noobie with simple SLS questions - PeachParts Mercedes-Benz Forum

shorpkenoff · #1 12-25-2011, 12:08 PM

Hi, I am the new owner of a 1982 300td. I am located in Petaluma, CA (northern Bay Area). I have been reading many threads on the functioning of the SLS system and I have two quick questions for those with experience.

One, to check the functioning of my pump, how much fluid flow is normal? When I look at the reservoir and unscrew the fitting that lets the hose with the filter attached to it I get a flow from this filter. It really isnt much flow, but there is certainly fluid coming out of the filter. I'd guess about 2-5 ml of fluid per second (based on how it pooled on the top of the reservoir).

My second question concerns the accumulators in the rear. I have read on the pencil trick to test the integrity of the diaphram -but where do I put the pencil? The entire thing feels to be solid steel. I am I to undo the banjo bolt or the hard line that goes to the accumulator and insert the pencil at either of those points?

Thanks and merry xmas,

joe

vstech · #2 12-25-2011, 12:23 PM

Merry Christmas! and welcome to the forum.
can you describe the symptoms that is making you test the function of the sls?

the pump develops pressure, not much sure of actual flow volume...

shorpkenoff · #3 12-25-2011, 01:26 PM

Hello vstech,

In getting ready to purchase this car I have read many of your threads and replies. Symptoms making me question the SLS system are:

1. Extremely bouncy ride.
2. The car does raise and lower a bit -this morning, for example, the car raised up 1.5" (measured at the wheel arches) from its overnight position after driving. However, even after driving the car still sags a bit when there is weight in the back.
3. There was no fluid in the SLS reservoir. There are no leaks by the rear valve or by the accumulators.

Thanks for the help,

joe

Carpenterman · #4 12-25-2011, 03:11 PM

Your pump sounds functional. As Vstech said, it's a high pressure, low volume system. The pumps can be rebuilt. Usually when they wear the seals fail and engine oil gets into the fluid turning it black.

Your accumulators are gone. That's your bouncy ride. At that age (and if original) I would replace them anyway ($250 or so) but if you want to test them remove the banjo bolt at the accumulator and that's where you stick the pencil.

Sagging without any visible leaks is the SLS valve attached to the rear sway bar. You can buy a rebuild kit from a member on this site for around $10. Just a bunch of O rings.

Eventually you should also check the hoses to and from the pump to see if they are seeping. They don't last forever. There are some good threads here about buying locally available bulk hose and reusing the fittings. Saves a lot of money.

Good luck! The wagons are awesome.

kerry · #5 12-25-2011, 03:31 PM

Bad accumulators can also cause overnight sagging in my experience. Flow is not huge through the system.

shorpkenoff · #6 12-25-2011, 04:13 PM

Thanks, Carpenterman and Kerry. I didnt want to make a mess with banjo bolts if that was not where I was supposed to test. I am glad my guess of bad accumulators seems to be born out. Glad also that the low flow of the pump is normal.

Just wanted to check with the folks who know these cars. I've put a few hundred miles on it already, trying to get an idea of what my baseline state is before I start fiddling with things. I am enjoying the big, smooth , wagon ride.

The car sat for 6 years and was sold with as having "zero compression" -that seemed an odd ball enough diagnosis for me that I was willing to take a chance on it. Turned out after changing filters and priming the system and putting a new battery in she started right up (and snapped the alt and ac belts).

As I get to know the car I will continue to read the archives and post when I have more questions I cant figure out. I'm loving the wealth of info, though there sure seem to be a number of systems that can have problems.

Merry xmas.

kerry · #7 12-25-2011, 04:21 PM

Any idea why it snapped the belts?

shorpkenoff · #8 12-25-2011, 04:35 PM

No idea. The remaining belts looked pretty stringy, so I replaced those as well. Might have been all the time sitting with some animals and heat getting to it? Lots and lots of wasps came with the car, and some other unknown nests as well. It was sitting in a field. When I started it she ran ok and I went out around the block first, then on a five mile loop. When I came back and looked under the hood (after being all proud and showing off my "rescued" car to the family, I saw the flapping belts -one alt and the ac belt.

Biodiesel300TD · #9 12-26-2011, 01:07 AM

Bouncy rear is accumulators. Like stated above, to test them you'll have to remove the banjo bolts, be ready with a catch pan as you'll potentially drain a couple quarts of SLS fluid. If both accumulators are shot they will be full of fluid.

If the rear is lifting your pump is probably fine, but the sagging over night mean leaks. The SLS valve can leak internally and allow the passage of fluid causing the rear to sag after sitting. Sometimes they leak visably because the o-ring that seals the two halves together needs replacing.
Here is a link to the DIY for resealing the valve - http://www.peachparts.com/shopforum/diesel-discussion/271457-w123-self-leveling-system-o-ring-replacement-diy.html

If I were you I'd get new accumulators and when you're ready to install them be ready to reseal the valve at the same time. The valve re-seal is pretty easy. As are the accumulators, if things aren't rusty. Then flush the system with some fresh SLS fluid or mineral oil.

colincoon · #10 12-26-2011, 01:34 AM

My only advice that has yet to be given in this thread is during accumulator removal you NEED to use a flare nut wrench. Trust me, do not follow in my footsetps and use a regular 11mm box wrench.

Also check the main hose from the bottom of the reservoir to the pump and see if it looks "wet". Mine was and it was leaking fluid. No fluid in the reservoir could mean a few different things, but grab a liter of sls fluid and fill it up. Chances are the accumulators are full of fluid, or there just isn't enough in the system.

shorpkenoff · #11 12-26-2011, 02:58 PM

Thanks for all the advice. I was pretty certain it was the accumulators. I will also check the bottom of the reservoir for leaks, but I havent seen any evidence of a leak from that corner under the hood yet (its not like my car is without leaks, just not from under the reservoir).

Thanks for advice on using an 11mm line wrench, not open end. I will see if I can borrow one of those (all my line wrenches are SAE) or run down and buy one quickly.

Biodiesel300TD · #12 12-27-2011, 12:21 PM

I'd think about investing in some metric tools if I were you. Everything on your Benz is metric.

TchTchr · #13 12-27-2011, 06:07 PM

All good advice above.

Once you get the SLS up and going, you will LOVE it!

On a side note: Since the car has been sitting a field for six years, make sure to have the braking system thoroughly checked out.

vstech · #14 12-27-2011, 10:57 PM

Quote:

Originally Posted by shorpkenoff

Thanks for all the advice. I was pretty certain it was the accumulators. I will also check the bottom of the reservoir for leaks, but I havent seen any evidence of a leak from that corner under the hood yet (its not like my car is without leaks, just not from under the reservoir).

Thanks for advice on using an 11mm line wrench, not open end. I will see if I can borrow one of those (all my line wrenches are SAE) or run down and buy one quickly.

IF your line wrenches are TOP QUALITY, 7/16 is fine for the lines. DO NOT USE CHEAPO LINE WRENCHES on the brakes, or the SLS lines!!!!!

shorpkenoff · #15 12-29-2011, 01:54 AM

I hear you on the quality line wrenches. I invested in a mac tools set (about my highest price hand tools, item for item) for my previous projects (old volvos) just because when you need to use a a line wrench you want it to fit right. There is no easy replacing a nut or bolt if something gets rounded off.

As to the point on the brakes, yes I really want to get the whole system bled soon. Need to replace the rears so was thinking of replacing and bleeding at the same time. For now all 4 wheels brake well.