Replacement selector rod seal for (A5S390R)

Chamberlin · #1 10-01-2018, 08:09 PM

Quote:

Originally Posted by whizzkid23

Are you having issues getting the seal over the shaft or in the bore?
The fitting over the shaft should be quite easy - it's a sealing lip that is flexible.
The fitting in the bore is actually rather tight and the seal is quite difficult to get in - but I never would suggest to grease the fitting of any seal in it's fitting bore.
The seal needs to stick in it's position with a dry, non lubricated fit. You could eventually try to use a little bit of fuel applied to the outer diameter of the seal, as some fuel will make it slippery at the start and then evaporate, leaving the seal with no lubrication once fitted. But you would have to be quite quick in applying the seal before the fuel actually evaporates. Having done this operation a few months ago, I don't think that is possible. But you could give it a try.

Long story short. I used a socket with the right diameter to push (hammering is not a option, it destroys the seal) the seal in place. Used a lever against the drive shaft to get enough force to push it in -> so the drive shaft in place comes in actually quite handy for the fitting process.

Good luck!

Good info regarding no lube, but I can't see how this is going to go on without something, even some trans fluid maybe. And my drive-shaft is removed BTW so the lever action you described wouldn't be possible unless I re-install first. But it did seem like it was having a harder time getting over the shaft, vs. going into the bore, but that might have been an illusion. Maybe I need to re-try assuming it's the outer bore that's fighting back!

whizzkid23 · #2 10-02-2018, 05:22 AM

Quote:

Originally Posted by Chamberlin

Good info regarding no lube, but I can't see how this is going to go on without something, even some trans fluid maybe. And my drive-shaft is removed BTW so the lever action you described wouldn't be possible unless I re-install first. But it did seem like it was having a harder time getting over the shaft, vs. going into the bore, but that might have been an illusion. Maybe I need to re-try assuming it's the outer bore that's fighting back!

The friction you are encountering when mounting the seal can only come from the outer bore. The selector rod has to be free to rotate, so it's absolutely not a tight fit when speaking about the shaft / seal clearance.

This said, the seal is hold in place only by the tight outer bore / seal clearance. Obviously, because of that, it's supposed to be a tight fit, the seal should not move once installed. Applying lubricant on the outside of the seal will not compromise it's ability to seal... it will only lower the ability of the seal to hold itself in place.

For sure I was also tempted to add some lubricant to make the job easier. But hey...after 12 years of service, the old seal seal moved toward the outside on it's own (generating the leak) so that given and including my knowledge on mounting rotary shaft seals, I did not do it.

For your reference:

https://www.youtube.com/watch?v=QDVzAtU8xDc

Minute 2:10 ...

Anyway. If you decide to mount it without lubrication, due to it's tight fit, you will probably NOT be able to get the seal in place without a leverage force. Eventually it could help to first let the transmission warm up (heat will increase the size of the seal bore on the transmission) but you will still need a "press" action. Pay a lot of attention on getting the seal pushed in straight,mostly for the first mm, this is vital! Also...choose a socket that will applicate the force as close as possible to the outside diameter of the seal! The more you go towards the inner bore of the seal, the weaker it's structure gets!

If you decide to mount it with some minor lubricant, it will eventually work and hold in place. Noone can tell if the fitting is tight enough to take some lubricant or not....only time will tell. But no major damage will ocurr if the seal moves towards the outside on it's own... the only thing that could happen is that it starts to leak again. So if you're not able to get it on safely without lubricant, try it this way. Probably 8 out of 10 mechanics would do it...

80stech · #3 10-02-2018, 09:32 AM

The rubber coated seal needs to be and should be lubricated for installation. There also probably is a slight burr on the end of the shaft where the lever goes against which needs to be dealt with for the installation tool to fit over since it is a close fit. Some sort of sleeve should be used over the shaft if possible as well. The BMW version of the seal installer comes with plastic sleeves.

upallnight · #4 10-02-2018, 11:37 AM

You can use a lubricant that I use for my bicycles. It's called "White Lightning". It a lubricant suspended in an alcohol solution. Eventually, the alcohol will evaporate.

oldskewel · #5 10-02-2018, 02:25 PM

Quote:

Originally Posted by whizzkid23

The friction you are encountering when mounting the seal can only come from the outer bore. The selector rod has to be free to rotate, so it's absolutely not a tight fit when speaking about the shaft / seal clearance.

This said, the seal is hold in place only by the tight outer bore / seal clearance. Obviously, because of that, it's supposed to be a tight fit, the seal should not move once installed. Applying lubricant on the outside of the seal will not compromise it's ability to seal... it will only lower the ability of the seal to hold itself in place.

... Pay a lot of attention on getting the seal pushed in straight,mostly for the first mm, this is vital! Also...choose a socket that will applicate the force as close as possible to the outside diameter of the seal! The more you go towards the inner bore of the seal, the weaker it's structure gets!
...

I agree with most of this. But I'm not concerned at all with the lube on the outside letting it slip out.

Extra agreement is directed at the bold part above. That goes for pressing in almost anything. It applies here too, except you might think it should be easier than it is. It's not.

It took me some finesse to get the seal on straight, the pressing tool (I should have just ditched that and used a better socket) in place and aligned, and then that levering, ironically named wrecker bar pushing just right. Then it went in, after a few failed attempts. As mentioned briefly above, the width of the wrecker bar helped keep this pushing surface flat, which gave me one less thing to worry about vs. using a screwdriver for example. Tough to hold everything in place, then apply the force in just the right direction.

And on upallnight's White Lightning, I've got some of that too. Can't bike any more. It is wax in suspension. So it won't leave unless it melts and runs out. We used to use it here for mountain biking in the rainy season since oil would just be washed out with the water and mud. But the wax would stick on the chain forever, it seemed.

oldskewel · #6 10-02-2018, 02:11 PM

Quote:

Originally Posted by Chamberlin

Good info regarding no lube, but I can't see how this is going to go on without something, even some trans fluid maybe. And my drive-shaft is removed BTW so the lever action you described wouldn't be possible unless I re-install first. But it did seem like it was having a harder time getting over the shaft, vs. going into the bore, but that might have been an illusion. Maybe I need to re-try assuming it's the outer bore that's fighting back!

ATF as lube sounds like an ideal choice. Definitely won't have any chemical incompatibility there, which is the main thing to be concerned with. Does not have the benefit of grease staying in place better, but you just need it to stay in place for a short time.

But when I did mine, I did not lever against the drive shaft. I was worried I might tweak that and cause an imabalance, so I hardly touched it. There is a frame rail outboard of the driveshaft that I levered against.