Uneven steering – U-joint locked

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  • #26580
    Arild Jaeger

    At the end of last summer I noticed that when turning the steering wheel there was one point it was hard (but possible) to move past.  I didn’t understand the reason, so I started disconnecting the various parts of the steering system, and eventually found that the U-joint next to the steering box at the aft end of the system was stuck in one of the two movements.

    Just as Ronar M reported in another thread (https://nicholson38.org/?topic=steering-issues-found-by-surveyor-on-vanikoro), I found it difficult to detach the drag link from the stub-tiller on the gearbox.  The tapered pin holding the drag link was stuck.  I eventually used a wedge shaped fork between the stub-tiller and the drag link, which I gave a sharp tap after having heated the stub-tiller with a gas flame.

    The other challenge was to pull off the taper bushing from the front end of the aft steering shaft, so I could get the shaft through the bulkhead and out of the boat.  For this I had to drill four matching 10 mm holes in a 10 mm steel plate and use the four bolt holes in the taper bushing to pull it off.

    (Each of the two challenges took me a month to solve.)

    I replaced the jammed joint with a “type 1140 joint”.  The next time, I will sand down the inside of the holes (where the joint bearing cups go in) a little more, so I don’t have to use so much force to get the bearing cups in.

    I also took the opportunity to pour out the old oil from the aft gearbox (Mathway LS steering).  The oil looked OK after all these years.  I asked Mark at Parsons Mathway Marine what oil to use, and he recommended “SAE 30 or 15W40” and said they actually use a thick oily grease in LS steering boxes (BP energrease FG00).

    I sanded down and painted the parts I had take out of the boat and the tiller arm on the rudder shaft.  The arm was badly rusted.  The inside of the hull was uneven and rust stained, so I sanded it down and put on one layer of gelcoat and one layer of topcoat before I reassembled the steering.

    To get at the steering shaft and box, I disassembled the port bunk in the aft cabin and the plate above the sink under the window in the aft cabin.

    Arild Jaeger

    Mathway LS steering box

    Rather rusty, before removal.


    Thanks for a very informative posting! We’ve not faced this problem yet, but… Couple questions –

    1) have you ever found an oil fill hole in any of these gearbox oil bath containers?

    2) Do you have any recommendations about preventative maintenance, now that you were forced to make this repair?

    Marilyn, moderator

    Arild Jaeger


    Thank you for your response and questions.

    On the aft gearbox there is an oil fill hole on the top lid.  The other gearboxes are tilted, so the sides with the oil fill holes are not horizontal.  On “Far Out” only the forward gearbox (behind the steering wheel) needs to be replenished every year.  After 10-15 years (since last time I checked) all the oil was still in the aft gearbox, while the lower forward gearbox had lost a little oil.  In addition to checking the oil, there are several grease points which should be greased.  (You can also buy U-joints which can be greased, but I decided to stay with the maintenance free U-joint when I replaced one.)

    I suppose you should keep an eye on each gearbox to see how often you need to refill oil, and while you are at it you can add grease to the grease points.  I was surprised when one direction of our aft U-joint was jammed at the end of the summer season.  I would have thought this should have happened at the end of the winter layup, when nothing is moved for 7-8 months.

    I hope to get less seawater leaking from the deck onto the U-joint going forward, so there will be less corrosion and hopefully less risk of jamming.


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