Transom Clamp Bolts REALLY Frozen

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  • lindy46
    lindy46
    US Member - 1 Year
    Replies: 253
    Topics: 21
    #166468

    Well, here’s a new one for me. I picked up a 1955 Ducktwin and the transom clamp bolts are frozen. I’ve soaked in PB Blaster and even took the handle off to get to the square end beneath. I tried a wrench on the end, and she won’t budge. Anyone have this problem before? ANy ideas? I don’t want to break the bolt or the casting.

    bobw
    bobw
    US Member - 1 Year
    Replies: 435
    Topics: 24
    #166469

    If you haven’t tried heating it yet, go ahead and heat up the clamp bracket area around the clamp bolt and apply the PB Blaster. Keep applying heat and penetrant and see if you can loosen the bolts. My ’72 Evinrude had been a salt water motor and the clamp bolts were frozen solid. I ended up drilling 2 small holes through the brackets (one hole on each side of the bracket) to access the inner thread area of the bolts which allowed the PB Blaster to work its way deeper into the entire thread area after I applied the heat. Took a lot of time and patience but I got them out. I plugged the drill access holes with a dab of JB Weld.

    Bob

    1954 Johnson CD-11
    1958 Johnson QD-19
    1956 Johnson RD-18

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    dave-bernard
    US Member - 2 Years
    Replies: 827
    Topics: 10
    #166472

    the worst case cut the threads flush drill out with larger and larger bits till you are almost hitting the threads. then you can use a tap. and put new or user thumb screws in.

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    crosbyman
    Canada Member - 1 Year
    Replies: 1148
    Topics: 152
    #166489

    heat… then a freeze shock may help….

    use a keyboard “duster” air can held upside down and spray 10 seconds $4 at the Dollar store

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    garry-in-tampa
    Lifetime Member
    Replies: 3014
    Topics: 29
    #166490

    I like that small hole idea – I may fill the hole with a tiny grease. fitting.   I use a Dremel wire brush to clean the rust off the threads that I can reach. (There flexible shaft lets you get in tight places better and, as a bonus, the motor runs at a lower tempriture.) What has given me problems is the screw driver handle on the 3.3 HP Evinrude Sportwin with the fuel gage, and the 7.5 HP neutral clutch Fleetwin. . .

    frankr
    frankr
    US Member - 1 Year
    Replies: 4002
    Topics: 43
    #166502

    Being in a salt water area, I’ve seen literally thousands of those screws frozen. Heat doesn’t do a whole lot of good because both the screw and bracket are aluminum and expand at the same rate. Go ahead and try the conservative methods, but don’t be surprised if you wind up drilling them out. Fortunately, they are aluminum and easy to drill. I deliberately drill them off-center, using larger and larger drills till it reaches the threads on one side. Then you wind up with a C-shaped remainder that can be turned out. It is a learned skill. Goof luck.

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    billw
    US Member - 1 Year
    Replies: 1007
    Topics: 33
    #166512

    Sometimes, if you heat and cool, heat and cool a few times it can be enough to get things moving a bit. If it does start to tun slightly, just gently work it back and forth, in bigger and bigger arcs. Do not heat it burning hot and then try to turn it, or the threads might gall. Then you will definitely be drilling it out. On aluminum, I like CRC 6-56 for a penetrant. Drilling may be required and is probably the fastest way, anyway; however, if you’re not working against a clock, heat might be worth the try. The good news is, if drilling happens, at least the tap to clean out the threads is found in most standard tap and die sets. If you had an 18 or a 40, you’d be hunting down a larger tap.

    lindy46
    lindy46
    US Member - 1 Year
    Replies: 253
    Topics: 21
    #166515

    Thanks for all the suggestions. The darndest part is I see no corrosion on the exposed threads nor on the casting. I’ll go ahead and drill a small hole in the middle of the casting and spray PB Blaster in there and see what happens. I’m in TN so no salt water, but who knows where the motor has been in its’ 64 years. I do notice rust on some of the other bolts where there shouldn’t be rust – like the bolts on the mag plate. The condenser bolts were really rusted on and so were the bolts holding the spark plug wire clamps. I went ahead and replaced the whole armature plate. Surprisingly, the coils are very new Prufrex coils, so someone replaced them recently, but the points were original. Maybe this motor took a bath at one point in time. The pistons and cylinder walls are clean as a whistle, and compression is good, so we’ll see what happens.

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    mas
    US Member - 2 Years
    Replies: 158
    Topics: 39
    #166517

    I’ve got a Mark 25 that had a frozen clamp too…I spent over a month of a daily propane heat and PB blaster treatment. When I felt it budge just a tad, it was the most satisfying accomplishment. Few things have I spent so much time and effort…but worth it’s weight in gold.

    Keep at it,

    Mas

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    PugetSoundBoater
    US Member - 2 Years
    Replies: 975
    Topics: 135
    #166530

    I have thought the same as bobw ,drilling a hole through the side of the swivel bracket ,so i can get some lubricant way down in the middle of those inasscessable inner threads . I use a 50/50 blend of power steering fluid and acetone instead of PB Blaster etc. It works real well in my experiences, along with several many heating and cool cycles with a propane torch. I am not saying the other aerosol lubricants are not any good, just prefer mine.
    bobw’s comment about once the screw starts to move, moving it back and forth in bigger arc is a very good method. Even though it has begun to move ,i still apply more lubricant and heat, taking my time. BE PATIENT, don’t rush it or you very well may break the bolt off. mas spent a month working to free his clamp, can’t say i have spent that many days on it! It’s not like we have to drive it to work tommorow.
    frankr’s comment on the transom bracket and screw both being aluminum and expanding and contracting at the same rate is good to keep in mind,
    Many different approaches to this issue.

    All of these responses have merit. Keep them all in mind and take your time.

    "Some people want to know how a watch works, others just want to know what time it is"
    Robbie Robertson

    bobw
    bobw
    US Member - 1 Year
    Replies: 435
    Topics: 24
    #166600

    Forgot to mention on my ’72 Evinrude that one of the bolts was so eaten up from salt water there as no way I was going to be able to back it out. So I just hack-sawed off the exposed portion of the bolt that was messed up, then did the heating and penetrating fluid treatment. Worked real good when I drilled the access holes through the bracket to get penetrant to the inner portion of the bolt threads. This one that I sawed off had the bracket threads messed up a little bit so I just ran a tap through it to clean it up.

    Bob

    1954 Johnson CD-11
    1958 Johnson QD-19
    1956 Johnson RD-18

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    XR55
    US Member - 2 Years
    Replies: 286
    Topics: 29
    #166606

    I was given a Mercury 400 that was attached to an old fiberglass boat. The owner of the boat wanted to keep the boat. The clamp screws had not been moved since the motor was installed when new in the 1960s and it sat outside it’s whole life. After trying heat from a map gas torch and solvent I went to plan B. Since this was out in a boat yard storage lot I went back home for more equipment. I returned with a generator and my dremel tool and HD cut off wheel. I sliced the underside of each clamp bracket lengthwise just deep enough to touch the threads of the screws. This allowed the bracket threads to expand and release the screw threads. I was able to loosen the clamps then and remove the motor from the boat. Then after running the screws all the way in and out and cleaning the threads, I vee’ed out the slots and welded the the slots shut. Followed by light grinding to blend the weld and Bob’s your uncle all done. No drilling and all the original threads were saved. Then I went and gave the motor away, and as it turned out was a good running outboard.

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    PugetSoundBoater
    US Member - 2 Years
    Replies: 975
    Topics: 135
    #166621

    XR55- thats a great approach to the problem, kinda drastic measures ,but you got results, which you may not have ever gotten without cutting into the bracket.

    "Some people want to know how a watch works, others just want to know what time it is"
    Robbie Robertson

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    XR55
    US Member - 2 Years
    Replies: 286
    Topics: 29
    #166624

    Yes it was drastic, but both sets of the threads were undamaged, no twisted screws or levers twisted or broken, no drilling, no needed replacement parts. After welding and minor blending of the weld, you could not tell if any repair had been done and it all was on the bottom and not visible from the top side. Just thinking outside the box came up with a strong good looking repair.

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    PugetSoundBoater
    US Member - 2 Years
    Replies: 975
    Topics: 135
    #166630

    XR55-you did the cutting on the bottom side an the weld repair would be real hard to spot. Well done and good job!
    Jim PSB

    "Some people want to know how a watch works, others just want to know what time it is"
    Robbie Robertson

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