Coupling removal advice needed

[jsgonz]

I have a Hunter 28.5 on the hard for repairs. One repair is to replace the shaft due to electrolysis damage. I will also be replacing the strut due to the same reason. While I am at it, I will be installing a dripless shaft seal (PSS). I could not remove the shaft due to corrosion even after weeks of using PB Blaster and WD 40. I removed the shaft bolts on the neck of the coupler but not wanting to hammer out the shaft from outside for fear of damaging the transmission, I sawed off the shaft just aft of the coupler since I was going to replace it with a SS one.

Here is the problem. The coupler is one of those vibration damping types and has bolts not only through to the engine out drive flange but also around the 2" wide edge. I think these 4 bolt heads running the radius of the coupler are for adjusting. Now that I have removed the through bolts to the engine flange, it is still not moving. I cannot budge the adjusting nuts on the outside edge of the coupler to take them out in case they are holding onto the outdrive flange. Since I plan on replacing the coupler, shaft and installing a PSS seal, I am not worried about damaging the coupler. Do I need to cut out the coupler? What am I missing that prevents the removal of this rusty OEM coupler? I have knuckle fatigue due to the close quarters behind the engine and am near throwing in the towel unless someone has an idea. Thanks.

 

[Ed Schenck]

Picture?

Sure could use a picture. I cannot visualize from your description. That is probably because I also have a "shaft saver" between the shaft flange and the crankshaft flange. But it is not as you describe. The picture is fuzzy but you can see how this one was installed.

 

[Ed A]

ED S posted a picture of the drive saver installed on the back of the engine. The bolts on the drive saver are not an adjustment. There is no adjustment made here.

The coupling can be easily replaced as long as you match it to the drive saver. If you have that off take it to the prop shop to get a matched coupling. They are pretty standard. The set screws in the cupling hold it on the shaft. again they are not adjustments.

All adjustment is made by moving the entire engine. you can move it up and down and right or left as well as to tip it when you alingn it.

The alignment is critical. after the strutt is installed and the shaft set up you can move the bellows on the drive saver to see the shaft as it exits the boat. It has to be set up so the shaft clears the tube on all sides.

Put a v block under the shaft to hold it in the center. then move the engine untill the cupling is perfectly aligned with the propsavers flush side. You should need a feeler gauge set to about .005. get the engine moved to the point that the gauge feels the same all the way arround the shaft saver and cupling fittings. when it is straight. bolt it up.

Then run the boat for about 20 hours and check the alignment again. this settle in and change also they change when you put it in the water. its best to do the final alignment in the water.

If you have visible motion or vibration in the shaft youve got to start again.

good luck.

Ed

 

[jsgonz]

Ed A and Ed S, thanks for the replies and picture. The shaft saver is not what I have. What I have is wider with four nuts on top that I cannot for the life of me turn. This must be what is holding on to the crankshaft flange. I will try to post a picture of that today.

By the way what is the purpose of the red shaft saver? I have been thinking of installing the R and D flexible coupler. Is that the same thing and do you recomend this or the saver?

 

[Ed Schenck]

The "shaft saver" is more of a shear pin then a flexible coupler I would say. It could save your prop or tranny depending upon what you hit or wind up(like a crab pot). But it does have enough flex that a minor engine misalignment can be tolerated.

I am looking at the enlarged view of the R&D( http://www.randdmarine.com/flexiblesc.asp ) . Is that what you presently have? It appears to install very much like the shaft saver. One set of 4 bolts secure to the engine flange and the other set of 4 bolts to the shaft flange. So I still cannot make the connection to your problem.

 

[jsgonz]

No that is what I was advised to use on the engine side flange when I reinstall the new shaft. I was reviewing my picture files for a good shot of this coupler I have and I apparently do not have a good picture of it. I will post one tomorrow as I will have to take a new picture. I have seen one in a web site but I can't find that now. So I will provide a close up for you to see. Thank you for helping out.

 

[jsgonz]

Ed S and Ed A, here are pictures of the coupler that I am unable to remove yet alone move in any mearsurable way. The nuts on top are hard to get a hold with a socket as they are very shallow and not much to sink a socket or wrench into. Do they hold in the coupler to the Flange? Your thoughts are appreciated.

 

[Paul F]

Had a very hard time breaking loose the bolts on the coupler. The experienced marine mechanic who did the work used marvel mystery oil to soak the bolts for a few days. You will need to make a small tank to hold the MMO while it is soaking the bolts. It may take days and then tap with a hammer and use as large a lever as you have to bust the bolts free. They will come free it just takes time.

As long as you are replacing the coupler you could use an angle cutter to cut the coupler. It is amazing what an angle cutter can cut through. Wear safety glasses and hand-arm protection. Again with time it can be done.

 

[kloudie1]

Wow, That is one I've not seen on a boat. My guess is that the holes in the aft facing part have allen bolts in the holes. Those bolts probably hold the body to the engine output flange. The shaft probably terminates inside the little collar on that aft facing part. The coupling may be filled with something like shot to act as a torque limiter but it most probably is that the 4 outside bolts are pins that go into the little collar where it extends into the body .. again as torque limiting shear pins..?? I dunno.. I think pulling the big radial boalts will release the little collar and shaft stub.. Pulling the axial allen bolts that are hiding in the aft facing holes will release the coupling from the drive flange. Take some pics when ya get it apart.. should be interesting. .. ohh PB Blaster..ya might find that it is faster acting than MMO. Address the forward side of the drive flange where the allen bolts are screwed in (nuts therre maybe?) as well as the holes where the heads are hiding. Good luck with it !

 

[Rich Stidger]

I really hate tough problems like this one. You have my sympathy.

I would definitely use either PB Blaster or Kroil as a penetrating agent instead of MMO. It still may take serval days of soaking.

I would NOT use heat.

I would borrow or rent a heavy duty air powered impact wrench and compressor. A smaller compressor will work but you will only get short bursts of usage. Use a good 1/2" or 3/4" drive hex impact-rated socket. You may need to grind the end of the socket flush to get rid of the angle at the socket opening. That would give you the maximum bite on the bolt since the head is rather shallow. Be sure the socket fits snug- either english or metric size.

My experience with frozen bolts is that an impact tool will loosen and back out a bolt or nut without breakage or rounding the fastener. I have also found that a large breaker bar will allow you to exert so much torque that the fastener will break, resulting in a bigger problem.

Be sure to let us know what finally works. Don't despair, you WILL get it off.

 

[kloudie1]

Strange Coupling

jsgonz, Here is a quick sketch of what I think you may be looking at..
I agree with Rich.. Not fun to play with these.. again, good luck.
More looking and head scratching.. .. it could be a fairly hollow body with an elastomer insert.. 4 "vanes" of the insert taking drive from the big radial bolts .. the axial flange retainer bolts going through spaces between the "vanes" .. and the elastomer attached to the shaft drive collar
I dunno. but I think when the axial bolts come out, the whole shebang will come free of the transmission drive flange..

 

[jsgonz]

Thanks very much for everyone's input. Paul, Rich and Kloude1, I hope you guys are right that the bolts at 90 degrees to the shaft that will come loose with continued work and the loosening oil. I like the idea of the air impact drive wrench to work them out. The cuts on my knuckles trying to get these bolts off look like I have a clinical case of a real bad disposition or that I fight for a living, one of the other!


In any event, thanks for the advise and the sketch of the coupler. On closer inspection, I do see where the outside appears to be a housing for an internal coupler. That support what you have depicted in the sketch. This has been a big help. I will report back to you all with a pictures of the disassemble parts when I achieve removing this item.

 

[tomgrigsby]

Regarding tools, Harbor Freight and others sell electric impact drills. We used them extensively when I worked in the shipyards for removing heavily rusted and fused 3/4" and larger stainless steel bolts (yes, stainless isn't). Make sure you use sockets rated for impact wrenches. I believe the electric impact drills actually had more torque than the air powered units, and no hoses to fool with!

 

[jsgonz]

Thanks Tom. I will look into the electric impact tool at lowes or home depot if they have it. Weather permitting, I will try removing the bolts this weekend now that I given them a good soaking. I plan to post pictures of this coupler when removed since I have not come across anyone who has seen this particular type.

 

[jsgonz]

With much effort and a little drama, I was able to get only one of the four bolts out of the coupling. It took a 1/2 inch air impact wrench with a 7/8 inch socket and a lot of PB Blaster to finally break the hold that rust and time has had on the coupler. I was not able to budge the other 3 bolts. In fact, I stripped the head of one of the remaining bolts. The removed bolt is similar to the sketch but the bolt is as large as the diameter of the head of the bolt itself. It also has a hard rubber bearing around the bolt of at least 1/2 inch thick fitting tightly into the sleeve of the coupling. This apparent design to provide a cushion from vibration. The bolt only has threads on the very end and requires that you pull it out with a pair of vice grips because of the tight hold bearing has into the coupling. I will get a picture of this next week in case anyone else may have this type of device on their boat. Regarding the strip nut, I plan on using a smaller fitting socket forced over the nut. If this fails, I will try to drill it out.

 

[Paul F]

Time to move on.

Unless you wish to reuse this coupling, it is time to move on. Get out the angle grinder with a cutting blade and cut the coupling off the shaft.

 

[jsgonz]

I agree. I don't plan to use it again for sure. But with the angle grinder, will I risk cutting the output flange off of the shaft drive from the transmission? I need to perserve that do I not? Believe me, I would like to end this quickly.

 

[Paul F]

Yeah, you need to be careful of course. You might want to at least see what the new coupler you are buying looks like before you go at taking off the old one. Since you have to do it anyway might as well do it now and see what the next step is before you get somewhere that you can not come back from. Best to you on this.

 

[jsgonz]

I was able to remove one bolt only. It was as large as the nut in diameter but was incased in a thick rubber bearing/coating that prevented its removal however, a pair of vise grips helped pulled it out. The other three could not be removed as I stripped the nut head with the air impact wrench. There are no corners remaining on the nut heads any longer, I can assure you. I had a some one from West Marine on his own time come by and look at this beast and he suggested that I pull the engine and take it to a machine shop and have them remove the coupler for me. I think the inside of the coupler itself is very much like the sketch that was submitted. PB Blaster and other lubercants just could not break this hold so, any suggestions out there are appreciated as I really do not want to pull out the engine.

 

[jsgonz]

An odd thing happened yesterday. Having had no success in removing the top bolts of this coupler except the one, I gave up and hired a marine mechanic to take a look as others were telling me that I need to remove the engine or transmission and take it to a machine shop for removal.

The mechanic came by and after looking at it for a minute or two, he advised to rap the coupler smartly one time with a hammer and then use a pipe to stick in the hole left by the missing bolt and pry easily and that it should fall off. He felt it was simply rusted onto the output flange as the top bolts do not hold the coupler to the engine. Having no hammer, I paid the kind fella for an hour's work and left. Later that day I returned with a mallet as he instructed, I hit it one time, and then took a short pipe I had in the garage, put it in the hole for leverage and pulled down. Voila', off it went with one pull!

Finally, I am ready now to replace with a new coupler, shaft and PSS seal. Best $75 I've paid in some time!