would replace the ujoints while you are in there. Moog 315G or equivalent should fit the ones with inside retaining rings. When I used them on my gen 1 years back they were like $15 vs what the "marine" ones are listed as.

I just replaced the perma lube ones on my current boat - it had about 300 hrs on it and had never had water in the bellows = they looked way worse than the much older greaseable ones on my gen one. So much for lubed for life.... also the GKN number on these ones (outside retaining rings) crossed over to RWD Volvos - same ujoint used on every 240/740/940 for like 20 years. Dispelled the myth of marine parts in outside of fuel and electrical components.

I replaced the U-joints after I removed the outdrive to do other repairs, but didn't remove the shaft and yoke because oil covered any corrosion that may have been there. Those are fine, the old ones barely wanted to move after sitting over the Winter. The shaft has always turned the rest of the drive easily and the gears look great- no pitting, gouging, corrosion, etc and it seems that the O-ring did its job.

WRT 'lubed for life', I had a '92 Buick LeSabre and when I heard the front wheel bearing whining, I called a friend who had worked at GM's Desert Proving Ground ot get some info. I told him that I didn't see any grease fittings and he said they're permanently-sealed. I asked why they fail if that's true and he said "That's the beauty of the design". Har, har. What a funny guy.

 

[jimn]

When you replace the seal, wether just the seal or the seal and alum carrier its pressed into. Do a mock assembly taking note of where the seal lip rides and direction seal is installed. Then take apart and you can press the seal within the Alum carrier just far enough to get the seal lip to ride on fresh steel on the yoke.

This saves the need to replace the yoke and will give you quite a few years of normal sealing.

Also if you dont use spacer and have to do a rolling torque, make sure you clean threads and use RED loctite on nut/threads.

Purely as a test, I chucked the yoke in my drill press and used Emery cloth to remove the rust and it cleaned up pretty well. I had used my vernier caliper to measure the diameter where the seal rides and it came in at 2.250". If a replacement was absolutely impossible to find, I would consider having this turned down to clean metal and using a seal that's sized appropriately- we have a place called Bearings, Inc that sells all kinds of these parts for any application and I had asked about this possibility. I'll measure it, but I don't think the groove is >.005". Machining it would restore the surface to original, rather than polished and unable to seal properly but again, it was only a test.

Still, a $50-$75 yoke and new seal won't be terribly expensive and it will be standard dimensions.