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4 Speed Main Drive Seal and Sprocket

Started by JW113, July 02, 2019, 04:52:23 PM

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JW113

Couple questions, I should know this but don't and the FM is of no help.

Main drive seal: FM says press it in flush with the case. However if I do that, which did, the outer lip is not quite on the flat surface of the spacer, and is riding through the groove where the spacer key sits. That can't be good, can it? In fact I'm in there right now trying to fix a trans leak right at that seal. Maybe press it in until it clears the spacer key groove?
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Next question, also not answered by the FM. The trans sprocket is dished. Which way does the dish go? Toward the trans, or toward the clutch? I've been putting it dish towards clutch, but I kinda remember somebody saying it goes towards trans. If it were important, would be nice if they would have said something in the FM.
[attach=1]

thanks,
JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Ohio HD

I would press the seal on until the lip clears any obstruction, grove, etc.

Sprocket, flat side out.


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JW113

Thanks Ohio! I thought I had heard that somewhere, here in fact but could not remember. And thanks for including the FM page. After looking at it, I took a look at my old 70-78 FM, and sure enough, there it was. I've gotten into a habit of looking at a 78-84 FM, which in general tends to be written a lot better than the earlier manuals, and no mention of this at all. It even has a section for the transmission sprocket! But they forgot the part about flat side outboard. But now I know, and now will remember. Flat side outboard!

thanks,
JW

[attach=0,msg1305048]
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Ohio HD

 :up:

I "thought" flat side, but I had to look. It's a long time since I worked on a 4 speed with chain drive.

JW113

Man I totally forgot how much I hate replacing the main drive gear seal. I pulled the old one out, went to push the new one in, and saw that the inner seal lip turned inside out on the gear spacer. And realized that the last time I replaced this seal, it did the same thing. Damn, getting old is a bitch.

I picked up a new seal, and this time wrapped the mainshaft with tap so there was not a harsh step where the seat lip passes over the gear spacer. All went sort of OK, but after the last tap on the seal to get it fully in, there was a small piece of the lip bent outward. The "right" think to do would be pull the seal and try again, but I had bought the last 4 speed drive gear seal in the entire south bay. So either internet order, or... I used a small screwdriver and managed to tuck the lip back into position. I have no idea if the spring on the other side came loose or not, or if I damaged the lip surface. And am sure I'm going to regret having to tear the primary off again to fix it, but what the hell, will roll the dice and see what happens.

So the right way to install the main drive gear seal is to put the gear spacer in it before putting it on the drive gear, and press them in together. The problem is, when you're using one of those gear spacers from sandbagrail with the inner O-ring, there is no way to do this. It's freakin damn near impossible to get the gear spacer on the shaft past sprocket splines, especially without damaging the O-ring. So you have to do the spacer, then seal afterwards.

Since I already know the seal is going to leak, will order a case of them but also get another drive gear spacer. I'm thinking if you put an extra drive gear spacer in the seal from the outside (i.e. facing the clutch), then slide it up against the other gear spacer in the trans, the seal should slide in without catching the lip and bending it outward.

So how do you guys do it? Any clever tricks that you'd like to share?

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Ohio HD

JW, I always slightly deburred the edges of the notch with a hand held mechanical deburr tool. You could even sand the edges a little to make them less sharp.

drifter

Hey JW
I'm no expert, but I watch Tatro Machine on Youtube probably more than I should!  In one of his 4 speed videos he says that the old instructions were to press the Main Drive Gear seal flush with the case, he says now it is recommended to press it in so it is inside the case (1/4" +/_, I forget now) so that the Main drive Gear doesn't move in or out.  He made a special tool with a lip to install them with his press.  If you have time, you can check him out for another opinion.  If you have lots of time, he has hundreds of hours of videos of him working on Harleys from the 1930's through twin cams but he prefers Panheads and earlier.  I enjoy his tutorials and I learn a lot, hopefully correct procedures.
Warren

Burnout

If you push the seal in too far, the inner lip will contact the flange on the spacer, and that may have unexpected/unpredictable results.
They don't call me Ironhead Rick just because I'm "hard headed"

billbuilds

      JW,
     Are you using the cork seal behind the double lip seal?  Apparently they were required for the old non-coated oem style seals but with the modern coated James I'm not sure that they are. Would leaving that out give you some extra room to move the double lip seal in?   Bill

JW113

Yes, am using the cork o-ring behind the seal. But that's not the problem. The problem is trying to get the seal onto the main drive gear spacer without hanging up the inner lip and turing the seal inside out. You have to do this essentially "blind", and once the lip gets hung up, it's too late. The suggetion to radius the spacer is worth a try, but you can't do much as that is what the trans sprocket sets against. I think my idea to use another spacer, push it into the seal, then press the seal into the trans should work, since the lip will then ride across the "helper" bushing and onto the one in the trans with no abrupt edge to hang up on. And maybe even put a piece of tape over the joint between the two spacers. I have it all back together, will take for a spin in a bit and see if I have to pull it back apart or not. At least I finally figured out how to get the inner primary off without pulling the battery and oil tank to get at those two starter mount nuts.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

billbuilds

      If the seal will not seat deep enugh in the case to allow the outer lip to fully contact the spacer then I'd say that it is a problem. I have an email from Ray from over three years ago and the perrsn he quotes in his iostructions says to install the spacer on the seal first then install the two together. You need to do the deburriing that others have mentioned and you'll need to tightly wrap the main drive gear threads with electric tape and then lube with tranny lube. 

Burnout

Get the seal barely started and then check to see if the seal is getting caught, using some kind of probe that won't cut the seal push the seal lip into proper position. Then finish pressing in the seal.

Be careful if the seal lip is rolled back too far the garter spring will pop off.
They don't call me Ironhead Rick just because I'm "hard headed"

JW113

Bill: have you ever tried to push on one of sandbagrail spacers with O-ring? If you think that trying to push it over the edge of the splines of the main shaft will just slip right over, think again. You damn near have to hammer it on. The rubber seal of the main driver gear will certainly not push it on.

Don't get me wrong. Sandbagrail's "cure" for transmission oil leak is spot on, and works. But installing it is a total PITA. And you can't press that gear spacer on with while installing the main driver gear seal.

Just sayin'!

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

billbuilds

      JW,
    No I haven't tried it yet. One thing that Ray stressed in his emaill to me was making sure that you have the o-ring properly seated in the groove on the inside of the spacer. Again, he quotes another forum member who explains how he installed his and then he goes on to offer some tips of his own. I thought it might be useful information for you and might offer you some insight into how to get it installed properly. If you'd like me to forward that email to you then send me a PM with your email address and I'll do just that. Bill

crock

July 06, 2019, 08:24:02 AM #14 Last Edit: July 06, 2019, 01:15:15 PM by crock
I think my idea to use another spacer, push it into the seal, then press the seal into the trans should work, since the lip will then ride across the "helper" bushing and onto the one in the trans with no abrupt edge to hang up on.

I believe your idea is spot on JW. If you still have trouble with the transition between the spacers try warping a piece of .005 shim stock around the spacer before sliding the seal on and leave it hanging off the end of the spacer a little
Crock

billbuilds

    JW,
    I forwarded the email that I got from Ray to you, hope it helps. Bill .

Mule

I am pretty sure you figured it out by now, that seal in the pic is installed backwards.

JW113

Why so? Pretty much every seal that I've installed has the large lip with spring towards the wet side. So in this case, pointed to the inside of the trans. That seal in the pic (James) is a dual lip, big lip on inside, smaller one on outside.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Mule

That James seal has one lip at the edge and one lip recessed from the face on the other side , Installed backwards the lip at the edge pushes out to the edge of the seal spacer, installed correctly the recessed lip is recessed from the face of the seal allowing the seal spacer to protrude a almost 1/8 of an inch.  I just installed one of those over engineered James seals yesterday.

billbuilds

 :idea:   Good observation Mule. Did you use a press to install the seal or tap it in using a drift of some sort?  Also, what if anything do you use to seal the outer edge of the seal to the case? Bill

Mule

The plastic coating on the steel outside edge is supposed to seal it to the case, I used a piece of ABS pipe and a brass drift. This seal is the only type I could find at any of the shops that sell parts, I tried to find a stock type but all the locals only stock these  James seals.

JW113

Hmm, so you're saying the side with the spring goes to the outside of the trans?

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Mule

All I am saying is yours is backwards in the pic, Obviously  the big lip recessed from the steel face is correct to the outside , Other wise the soft seal that protrudes will push out like yours. I didn't pry back the lip and look at the spring. If you are good with the way yours is installed that's all that needs said...

72fl

My friend that rebuilds 4's puts the seal in what I say is backward with that being said , the spring is on the outside and he never has a problem with them leaking. There is also a Super Nut by James he use's

crock

Quote from: JW113 on July 04, 2019, 09:13:26 AM
Man I totally forgot how much I hate replacing the main drive gear seal. I pulled the old one out, went to push the new one in, and saw that the inner seal lip turned inside out on the gear spacer. And realized that the last time I replaced this seal, it did the same thing. Damn, getting old is a bitch.

I picked up a new seal, and this time wrapped the mainshaft with tap so there was not a harsh step where the seat lip passes over the gear spacer. All went sort of OK, but after the last tap on the seal to get it fully in, there was a small piece of the lip bent outward. The "right" think to do would be pull the seal and try again, but I had bought the last 4 speed drive gear seal in the entire south bay. So either internet order, or... I used a small screwdriver and managed to tuck the lip back into position. I have no idea if the spring on the other side came loose or not, or if I damaged the lip surface. And am sure I'm going to regret having to tear the primary off again to fix it, but what the hell, will roll the dice and see what happens.

So the right way to install the main drive gear seal is to put the gear spacer in it before putting it on the drive gear, and press them in together. The problem is, when you're using one of those gear spacers from sandbagrail with the inner O-ring, there is no way to do this. It's freakin damn near impossible to get the gear spacer on the shaft past sprocket splines, especially without damaging the O-ring. So you have to do the spacer, then seal afterwards.

Since I already know the seal is going to leak, will order a case of them but also get another drive gear spacer. I'm thinking if you put an extra drive gear spacer in the seal from the outside (i.e. facing the clutch), then slide it up against the other gear spacer in the trans, the seal should slide in without catching the lip and bending it outward.

So how do you guys do it? Any clever tricks that you'd like to share?

-JW

Quote from: 72fl on August 06, 2019, 03:47:35 AM
My friend that rebuilds 4's puts the seal in what I say is backward with that being said , the spring is on the outside and he never has a problem with them leaking. There is also a Super Nut by James he use's

I would indeed have installed it as you did JW but if it were installed "backward" it would eliminate the problem you were having. Then the secondary "dust" seal would hold in the oil. But is that enough????   :scratch: :scratch:
Crock