SLS removal or beating a dead horse. A few thoughts/questions... - PeachParts Mercedes-Benz Forum

Matt Petty · #1 02-06-2008, 03:38 AM

Hello,
I picked up an '85 300td wagon this afternoon. 150k. A major leak in the self leveling system had stopped the PO from driving the wagon. Leak is back left. I have experience with with the sls system with a number of my friends and my wagons in the past. I totally agree that the system is wonderful when working properly, not mysterious, but potentially expensive. I'm on a budget. First off I will diagnose the leak. If the fix is clear and the rest of the system appears sound I will of course keep the SLS. However, I'm drawn to ditching it all together. The main motivations being reduced complexity, low future costs, basically making the thing bulletproof on a budget.

My main question, directed at the folks who wouldn't recommend removal, is; why couldn't the proper springs, spacers and bilsteens handle properly over a pretty wide range of loads and conditions? My driving habits, and the car's loading, will be similar to those experienced by my (now stolen and crushed by a tree) w126 300sd. Basically 2 person surfing, camping, diving. The sd handled very predictably when heavily loaded. You would obviously have to adjust your driving imputs but it wasn't unsafe by any means. Also, this wagon must have been produced for the world market without sls?

Having the proper springs, spacers and shocks would obviously be KEY to the conversion, which leads to my second question.

Does anybody have experience with the **************.com 300td sls removal kit? They pitch it as heavier than stock springs, the proper combination of spacers to tune the ride height to be level or slightly tail up, and bilsteens with some sort of mystery spacers to make them fit. Anybody running this kit????

Thanks,

Matt

#2 02-06-2008, 03:51 AM

Mercedesource is a con, avoid them at all times.

Suspension conversions usually fail to impress because the TD has much more weight hanging out further back than the sedan and the TD has much higher cargo capacity than the sedan (A little over 1000lbs). Putting a load in the back has more leverage against the suspension than it does in a sedan. You wouldn't be able to put even half the cargo in the back of a converted TD without it sagging.

Matt Petty · #3 02-06-2008, 04:39 AM

Hello,

I really want to keep the sls based on my own experience, but may not be able to afford to. I also know that as our wagons age the engines will be harder to source, sls parts will become more scarce and exploring this option may keep a few more on the road.

How about euro wagons? All sls?

Help me fine tune my understanding of the system: there is a baseline spring rate from the coils and the struts then add supplimental spring force as needed based upon load, no? I'm assuming that dampening is constant and also isn't adjusted based on load.

If so, there then must be an perfect single spring rate for any given load and also a single spring rate that is acceptable over a normal range of load. The car is then a little stiff empty, perfect in the middle and soft when overloaded. So many vehicles of all shapes and sizes make these tradeoffs.

On another note I've read concern over upsetting the critical balance between front and rear suspension. If, with sls the balance isn't upset by a range of spring rates in the rear, then, why would it be upset by a single rear spring rate falling in the middle of the sls range? I can see the normal changes in handling experienced in a loaded car, but nothing drastic.

Is the dampening constant regardless of hydraulic input?

Is the con with the above mentioned being selling cheap parts in cute little kits for too much money with instructions you could find here for free? Please elaborate if you think it is proper in this public forum.

Matt

#4 02-06-2008, 04:51 AM

Download the entire guide HERE.
Here are some diagrams.

Quote:

Is the con with the above mentioned being selling cheap parts in cute little kits for too much money with instructions you could find here for free?

Correct. Many of his items are well above retail price. His main goal is to make money, not help people. Go into his forums, most of his posts tease them with some of what they need then redirect them to buy one of his guides for the rest.

Matt Petty · #5 02-06-2008, 05:04 AM

OK forcedinduction, I just noticed what you drive. You obviously have ZERO fear of going against the holy scriptures of mercedes design. I had attributed most of the fear surrounding this project found on this board to folks who are very by the book, purist types, who wouldn't deviate from mercedes original plan.

How is the wagon different from a pickup? Wide load range, long out back? Obviously apples and oranges but your argument was based on the wagon experiencing greater loads than a sedan and requiring a variable spring rate. A tacoma is a little stiff unloaded, no biggie. Perfect in the middle and soft loaded up. What about other brands of wagons?

Thanks.

Matt

Matt Petty · #6 02-06-2008, 05:08 AM

Damn, Thanks for the tech manual. Wonderful. I'm going to make a stand to retain the sls if my budget doesn't drive me down the removal dice roll. I still think that a test of this kit would be interesting if the wagon/owner was cornered finacially.

#7 02-06-2008, 05:17 AM

Quote:

Originally Posted by Matt Petty

I had attributed most of the fear surrounding this project found on this board to folks who are very by the book, purist types, who wouldn't deviate from mercedes original plan.

I used to have a 300TD and I did try to remove the SLS system after the pump cr@pped out, I used air shocks in place of the struts. It worked but not to the point I was happy or would load anything into the rear.

Quote:

How is the wagon different from a pickup? Wide load range, long out back?

Pickups are made primarily to work, the 300TD was made as a people hauler/light work horse. Comfort was the primary focus instead of load capacity. 1000lbs is still fantastic for a station wagon but they could have easily beefed it up to 2000lbs with some floor reinforcements and a stiffer suspension setup. The SLS is a great system, it's only downsides are expensive repairs and few people understand how it works.

Several people have tried to delete the SLS system and the majority of those that have reported back haven't been happy with the results.

Preventive maintenance is the key. Use only the correct Febi/MB suspension oil, never let it run low on oil, change the fluid and filter every two years or 30,000miles, fix leaks asap, don't overload it and replace the accumulators in pairs if it has a very hard or very soft ride.

johninva · #8 02-06-2008, 06:54 AM

theres a guy on ebay selling brand new pairs of accumulators for $160.00 pretty regularly. I got some. SLS valve rebuild kit is $100.00. Big cost is those darn hydraulic shocks, id try and find some used ones, as i understand it, if they're not leaking they're ok. hope its not your shocks. let us know where the leak was coming from.

Maxbumpo · #9 02-06-2008, 01:00 PM

You'll be much happier if you keep it. ForcedInduction is spot-on, I've never heard of anyone being happy with a conversion, even those who spend as much money on new parts (read: custom shocks) as it would have cost to repair original system.

If you are on a budget, get used parts from junkyard. When my '85 wagon's sls control valve died, I scored a used valve for $10, and it worked for another year. Then I bought a new valve for about $200. Another tip: a good hydraulic shop can manufacture new steel lines for you or repair yours; if you provide all the labor of removing and installing, cost will be neglible (if your leak is simply a rusted line). Used hydraulic struts would be a great value, the only failure mode is leaking.

#10 02-06-2008, 01:28 PM

Also check that the rubber line supports are in place under the body. One of mine went missing and rubbed a hole in a line.

Matt Petty · #11 02-06-2008, 01:57 PM

hey all,
should ze vagon be towed if the rez is nearly dry? My impression of the leak based on the PO's driveway stains and description is that it instantly dumps fluid. Can I short loop the pump and drive it, or just drive, it 5-25 miles? Thanks in advance!

Matt

#12 02-06-2008, 02:02 PM

Yes, reroute the pressure line from the pump back into the tank or have it towed.

Driving with low fluid is the worst thing you can do besides using the wrong fluid.

Matt Petty · #13 02-06-2008, 02:11 PM

hey,
I drove it for 10 mins yesterday and let it idle for 10. Would damage be likely over such a timespan?

Thanks again,

Matt

#14 02-06-2008, 02:19 PM

If it is low enough to the point the rear end does not lift up or is very slow to respond, any time is too long. The $1100 suspension pump is lubricated by the suspension fluid, as is the leveling valve. Driving without suspension fluid is like running the engine without oil.

And, just like running an engine without oil, your mileage may vary as to how well it works later.

cestes · #15 02-06-2008, 03:38 PM

Thanks for posting the manual and all the good info (as usual)...

I'm happy to see on earlier cars, the reservoir was located on the right side. I'm in the process of relocating my reservoir so I can use the space at the left front.

Some questions:

1) Can I use some hydraulic-rated rubber (or something) hose to route from the return line to my new location? Does it have to be hard steel line? I can't imagine that it's under much pressure, since it just dribbles back into the reservoir.

2) Can I use a smaller reservoir? The OEM part is huge... i drained more than 1/2 a gallon of fluid (nasty, dirty stuff, too!) from mine! Surely I could get by with a smaller one? Anyone have part numbers from a different model that uses a smaller tank?

Thanks!