Emergency SLS repair...damage assessment - PeachParts Mercedes-Benz Forum

bpeters2 · #1 04-05-2009, 09:14 PM

I had a major sls rupture (tons of fluid dripping off differential). I was on a road trip and needed to make it back home but didn't want to run the pump dry....so...I hack sawed the pressure line right after the rubber hose (I been battling rusted sls lines so I figured I would replace all the lines under the car IF I repair the sls at all) and ran the pressure line right into the fluid reservoir (where the filter usually goes). I duct taped it in good so no dirt would get into the system and filled it up with ATF (it was all that was available). I drove the car about 200 miles and everything seems fine...other than a seriously sagging rear end.

First Question:
1) May have I done any significant damage to the system since I'm sure a lot of air got into the shocks, valve accumlator etc.?

2) Think my seals are OK in the pump after 200 miles with ATF, how quick do I need to get real MB or FEBI into the system (luckily I won't need much fluid since my entire "system" is only about 4 feet now)?

3) Its going to be little tricky to locate the leak now that pressure to the system is disconnected (the whole valve area is pretty coated with fluid). I'm assuming that a line is what ruptured so I'll probably just replace all the sls lines. Is it common (or possible) that the actual valve could have ruptured or leaked? If so maybe I need to think about replacing (or repairing that too to fix the leak).

kerry · #2 04-05-2009, 09:22 PM

I wouldn't have worried about running it dry since some members here have driven for months without any fluid in the system without damage.
No big hurry on the correct fluid. Seals will be fine. System should be fine apart from the leak. I'm guessing a leaky line. Haven't heard of a catastrophic failure on the valve.

MTUpower · #3 04-05-2009, 09:43 PM

I'd get that ATF out soon. The seals and o rings dont like anything but SLS fluid, and the proper stuff. They'll be leaking soon and you have to replace alot of stuff later unless you get febi in there.

bpeters2 · #4 04-05-2009, 10:07 PM

as long as I have the attention of the "SLV community" does anyone know of someone who has O-ring kits for rebuilding the SLS valve? Thanks

tobybul · #5 04-05-2009, 10:14 PM

Air in the sls would not be an issue as in your case since it will eventually be refilled with oil. One of the most common problems with sls systems is the accumulator (air cell) going bad (the diaphram ruptures). Generally, the shocks go for a long time.

Of course, in your case rusted tubing becomes a problem too.

And yes, Febi oil would be required. They are expensive (about $15/bottle). When I replaced my accumulators, I used hydraulic oil (much cheaper) temporarily. You can get them from NAPA or in my case from Menards ($9.99/gal). Once all the repair was done, I replaced it with Febi.

shadetreemechan · #6 04-05-2009, 10:35 PM

My pump was dry for an unspecified amount of time until I bought the car. At least the 800 mile trip home from buying it.
When I got home I put regular hydraulic fluid from tractor supply in it. It has been fine with no seal leaks for over 2 years.
I wouldn't waste my money on the febi fluid.

tobybul · #7 04-05-2009, 10:42 PM

Quote:

Originally Posted by shadetreemechan

My pump was dry for an unspecified amount of time until I bought the car. At least the 800 mile trip home from buying it.
When I got home I put regular hydraulic fluid from tractor supply in it. It has been fine with no seal leaks for over 2 years.
I wouldn't waste my money on the febi fluid.

Glad you shared this bit of info about hydraulic oil. I always wondered if anyone had used it longer like you have. I guess thats good enough for me.

I just did not have the guts to do it since a few members warned me about using anything but Febi. But when you think about it, thats what hydraulic oil is really used for.

OldPokey · #8 04-05-2009, 11:40 PM

I have been running ISO 46 hydraulic fluid in my SLS for two years now, and I have not seen any leakage from anything. The struts are dry. The valve is dry. The car sits level. If you investigate the differences between the Febi Fluid and ISO 46, you will find there is basically no difference. When I received the car, I found it had huge leaks from rusted lines, and what little fluid was in the reservoir was green - the PO's mechanic had been using Jaguar branded fluid and who knows what else.

That doesn't mean you can run just anything labeled "hydraulic" in your system - and there are many different kinds. You cannot use brake fluid or the Citroen "red" hydraulic fluid - that will definately kill your seals, as it is a completely different chemistry (glycol-ether vs. mineral oil). There are many other base stocks that go into different types of hydraulic fluid, and as a general rule they cannot be mixed.

ATF is ISO 46 with friction modifiers introduced so that the transmission's clutch packs and bands will operate smoothly. It won't kill your SLS system, which is a lot less complicted than your basic 3 speed Hydramatic, and it has a LOT fewer seals. In fact the hydraulic system on your average tractor is at least an order of magnitude more complex.

The Mercedes hydraulic system is well designed and very robust - and it is dead simple. It is the best riding wagon I have ever driven - it's more comfortable than my 2005 Legacy, and it handles heavy loads better.

mobetta · #9 04-06-2009, 05:14 AM

I've been running type 46 since last fall, even at 25 below.

MTUpower · #10 04-06-2009, 08:04 AM

For certain do not use the green stuff- I put some in my wife's car- it was in a can from the yard (sealed and new) made by or for Audi. I was in german so I thought it had to be the same stuff as Febi. Now my wife's control box leaks and over night the car sags. Biodiesel300TD "makes" o-ring kits for your control box. I know (and proved here in this thread) that Febi is not the only stuff to use- but use at your own risk. I use Febi- at $11.67 a bottle I don't worry about the cost. If you need the accumulators let me know- I have several perfect one in my garage. New they are about $110.

bpeters2 · #11 04-06-2009, 01:06 PM

Quote:

Originally Posted by OldPokey

ATF is ISO 46 with friction modifiers introduced so that the transmission's clutch packs and bands will operate smoothly. It won't kill your SLS system, which is a lot less complicted than your basic 3 speed Hydramatic, and it has a LOT fewer seals.

Would you still suggest switching to ISO 46, or do you think I can expect the same performance from ATF as you have found from ISO 46?

Another question...I'm going to be replacing all the 6mm hardline for the SLS system. I really don't want to mess with dropping the subframe to route the lines in original locations. What do you all think about just running the lines (under the differential..ie between diff and ground...or somewhere else (suggestions?), just NOT between suspension and the body of the car), I would protect it with some rubber hose or something. I figure this would make the job A LOT easier.

bpeters2 · #12 04-06-2009, 09:16 PM

hate to do this but...bump

OldPokey · #13 04-06-2009, 09:28 PM

I would get rid of the ATF - I don't think you want or need the friction modifiers. You would be better off with the anti-foaming additives in ISO 46. And it's not expensive.

bpeters2 · #14 04-06-2009, 09:33 PM

can I get ISO 46 at any old parts store? Napa autozone etc.?

thanks

Any opinions on rerouting sls lines ?

mobetta · #15 04-07-2009, 08:32 PM

I haven't had to do sls lines yet- but I did sneak a new brake line up over the rear subframe.

I got type 46 aw(anti-wear) from TSC for under $20 for a 2 gal jug. I was chasing a leak, and the cost of a gallon was 70% of the 2 gal jug. I have seen it in fleet farm, and O'reallly Auto before, too.the stuff I've seen at menards is NOT type 46.

the type 46 seems to work fine, but it is not recommended in the manual, so use at your own risk, YMMV, etc.