Hydraulic gearbox/drive advice

[spicemouse]

Hi all,

 

I'm still getting the hang of my boat, and am new to narrowboating in general. I've got an old Beta 1903/43 attached to a hydraulic gearbox/drive setup. I do enjoy being able to smoothly switch drive without dropping revs, and the extra room at the back is nice. 

 

However, I want to check the oil levels and top it up as I think it needs it. I can't see a dipstick, but there is a small bolt (see blue circle in image) which opens to a tiny hole. The cap you can see says Parker Hannifin, and the cooler attached is by E J Bowman with a 1974 stamp. 

 

 

 

If anyone has any information on the setup (maybe you have one similar?) or can confirm how I'd check the levels and top up I would really appreciate as I have a feeling even such a simple ask would be expensive to get an engineer for. Also which hydraulic oil should I be using? 

 

Cheers! 

[Mike Adams]

Have you a picture of the drive motor on the propeller shaft and the control valve? That would be helpful in analyzing the system. I suspect the brass plug may have a dipstick if you unscrew it. 

[spicemouse]

4 minutes ago, Mike Adams said:

Have you a picture of the drive motor on the propeller shaft and the control valve? That would be helpful in analyzing the system. I suspect the brass plug may have a dipstick if you unscrew it. 

 

No dipstick I'm afraid, just a very narrow hole. Maybe there was once a dipstick? Worries me it has since fallen in..  

 

I can't get a photos of the hydraulic engine at the moment as the previous owner installed a new stove on the same floor which covers it, without installing any means of access. 

[David Mack]

Parker Hannifin are a major manufacturer of industrial hydraulic equipment, and seem to have an extensive range of current products. If your setup is as old as the Bowman oil cooler, then the components are likely to be long superseded, but the manufacturers or their agents may be able to find the original product details. That means that in order to establish the requirements for your setup you really do need to know the part numbers of the main components - pump, control valve and motor. The unit attached to the back of your engine looks to be a combined hydraulic pump and reservoir. Is there not some kind of identification plate on the side, or a model/part number stamped into the metalwork somewhere?

[spicemouse]

I'll try and have a look for numbers. Did email Parker Hannifin a few days ago but no reply yet. 

[Tony Brooks]

Yes, submerged pump in the reservoir much like the hydraulic Broads boats I was familiar with. As long as the oil has an inch or so headroom to expand into when it heats up in use the actual level is not important in my view. The silver cap is the breather that lets air in and out as the oil cools and heats.

 

The only different thing is that yours seems to have a remote control valve and possibly PRV. The Broads boats had the control valve on the tank and PRV in the tank. Later the PRV was part of the control valve.

 

I think the sort of hydraulic oil farmers buy would do the job. From memory, it was about SAE30.

 

It may well have been put together by the boat builder almost certainly from standard parts apart from the hydraulic motor that normally requires bi-directional thrust bearings to take the prop thrust. Many motors do not have thrust bearings.

Edited April 26, 2021 by Tony Brooks

[Alan de Enfield]

9 minutes ago, Tony Brooks said:

I think the sort of hydraulic oil farmers buy would do the job. From memory, it was about SAE30.

 

Good(ish) memory - it is actually 'ISO Hydraulic Oil 32', rather than SAE.

SAE is the American 'Society of Automotive Engineers.'

 

Hydraulic oil is manufactured to ISO specifications.

 

I use ISO 32 in my digger and tractors.

 

 

Edit to add a link if the OP wants any :

This is the one I normally buy as the 10 litre cans are easier to lift to a height and pour

 

Mannol 2x10L ISO 32 Hydraulic Oil High Grade Shell Tellus 27 DIN 51524 part 2 | eBay

Edited April 26, 2021 by Alan de Enfield

[Tony Brooks]

3 minutes ago, Alan de Enfield said:

 

Good(ish) memory - it is actually 'ISO Hydraulic Oil 32', rather than SAE.

SAE is the American 'Society of Automotive Engineers.'

 

Hydraulic oil is manufactured to ISO specifications.

 

I use ISO 32 in my digger and tractors.

 

 

Edit to add a link if the OP wants any :

This is the one I normally buy as the 10 litre cans are easier to lift to a height and pour

 

Mannol 2x10L ISO 32 Hydraulic Oil High Grade Shell Tellus 27 DIN 51524 part 2 | eBay

 

I was only going by how it poured, I am sure the oil you link to will be fine.

[spicemouse]

I'll take a look at the Iso 32 suggested, thanks! 

 

So the pipe going into the top will be the return from the motor, and the box is a sort of sump?

The oil filling it's picked up by the pump which sucks back up and drives under pressure back round again?

Or is the top pipe the control?

Edited April 26, 2021 by spicemouse
Correction

[Tony Brooks]

3 minutes ago, spicemouse said:

I'll take a look at the Iso 32 suggested, thanks! 

 

So the pipe going into the top will be the return from the motor, and the box is a sort of sump?

The oil filling it's picked up by the pump which sucks back up and drives under pressure back round again?

 

Yes the box is a sort of sump.

 

I suspect the hose going into the top is the pressure feed from the pump. I can see a metal pipe low on the right-hand side of the box. If the return was into the top t would aerate the oil unless it has a  dip tube on it. It might be a bleed return form the motor but it looks a bit large for that. If aerated oil gets drawn into the pump you are likely to get cavitation and that erodes pump parts.

 

The hose may come from a PRV that is inside the box.

[Mike Adams]

9 minutes ago, spicemouse said:

I'll take a look at the Iso 32 suggested, thanks

My system uses iso 37 if that is any help, available from Smith and Allen.

[spicemouse]

There are two pipes going into the box at a lower level, so I don't think the top is a return. 

[Mike Adams]

Depending on the motor type the top pipe will be a leak off from the motor (bent axis or similar) and will only be low pressure but it could also be from the control valve/PRV if this is remote again at low pressure possibly with a dip tube inside the tank.

[spicemouse]

I've got a lot to learn about these hydraulic systems! 

 

I'll try and get a look at the motor, and update this post when I can get access. 

[Tony Brooks]

Looking at the hoses I would say the lower one in the photo is the pressure out of the tank, the top one is the bleed back from the motor and the stll pipe at the top of the photo is probably the return.

 

The motor could be a sine motor because they had bleeds as well as those mentions by Mike. They gave us problems so we gradually changed to gear pumps and vane motors because they were better able to cope with something less than pristine oil and were far more reliable. Not a sufficient as other types though.

[spicemouse]

4 hours ago, Tony Brooks said:

Looking at the hoses I would say the lower one in the photo is the pressure out of the tank, the top one is the bleed back from the motor and the stll pipe at the top of the photo is probably the return.

 

The motor could be a sine motor because they had bleeds as well as those mentions by Mike. They gave us problems so we gradually changed to gear pumps and vane motors because they were better able to cope with something less than pristine oil and were far more reliable. Not a sufficient as other types though.

I don't suppose you know of an diagrams that might help me understand all of this? I'm confused by the difference between the return and the bleed, happy to go read up if I knew where to start. 

[Mike Adams]

I think this diagram might help

[spicemouse]

I think a lot of that must be hidden in the box I have, so mysterious.  

[Tony Brooks]

6 hours ago, spicemouse said:

I think a lot of that must be hidden in the box I have, so mysterious.  

 

Almost certainly not a lot of anything apart from oil. There will be a hydraulic pump that will look a bit like the motor on the end of your propshaft. That will have  a big threaded hole in it by which it sucks oil into itself. It will also have an outlet port with what is probably steel pipe  screwed into it. This pipe will run to a pressure relief valve and from there to the connection for the larger of the two hydraulic hoses. That's all.

 

I think your system will be simpler than the one Mike posted and we found filters had  a short life so we got better reliability by ding away with them, you probably do not have a filter.

 

The oil cooler is probably in the return from the valve so it is not subject to pressure

 

Here is a simple diagram for a system with a remote tank.