rear thrustershear pin replacement on R25 shear pin

jimbeam

Well-known member
Joined
Aug 21, 2019
Messages
172
Fluid Motion Model
C-248 C
Hull Identification Number
FMLT2545G708
Vessel Name
waite & sea
How difficult is it to replace the shear pin on the stern thruster of an R25? Should you take it out of the water first?
Looks difficult just to get at. In fact it looks almost impossible :x
jimbeam
 
Is it a Side-Power thruster?

It is hard but not 'impossible'. Getting their specialized tool to remove the Allen keys makes all the difference. I was able to modify a similar key on Amazon with a dremel but it was still 10x easier to use the proper tool. I had to cut down an allen key bit as well as shave the head down in order to fit into the confined space. However, it should be possible while in the water (speaking from R31 experience)

Proper tool
https://www.fisheriessupply.com/side-po ... smtool-6mm

You might get it to work tool
https://www.amazon.com/gp/product/B000X ... UTF8&psc=1
 
I had to replace the thruster in my c28. Challenging but not impossible. Like others have said the correct wrench will make it better. I slipped while reaching down to remove the thruster and broke a rib. Had a friend come and help install the motor. I found a few posts on this forum that helped do a little search for them. In the cutwater you have to reach down through the rear seat. not sure what your tug access is like but I am sure it is tight. Take your time Good luck.
 
There is no reason to take the boat out of the water to replace the shear pin. Your arms will not grow any longer by removing the boat from the water and the access is the same way - under the rear seat from inside the boat. The best trick is to find a friend with long arms or just plan on stretching down there to reach it. ( I am 5' 6'' and managed to do mine, but it was not the most fun I ever had on a boat.)
 
Not sure which R25, but on my '09, I found that the "might work" right angle ratchet worked if you broke the bolts loose with a standard Allen wrench first.
Other tips: 1. Take out the bait well/goodie locker so the deck access hatch under it will open all the way. 1.A. clear the area of those with sensitive ears.
2. If you take out the start battery it may be easier to reach the port side bolt on the thruster. I also removed the deck drain hose behind that battery.
3. A piece of 2 x 6 about 10 - 12 inches long laid on the floor of the bilge under the motor plus a small wedge shaped piece of wood or a door wedge will help to hold the motor at about the right height while you put the bolts back in.
4, I did not have to undo the wiring to change the pin; there was enough slack to stand it on its rear end and knock out the broken pin.
The next time, the fiberglass divider between the teak doors comes out first! Since a saw will be required, I already have the reinforcing splices made to reinstall it. The best thing about this job is that it makes the water pump seem easy.
 
I did this job on my 2013 R27 which is probably the same as yours. I made my own Allen wrench by just cutting one down to a size to fit in the limited space. The most useful tip I picked up in other threads here on this same topic was to buy a bolt the same size as the 2 that hold the thruster in place (6mm?) and cut the head off it. That leaves you with a stud you can put in the inboard hole. That gives you a way to align and hold the thruster motor on one side while you get the outboard side bolt started. Once that bolt is part way in you can remove the stud and replace it with the proper bolt.
Then snug up both bolts and you’re done. I did that instead of the whole block of wood and wedge trick to support the motor. I did the whole job by reaching down into the rear seat area and had a pretty sore bruised up chest when I finished. The whole job took about 2 hours but I’m a pretty experienced mechanic.


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Do you know the size and length of the bolt you cut to make the stud? You said "6mm?" I would like to get a couple to have in the tool box. Couldn't find it on the Imtra site. I could take one out of the front thruster if you don't.
Funny note: When my boat was surveyed, the surveyor noted the "unexplained 2 x 6" in the bilge, and also noted he couldn't figure out why it was there. I learned someone else used to hold the thruster motor up for reinstallation when I did it. They cut it a little too long to get it out after the installation. It is still in there.
Thanks
 
I took the Allen head bolt to the hardware store and matched it up with a regular bolt, same size, thread count etc. about 1” longer. Then, with the head cut off the new bolt there’s about an inch sticking out once the thruster is in place that you can hold on to to unscrew it once the other bolt is in place. You’re basically creating an alignment pin to hold the thruster in place temporarily while you get the other bolt started in. The bolt/alignment pin only needs to thread in a few threads. No need to screw it all the way in. Just enough to support the weight of the thruster and keep it in place long enough to get the other bolt started in the threads.


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