hydraulic jack oil change

[brick8]

I have a 3 ton Craftsman hydraulic jack. I think it is time to change the hydraulic oil, but I can't figure out how to do it. I went to the Sears website but couldn't find anything. Also went to the store where I bought it several years ago and the guys there didn't have a clue. Any advice would be greatly appreciated. Thanks!

[kip Foss]

One: you don't need to change the oil in a hyd. jack.

Two: If you are just eaten up with wanting to change it there is usually a small rubber plug in the side of the barrel. Ease it out with a small screwdriver. You stand a chance of breaking off the inside part. If you do break it off it won't effect the operation of the jack but you will now have to find a new plug. Check out the local hydraulic repair shop, they might have one.

Any light (5 wt.) oil will do to refill the jack. They make oil specifically for jacks but I don't really think it makes that much difference. I use Moble DTE 25 in my 'Porta Power' equipment at work and it does just fine.

[kmaysob]

i agree. i have never changed the oil in any of my jacks. when refilling use a hydralic fluid such as brake fluid or jack oil. i wouldnt trust regular oil in somthing that could kill me

[kip Foss]

In this regard oil is oil. Any light oil will work. Break fluid on the other hand is very aggressive chemically, esp. on o-rings, and probably should not be used. Any liquid, including water, will work but oil is best.

[kmaysob]

Originally Posted by kip Foss

In this regard oil is oil. Any light oil will work. Break fluid on the other hand is very aggressive chemically, esp. on o-rings, and probably should not be used. Any liquid, including water, will work but oil is best.

been using brake fluid for years. i severly hope you dont think you can use water. if you think that, you dont belong around cars or anything hydralic for that matter.

[Nate]

x2 on no water... and there's not really much reason to change it unless it leaks

there's rubber every single hydralic braking system system, CLEAN brake fluid has yet to eat holes in anything that's less then 25years old... if your jack is that old, I wouldnt trust it.

Why does anybody say it could kill you? use JACKSTANDS!!! The jack's for putting it onto the jackstands, not for acting like one...

~Nate

[kmaysob]

Originally Posted by Nate

x2 on no water... and there's not really much reason to change it unless it leaks

there's rubber every single hydralic braking system system, CLEAN brake fluid has yet to eat holes in anything that's less then 25years old... if your jack is that old, I wouldnt trust it.

Why does anybody say it could kill you? use JACKSTANDS!!! The jack's for putting it onto the jackstands, not for acting like one...

~Nate

nate, for most of the solid places to place a jack stand you need to crawl under the car slightly.

[Eskimo]

Unless a manufacturer has actually specified its use, I don't believe it's advisable to use brake fluid in a hydraulic jack.

Yes, a brake system is a hydraulic system, and brake fluid is a hydraulic fluid - but it's a special hydraulic fluid that carries with it its own baggage as a result of compromises made when formulating it to meet the particular requirements of an automotive braking system. The components of the braking system are designed knowing full well the nature of the fluid, so materials compatibility should not be a problem.

Our hydraulic jacks don't require some of the special characteristics of brake fluid, so we don't need the baggage that comes with it. We can use ordinary (kinder, gentler) hydraulic fluid.

I don't personally know enough about the composition and compatibility of the seals used in hydraulic jacks to make any statement about whether or not brake fluid might be expected to cause damage to the seals. Some of the manufacturers of jacks, however, make if very clear that brake fluid is NOT to be used in their products. This isn't always a case of them pushing their own oil, either. From the documentation that came with my floor jack:

Any good hydraulic oil of viscosity of 10-32 cSt/40° can be used. NEVER USE BRAKE FLUID.

(For what it's worth, they also note that, "Pump and cylinder form a closed system and refilling of oil is only necessary in exceptional cases.")

One might also see what one guy who sells and services jacks has to say about it: Otto Service - Jack Basics.

[kip Foss]

kmay,

You missed my point about the water entirely. The jack, being a hydraulic system, will work, and work quite well on water. It won't last long on water as any dolt would know, but it will work.

That you should not use brake fluid in a jack, the nature of whose internal seals you probably do not know, is the same reason the you should not use modern mineral based brake fluid in old style systems. It will often disolve the seals.

ps. I have been working on machinery, everything from lawn mowers to 50,000 hp marine engines all around the world, for a bit over 50 years now so I am fairly confident that I know what I am talking about. I currently operate two 2,000 ton per hour bulk ore ship unloaders that have about 1,500 hydraulic horse power each so I deal with hydraulics on a daily basis.

[Monomer]

A hydraulic system works off the fact that you cant compress a liquid.


Therefore, just about ANY liquid will work, just some better than others. You want oil - something that'll clean, lubricate and protect.

[John Doe]

I would think you would possibly cause more problems than you could solve changing oil in a floor jack. There would be no thermal breakdown, and no foreign particles in the oil, unless one had been checking the oil level periodically and opening the cylinder If the viscociy in the oil is the same as when you started and is clean, why mess with it and risk a leak or introduction of dirt into the cylider?

[Dee8go]

If it ain't broke, why are you trying to fix it? I never heard of changing the oil in a jack. I started reading this and thought "OMG, was I supposed to be doing that?"

If you really need something to fix, come on over to my house. I have plenty of things that DO need fixing!

[brick8]

I thought of this because the local store where I buy my tools sells the oil next to the hydraulic jacks. I bought some, just in case. Based on the responses here I will let it sit on the shelf next to some of the other handy-dandy chemicals I have accumulated over the years. BTW, I did grease the thing using the zerk fitting and that made a huge difference.

[kmaysob]

Originally Posted by John Doe

I would think you would possibly cause more problems than you could solve changing oil in a floor jack. There would be no thermal breakdown, and no foreign particles in the oil, unless one had been checking the oil level periodically and opening the cylinder If the viscociy in the oil is the same as when you started and is clean, why mess with it and risk a leak or introduction of dirt into the cylider?

jack oil does get dirty even when kept sealed. and the level will drop over time eventully. when my jack stops working properly i open it up and add a little BRAKEfluid. my grandpa did that all of his life.

[cscmc1]

Originally Posted by kip Foss

kmay,

You missed my point about the water entirely. The jack, being a hydraulic system, will work, and work quite well on water. It won't last long on water as any dolt would know, but it will work.

That you should not use brake fluid in a jack, the nature of whose internal seals you probably do not know, is the same reason the you should not use modern mineral based brake fluid in old style systems. It will often disolve the seals.

ps. I have been working on machinery, everything from lawn mowers to 50,000 hp marine engines all around the world, for a bit over 50 years now so I am fairly confident that I know what I am talking about. I currently operate two 2,000 ton per hour bulk ore ship unloaders that have about 1,500 hydraulic horse power each so I deal with hydraulics on a daily basis.

Well said. I know well enough not to use modern brake fluid in my TR6 brake system... gotta source the Castrol fluid or risk damaging the seals in the system!