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Pre Alpha I/O Replacing Gimbal Housing

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  • Pre Alpha I/O Replacing Gimbal Housing

    Well I found out my driveline bellows mount on the gimbal housing was to far gone to fix. Purchased a replacement part, the seller looks at the pictures I sent him an tell me this is a pre Alpha drive. Well The engine is a 1986, but the drive is the original 1977.

    Removing the old casting from the transom has turned into a tug-o-war. I have it just about off. There are only 6 attachments but middle two are hard to get to and a full length 1/2 drive ratchet handle could not budge them. So I am cutting the casting away from those two fasteners (left side shown in image attached). Then I can put it together, here is a pic, also not my engine alignment tool, turned on the lathe to match the flywheel coupling spines major diameter:
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  • #2
    To get the gimbal housing casting off I isolated the bolts from the casting and split the casting in half. The four lower bolts were full dead, I will include a picture of the best of the four lowest bolts.

    The boat had a leak, the casting shows water passing between the transom and the casting. The transom was not level, my first guess is the plywood had voids in it. You can see the plys and how they line up.

    The mechanical rule of thumb is 3 bolt diameters from the edge to any hole to provide enough meat to support the load on the bolt, doesn't work with this design. I will need to level the transom, then pull the engine to install the gimbal housing, and reassemble the boat.


    • #3
      Thanks for the pics, I will start break free now now so I might have a chance of getting those middle ones off easier. Did you find the housing at a shop or private seller? I have the pre-alpha also.


      • #4
        After a weekend on the bigger boat I am back on finishing the 17 footer.
        Here is a picture of the new gimbal housing mounted to the tansom, next is the gimbal, then the bell housing.
        The trick in doing this work is prefitting all the parts, I chased all the thread. Even with this prep work I found that the transom holes weren't perfectly matched to the new housing, even 1/16" error and the bolts won't take. My recommendation is to prefit even the housing to the boat before the using the messy goo to hold the seal in place.


        • #5
          4200 or 5200 messy goo? I guess if I want to remove it in the future, 4200 would be better but I happen to have a tube of 5200 handy. Looking good.


          • #6
            I did use 5200. Heat will cause it to release. I decided to not install the aluminum grounding electrodes/bolts. They are 1/2" double ended bolts which have a threaded top that the conic shaped zinc can be screwed on to. The bolts are no longer available. I purchased the zinc that goes over the power trim hydraulic coupler. It is bolted to the bottom of the gimbal housing. It too is below the waterline and is still easy to find. I will need to shift the holes in the zinc about one bolt diameter, but that should be easy to do. The down side is the holes for these aluminum bolts are inside the housing seal, so I used 5200 there too.

            I went out tonight to attach the gimbal and found that I needed a shim to set the free play in the gimbal bottom pin. It has a top and bottom casting feature that keeps the drive from bouncing up and down. You can see the holes for the pin at the bottom of the picture I posted.


            • #7
              Yes, the shims that go on top and one on the bottom if I remember correctly and set the play to .0025" up and down. I have been looking for those 1/2" double ended bolts as they were corroded thru(part of one still stuck in boat). Guess I will be sealing those also. I am wondering how you are going to shift this holes so if you can put a pic up, that would be great.


              • #8
                I was able to order those 1/2" double ended bolts for the zincs at the local marine shop...just an FYI incase you decide to go a different route.


                • #9
                  Yes, send me the details and I will have a backup option. I did start to install the gimbal. Found the top pin difficult to put in by yourself. I have it half way in but the top nut jumped off the pin.



                  • #10
                    I haven't got them yet, but I have them coming from Flowers Marine in Oak Harbor (360-675-1555), the part number look like 8M0030655 but that is what is scribbled on my receipt. Call them, they will help you. Not sure how far that is from you. I'm fighting getting the top pin out of the gimbal ring as the spreader nut was corroded and accepted no type of tool other than a drill bit. It is the last part that I have to disassemble and replace. PITA!


                    • #11
                      Did a quick check, that is the correct P/N and they are online if you just type it in the search bar.


                      • #12
                        Flowers is the same town, so not much work to stop by.

                        Since I was replacing the gimbal housing (the outside transom part) I just use a 6" diameter narrow kerf grinding wheel and cut the housing so I could just pull the ring and hinge pin out. Those parting wheel really work fast!

                        I took several hours to remove the set screw that tightens the pin. The thread on mine is a 1/2X20 threads per inch.
                        I found that If I used drill bits at small increase inincrements I could reach the correct hole size for a tap. I needed to use M2 drills, those gold colored bit just aren't hard enough.

                        Then I put the tap in for 2-3 turns and then back it out, check the hole and check the tap to remove the set screw thread that tended to release as the tap worked over them. In about 30 minutes I had the thread back.

                        Then I used a putty knife that I set the width of the blade (using the same grinding wheel setup) to match the split in the shaft and worked it through the split to get all the metal chunks out.

                        I did use MAP gas to heat the gimbal ring and a few wacks and the pin came out.


                        • #13
                          Well that is way more scientific than my process. BFH, heat, dremel, broke about 6 drill bits in order to get the spline nut out of the way. Had both openings completely clear of any debris that would keep them open and ended up pressing it out in 2 minutes after 5 hours of insanity. I can see how that would be a pain to put in by yourself. Flowers can get the parts but better if you can do the work yourself as they are stacked with work this time of year.


                          • #14
                            Tomorrow I will finish the gimbal ring, pulling double duty, with that jump between the inside and outside.

                            Then I will either install the bellow or remount the engine. I am leaning towards the engine to ensure that it is aligned properly. It was good before I pulled it (another job that a helper can speed things up, I move the boat/trailer around to get the engine over the mounts). I should be back together by Sunday.

                            Tonight was installing a new hydraulic brake booster in the Ford pickup.


                            • #15
                              Sounds like fun, I'm about a week behind you, just finished installing my heads and intake manifold. Waiting for all the gimbal housing parts to come in. An extra hand is nice when trying to get things installed without dinging them or something else up. If you ever need a hand, let me know. As for the Ford...seems if it isn't one thing it is another.