Hydraulic Steering Drifting

[idpnd]

Hello all,

I've got a Capilano 275V with model 50 Uniflow valve from 1988 or so.

Lately the rudder has been drifting up to the 5° mark in port over the course of a few hours; there is a strong cross current here.

I de-aired the system thoroughly and I felt there was a lot of air in it considering I had last done it 6 months ago. Checkvalves were also cleaned (oil clean, no grit).

The steering shows no other symptoms otherwise - works great on manual and autopilot.

Opinions?

Thanks for your time!

[Pete7]

Tiny hydraulic leak back past the pistons in either the ram or hydraulic pump. Used to happen to us on our rib. Stern drive had hydraulic steering and due to the huge torque from a single propellor the steering wheel would slowly need to be turned in one direction more than another. However, it only affected us on long passages in a straight line so ignored it.

For you though it will make a mess of any autopilot steering system that transmits drive via the ram. The solution would be to use a local truck hydraulic firm to rebuild the ram and pump.

Pete

[idpnd]

Thanks Pete,

the autopilot probably corrects the error, that shouldn't be an issue.

Replacing the system would be heinously expensive since it's outdated (three lines with a separate junction valve, nowadays its all two lines with the univalve inside the steering block), I would have to replace everything. The ram seems to be a bit oily, so its probably that. I will have it overhauled in the future.

[Pete7]

Yes, should be cheap enough even if they have to re-chrome the rams etc. This will be bread and butter stuff for them especially as it's a low pressure system.

Pete

[idpnd]

The ram looks to be in beautiful condition (bronze & chrome in feckless condition), I assume it's the o-ring..