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PDS Seal Installed 'backwards'?

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mike77cj

Regular Contributor
The VP manual states to install the AFT PDS seal with the 'open' side facing out. Is this done to allow old grease out and new grease in?

Also, I noticed there is roughly 3/4" between the backside of the AFT seal and the second snap ring. I would think the AFT snap ring should be snug against the seal. Comments on this?

Lastly, can anyone advise a brand of sealant to glue the forward seal in place?

Thanks!
 
mike77cj said:
The VP manual states to install the AFT PDS seal with the 'open' side facing out. Is this done to allow old grease out and new grease in?
Short answer...... Yes!
A lip seal will typically increase it's holding ability hydraulically when installed conventionally.
We want the FWD seal to have the greater holding ability in the PDS scenario.... hence the AFT seal is installed non-conventionally (or backwards, as you are calling it).
So yes..... when installed correctly, we will see the lip tension spring facing us... and this is so that hydraulics will not increase the holding ability.
FWD seal....yes!

Also, I noticed there is roughly 3/4" between the backside of the AFT seal and the second snap ring. I would think the AFT snap ring should be snug against the seal. Comments on this?
The first installed snap ring "stops" the bearing, and consequently, the PDS from moving FWD/AFT.
Second installed snap ring "stops" the seal........ the seal actually presses in against this aft snap ring and just rests there.
None of the V-8 flywheel covers will offer a snap ring that retains the seals.... these will be friction fit only.

Lastly, can anyone advise a brand of sealant to glue the forward seal in place?
Any semi hardening sealant (short of silicones) should do the trick!
Permatex, for example.
If concerned, I suppose that the bore could be "staked" around the permimeter.
Anything to prevent this seal from being pushed out by grease pressure.
Loose the FWD, and no future grease will make it to the AFT bearing.

Thanks!
Click to expand...

Be sure to pre-fill the grease cavity prior to installing either seal. This way we can spin the PDS until we see grease come through the ball cage.
Once grease is seen, stop and install the two seals.
As you can see, the AFT-most bearing (V-8 for example) is the more important bearing.
This bearing will receive the grease exchange during dynamic lubrication in the future (engine running at idle while greasing it).
Again, the FWD seal must remain in place, or no future grease will be exchanged at the AFT-most bearing.

Hope that makes sense.
 
Last edited:
"The first installed snap ring stops the bearing, and consequently, the PDS from moving FWD/AFT.
Second installed snap ring stops the seal.... the seal actually presses in against this aft snap ring and just rests there."

It looks like I made an error, from fore to aft I installed in the following order: AFT bearing, snap ring, AFT seal, snap ring. Based on the following image: http://www.volvopentastore.com/mall/image/view/7/6/7188_1.png it looks like I should have installed AFT seal behind the second snap ring.

I may try running the boat with the configuration I installed. Technically the seal could not interfere with the AFT bearing since there is a snap ring behind it. Also, if I glue the forward seal in place and add grease over time the excess grease will either push through the AFT seal or push the seal backwards until it seats against the second snap ring. What do you think?

Thanks!
 
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