Restoring my SLS on 300TE
 

Alrighty!! Next project is SLS I think. Transmission is done, all Suspension is done, A/C is done...what is next?? SLS!!

I started a thread a few years back, and the consensus was that the SLS pump seals are probably bad.

Symptoms in short:

• Has NEVER worked since I owned the car since 2006 @ 63k miles. Never had ANY issues at all though with it not working so it hasn't really bothered me and that includes hauling 4 house moves worth of heavy stuff!
• Does not raise rear with weight
• Manually moving SLS valve does not raise rear
• SLS fluid IS flowing as I removed return and it was moving
• No leaks in the system

Firstly, I plan to replace both rear accumulators as they are toast (part # 140-328-05-15)
. The rear end is bouncy, or at least ONE is dead. Sticking with Corteco or Genuine MB, depending on price difference.

Questions:

1) Are there any places that sell the tandem remanufactured vickers pump without spending astronomical amounts of cash? (Part # 124-460-15-80)
I understand there is a seal kit, but I'd need to buy a spare pump to do it with and I am not sure if after all of that, if its just easier to buy a remanufactured one anyway ya know?

2) Should I worry about the SLS Valve or leave it be until I have replaced the pump?

3) Any hoses OTHER than the reservoir->pump line to concern myself with?

Parts already have and/or replaced:
Cleaned SLS Tank fully
Replaced Return hose to pump (was on its LAST leg literally!!)
Have new reservoir filter
Have new SLS Fluid to drain, flush and refill.

Any help or suggestions on this?

ask C&M hydraulics in Vegas ,they might shed some light on this.

I've seen they remanufacture on a few retailers, but they want like $450 + a $400 core...but maybe thats the cost needed to resurrect this system...

ps2cho:

"Does not raise rear with weight
Manually moving SLS valve does not raise rear
SLS fluid IS flowing as I removed return and it was moving
No leaks in the system"

Given these statements, consider making the leveling valve your first area of attention. Loosen the output line(s) to the struts/accumulators, and check for flow (not just residual pressure) at that point when the valve is manually moved to the "raise" position. It will be necessary to have all load off the struts when doing this, and any residual pressure released. If there is no flow, investigate the valve. If there is flow, suspect that the pump is either worn internally, or the pressure relief valve in the pump is opening at too low a pressure.

The condition of the accumulators is a real but secondary matter. Even with defective accumulators, the system should raise and lower the car.

Keep an eye in the pull and pay junkyards. All the 4-matic 124s will have the tandem pump, the ASD diesels will have it, and there are other models with SLS that may also have it. Its not a super rare part. I'd completely exhaust the yards before paying that much for a pump.

Would removing the line to the struts be a "cleaner" option so it doesn't spray everywhere? Also, what am I exactly looking for since I already know the system is flowing? How can I tell what correct pressure looks like?

Removing the line would indeed be cleaner; especially if replaced with a hose that can be directed into a container.

You have stated that you are able to observe return flow; this test is to determine if there is flow to the struts.

Since the flow is from an open line it will be at atmospheric pressure. To test for operating pressure will involve teeing a guage into a strut line.

x2 on checking the SLS valve first. The SLS valve is also controls residual pressure which impacts strut damping. Even after replacing the accumulators on my 91 300TE the ride was inadequately damped so I replaced the SLS valve which solved the problem.

Also, it is very rare for the tandem pump to fail unless it was run dry. I resealed the TE tandem pump due to external leakage, not inadequate pressure or cross contamination issues. That particular version required a special tool to remove the pump chamber heads which I can lend to you if you pursue that path.

Once you get your SLS system up to snuff you will be amazed at how well controlled yet supple the rear suspension becomes. I wish my 01 wagon had the skyhook option which fits SLS on both axles. Mark

Thanks I will go ahead and run the test soon and report back.

I am back and this is now on the list to tackle. How much pressure should I be seeing at the struts.

So I understand since I have fluid returning, the pump MIGHT be OK...so I need to check for fluid to the struts. Does this need to be done on the ground, with the rear in the air?
I want to make sure I don't do it wrong and get false positives etc...

With the engine at high idle, open the bleed screw on the SLS valve. If the fluid is clear, the tandem pump is likely OK. If the fluid is foamy and stays foamy, pump is not ok. If foamy, disconnect the rubber hydraulic hose (high pressure output side of the TP) where it connects to the metal line (on the wheel well near the exhaust manifold) to confirm the fluid is foamy. [Aside, when I installed my rebuilt TP, I had to disconnect the hydraulic hose to get the pump to "prime"] Continuous foamy fluid means worn out TP.

If you put the rear end on ramps and move the valve to the raise position, does the rear raise? If so, doesn't that mean you have enough pressure in the system? The FSM you host has a section to test pressure on those lines as well.