What oil should I use Hydraulic or ATF??

[rogersimms]

Hi all

Firstly apologies if this has already been discussed but oil comes up in hundreds of threads and I was getting no where

I have recently repaired my hydraulic autopilot. One of the magnets had fallen off which seems a fairly common problem. I now need to change the oil but am a little confused as raymarine have suggested ATF40.

Can someone enlighten me as to the the difference between ATF and Hydraulic oil. I have bought a can labelled Hydraulic oil (seemed fairly cheap)and some ATF DEX1II for a borg warner gearbox which was a lot more expensive so there must be a difference.


Thanks

 

[Bosun Higgs]

I don't know - but I thought I would reply and tell you that.

I know there are synthetic and mineral hydraulic oils and in some cases the seals dont like one or the other. ATF is a sort of hydraulic oil but what makes it different from the boggo, I do not know. FWIW I simply stuck hydraulic oil in my Simrad autopilot ram.

 

[Bodach na mara]

Like Bosun, I don't know, but the 40 figure may be a viscosity. My hydraulic steering uses a hydraulic oil of 20 (centipoise ???) but it is a STEERING system, not an autopilot.

 

[Heckler]

Hi all

Firstly apologies if this has already been discussed but oil comes up in hundreds of threads and I was getting no where

I have recently repaired my hydraulic autopilot. One of the magnets had fallen off which seems a fairly common problem. I now need to change the oil but am a little confused as raymarine have suggested ATF40.

Can someone enlighten me as to the the difference between ATF and Hydraulic oil. I have bought a can labelled Hydraulic oil (seemed fairly cheap)and some ATF DEX1II for a borg warner gearbox which was a lot more expensive so there must be a difference.


Thanks

Hydraulic oil is oil, if you see what I mean. ATF is oil based but has additives to make it more resistant to heat, a lot is generated from the clutch and brake bands plus the slippage in the fluid flywheel, in an automatic car, generates a lot of heat quickly. It also must be able to be "squeezed" out of spaces quickly, think brake bands in auto boxes being applied to a drum.
If Raymarine say ATF then use that, I dont believe hydraulic oil will do any harm in this application though. In fact I have just bought some 32 hyd oil for my B&G autopilot.
Stu

 

[rogersimms]

Thanks guys for your replies. Just to let you know what the figure 40 is in reference to the email I got from raymarine

"Regarding Oil recommendations, we recommend using a "Dynobear 10" oil, as this had additives that help keep it working well in hotter environments. The oil basically has to have a scale of 'Tellus 10'. We also recommend Automatic transmission Fluid ATF40 CST@40deg"

I am in malaysia at the moment and its hard enough just explaining hydrualic oil, So I am just trying to get an uderstanding myself before I go into a shop and make a complete fool of my self

 

[vyv_cox]

Yes, Stu is correct. Both are hydrocarbon based. Don't get confused about synthetic in this context, it simply means that the oil is produced by synthesizing gas/light liquids to obtain more regular molecular lengths. Unlike automotive brake fluid, hydraulic fire pumps, mining applications and others, also synthetic but very much not hydrocarbon.

Hydraulic oil contains additives that are boundary lubricants, to lubricate steel-on-steel components under heavy load. ATF is heavily loaded with boundary lubricants but also quite a lot of anti-oxidants and other things.

So an application that doesn't get hot will probably be OK with either type but hot applications, like automotive automatic gearboxes, must have ATF.