Replace transom clamp screw

[Heronwater]

I have an old 15 HP Mariner. The transom clamp screws were twisted so I have cut off the cups, and bought new screws. How do you fit the washer cup onto the end of the screw?? The screw has an Aluminum end but I cannot see how to get a hammer to it to expand it to stop the cup falling off as the screw has to be put through the mounting clamp hole before the cup is attached! Is there a knack or is there a special tool? Sorry to ask what must seem such a simple question.

 

[Whoopbass]

Re: Replace transom clamp screw

Put the flat end of the screw in a vice then install the washer and smash the end with a hammer to flatten it out.
The hardest part will be keeping the screw straight while hitting it with a hammer.

If you don't like that idea then cut the end flush where the washer goes on, drill a hole in the end about an inch deep and run a tap in it to make threads so you can install a bolt.

 

[kabcpapc]

Re: Replace transom clamp screw

On my 1983 Merc 25hp the washers are held in place by a small bolt. I had to buy a new clamp screw to replace a bolt that the previous owner had used to attach the motor to the transom. It was easy to attach the washer after I had screwed the clamp screw through the hole.

 

[Heronwater]

Re: Replace transom clamp screw

Put the flat end of the screw in a vice then install the washer and smash the end with a hammer to flatten it out.
The hardest part will be keeping the screw straight while hitting it with a hammer.

If you don't like that idea then cut the end flush where the washer goes on, drill a hole in the end about an inch deep and run a tap in it to make threads so you can install a bolt.

Thanks. Unfortunately the toggle end is wider, so the washer must be put on AFTER the clamp screw is put into the motor frame. Hence my problem. I can't get at the end of the screw with a hammer or any leverage once it is in place. I think drilling a hole in it and putting a small screw in is the only option. Obviously they have a special compression jig to do it in manufacture. Unless anyone knows a better way. Thanks.

 

[kabcpapc]

Re: Replace transom clamp screw

How old is your motor? What is the serial number?

Check out this website.

http://www.lmmarine.net/pages/parts/viewbybrand/59/MercuryMarine.aspx

If you can figure out the size of your old clamp screw, maybe you can order one that fits a later year motor that has the washer attached by a small bolt.

 

[timdan94]

Re: Replace transom clamp screw

place a small plate of metal between the transom and use an appropriately sized ball bearing to crush out the end of the transom clamp. It goes the plate then the ball then the washer then the bolt. You then proceed too crank down on the transom clamp forcing the metal on the clamp to spread holding the washer on.

 

[Whoopbass]

Re: Replace transom clamp screw

I just repaired a couple transom clamps by drilling a hole in them and taping new threads. It was easy to do since their aluminum and they work great.

Buy a nut that you can screw down part way on the transom screw so your vise has something to clamp onto besides the threads.

 

[Heronwater]

Re: Replace transom clamp screw

Thanks everyone. I decided to trim off the end of the transom screw and tap a thread into it, then used a screw with an Allen key head to hold the washer on so it was easy to tighten with an Allen key. The steel was very strong and I doubt that the ball bearing approach would have achieved the rivet end desired. Obviously motor manufacturers have a special tool to fix the washer on neatly.

 

[StinkingDingy]

I used a 3/8 inch drive, 3/8 inch deep socket. Putting the socket end over the screw end and up tight against the washer and turned it in like a press until it squeezed the washer flat. Worked like a Champ made to impress using the transom clamp as it's own press.