SAME Mercury 85 oil leak in the bell housing

[mark in portugal]

This is a 1985 SAME (now SDF) 85HP Mercury 85.
I had a lot of of leaking from the starter motor (???!!), it was from the bell housing, flying around in there.

I assumed it had to be the rear main engine seal, but it turns out to be gear oil leaking through an end cap.
There's an Oring in there, it might be a special profile or maybe the old one is just deformed over time. Anyway, I ordered the part by number from the catalog, so I'll see what comes.
The seal is compressed along the face of the cover plate, but there's no provision for clamping it down, it's held in by a big circlip. It seems sort of optimistic to me.

Note; to remove the bell housing, the throwout bearings come off first. There are 4 springs behind them that have to be unhooked; easy enough, but getting them back on again is going to be great fun (not).

The FEL / ROPS frame is half resting on the dolly below. The engine is supported by the overhead hoist.

Rear main engine seal, looks good but I'll change it anyway.

I did a little test; this just took a minute and confirmed the source of the oil.

The throwout bearing assembly; I pressed it apart to change the bearings. That required a couple of jigs to be made. I'll try to get a picture.

After cleanup; the pink colored cap below the main shaft is where the leak is from. It's a cast iron disk.
I made the adjustable jackstand earlier.

 

[ptsg]

Fun times ahead Mark!

I agree with changing the rear main seal while you're at it. Kinda reminds me how I lost the brand new transmission input shaft seal on my Agria and decided to go with the old one. Guess what leaked once I started the engine?

Have you checked if there is any seal between the transmission input shaft and the PTO input shaft? Might be a good time to investigate that as well.

If you need any parts, there is this tractor parts shop in Aveiro, called Casa Rola. They can get pretty much anything for just about any tractor. I'm sure they can ship parts to you as needed.

 

[mark in portugal]

Thanks, Pedro;
I looked at the parts diagram, there is no seal or oring to be seen on the outer or inner gearbox shafts. What keeps the oil from coming though is a mystery to me, but the oil level is below the shaft so I guess magic is sufficient.
I lightly pressurized the gearbox with air to check.

I asked my local shop to get the seal for me. I found it at various online shops, online it costs about 50 cents + 30 euros postage. I intend to machine a grove and add a second Oring; when I post pictures, you'll understand.

I asked him to get the throwout bearing also, just so there would be some decent markup in the deal.
I found that the throwout bearing is used on other tractors and trucks, so I could probably order it at auto parts store too. Auto-doc has it.

There is also a bearing for the PTO clutch, which is a huge standard bearing (75x130x24) because of geometry, and cost 85 euros new; I'm going to clean and repack the old one. It hardly gets spun at all, and even then the pressure against it is negligible.

 

[ptsg]

Thanks, Pedro;
I looked at the parts diagram, there is no seal or oring to be seen on the outer or inner gearbox shafts. What keeps the oil from coming though is a mystery to me, but the oil level is below the shaft so I guess magic is sufficient.
I lightly pressurized the gearbox with air to check.

I asked my local shop to get the seal for me. I found it at various online shops, online it costs about 50 cents + 30 euros postage. I intend to machine a grove and add a second Oring; when I post pictures, you'll understand.

I asked him to get the throwout bearing also, just so there would be some decent markup in the deal.
I found that the throwout bearing is used on other tractors and trucks, so I could probably order it at auto parts store too. Auto-doc has it.

There is also a bearing for the PTO clutch, which is a huge standard bearing (75x130x24) because of geometry, and cost 85 euros new; I'm going to clean and repack the old one. It hardly gets spun at all, and even then the pressure against it is negligible.

I'm sure you'll have a solid solution to figure this one out.

I feel you on the throwout bearing. I can't tell you how many days I spent just researching release bearings, just about eveywhere. The one for the Agria was completely trashed and I didn't want to buy the entire assembly for 120€ when I knew I could get just the bearing for 20€. The big issue is that hardly anyone publishes the dimensions of the bearing.

Somehow I ended up on a Chinese bearing supplier that had a big catalog, so I figured what I needed and finally ended up buying one online from a store up north.

I bought all the seals from this place, even though it takes a bit for them to ship stuff. They list a lot of bearings, some with dimensions. If you want to check it out: Pesquisa: 82 resultados encontrados para "rolamento* embraiagem*"

 

[mark in portugal]

Tractor shop says he'll have the main throwout bearing tomorrow; I didn't aske the price but he's usually reasonable and Auto-doc has them for around 40.
The big bearing for the PTO clutch is repacked and reassembled. I had to cut a pipe to press it apart, but it goes back together very easily.

Pressed it back with the "horizontal press"

Tractor guy thinks the seal must be a regular Oring that has become deformed over time; he's probably right. I should have just gone to the bearing + seal shop and bought a pile of possibilities to try.

The cap is 10mm thick, so I can cut a groove and set another Oring in there. That will make me feel better, but I also need to cut a threaded hole so I can pull the cap off again.

 

[mark in portugal]

After reading about how you had a leak at your transmission shaft, I looked through my parts diagram again and found there is a seal in there (listed on another page), probably in the neck tube.
I'll take it apart tomorrow.

 

[mark in portugal]

There are 2 gearbox shaft seals, one on top of the other, both the same size.
The parts book lists one of them as "special seal". A part number search brings up regular seals of that size. Anyway, I ordered 2 new (normal) ones.
There is also a seal between the inner (drive) and outer (PTO) shafts too, also listed as "special". That one is deep within, so I'm not going to go there unless it actually leaks.
And maybe not even then!

I took the triangular section Oring to the tractor shop; all agreed it looks like it was made in that shape, but that it could have been originally round.
I'd looked up the number and found that it's common to quite a few tractors. The old man of the shop said he'd never seen a triangle section Oring; and since he's the old guy and I'd found it was a common part, we all agreed therefore, there are no triangle section Orings.

I ordered 3 different thicknesses of regular round Oring to try.
It will be necessary to press the cover in with some force to compress the Oring before putting the circlip in, I'll need to rig up something for that.

 

[ptsg]

I don't think any of those shafts are actually under the oil level. Only if working on hills and the front is pointed downhill. Just guessing here. I'll say you'll be alright without messing with the seal between the two shafts.

For the rest, since those are more or less easy to change, might as well do it now and have the piece of mind.

I agree on the o-ring being round. It's most likely just deformed from being pressed all of these years.

That cap is indeed asking for an o-ring on the OD. Maybe a 2 mm section o-ring, so you don't have to cut an huge groove.

 

[mark in portugal]

Yes, I'm thinking 2 or 3mm; I'll see what the shop has in stock. I have to wait a day or two until he gets the seals.
Luckily, there is a bearing + seal shop within driving distance, about 30km north in Odemira. The larger towns to the south don't have one anymore unless I go all the way to Faro, 100km.
I don't know how the shop in a small town like Odemira has enough business to stock as much as they do; the guy is really enthusiastic, maybe he just likes it.

The upper rotating shafts are above the oil, but the lower one with the cap is not.

 

[mark in portugal]

I got the new throwout bearing and some seals, but I'm still waiting for the rear main engine seal.
When I unpacked the new bearing, I found the grease cover is smaller than the old one, so the spacer/ grease plate doesn't fit inside it.
That was Friday; if I return it I won't get a new one until Monday or tuesday, and it might be the same.
So I made a replacement spacer ring to solve the problem. I used a lump of flame cut plate so it took a couple of hours.
Satisfying though.

old throwout bearing;

old + new bearings and rings.

new spacer / grease ring pressed onto bearing collar

Throwout bearing assembly;

Cut a mounting groove into the iron cover, made a pullout thread and an oring groove.