Hydraulic oil/fluid grade for suspension? - PeachParts Mercedes-Benz Forum

azitizz · #1 10-06-2009, 12:58 AM

Hi there, I need to top up my suspension hydraulic oil on an 85 300td wagon. I was hoping to flush it at the same time and replace the filter as the fluid in the big White/Beige container that says OEL on it is looking pretty dark. I read on a different post that it would be fairly easy to flush it simply by continuously adding the new oil to the container as you catch the old stuff in a different one. Im trying to find the right kind of fluid to replace it with. Does it make much difference or can you go with generic hydraulic fluid? Any advice on at least some specifications that should be considered when choosing the right hydraulic oil?
Thank you.
The lid seems to be leaking on the container and Im suspecting this is why I have to add more. It seems like the metal hose puts lots of uneven tension on the filler lid so it wont seal properly.

H-townbenzoboy · #2 10-06-2009, 03:44 AM

Use OEM or Febi fluid only.

kerry · #3 10-06-2009, 09:28 AM

It's available from Buy Parts on the top of this page but I see you're in Canada. Don't know the best source in Canada, perhaps the dealer but it will be pricey.

azitizz · #4 10-06-2009, 10:32 AM

Quote:

Originally Posted by kerry

It's available from Buy Parts on the top of this page but I see you're in Canada. Don't know the best source in Canada, perhaps the dealer but it will be pricey.

Exactly, Thats what I mean, Im sure all they do is get some generic oil or something and slap a mercedes star on it and mark it up by 3 or 4 times. All the specification Ive found in manuals etc.. say use only genuine mercedes hydraulic fuid. I just shake my head when I see those reccomendations. A money grab is what I say. Im sure theres some grade that will do the job, I just know nothing about them.

Biodiesel300TD · #5 10-06-2009, 10:59 AM

You want mineral oil, not regular hydrualic fluid.

kerry · #6 10-06-2009, 10:59 AM

Look for Febi Bilstein Hydraulic oil ZH-M 02615. Import parts suppliers should have it. Or, if you know anyone who drives a Citroen, ask them where they get their oil.

babymog · #7 10-06-2009, 11:10 AM

x2 on the Febi.

Are you sure it says "OEL" and not "730"?

;~)

vstech · #8 10-06-2009, 11:16 AM

ISO 46 is very close to the OE oil specs...

azitizz · #9 10-06-2009, 11:18 AM

It should be very thin right? is the Mercedes "Oel" green in color?

babymog · #10 10-06-2009, 11:30 AM

Clear I believe.

azitizz · #11 10-06-2009, 11:44 AM

yep, just called the dealership. $23 a litre not including taxes so Im looking at close to $30 for a litre if I want to buy Name Brand stuff. What a rip.
I could get a 5 Gal pail of the iso 46 for about $10 more but Id never know what to do with the rest. I guess I could burn it in the engine eh? Anyone know approximately how many litres it would take to bleed and flush the system?

jkubica · #12 10-06-2009, 12:03 PM

Quote:

Originally Posted by azitizz

Hi there, I need to top up my suspension hydraulic oil on an 85 300td wagon. I was hoping to flush it at the same time and replace the filter as the fluid in the big White/Beige container that says OEL on it is looking pretty dark. I read on a different post that it would be fairly easy to flush it simply by continuously adding the new oil to the container as you catch the old stuff in a different one. Im trying to find the right kind of fluid to replace it with. Does it make much difference or can you go with generic hydraulic fluid? Any advice on at least some specifications that should be considered when choosing the right hydraulic oil?
Thank you.
The lid seems to be leaking on the container and Im suspecting this is why I have to add more. It seems like the metal hose puts lots of uneven tension on the filler lid so it wont seal properly.

Hi

I had the same problem when my accumulators (air balls) failed. My oil was very dark - almost black.

The Mercedes dealer here in Houston wanted $30 per liter for their fluid(you need four liters to flush the system). Febi brand fluid is available online at $10 -$12 per liter - plus shipping.

Mercedes also approves two hydraulic fluids made by Shell for the SLS - Areo (aircraft systems) and Tellus. I bought Tellus 15 for about $15 per gallon - enough for a flush - in a five gallon pail.

I called the Shell Technology Department and spoke with an engineer there. He said the main things about these fluids are: High quality control, Being non-reactive to hydraulic system components and the ability to hold their viscosity over a wide range of temperatures.

Regarding your leaking at the cap, I would unscrew the hard return line to get the cap free and then remove it and try to fit it back correctly. It sounds like someone tried to take it off without removing the line and bent something out of place. A little adjusting should put things right. Another possibility is that the filter is plugged causing a fluid backup.

As you said, flushing the system is simple. Disconnect the return line at the cap and using a little fuel hose direct the returning fluid into a gallon container. While running the engine at idle, keep adding new fluid to the tank until the catch gallon container is almost full.

Then stop the engine and reconnect the return line for the cap - then check and adjust the fluid level via the dipstick. If the fluid level is too high, the filter won't be able to filter the fluid.

Before starting the flush you can replace the filter in the cap. Some folks like to work the SLS control valve up and down and use the bleed screw to work the old fluid out of the hydraulic pistons and accumulators in addition to just doing the flush.

Good Luck,

Joseph