LU reseal

noah4009

Petty Officer 1st Class
Joined
Nov 6, 2008
Messages
283
I have a 1971 55HP outboard Chrysler, Model 557HC Serial 3188. I found mostly water in the LU. I just received my LU reseal kit and am going to do it this weekend. I also receivied the Impeller. Question is: When I remove the LU (mine has a extendion on it) Do I need to remove from the below Motor leg down or from below the extension down? Is this going to be as hard as it looks? I do have all the Chrysler manuals for this particular outboard motor. (service, parts, and electrical manuals) Any suggestions?
Also will I need any special tool to remove parts behind Popeller to change seals? Will regular tools do to do this job?
Thanks
 

arsenalpsu

Petty Officer 1st Class
Joined
Dec 1, 2008
Messages
290
Re: LU reseal

Hey there, I have a 1970 55hp I did the same thing on this past summer. (always had lots of water after each use) You should not have to remove the extension, just the LU. When you get the LU off there will be 2 nuts to remove, first the one by the impeller. The second is in the gear box, you have to remove the rear housing of the LU to get to it.(where the propeller is) It's hard to get to as there is little room. After these are removed the gear housing should come off the LU with a little light pressure. The seal that you put between the LU and the gear housing is very thin, I had to remove mine twice as it did not seal the first time. (cheap crappy seal in the kit) I replace this seal with a thicker one that I cut out, you want to consider doing the same. Be sure to look at the gears when you remove then so you can put them back the same way. I soaked mine in cleaner to remove rust and any other dirt. The drive shaft seal below the impeller can be a pain to get out, but it needs to be done.

For the impeller i would replace the housing as well. I did on mine and it cools like a champ.

Also, do you have an electronic copy of your manuals? I would love to get a copy if you do! If you have any more questions or need further clarification (*or can send me those manuals) my e-mail is jvarsenault1@verizon.net. Let me know how it goes
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: LU reseal

It is not nearly as difficult as you think it is. All you need are hand tools, but the nut inside the gearcase must be loosened with a small head 1/2 inch open end wrench. Box ends, sockets, and flare nut wrenches will not fit.

The most difficult part will actually be removing the shift rod joiner and replacing it properly. It adjusts the length of the shift linkage and is located under the mid-leg shroud. Both halves of the shroud must be removed to access it. Actually, only the one side, but both halves are bolted together and clamp to the mid-leg on rubber gaskets so you might as well remove both.

The joiner is threaded in opposite directions on each rod like a turnbuckle. You must loosen the jam nut then screw off the joiner. Leave the jam nut in position to mark correct alignment when you reassemble. After assembling test at least several times in each gear to be certain both forward and reverse engage properly.

Do not be tempted to use a much thicker gasket between the gearcase and top portion of the lower unit. That gasket and the relief in the top casting LOCATES the bearing AND pinion depth of engagement with respect to the driven gears. While Chrysler lower units were set up very "loose" in this respect and there is some leeway, a better alternative would be to coat the gasket with non-hardening Permatex or gasket varnish. I am no big fan of Permatex but in this case it can be useful.

If you find nicks or unevenness in the gearcase and top casting mating surfaces, they can be dressed, but no more than a couple of thousands. Again, it is best to let a sealing compound like Permatex do the work.
 

arsenalpsu

Petty Officer 1st Class
Joined
Dec 1, 2008
Messages
290
Re: LU reseal

I had a few nicks (I'm assuming) from a previous owner who tried to seperate the gearcase with a screwdriver. It was just a slightly thicker gasket that when bolted added very little, I also used the Permatex. Worked great. Not sure if you'll need it, just though i'd throw it in.
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: LU reseal

Oh yeah! I forgot---water or moisture tends to work its way up the front stud that holds the gearcase to the upper casting. Sometimes you need to hammer on the top of the stud to free it. If this is the case, be sure to leave the nut threaded on the stud so the threads are not deformed or ruined. It is also good practice to work some anti-seize in through the stud hole to prevent future corrosion.

The front cavity (where the lower shift rod enters the seal in the lower unit) in the lower units on the older 55s was a blind cavity. If the engine was used a lot in dirty or silty water, silt and sand would tend to settle around the shift rod. it eventually sets up like concrete, jamming the shift rod. There is so much compliance in the shift linkage that it will bend and the engine will no longer shift.

So, if your lower is the same, either drill one or two small drain holes or be especially vigilant in flushing out the lower unit periodically.

What I did on my '67 was to drill two 1/8 inch holes in the front of the leg, on either side of the point, about 1 inch above the gearcase gasket, at an angle so they missed the stud. When the engine is moving through the water, they admit pressurized water to the blind chamber and clean it out. They also allow drainage when the engine is not in use.

If you do decide to drill, measure twice and inspect 3 ways from Sunday to be certain you do not drill into a sealed chamber of the gearcase.
 
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