Now I know why 904 was having issues

[70aarcuda]

[ame="https://www.youtube.com/watch?feature=player_embedded&v=NxOQJ4mvz7Y"]LipWizard Installation Tool - YouTube[/ame]

 

[TrailBeast]

The inner seal is hanging up in the groove for the spring retainer ring (a sharp unbeveled edge) and there was a tool for that.
Ours were stainless steel and made exactly for that type of installation.

This picture shows the idea of what you need to do, but this is a piece of transparency film from an overhead projector.
Put it in the hole where the seal is and press both over the hub together, then pull the plastic out.

 

[Creedmoor]

The inner seal is hanging up in the groove for the spring retainer ring (a sharp unbeveled edge) and there was a tool for that.

Not understanding this part. The inner seal is already in place in its groove BELOW the groove for the retainer. The chamfer on the inner bore of the piston hits that seal and stops. I can practically stand on the piston and it won't go. Do I have this seal on backwards? Should the lip be facing up INTO the chamfer on the piston?

Gave up yesterday. I even took the big outer seal off and the piston still just hits a hard stop at the inner seal.

Apparently the lip wizard is not for sale but included in "select" kits.

 

[Woods74]

Does the piston go in with the inner seal removed? Some kits include an optional 'meatier' inner seal for that direct drum that is an 'upgrade' to the original. So this might have something to do with that... But then again, if it's only the 'umbrella' portion hanging out past the edge and not the flat part of the seal you should be good to go..

Can we get a picture of the inner seal as she is now?

 

[Creedmoor]

Piston and outer seal goes in with no trouble if that inner seal is removed. The new seal and old appear identical. The kit did come with a slightly smaller diameter version of this seal. In the pic you can see a faint line of lube on the seal itself. That, is where the chamfer/bore are making contact. With both seals in place, you can feel the piston rock on the inner seal.

ETA: Here's a pic of the old inner seal and the smaller of the two new ones. Hard to tell from the pic but the ID's are a quarter inch different. Given the size difference, I'm pretty sure I used the right one.

The open end of the "umbrella" should face towards the bottom of the cylinder right??

 

[AJ/FormS]

Yes the umbrella points away from you and down into the drum. It only properly fits one way, as the drum is step-machined.The inner, smaller seal should not be a problem.It sounds to me like it is not properly seated or it is the wrong type. The hub is step machined to match the shape of the seal. Sometimes I have needed to to take a jewelers screwdriver and place it inside the installed seal and circle the hub with it to seat that inner edge.
If the seal is correct, and it is correctly seated, the piston, without the outer seal, should just drop down over it with mild thumb pressure.

 

[Creedmoor]

AJ, that has to be it. It just must not be seated all the way in there. Is it possible it stretched too much on install? I was pretty careful. I'll work on making sure it's in there and see what happens.

On a positive note, the rear clutch pack went together with no fuss whatsoever on the first attempt. I'm gonna hoist a frosty bottle to the Mopar gods, sprinkle some tranny fluid in a circle around the workbench and arrange all my sockets in occultic Pentastars, and give it another go.

 

[AJ/FormS]

No, you'd have to go nuts to overstretch them. I use that jewlers screwdriver to spiral them in there. If the seal is seated, the lip will fit into it's step with light finger pressure and be flush with the hub surface.

 

[Creedmoor]

Found the problem!!

I feel better...sort of. Just because that damn inner seal was in there as good as it possibly could be, and no way was it going to get better, I did an experiment. I cleaned up my old drum, popped the new seal on there and could tell immeadiatly, it fit like it should. Piston went in first try no issue at all. My shiny new drum is apparently the WRONG part!!! At least I'm not the incompetent boob I thought I was becoming.

It's really hard to see the difference in the cut for that seal it's so far down in there. But you can sure "feel" the difference. Every other dimension on this drum is the same - except that seal groove. What the hell??. There is no other seal in the kit that is remotely gonna work either (did they ever use o-rings here?). Just for the heck of it, I tried the smaller diameter seal. Same result as the proper seal.

Bought the new drum from WIT. Mine was one of two in stock. Wonder what's in the '68 904 sitting under the carport.

Thoughts??

 

[TrailBeast]

Do I remember that some drums used a flat O ring type seal instead of a lip seal, and could this be the case here?
Is there a rubber ring that fits that groove in your kit?

A lip seal groove has these shoulders for the lip to fold down into, and a flat rubber ring seal groove does not.

PS. Sorry for mixing transmissions up in my head again on that last post.

 

[Woods74]

Found the problem!!

I feel better...sort of. Just because that damn inner seal was in there as good as it possibly could be, and no way was it going to get better, I did an experiment. I cleaned up my old drum, popped the new seal on there and could tell immeadiatly, it fit like it should. Piston went in first try no issue at all. My shiny new drum is apparently the WRONG part!!! At least I'm not the incompetent boob I thought I was becoming.

It's really hard to see the difference in the cut for that seal it's so far down in there. But you can sure "feel" the difference. Every other dimension on this drum is the same - except that seal groove. What the hell??. There is no other seal in the kit that is remotely gonna work either (did they ever use o-rings here?). Just for the heck of it, I tried the smaller diameter seal. Same result as the proper seal.

Bought the new drum from WIT. Mine was one of two in stock. Wonder what's in the '68 904 sitting under the carport.

Thoughts??

I'd compare the drum to the old one, make sure it's the same height, sealing ring lands, bushing location, fluid ports.

I believe there are 3 styles the pre 75, the 75-77 and the 78 on.

It's difficult to keep track of what is what. I would mic the piston shaft and order one that matches with the one you have; IF everything checks out.

 

[Creedmoor]

So, I'm in over my head...

 

[AJ/FormS]

Naw. just behind schedule.
Check TBs drawing. That's what I meant when I mentioned "step-machined"