Can anyone tell me if there are some additives in hydralic oils that would cause the depletion of brass and copper?

Yes, anti-wear (AW) Hydraulic Oils contains the additive ZnDDP (zinc dialkil dithiophosphate). This additive can to react with non-ferrous metals such as cooper, brass or other. If you have in hydraulic system any parts with these metals it will be better to use non-ash (Zn-free) Hydraulic Oils, for example Chevron Clarity Hydraulic Oils AW.

Mikhail

Dear Brtowry,

Mikhail is correct. Incidently most of the hydraulic oils have this ZDDP antiwear additive package. The product brochure invariably cautions its use where Copper/Brass bearings are used.

Some time back Castrol had introduced a ZZ ( Zero zinc ) series of Hydraulic oils, you may like to have a shot at this.

Regards.

Hussam Adeni

One oil that works fine in air compressors that require a non-ZDDP oil is the Multilec 6800 series from Lubrication Engineers. It works GREAT! Contact me at MikeTheGreaseMan@aol.com

I might be wrong here but... I have rebuilt hundreds of hydraulic pumps from various manufacturers and they almost all use brass for wear plates in the cartridge housings. All these manufacturers will recommend a AW classified oil. The only problem I know when it come to yellow metals being attacked is when it is lubed with EP classified oils at elevated temps. Further more Dexron ATF can be used as a hydraulic oil with amazing results.

Jim Ott,

You are right,Dexron ATF (Automatic Transmission Fluids) can be safely used in many hydraulic systems. They are generally between ISO VG 32 or 46 grade of oils.

Oils with ZDDP additive packages (most oils have this anyway) creat problems at elevated temperature the problem is further compounded in the presence of moisture/water. The packages collapses and chokes mesh/filters/lines.

M Hussam Adeni

Yes
ZDDP is having a threat to the attack as well as producing solid precipitates which get stuck in the clearance in valves and cause erratic performances of systems.
Tribol 943 AW series is a Hydraulic oil without ZDDP Package antiwear
this is freindly and has been proven in Vickers vane pump test.
May try this and also hs a good demulsibility.

Arupanjan Mukherji

Arupanjan,

Welcome aboard. Can you recommend an OKS or Kluber product?

Hussam Adeni

There is nothing from OKS range and Iam not sure about the Kluber range.Lamore could be the rangewith appropriate viscosity grade.

Arupanjan Mukherji

ZDDP Additive stability is based on base oil
chemistry.Note that additives function efficiently in base oils which contains minimum
impurities.Inadequate oxidation and thermal stablity of base oil will cause additive breakdown and eventuall metal corrosion.

I think that it is good idea to use ATFs (Automatic Transmission Fluids) in most hydraulic systems. For example, many our customs used it in different equipment. ATFs have some characteristics, which makes their very suitable for hydraulic systems. Their viscosity is in range normally hydraulic oils. High VI (viscosity index) of ATF allows used it year-round in most climatic conditions without season oil change. Oxidizing and thermal stability allows used their long time. And color of ATFs makes easy leaks identification. Our customs thanks for advice apply ATFs instead hydraulic oils.
But this context does not detract from high-quality hydraulic oils. Now we have on market long list of oils for hydraulic systems – mineral and synthetic, anti-wear and without AW additives, with usually VI and high VI (HVI), with ash and full Ashless, special oils for silver parts applications, for arctic climate and for marine, an so on.
Thanks.

Brtowry, any good hydraulic oil will not cause depletion of brass or copper. Perhaps in the past some sulphur additivated hydraulic oils were used, or gear oils applied for hydraulics, but it is not the case any more. Why are you asking, what was the problem you found? If you found abrasion it was not any specific additive but the lack of them thereof.

quote:

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Originally posted by Ricardo:
Brtowry, any good hydraulic oil will not cause depletion of brass or copper. Perhaps in the past some sulphur additivated hydraulic oils were used, or gear oils applied for hydraulics, but it is not the case any more. Why are you asking, what was the problem you found? If you found abrasion it was not any specific additive but the lack of them thereof.

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I agree with Mr Ricardo .

With the advent of the stable ZDDPs in the early 80's the problem of attack of brass and copper was not seen as Hydraulic pump manufacturer uses phosphor bronze bushes for variable pumps where the flow and pressure can be adjusted.

Moreover the copper corrosion test is good indicator of brass and copper attack.

Hussam is correct.
Castrol have a range of hydraulic oils with Zero Zinc, it called Hyspin ZZ range and it comes in 32, 46 and 68 viscosities at 40 Degrees c. The range meets DIN 51524 part 2

We had tried an ashless additive from a reputed additive manufacturer without any zinc content and had problems of jell formation at higher temperatures in mobile hydraulic and compressor systems .

Does anyone have a similiar experience ?

Franky,

Gell formation in hydraulic oil is due to
additive dropping out of oil.High paraffinic
base oil has miscibility problem with certain
additives.If i'm correctly remember,Carriers
were added to avoid dropping out of additives.

Good Luck

Bala.