PDH on the old setups

"RE: the PDH from Holman Moody

"RE: the PDH from Holman Moody, Eaton, Chris Craft, etc.

Just would like your opinions and thoughts on the discussion I got from a Donzi website regarding the bearing replacements.

"I just tore all this a part and rebuilt it on my 1968 Magnum with 350 SBC engines.
The set up I have has an intermesiate shaft with 2 lip seals and two bearings and was supposed to run with gear oil as lubricant. This I rebuilt with two sealed bearings, eliminating the lip seals and the gear oil.""

"Jay, I am very familiar with

"Jay, I am very familiar with most all of these extended Borg Warner pattern -slash- Volvo Penta PDS Adapter housings.
The way that I see this, is that using a "sealed" bearing creates a scenario where you are unable to lube these Primary Drive Shaft bearings in the future...... I.E., engine oil change interval, for example.

Note that the Holman Moody (and most other) PDS Adapter Housing uses a smaller AFT bearing than does Volvo Penta in <u>their</u> B/W-slash- PDS Adapter Housing (a much shorter one, btw).
A #6206 vs a #6006 bearing to be exact.
They won't go quite as many hours as a #6206 will!

Also, open bearings with the "lip seals" were installed to hold grease in the housing allowing for purging primarily at the AFT most seal/yoke during lubrication intervals! (got to be a place for the old grease to go!)

Donzi must have modified the housing if oil were to be used in lieu of grease...... in-that the AFT most seal would no longer be sealing against the universal shaft <u>"Female Yoke" surface</u>.
If oil was used, it may leak through/around the splines and out from the internal "cap" at the yoke!

Although unfamiliar with the wet system, this is prefect to relieve grease pressure for purging! (these seals can be blown out of position quite easily)

Not sure I understand what question you have other than using sealed ball bearings on this PDS.
Me??? I'd not use them unless I was willing to replace them at a regular interval... Or if the PDS housing did not offer a grease port!

If it were mine, I'd pick the seals from each bearing, then I'd then pre-fill the grease cavity as I spun the shaft... (a good high pressure bearing grease.... not green marine grease)... just prior to installing the two seals. We want grease up to and through the ball cage.
The Holman Moody should take a 35x62x7mm at the FWD area, and a 35x55x7mm AFT.

But if you leave as is.... I think you'll be fine.... just don't wait to long before you at least change the AFT bearing again.

.
"

You answered my question - tha

You answered my question - that being using sealed bearings and forgetting about using any grease.
Not a good idea.

"Jay, I'm not making an ab

"Jay, I'm not making an absolute suggestion that you not use them.... just replace earlier than you normally would.

The sealed bearing (same p/n w/ extension alpha character and #) is the same bearing with a very small recess machined into it for the seals. The seals can be picked from the bearing (both sides), and you will have an open bearing."

"Someone once posted (unfo

"Someone once posted (unfortunately AFTER my mechanic proudly announced he had changed over to sealed bearings during the re-engine..."You'll never have to worry about them again...!" ) That one should use bearing sealed only on the outboard side and drill another grease port on the bottom, putting a hose with a zerk fittin on it and a pipe plug in the existing hole on the top... instructions: after prefilling the housing by hand with grease, before installation, and for routine (annual) lube, remove the pipe plug and pump in new grease until some old grease comes out the pipe plug hole."

"I respectfully disagree!
No

"I respectfully disagree!
No need for more than one grease port and here's why: (and of course, this is my opinion only here!)

If the cavity has been "pre-filled", (I mean filled while the shaft was being rotated and until grease reaches through each ball cage)......
and if this area is clean (of which is will be).....
any future grease being pumped into the cavity has only one place to exit!!!!!!
The bearings themselves!

And if we rotate the shaft again (I.E., engine at idle) while we lubricate this at each service interval, the ball cage receives a more complete exchange of new for old grease.....
just as our "EZ Lube" or "Shure Lube" trailer spindles allow us...... our wheel bearings are greased with the wheel in the air and spinning!

Any bearing like this should be lubricated dynamically.... not statically, if we can help it.
There is a huge difference between the two methods!


This is also why we don't want an absolute grease tight seal at the PDS/female yoke..... we want a little purging to occur here or we won't get an exchange, and we risk blowing the FWD seal out.

If you have water inside of the bellows, you have other more important issues anyway.

Make sense? Hope so! But I am always open to being shown otherwise.

."