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aussie9
28-11-2007, 11:00 AM
Hi guys,

First post and its a question.

I have just bought a 17' 1/2 cabin Savage (115 Johnson)and it is fitted with wind-up / wind-down hydraulically operated trim-tabs.
I have nevere seen these before as any other boats I have owned have had electric jobs.
The question is.

Both the cylinders in the cabin are empty of oil and the guy I bought it off said he was trying to change the oil in them (who knows why) and couldnt get them to work after that.

Does anyone know how to fill these and bleed them back to the trim-tab rams?

Also, what oil to use?


Thanks heaps

Noelm
28-11-2007, 02:38 PM
not too sure I am on the same track as you, you said Manually adjusted tabs, but you have Hydraulic Cylinders/rams?? might be just me, but I don't quite get your setup.

Chimo
28-11-2007, 04:09 PM
Hi Ausie9

Do these have a brand name?

I had a set of perhaps something similar about ten years ago that I used on a 5.6m mono hull.

I seem to recall I just used normal hydraulic ram cylinder oil a la of the tractor kind.

Are your tabs the ones with a couple of pump type levers in the cab by the throttle that you pump and from memory there was a pressure release knob somewhat similar to that on an hydraulic jack to release each tab?

They worked well and I think from memory we bled them by pumping and releasing pressure at the stern to get the air out, a bit like bleeding brakes but with no refinements at all. You need lots of oil and a couple of people to do it.

Hope this is of some help; what would be even more useful would be the instructions if I could ever find them.

Cheers
Chimo

aussie9
28-11-2007, 04:41 PM
Guys,

There are 2 separate cylinders behind the dash. One for each side
These have a plunger on a thread that is would up or down via a crank handle through the dash. Sort of like a syringe on a thread

When you wind the handle down, this forces oil through a tube to the rams that operate the trim tabs and extend the ram to push the tab down.
The trim-tabs ram is spring loaded I think so when you wind the handle back up, the ram returns the oil back to the cylinder behind the dash.

Seems to be a simple design (no brand that I can see though).

The boat was manufactured about 1977 I think, so they could be original

Chimo
28-11-2007, 05:40 PM
Different to what I had

Wonder if you could still fill and prime the same way tho?

Chimo

aussie9
28-11-2007, 05:48 PM
Hope so Chimo.
The only problem I can see is that you have to take the plunger out to pour the oil in.
You could not escape getting air in the lines when you replace the plunger as the plunger fits from the top.
Only thing I can think of is to fill the cylinder, fit the plunger, turn it upside down to get the air out via the outlet for the oil lines.
Then refit the lines and bleed back to the rams.

No wonder the previous owner didnt worry about fixing them..

Chimo
28-11-2007, 07:40 PM
Hey Aussie

What about filling and priming slowly from the stern?
Could you rig a large source of hydraulic oil at the rear with a length of flexible line so you can lift the oil source for more head and lower it to reduce it. With this set up connected to the line from the rear to the pump in the cabin and let gravity slowly fill the lines from the back to the front.

From what you say if you took the screw down plunger off or at least had it sitting on the top without a seal you know the systems full when the oil leaks out past the loose plunger.

Then attach the line at the rear to the previously filled ram on the tab and with someone at the rear fit and tighten the plunger which should force any air out the rear by the ram which the rear man then tightens as the front plunger goes in.

You might have to fiddle but I guess it could work?

Cheers
Chimo

PS don't wear your good clothes while playing with this

aussie9
29-11-2007, 05:11 AM
Thanks Chimo.

I'll play around with it over the next few days.