very similar discussions happen onthe Harley boards all the time.

MB won't tell you what it is or label the container with the specs. They want it to stay a mystery so you keep buying it from them.

It's the same crap that HD does with their "mystery" oils.

There is no mystery oil. The MB oil is not the only acceptable hyd fluid or else MB must provide the oil for free. The law states that a manufacture cannot require a specific brand oil unless it is provided at no cost.

Most owners manuals say "use a XXX type oil, such as MB mystery oil"

My harley manual says if you can't find HD brand oil, use an oil rated for diesel engines. It's a pretty vague statement but keeps them legal without telling you the specific. You have to find out what oils are ok for diesel engines.

For the suspension fluid, I bet generic PS fluid is the same stuff, or meets all the required specs. I'm not talking about red colored ATF, which is specified for many cars PS systems, but the clear PS fluid that AZ & WM sell for about $2 quart.

PS fluid and ATF are both hydraulic fluids. there is very little, if any difference. All the navy aircraft I've flown use a red colored hyd fluid. Mainly to help identify leaks and prevent using it as engine oil & visa-versa.

I bet aircraft hyd oil is probably auto ATF, marketed at 10X the price.

I suppose HD specifies a diesel oil because their engine technology never got past 1940's tractor engines. ;) j/k, friendly biker to biker jibe. ;)

Anyway, if law requires MB to provide a specification in addition to a recommendation for their own oil, can we just call them up and ask what the spec is so we can find our own?

I'm worried about using other fluids not because they aren't MB branded, but because sometimes there are subtle differences in fluids that mean a lot for compatibility, like Dot 5 and Dot 5.1 brake fluids. If I were comfortable with the spec, I'd be happy to poke through catalogs and interrogate tractor shops to find a similarly spec'ed fluid, which some of these FEBI fluids mentioned may be. I just don't know...

Damn you, stuttgart, for keeping us in the dark about our ass-ends!

peace,
sam

odie

"For the suspension fluid, I bet generic PS fluid is the same stuff"

I dont think its mineral based tho, which is, what I understand to be the big difference. After a quick check around on line I couldnt find any mineral based hydraulic fluid cheaper than the MB stuff at $10 a ltr.

When I was looking for a substitute for the MB hydraulic fluid two years ago, I found that not all hydraulic oils are alike. I'm sure there is an over-the-counter oil that can be used in place of the MB hydraulic fluid, but which one, and who can absolutely tells us it'll work without harming the seals?

FWIW, I took some of the MB hydraulic fluid and had my colleague run an FTIR analysis to tell me what it is in hopes of reverse-engineering the fluid. The information I got was that it is a high-quality hydraulic fluid. I couldn't get more detail or research it further since this was a freebie done on company time.

basically the law says...

If a manufacture requires you to use a specific brand or only their brand, they must provide it at no cost. That means if MB requires that your warranty is only valid if the car is serviced with MB brand fluids, filters, pads, belts, hoses, etc...then they MUST provide those items at no cost.

That is why your owners manual will never say you MUST use their products or void the warranty.

They cannot refuse a warranty claim as long as you are using the specified TYPE product.

If all MB will tell you is "hydraulic" fluid, then they can't say later "no warranty" if that's what you used. Granted our cars are way past warranty. But is this, or similar, system in use on current production cars?

I think the manuals probably say use "MB fluid, OR a fluid designed for MB cars" which means you are free to use ANY fluid that any petro-chemical company wants to label as "ok" for MB suspensions...since that company has now accepted responsibility for the compatibility of it's fluid.

As with the HD senario, HD does not usually state the type or weight oil for the chaincase or transmissions...however, there are other brands available that specifically state they are for use in HD trans & chain cases. And they don't tell you the magic formula either. But they are also accepting responsibility if their product ruins the bike. But you do have to show a direct link to the oil causing the problem. I guess that's when HD fixes the bike & says the oil caused it.