Shaft Saver?

[Dixie Life]

My BW tranny seal has started to leak. A friend suggested installing a shaft saver when I replaced the seal. He said it is kinda like a bushing that helps protect the seal. Are any of you guys familiar with this? Advise please. Thanks. (FL120 w BW Velvet Drive tranny)

 

[obthomas]

Shaft Saver is a trade name for a flexible coupling. They supposedly provide some shaft mis-alignment tolerance. I have Shaft Savers on my boat.

 

[Bensjoy]

I have a drive saver made by Globe Rubber. PYI also makes them. Simple install.

 

[No Mast]

Regadless of the shaft saver installation if you have an alignment issue I think you may want to adress that.

 

[Bensjoy]

I agree. I have an exposed propeller on my boat and installed the Drivesaver in the hopes that it would reduce impact damage should I strike an underwater object. The Drivesaver is designed to shear in this event.

 

[Capt.Bill11]

R&D Marine Flexible Shaft Coupling Vs. Globe Rubber Drivesaver - Seattle WA

http://www.globecomposite.com/Marine_Products_Drivesaver

 

[ancora]

I believe the "shaft saver" he is referring to is a thin tube with a polished and ground surface used to cover the groove worn into a shaft by a seal. They come in many sizes both inch and metric and are made by C/R and others. They are readily available online or at any bearing house. You simply drive the tube on with the aluminum driver supplied with the tube and then use a pair of "dikes" to tear off the "top hat."

 

[Ski in NC]

Two different things. Drive saver et al are the rubber things that go between the flanges.

Redi sleeve et al are pressed on shafts to cover a groove worn into where seal rides.

In op's case, if a groove is worn in output flange, just replace it. And unless it has a gazillion hours, I bet there is no unmanageable groove. Minor ones can be cleaned up.

 

[LarryM]

There are repair sleeves that are used to restore a damaged or worn surface on a rotating shaft so that a seal can be replaced and function properly.

It sounds like that is what your friend is referring to as a 'shaft saver'.

Some are very thin and can be installed directly over the worn area. without machining. Other repair sleeves are thicker and require that the shaft be turned down so the repair sleeve can be slipped over it. The sleeve is heated during installation so that it has an interference fit when cooled.

Another repair method is building up the surface by welding or spraying metal onto the damaged surface and turning it back down to the original size and surface finish.

Any of these methods will require removing the output shaft from the transmission to be able to slip any kind of repair sleeve over the shaft.

Good luck!

 

[meridian]

Are you sure it's the seal and not the shaft splines leaking past a loose nut? That nut should be torqued to 200 ft lbs. If it is loose trans fluid will leak out. Can you tell where the leak is coming from?

 

[Dixie Life]

I haven't taken it apart yet; just ordered the seal yesterday. The fluid is going into the rubber part of the Federal drive coupling at the rear of the tranny. When the boat is in forward gear it slings it out through the four rubber bushings in the steel housing of the coupling. BTW, does anyone know the size of the nut that holds the flange in the rear of the tranny? I'll have to purchase one to do this job. I'll know then if I just have a loose nut problem.

 

[meridian]

A new trans end coupling is only $100 if that what the problem is. nut size is 1 11/16, nut is a one time use. before installing nut, fill cavity with RTV sealent then put on nut and torque. I would also use some Loctite.

 

[Dixie Life]

Thanks for the info Meridian. Are you also telling me I need to locate a new nut?

 

[Ski in NC]

First find out if nut is loose, and whether the leak is coming past the nut.

You can always tighten it now, then order replacement later.

 

[angus99]

Another repair method is building up the surface by welding or spraying metal onto the damaged surface and turning it back down to the original size and surface finish.

What kind of hardness do you get with this process on a prop shaft? I have some very slight grooves where the shafts pass throughout the stuffing boxes. Thinking I may need to build them back up and would like to run Gore packing to reduce/eliminate leaks. I've heard the Gore can be tough on shafts, so I'm wondering if the build-up material might be more or less resilient than the original steel.

Thanks.

 

[LarryM]

What kind of hardness do you get with this process on a prop shaft? I have some very slight grooves where the shafts pass throughout the stuffing boxes. Thinking I may need to build them back up and would like to run Gore packing to reduce/eliminate leaks. I've heard the Gore can be tough on shafts, so I'm wondering if the build-up material might be more or less resilient than the original steel.

Thanks.

Here is a link to StraightLine Marine in Fort Lauderdale where the process is described in detail. I suspect that on smaller shafts it might be more economical to simply replace the shaft. I'm sure they could advise you.

 

[angus99]

Here is a link to StraightLine Marine in Fort Lauderdale where the process is described in detail. I suspect that on smaller shafts it might be more economical to simply replace the shaft. I'm sure they could advise you.

Thanks, Larry!

 

[Capt.Bill11]

I've heard the Gore can be tough on shafts,

The old school white Teflon packing was hard on shafts. Mostly because people over tightened their nuts.

Gore on the other hand is not at all hard on shafts from what I have seen in.

 

[FF]

The Teflon packing was hard on shafts as it would hold fine sand or metal shaft flakes on its hard surface and score the heck out of the shaft.

With no need to run water as a lubricant modern packing is soft enough to absorb any metal flakes.

 

[meridian]

See Below:

ALT23320

$12.95
Quantity in Basket: none Nut Coupling with Washer Borg Warner Velvet Drive Transmission 1000-149-034


[FONT=Arial, Helvetica, Sans-serif]Coupling Nut with built on washer for Borg Warner Velvet Drive 1017 1018 Series including "V" Drive, and 5000 Series Transmissions. This takes an 1 11/16 socket to remove. Used on all newer style transmissions without seal holder.
OEM: 1000-149-034 [/FONT]

ALT23321

$12.95
Quantity in Basket: none Nut Coupling Output Shaft Borg Warner Velvet Drive Transmission


[FONT=Arial, Helvetica, Sans-serif]Output Shaft Nut for Borg Warner Velvet Drive Transmissions. Uses a 1 1/2 inch socket IF your nut uses an 1 11/16 socket, then this is not the correct nut. See ALT23320 [/FONT]

Guy

Attached Thumbnails

 

[Dixie Life]

This is great info Terry. Seal is on the way from AD. I ordered a 3/4 drive socket set today. Didn't have a socket that large in my tools. I'll keep you posted.

 

[Driftless]

Great information, guys.

I've done a couple of repowers, and when we found old style packing had worn grooves in shafts, on two occasions, we installed Dripless seals which positions the shaft collar further toward the engine than the original packing. Thus the dripless seal performs as-designed with no compromise due to the damaged surface at the original packing position.

When I repowered Driftless, I was replacing the original 25mm shaft with a 1" so everything had to be new regardless. The good news it was that being only 1" diameter, it was a really small shaft anyway and nothing was very expensive.

The shaft, screw and all the related hardware (including the drive saver coupling) cost more than the new Isuzu diesel engine, which I got through a stroke of luck for $2,000.

Thanks!

JS

 

[Dixie Life]

Meridian,
You were on the mark. The nut was only finger tight. I followed your instructions; RTV, 200+ torque, etc. Haven't taken a test run yet; ugly weather. But, not a drop of fluid in the pan after several days now. A couple questions though. One, the nut took a 1 11/16 socket but has no built on washer. It looks just like the lower nut in the post(#20) above. Do you think a yard guy could have installed the wrong nut? Second, do you know how much alignment error is acceptable on a Federal Flex Drive Coupling. I called the factory but the guy refused to give an answer. He said, ".003 on direct shaft coupling. But with rubber mounts on the Federal you have much more flex." Still, no number! My tranny is about .015-.020 out at the 8:00 position looking from the rear. That's as close as I can get it without major work. There's no vibration so the .015 may be OK with the rubber bushings.

 

[meridian]

I wonder if he used a used nut. When I took mine off, the washer had separated from the nut. Did he use any kind of washer? Brian at AD said it was a one-time use nut. I guess you can just keep an eye on it. No idea about the flex drive.

 

[LarryM]

Meridian,
You were on the mark. The nut was only finger tight. I followed your instructions; RTV, 200+ torque, etc. Haven't taken a test run yet; ugly weather. But, not a drop of fluid in the pan after several days now. A couple questions though. One, the nut took a 1 11/16 socket but has no built on washer. It looks just like the lower nut in the post(#20) above. Do you think a yard guy could have installed the wrong nut? Second, do you know how much alignment error is acceptable on a Federal Flex Drive Coupling. I called the factory but the guy refused to give an answer. He said, ".003 on direct shaft coupling. But with rubber mounts on the Federal you have much more flex." Still, no number! My tranny is about .015-.020 out at the 8:00 position looking from the rear. That's as close as I can get it without major work. There's no vibration so the .015 may be OK with the rubber bushings.

I must say that .015-.020" sounds like significant mis-alignment to me. Many references I have encountered over the years refer to an alignment error of no greater that .001" per inch of coupling diameter. Another common rule of thumb is no greater than .004". In the Yanmar installation manual for small diesels, it lists Coupling Face Run-out of 0-0.2 mm (0-.0078 in.). This is almost twice the generally accepted standard, but does include use of their very flexible engine mounts and a flexible coupling when the propeller shaft is short. R&D specify no more than .010" with their flexible couplings.

Henry H. Smith & Company is listed as a Federal Flexible Coupling distributor so you might give them a try at 800-338-8900 if you haven't already.

Good luck!

 

[Ski in NC]

0.020" out on the flange faces is quite a bit. How hard is it to tweak your engine to get closer to zero? May be a creative way to shim it/budge it/whatever etc to get closer. I don't know your flex drive, but do know that running with misalignment works the output shaft/flange joint and that may be why nut loosened.

 

[jleonard]

I wonder if he used a used nut. When I took mine off, the washer had separated from the nut. Did he use any kind of washer? Brian at AD said it was a one-time use nut. I guess you can just keep an eye on it. No idea about the flex drive.

Yes it is supposed to be a one time nut. With the RTV it will likely stay in place.
Yes I agree .020 is too much out of alignment. A In addition to what Ski said, it has also been torqueing on the rear tranny bearing which is already under stress in the best of conditions.

 

[C lectric]

I always used ~ 0.001" per inch diam of the coupling. So for a 5" diam coupling 0.005" was ok, not best , but ok. I usually get within 1 0r 2 thou. but total.