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Discussion Starter #1
Perhaps someone can help me with this. I just finished replacing my clutch on my 1968 Spider Junior. I also replaced the rear main seal (which was leaking pretty badly).

Everything seemed to go well, but after finishing and starting it up, I heard a strange hissing sort of rubbing noise when the engine was running. Everything seemed to be fine, but the hissing noise never went away even after the first run in the car to get everything hot. I came back and pulled the clutch inspection cover, and I see little bits of orange rear main seal when I look up between the back of the motor and the flywheel. The seal drove in straight (well, not exactly straight to start, but it did not go on crooked) and it seated neatly and looked good after I had finished. Also, no leakage after driving for 30 minutes.

Someone tell me that I am just seeing a new rear main seating itself after it is pressed in, and don't tell me that the seal did not go in properly and I have to go back and put in another one.

I await your thoughts with baited breath.
 

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Sigh. You put the oil slinger in wrong. Its a big steel washer-like thing that just fits around the crank. It should be under the rear seal on the engine side of the seal and held in place by it. You put it on the outside next to the flywheel. Unconstrained is spins like a top making that characteristic zinging sound of steel sliding on steel.

And it chews up the seal.

You gotta take it all apart again and start over. And you'll need a new slinger as the spinning wears the hole larger so it becomes ineffective.

Hopefully you've not driven the car much. Too long like this and you wear a groove in the end of the crankshaft. Then when assembled corrctly the groove is right where the oil seal rides and the seal surface is ruined. Then you get to reweld and regrind and polish the crankshaft.

I did this the first time I rebuilt my engine. I guessed the cause correctly so I didn't drive at all and saved the crankshaft.

Robert
 

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Discussion Starter #3
Hmmm. I don't think I took the slinger out when I took to old seal out. I just pulled the old seal, cleaned everything up, and drove the new seal in. I remember wondering what the washer-like thing was loose behind the seal, because I didn't see it in my manual, but I am sure I left it in and drove the seal in on top of if. There is nothing outside the seal except the flywheel, and you just see the edge of orange seal sticking out if you look up between the flywheel and the back of the motor. Also, the noise sounds more like rubber or plastic rubbing on the moving crank or flywheel, not steel.

However, your response has me nervous enough that I think I'm going to go back in a replace the seal again and stop running it.

After all, it's wintertime, and my house is full of women (wife, two young daughters, and one old female diabetic cat), so I need to stay busy in the garage.

Any more thoughts would be appreciated.
 

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Throw-out bearing?

You mentioned that you replaced the clutch. Did you replace the throw-out bearing too? Although I've never experienced it I've heard of new throw-out bearings (thrust bearings) being bad or noisy. This noise would usually go away though when you press the clutch pedal.
Just a thought but a bad throw-out bearing can sound similar to your noise description. (Hissing, Zinging, whining)
Good Luck!!
Bob
 

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Ho hum! I have never come across a "slinger" in all the Sprint, SZ, Lightweight engines that I have built, and in all the parts books for those cars I have, there is no mention of it. However after saying that I have just noticed in my GTA book on my desk that there is a reference to a ring, part no 105.00.01.188.00 which sits over the flange at the end of the crank and which clearly is what you're referring to. Are you suggesting that the seal was not fully home and there is north south movement of the ring on the crank axis as a result? If so will not the pushing home of the seal have the desired effect? OK if that is the case can one make up a right-angled tool which could push on the seal using the inside face of the flywheel as a fulcrum to properly trap the slinger. I do so want to save the roblem of removing th4e bearbox for "othercarsaford".
 

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Discussion Starter #7
Thanks for the responses.

Bob, I did replace the T/O bearing, but it seemed to be nice and smooth when I inspected the part. Also, it doesn't appear to be rubbing against the pressure plate and the noise does not change when I depress the clutch.

Stuart, there is a slinger behind my new seal, but I never took it out, and the seal seemed to drive home once it was on straight, and there is no more room to go in. Also, the amount of seal that "hangs out" past the wall of the rear of the block is identical in appearance (if not spec) to the old seal. Is it possible for the slinger to become misaligned back in there after the old seal was removed? Is it possible to "over-drive" the seal into its boss? I can't imagine how in either case, but I am no seasoned expert.

I am already to the point of removing the gearbox again, so I'll probably just finish taking it apart and replace the seal again (this time, much more carefully). I'll let you know if I can figure it out.

In the meantime, keep the thoughts coming.

Thanks.

Thomas
 

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Discussion Starter #8
OK, here is what I think may be happening...the slinger is somehow stuck in its race.

I took everything off today, took the new rear main seal out, and the slinger won't move or come out. I think I remember from the first time that the slinger was loose once I got the old seal out, but I may be wrong. This time, the slinger won't budge. Is my recollection wrong, and the slinger is supposed to be fixed in there? If it should be loose, does anyone have any suggestions for getting the slinger out without taking the rear main bearing cap off? I think I want to replace it.

Thanks again.

Thomas
 

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Discussion Starter #9
It's out now. It is slightly bent, so I bet it is getting hung up on the crank and spinning with the crank and chewing up the seal. Anyone know where I can get a replacement rear slinger?

Thanks
 

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Discussion Starter #10
I found one in my bottomless Alfa junk pile.:rolleyes:

It has a slight scratch in it that I can buff out with some steel wool, but it is true and straight. Anyone see any reason why I shouln't use it?

Man, all I have to do is ask, and I can answer myself. Hey...I am having a Bulletin Board conversation with myself...and I am even answering myself...

Time to call the guys in the white coats with the padded cell.
 

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But I (for one) really appreciate the information contained in your conversation. I don't get into these engines often (my first Alfa rebuild is my wife's '92 164S V6 12V under way in the garage), and it's nice to see some questions answered before I run headlong into them myself.

Michael
 

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Discussion Starter #12
I put the replacement slinger in and drove the new rear main seal in this morning. It was difficult to drive it in perfectly straight, and I have done a good bit of tapping to get it to seat (I do not have a factory driver, but the one I have gits the job done). The seal never canted more than maybe a millimeter or so on either side until it seated. I don't think it deformed or bent, and it looks fine in its seat. However, given the firmness with which I had to drive it to get it in, I am concerned that I may have been too firm in my application.

Is it likely that you will deform the seal by having to firmly drive the seal home, or is heavy-handedness forgiven when it comes to driving in rear main seals? Is there any way to tell short of putting everything back together and starting it up?

One thing's for sure, I am not concerned about crankcase pressure spitting the rear main seal out if my crankcase breather ever clogs!

Thanks.
 

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Hi Thomas,

I am considering replacing my rear maun seal and I came across this thread. How did it all work out? What should I look out for and what kind of time commitment should I allow to pull the gearbox and replace the seal?

Thanks
 

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Discussion Starter #14 (Edited)
Hi Bob,

I was afraid someone would ask! No, thanks for the follow up.

I finally wound up pulling the motor and doing everything with the engine and gearbox out of the car. I could not stop the hissing noise, and I could never get anyone to get me comfortable that that noise was not going to destroy my crankshaft. Also, I realized how bad all my pan gaskets and other seals (like tach drive and front main) were leaking and how old my motor mounts looked, so I did everything at once, cleaned up my motor/gearbox in my garage and detailed my engine bay.

To replace the seal, I decided to loosen the rear main cap and re-tighten it with the new seal in place (the alternative on this Board to driving a new one home with everything together). Also, since I was afraid that the hissing noise was my rear "slinger", and because the collective wisdom on this Board was that I did not need a rear slinger on a 105 given new seal technology, I replaced the rear main seal without the slinger, but with little tabs bent down on the oil return plate on the back of the motor and with big washers holding the seal in place on the bottom (see picture attached).

After doing all this, the seal did not look any different in its race, so I decided to put it all back together and run it in, assuming that if I still got the hiss, this time I KNEW that it wasn't metal-to-metal contact on the crank. After all was together, I started it, and I got the same hiss. However, this time, I patiently drove the car in ever-increasing increments of time and speed, and the noise (and a faint, acrid, burning-rubber smell) went away after about 200 miles.

No problems since.

Lesson #1: The hissing sound you hear when you first crank it up after putting a new seal in is likely the new seal running itself in. If that sound doesn't go away after a few hundred miles, or you see oil puking out of the back of your motor, then something may be wrong. If the noise is more than a hiss, then something may be wrong, but if sounds like rubber rubbing on metal, then it is likely rubber rubbing on metal (i.e., SLOW DOWN AND DON'T JUMP TO CONCLUSIONS).

Lesson #2: The slinger had nothing to do with the hiss (see Lesson #1), and I could have left it in.

Lesson #3: Not having the slinger in there has not affected the operation of my motor (including oil pressure). Not sure if my tabs/washers are the only thing keeping it in place or not.

Lesson #4: If I had to do it again, I would have gone down to Pep Boys and purchased a 2-Ton Crane for $128 (with rebate) and taken the motor and gearbox out first rather than attempting the repairs with the motor in the car. Also, this allows you to do a bunch of other repairs that you will put off if you don't. Also, everything (like clutch and pilot bushing, etc.) is much easier and fun to do with the motor out, and you'll feel like a pro! Further, that crane is just fun to play with.

Lesson #5: Try to get all Alfa repairs done within one month of starting, as your marriage will be at risk after that.

Lesson #6: Allow a couple or three weekends of part-time work, or more if you want to do other things while you're in there.

Good luck.

Thomas
 

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Man, all I have to do is ask, and I can answer myself. Hey...I am having a Bulletin Board conversation with myself...and I am even answering myself...
I can never seem to get an inteligent answer when I am having a Bulletin Board conversation with myself :D

I juat got done replacing my rear main seal on a freshly rebuilt engine. I feel your pain. :(
 

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Discussion Starter #18
This is actually a picture of a different car that was sent to me by another Alfa expert. Mines look like that, except, not as pretty.:D
 

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Rear seal

Did you lube the seal when you put it in? as If I heard that it was makeing a noise and had bits of seal and burning, you still have a problem, you just don't know about it yet! you do not run seals in, they fit, or they don't, and if bits are burning off, then its does'nt fit end of story!

Roger
 

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Discussion Starter #20
I did not lube the seal, but since the rear main was loose, it fit without lube. Perhaps you are right, but I set 4 different seals, and they all did the same thing. Also, it has now been almost six months since the car got back on the road, and I have had no leaks or loss of pressure. We will see.
 
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