09-MAR-2006
Removing The Coupling From The Transmission
Day One:
1) Loosen the packing gland nut.
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2) Loosen and remove the four nuts between the transmission and coupling.
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3) Push the shaft towards the stern separating it from the transmission.
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4) Apply penetrating oil to the shaft and coupling with PB Blaster or Thrust. Do not use WD40 or Liquid Wrench these are NOT true penetrating oils. PB Blaster or a product called Thrust are incredible products! Apply to both the prop end of the coupling and the transmission end by sliding the shaft towards the stern tube. Then align the shaft upright and remove the seizing wire and two bolts that lock the coupling to the shaft. Next fill the two bolt holes with PB Blaster, wait a few minutes for it to absorb into the holes and repeat a few times. By hitting both ends of the coupling, and the center where the holes are, with PB Blaster, you will get better Penetration than just wetting the prop end of the coupling. It's best to fill the cap with PB Blaster & then use a Q-tip or use an eye dropper for application.
09-MAR-2006
Removing The Coupling From The Shaft
Day Two:
1) Insert a deep drive socket that is slightly smaller than the shaft size between the center of the shaft and center of the transmission hub. See the picture below for a close up of the socket between the coupling and the transmission hub.
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2) Insert four long FINE threaded bolts, preferably without shoulders (the part on longer bolts with no threads). Ignore the bolts in picture as I did not need fine thread. This pic is for illustration purposes only. My boat was only a year old and the coupling was not that tough to get off compared to my last boat a 1986 where I did have to used FINE thread. Be sure to use washers between the coupling and trans hub and begin tightening evenly. Be sure to put never seize on the bolt threads to prevent galling. It will also make it easier to turn the wrench. Coarse threads will not work as easily on an old coupling so be sure to use fine threaded bolts.
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3) After some initial tightening, and with the bolt pressure still on the shaft and coupling, you may need to go outside the boat and strike the prop shaft towards the bow, yes the bow, with a dead blow mallet to break it free. Use a scrap piece of maple between the mallet and the shaft to prevent potential damage to the end of the shaft from the dead blow. Then re-enter the boat and continue tightening until the coupling is off the shaft.
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4) Optional: Bring the coupling home to clean and paint it with a rust proof paint.
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WARNING. WARNING, WARNING!!! Be very careful NOT to get PB Blaster near ANY engine or transmission seals. True penetrating oils will EAT engine seals causing catastrophic failure of that seal. The most common seal DIYers destroy is the transmission output shaft seal. Be very, very careful using PB Blaster on your engines coupling bolts and DO NOT use the spray feature when working that close to seals. If you need to use a penetrating oil on coupling bolts fill the PB Blaster cap with the penetrating oil and then use a Q-Tip to dab PB Blaster on the bolts being very careful not to drip ANY on or near the transmission output shaft seal.
09-MAR-2006
The Coupling Has Started To Move
In this picture you can see the effect, and penetration, of the PB Blaster penetrating oil. The coupling has broken free and is beginning to come off through the tightening of the bolts.
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If you have trouble getting the shaft and coupling apart you can heat the CENTER of the coupling very slightly with a blow torch (make sure you have an extinguisher on hand just in case) heating it in the CENTER will draw the PB Blaster into the coupling due to capillary heat draw. Use this as a last resort only.
10-MAR-2006
Almost Done
In this photo you can see that I have painted the coupling and am in the process of fitting everything back into place.
A few words on solid couplings:
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1) If you are removing a coupling that is more than say two years old, depending on bilge moisture, you should not re-use it. Solid couplings are a one time use after they have become "made on" as Mike the manager at H&H Prop refers to it as! Why is this?
When you remove an older coupling you will break a layer of rust free. This rust was your tolerance. A shaft and coupling are meant to fit together very, very snugly. In all my years of boating I have only had one coupling go back on and maintain the tolerance and that boat only had a few months of service on her. Re-installing a used coupling can ruin your shaft. Shafts are expensive couplings are cheap in comparison!
The machine shop I use & the largest shaft and prop shop in the North East, fits the coupling to the shaft with a tolerance better than .001". The actual SAE J756 & ABYC standard calls for a maximum variance of fit between the shaft & coupling of .001" but good shops will try for better than .001" as mine does. On a properly machined shaft, without any anti-corrosive agent like Tef-Gel, it will slide on about a 1/4 to a 1/3 of the way before you experience some serious resistance. This initial fit is often referred to as "lead" meaning they give you a little bit of leeway to get the shaft started into the coupling. The coupling and shaft are machined to exacting tolerances of at least .001" or better so there can be NO wobble or play between the shaft and coupling. Any wobble will cause excessive shaft, key and coupling wear and could eventually lead to a failure.
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2) The shaft is usually fine and can be cleaned and re-used. It is the steel coupling that gives up surface material, and this lost layer of rust means you can't re-use it. If the coupling just "slides" back on it is too loose!
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3) When reinstalling a new coupling to an old shaft you should always have it fitted and faced by a machine shop or prop shop. Shops charge around $65.00 for a fit and face. While you are at it have the shaft trued. Shaft truing is more costly than a just a fit and face but generally cheaper than a new shaft and it will get rid of any annoying vibrations. Another good practice to eliminate vibrations is to "lap fit" the prop to the shaft and you could actually do this yourself.
If you hit something and bent the tapered end of the shaft near the prop the shaft is usually considered ruined and most any reputable shop will not straighten it.
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4) When re-installing the shaft you should get it started with the machined in "lead" then lightly tap it home with either a rubber mallet or an oak or maple block protecting the shaft and a hammer. For this job need two people or many trips up and down the ladder. Pound it in while looking in the coupling holes until you see the dimples for the set screws. Don't over do it cause backing it off is more of a paint than driving it in.
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5) Shaft keys should fit snugly but not so snug that they are "key bound". If the key has any play have a machine shop make you a new one.
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6) Anti-corrosives like Tef-Gel can sometimes aid in future removal but it is no guarantee. As Mike at H&H says about using Tef-Gel or any anti-corrosives/seizes "It won't hurt nothin' but a properly machined shaft and coupling should shave any thing you put on that shaft off as you fit the two together". He says it won't hurt but in most cases it won't help either. You should also not use a never-seize product containing any aluminum, copper or graphite as it can add to galvanic corrosion issues.
Contrary to what Mike says I have been using Tef-Gel and had good to mixed results up to about two years with coupling removal. It does aid some in the removal but does not always mean it's re-usable. I will be pulling my coupling in a few weeks to do some tranny work, and it is also at the two year mark, and this time I will photograph any rust or lack there of.
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7) If you can don't replace the coupling with a solid coupling and instead replace it with what's called a "split coupling". This will make future removal and re-install much easier. Even with a split coupling you should still have it fitted and faced after removal. The $65.00 +/- is well worth it.
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8) Never use a hammer to pound directly on a coupling that is connected to the tranny. You can damage the bearings and the soft aluminum cases many transmissions are made of.
10-MAR-2006
PSS Shaft Seal - With Painted Coupling
When re-installing the shaft and coupling apply liberal amounts of Tef-Gel mixed with Never Seize. Coat the shaft and the inside of the coupling and you'll be able to get it apart in the future!
WARNING !!!
If the coupling does not want to come off the shaft with the above method, without over tightening of the fine threaded bolts, have a piece of 3/8 steel cut, at a machine shop, with the same hole pattern as the coupling. To measure the bolt hole centers you can use an inexpensive set of calipers available at Home Depot or transfer the hole pattern with paper. Use this piece of steel, with the deep drive socket in between, instead of the transmission output hub, to break the coupling free. The transmission output hub CAN be broken if you over tighten! This is why it is safer to break the coupling free by hitting it towards the bow and not the stern. If the coupling does not come off, with reasonable tightening, DO NOT over tighten or you'll be looking at a transmission re-build to install a new output shaft!
Don't forget to sand the shaft to remove any burrs before sliding the PSS stainless steel rotor face onto it. Inside this stainless steel rotor face are two rubber o-rings. these o-rings prevent water from leaking into the boat from between the prop shaft and the rotor face. If you slide these o-rings over a metal burr you may cut them and have a potential leak! Use dish soap, as a lubricant, to slide the rotor onto the shaft after de-burring with wet sand paper or a small file if necessary. The shaft should be as smooth as glass when you rub your fingers on it. I put one of my wife's scrap nylons on my hand and rubbed the shaft with the nylon covering my fingers. If the nylons catch on any burrs more sanding is required. Be very careful to ONLY sand the burrs and not to reduce the diameter of the shaft or a wobbly coupling could occur. The burrs are usually along the "key way slot" and the "set screw holes" but could be other places too...
Good Luck,
28-MAR-2007
PSS After One Seasons Use
After an entire season all I have to show for this installation is a tiny carbon/graphite line, which is barely visible. This is line is left over from the break in process of the face and carbon rotor facing (smoothing) each other. The bilge is now bone dry & keeping the boat as mold free as possible is a good thing. Notice that everything below the water line is double clamped!
28-MAR-2007
Vent Hose Routing
To get the vent hose above the waterline and into the engine compartment put a smooth bend with enough slack for flex and then route the hose into the engine compartment. Make sure it does not chafe on anything along the way.
28-MAR-2007
Vent Hose Water Collection Bottle
I had the PSS up and running for a while before I noticed a minor problem. It seems that every time I put the boat in reverse I had a tiny bit of salt water on the floor around my engine compartment. The reverse thrust of the prop is in a direct line of sight with the shaft seal and can force an initial burp of water up the hose. The water does not continuously squirt out, and it equalizes quickly, but the initial thrust, of reverse, would push about an 1 oz of water up the tube and into the boat.
To solve this problem I added, to the existing vent hose, a couple of brass elbows and a bicycle water bottle and bottle holding bracket to catch this "reverse thrust" water. To make sure the system was still able to vent air I made a hole in the top of the bottle to facilitate venting and routed the vent hose into the bottle below this hole. After about a month of sailing the bottle would be half full and I would empty it when I checked the oil. IF you are venting a PSS internally be aware that running the engine in reverse can and will push water back into the boat..
28-MAR-2007
Water Collection bottle Vent Hose Fitting
The new style of the PSS Shaft Seals are all vented so no air can become trapped in the stuffing box. An air-bound stuffing box can become very hot as the rotor faces are water lubricated. Even with slow turning shafts this can become an issue without proper venting. The vent hose keeps the seal lubricated by venting or displacing the air and allowing water to take its place. The problem is this hose needs to be routed above the waterline with NO low spots! Low spots trap water thus preventing venting! In the Catalina 310 it was vary hard to find a route that would not have a low spot, where water could become trapped, preventing the vent hose from venting the shaft seal. Essentially a low spot in the vent hose becomes a p-trap! The engine compartment route was the only way I found that did not hold water or impeded the flexibility of the vent hose on the shaft seal. Routing into the engine compartment, on the 310, solved this problem. The hose barb pictured just pressure fits nicely and is easily removed to empty the bottle from "reverse thrust" spillage.
28-MAR-2007
Close Up Of Water Collection Bottle
This picture gives you a better idea of what the completed set up looks like. At first I was concerned about heat from the exhaust riser but an infrared thermometer confimed that the bottle stays plenty cool and besides it fits well.
The blue tape on the back wall is reminding me of the engine hours when I last changed the oil. It's a crude system but it keeps me on a 30 hour engine oil change routine.
