Re: Prop is spinning freely


 

Chris,

There is usually not a simple answer to your question. 

 The most common issues for non-braking are mechanical within the caliper mechanism. Non-braking is usually caused by the following in order of probability:
  • The caliper bushings will wear and cause misalignment and open calipers
  • The brake shoe pads will wear
  • The caliper frame may be loose on the hydraulic cylinder
  • The hydraulic cylinder spring may need adjustment
  • The hydraulic cylinder may need an overhaul
  • The caliper mechanical springs may be broken or defective
  • Or, something else I haven't thought of 
The most common issue for not releasing is hydraulic in nature.

The quarter that Courtney refers to will usually solve the problem when the bushing is worn, or the brake pad is worn.

It is possible that the Italian-made Caliper you have is no longer made. If so, Amel will supply you with a new model that will work, but not necessarily fit without minor modification.

I believe that you can either leave the prop free spinning or place the transmission in gear to stop the spinning, however, I do not recommend either of those because I have not been able to verify the long-term issues, if any, in doing either.


CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Sun, Jan 3, 2021 at 9:37 AM Chris Likins <likinsca@...> wrote:
We have A54 #133. Today when sailing I noticed that the prop was spinning freely(in reverse) each time a wave would pass under us. It’s easy to see that the shaft brake is not engaging when the engine is in neutral or shut down. Referencing Bill Rouses book p.305, it reads that the hydraulic shaft OPENS the calipers when pressurized by the transmission. Currently the shaft is retracted into the piston at all times allowing the calipers to remain open. I understand that the calipers are supposed to spring shut on the disk when transmission pressure is lost on the shaft. I am a bit confused by this as there is no mechanical connection between the hydraulic shaft and the outer caliper. It seems like the calipers should close when the shaft is extended.. So my questions are
1. Can someone help explain this system in more detail? 
2. What position should the shaft be in when pressurized and not pressurized? 
3. Is it most likely a bad spring on the caliper? 
4. Most importantly for now.. Is it ok to allow the prop to spin freely for the duration of the passage or would it be better on the shaft if we remain in forward gear. 

Thank you for the help! 

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