Tips/tricks for re-installing a 348 clutch housing?

Any suggestions on putting the pumpkin back on? I have the thrust bearing fully retracted (held in place by a closed bleed port) and I never opened the clutch pack (no grease inside the bell housing plus alignment verified using a Hill tool).

The housing goes onto the shaft nicely but it will not slide on enough to engage the splines. I tried wiggling and lightly malleting to no avail.

Searching here leads me to this:

But I'm not even getting contact with the splines in order for them to mesh.

So, what am I missing?

 

Where I'm at now. The last photo is taken from underneath.
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turn, push, turn, push, turn, push, turn, push. Repeat as necessary. Aligning two sets of differing splines requires patience.

 

And... try and remove... try again and remove... and again...

Fortunately, I have nothing else to do today.

 

The darn pumpkin is heavy. Not only do you have to push turn but wiggle too everything needs to go on just right. Often people are not parallel putting pumpkin centerline with the shafts. Then turning the ring gear as you slide it home gets the shafts to index. The whole thing will drop in place with a small 1/2" gap of bellhouse to gearbox. Then you can use the nuts to drive it the rest of the way home.

 

So far I'm not even making contact with the shaft's splines to the keyways on the clutch.

As I suspected, the o-ring is hampering my progress and I've nicked it in the process.
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The o-ring is item number 50 in the diagram (104984)

Ferrari 348 Parts : Table 24 - CLUTCH AND CONTROLS

 

Of course, due to age (shrinkage and compression) the original is thinner.
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new ring is toast, get another.

 

Found another reference:

But I still can't get past the o-ring, even with the old one back on (for now).

Guess I'm not cursing enough.

Going for another try tomorrow.

 

Lube it up and get tough with it

No fineness here, she likes it ruff in the rear

 

My Twin Clutch & Flywheel are off at the moment and I will be facing the same job soon so Wade's "alarm" is very timely for me. First, the o-ring - the new one I got from a Ferrari parts supplier is also 1.7 mm thick; is this the correct thickness?

I couldn't measure the old one as it was disintegrated and like bakelite. Wade, your old o-ring looks still quite good; due to compression, it should have slightly smaller thickness in the radial direction and maybe slightly bigger thickness measured in the plane of the o-ring. So, your measured 1.5 mm may actually be the correct thickness. Does anyone have info on what the thickness should be?

From what I can see, the splines of both clutch plates have inner diameter (between tips of the splines) same as the bearing inner race where the o-ring engages. This means that the clutch plate splines have to pass tightly over the o-ring (cutting in in the process). So, the o-ring thickness has to be correct (?), the o-ring should be Viton (tough, will better withstand rubbing by the splines) and I would slightly round and polish the sharp corners of the splines that "attack" the o-ring when installing (see pic). All well lubricated.
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It's an inexact science.

Patience is the key. Sometimes it goes on right away; other times it's an S.O.B.

 

Maybe try to slip it on without an o ring just to see if that is what is really holding you up or if you're just beating it up while getting hung up on something else. If you can get it to go with out the o ring at least you know you're chasing the right problem. Also every time you get it to go you start to get a better feel for how you need to turn, jiggle, push. Practice makes perfect.

 

The reason you can't get it all the way in is because of those finer splines on the end of the prop shaft aren't lining up with the splines at the very back of the flywheel. Once you get those lined up then you should be able to get it slid on over the larger clutch grooves. It will either go on or it won't there is no forcing it. Once everything lines up it will slide in easy.

Here is what I try when doing this. Using the Hill alignment tool, insert it, then ever so slightly rotate the clutches. I also try pulling the propeller shaft out enough to rotate it one tooth then slide it back in.

Don't give up, it will go back on. I have spent the better part of half an hour + trying to get the clutch back on, and I have also had it slide back on the first shot. Just keep at it and when everything is lied up just right, on it goes with minimal force.

 

+1

 

Wade, the cuts only on top of your o-ring suggest that your clutch was positioned a bit lower while trying to push it in. I plan to temporarily replace 3 of the housing studs with longer guide-studs to keep the clutch concentric when approaching the o-ring. To verify whether the o-ring is correct thickness, you can measure its OD when installed on the shaft. As the bearing inner race is 30 mm ID, the o-ring OD should not be more than about 30.3 - 30.5 (I am guessing here). Also, I wouldn't wiggle the clutch too much until I (hopefully) can feel that the clutch plate splines have started passing over the o-ring and have contacted the splines to engage. Then, rotating the rear wheels in 5th gear should get the splines aligned.

 

The pumpkin is heavy and I do this with bumper on obscuring more. In the past I used longer positioning/holding studs to help exactly as you say. I don't do that anymore because I have done a zillion of these. But in the beginning guide studs can be helpful. The older you are and the newer at this service you are the more a long guide stud helps.

OP...make sure your clutch alignment tool fits back in perfect or better yet loosen the clutch pack and move things reinsert tool and lock it down. Then try again. It is possible all the heavy handed tussle will will move the discs and things won't fit.

 

Just did some measurements: the o-ring groove (bottom) diameter is 27.15 mm meaning that a 27 mm ID o-ring should be used. When I placed my new o-ring on a cylindrical piece having diameter 27 mm, the o-ring OD was 30.3 mm so the 1.7 mm thickness is correct. However, the new o-ring I got is not Viton so I will not use it; will get a Viton of the same size.

 

I think the answer to your problem is here

348 DIY "Restoration" - Page 126

 

Hey that's a nice trick, I'll have to try that the next time I have my clutch off.

 

Been pounding for half the weekend...

Truly a SOB

I was thinking the same, tried without and no luck.

 

My guess is that I'm making contact with the flywheel (red arrow) but not getting lucky with have the stars aligned at the same time. Whenever I push and hold, while rotating the ring gear, I cannot feel any contact at all.

I liken it to cracking a combination lock e.g. no resistance equals no contact.

I did use the Hill tool as you suggested and the alignment was off a bit. Perfect now.
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Right now, potential issues with the o-ring and disc alignment have been ruled out.

Granted, the back end of the car is on jacks (angle taken into consideration), and the bumper is installed. The exhaust, however, has been removed earlier.

 

Thanks Jeff, I did follow your steps which led me to "retracting" the TO bearing, so plenty of clearance there.

But so far, I can't get the shaft into the flywheel.