Gearbox Sprocket Oil Seal Replacement

[Guest]

I have engine oil leaking from the seal where the output shaft comes out of the transmission case (the one with the sprocket on it). Can I remove both of the old oil seals and replace them with new ones without have to split the crankcase. If I can, any tips on getting the old seals out would be handy. The bike is a 1977 GS550.

[Dink]

Where exactly is the oil coming from??
there is an o-ring in behind the spacer behind the sprocket, this is easily replaced.
The outer seal is a little harder, you do need to release a fair few of the case bolts, but it can be done.

Dink

[Suzuki_Don]

Thanks Dink. The 550 might be a bit different from the other models. I cant see where the "O" ring would fit. It does not show an "O" ring in the parts book. Just a seal that appears to be in 2 parts. The spacer does not seem to come away like it does on the 750, the parts book shows it as part of the mainshaft, but I will have another look. When the 2 clutch covers are off and the motor is running there is no oil leakage, but when the front sprocket is turning the oil dribbles (runs) down behind the sprocket. There is a large black seal where the mainshaft comes through the case. This is the one I thought I would have to replace. If you have a look on Alphasports.com you will see the difference between the 550 and 750.

Again thanks for your suggestions. I hope there is an "O" ring there somewhere. It will make it easier for me. It sure beats digging a seal out of the gearbox case.

[Suzuki_Don]

I have not had many responses to this question. Is there anyone out there that has had to replace the gearbox shaft oil seals (there are 2) on a GS550. Who could give me some idea how difficult it was, did they need to split the crankcases and any tips on accomplishing the task in a satisfactory manner. Apparently the GS550 is a bit different to the other GS's looking at the factory parts lists. The GS550 does not use an "O" ring on the shaft as the others do.

[bmt]

Did you end up replacing this seal? I noticed that my recently restored 82, 550M is also leaking at the drive shaft seal. The engine had sat for almost 10 years with no oil so I figure the seal finally gave out. The leak isn't bad but I would like to repair it.

my research found the same as you, that the seal is two parts, no o-ring so it does seem to be unique.

I'd like to find out how the replacement process went before I go down the path of removing the only 'slightly' leaking seal and creating a potentially much larger problem.

thanks for any advice.

[p_s]

My '85 has an oil seal and an o-ring. I replaced it without splitting the engine. I'd be a little surprised if you had to split the engine to do it. But your 550 is very different from mine.

[hampshirehog]

You should be able to prise that seal out with a dentist's pick and just slide a new one back in - maybe use a smear of sealant as a lube on the outside of the seal when doing so. Oh, and smear some grease on the inside of the seal.

Sometimes the shaft itself gets pitted and is the cause of the leak. Have a good look when it's exposed and if it is the case you'll have to split and rebuild. You won't necessarily have to get a new shaft as you can rub these down with some fine wet and dry to get a decent running surface again.

[SqDancerLynn1]

Make sure to chack the clutch push rod seal too.

[bmt]

I finally got around to replacing the sprocket shaft seals and thought I'd share my experiences. As has been previously noted the 550 has two seals on the drive shaft, an inner and and outer with an oil port between them. you can see that in the pic. oil port on the shaft and the drain in the lower crankcase.

getting a 30 year old drive sprocket off is a real pain, but I was able to get a 32mm axle socket from Autozone's tool loaner program. $20 I can spend on something else.



The outer seal was hard as a rock. the seal is basically a metal washer covered in rubber. kept drilling into the metal and pulling at it with a screw. be careful, drill too deep and you could damage the crankcase bearing.

The inner seal (left in the pic) popped right out. much thinner and more pliable. the outer seal is almost 1/4 inch think.



the old clutch push rod seal, left in below pic, came out easily and the new one went right back in. The new seal has beveled corners making is very easy to press in.

the inner drive shaft seal also went in very easily. it is pliable and thin with rounded corners.

the thick outer seal was almost impossible. it is over 2mm larger in diameter then the crankcase recess and is clearly designed to go in while the crankcase halves are separated. the seal has no pliability and is very thick with square corners over a metal core making is hard to press in.

as you can see in the photo the top of the seal began to peel back from the seal's metal core, and of course it leaks here when I ran the engine at idle.

I carved the bulge away and filled with RTV but am hardly confident that this will be any more reliable than the 30 year old seal I pulled out.





I considered removing the two vertical crankcase bolts to the left and right of the drive shaft but felt after 30 years of being sealed even without the bolts the halves wouldn't move enough to get the seal in safely. I was also worried I'd create a leak between the halves.

So there might be some creative way to get that outer seal in on a 550 without splitting the crankcase, but I'm out of ideas.

[Suzuki_Don]

Sorry that I have missed these posts seeing as I was the one to start it in the first place. I must have been away when the earlier replies came in.

I replaced the outer seal by removing the nut from the stud and the bolt adjacent to the seal housing (two in total). This released enough pressure to tap the seal in with silicon sealer on the outer circumference of the seal. This was done with a really large socket and then a piece of gal pipe cut to the appropriate size. A good large size hammer is used as the weight behind the striking of the pipe and socket means you do not have to hit it that hard. It went in without any great problems. Tighten up the 6mm bolt and the 6mm nut on the stud and job finished. All to do is replace sprocket, chain, etc.

And it didn't leak when the bike was started up after the work done.

If I was you I would redo the job. Won't take long this time as you know what to do and it's always quicker the second time round.

[Suzuki_Don]

BTW don't worry about the crankcases leaking by loosening or removing the bolts on either side of the seal housing as Suzuki used a non-hardening gasket sealant between the cases and this stuff has some give in it. I had no leaks when I put mine back together. The sealant used is called SuzukiBond No. 4 and is a non-hardening sealant.

It's only an afternoons work to remove the clutch cover, removed sprocket and chain. Loosen the nut on the stud to the left of the seal and remove the 6mm bolt to the right of the seal. Drill two 1/8" holes opposite each other in the outer seal, screw in two self tapping or Gyprock (drywall I think you call it) screws, clamp on a couple of vice grips and pull the seal out.

Silicon sealer on outer circumference of seal. Oil or grease the inner lips of the seal. Press seal in as described in my previous post and put it all back together. Make sure the surface that the seal runs on (inner shaft) is smooth, if not try and clean up surface with very fine wet and dry or Scotchbrite.

Best of luck.

P.S. A new seal is only about $12 so no great cost to doing the job over again.

[bmt]

Thanks Don for your help.

My new seal arrived from Bikebandit today and I followed your steps. I also warmed up the engine before I got started thinking that since the seal is an interference fit a little heat would help too.

I loosened those two vertical crankcase bolts, pulled the old seal, and was able to install the new seal without any tools. Just went right in with a bit of sealant on the outside.

Tightenend everything up and NO leaks!

[chef1366]

This is great!

[Suzuki_Don]

Congrats. I am glad it worked for you too.

Enjoy the ride.

Mine is still in pieces.