300TE Rear Suspension Sag
 

Just had my car aligned and the tech pointed out that the rear suspension is sagging on the driver's side. He suggested the accumulators (spring actuators) should be replaced. My question is could bad accumulators cause sag on one side? I will probably replace them as the ride is pretty harsh but want to know if this will fix the driver's side sag or if maybe this sag can be fixed by some other means.

Thanks,
UW

Sag on one side is probably not the accumulator -- bad accumulators give you progressively harder ride until they are completely flat, at which point only the tires have any "spring" to them. Unmistakeable.

Sag us either a bad spring or bad strut, and usually one bad strut causes the entire rear end to droop, I believe (I may be wrong).

These struts are not as expensive as the one's in the W123 chassis, but are somewhat more expensive than a shock.

Check the fluid level in the suspension reservoir, too, it could just be low.

Peter

Well it's worse than I thought. I had a large friend of mine sit in the back, closed the hatch, started the car and watched. After a few minutes the ride height had not changed.

The struts aren't leaking so I'm assuming it's either the pump or the controller.

UW

Just a little FYI, the accumulators are the "cheapest" part of this system. At least on my W123 TD. For my car they about $75 a piece. Get under the car and see if the shock is leaking at all.

rickjordan, I have a set of accumulators on order. They definitely need to be replaced no matter what else is wrong. The shocks aren't leaking, thank goodness. I hear those are pretty pricey.

A little update. I got under the car last night and disconnected the rod from the controller so I could see if the hydraulics work. By moving the arm on the controller up and down with the engine running I was able to get the back of the car to move up and down. The movement was very erratic though. Also when moving the arm, it moved very freely except for two "lump" of resistance in it's travel.

After I reconnected everything and drove around the rear was not as low any more and the car was level side to side (no driver's side sag).

I suspect the controller is not working right. Think I'll need to replace it when I have the accumulators done. :(

UW

There's a rebuild kit for the self-levelling valve. However, if you're not comfortable doing it, just get a new valve.

Whatever you do, make sure you don't cross-thread the connections to the valve. The aluminum valve strips VERY easy, and cross-threads very easy.

:-) neil

neil,

Thanks for the info. That's the first mention I've seen of a rebuild kit. Maybe I'll rebuild the one that comes off as a spare (actually sounds like fun to me).

I'd love to do the work myself. Unfortunately my house has no off-street parking. Laying under the car last night with traffic wizzing by makes me think it's not a good idea to work out on the street. My next house will definitely have a garage.

I've decided to let the dealer do the accumulator and valve replacement, though I'm buying the parts elsewhere to save money. Hope they know what they're doing.

Unless there's some kind soul with a jack and stands in Seattle with some free time next week...;)

UW

If you haven't got your parts yet, give Tom Hanson of Caliber Motors (MB dealership) a call in Anaheim Hills, Calif. (1.800.CALIBER). Tell him you're part of the Mercedes club, and that I sent you.

You might be amazed at the pricing for GENUINE MB parts, which have a 1-year warranty honored by ALL MB dealers.

I would definitely do this for accummulators and esp. the self-levelling valve.

:-) neil

BTW: why the dealer for just the labor? FWIW, to change the accummulators, valve, flush the system (1-qt. of hydraullic suspension fluid) and a new suspension fluid FILTER (get it), should take no more than 2-2.5 hours. I've done this procedure for both the wagon and the 500E.

I agree with Neil. Independently of the accumulators you should flush the self-leveling system fluid. It isn't hard and it does make a difference.

There is a thread on this site, I believe posted by Neil, telling how to replace the fluid and the filter.

Jeff

Neil, Thanks for your offer to let me use your name at Caliber Motors to get my parts. That's very generous of you. Unfortunately the parts are already on order. I'm not too concerned about the parts being any different from the ones sold by MB since I assume there is only one manufacturer for these unique parts. Still, I understand what you're saying about the warranty.

Regarding having the dealer do the work it's mostly a scheduling issue. The parts arrive on Monday, car goes into the shop on Tuesday, big family reunion starts on Wednesday. This is my first Mercedes and I haven't found an independent shop I like yet. Going to the dealer gives me the highest confindence that the car will be ready to go on Wednesday. Also, the other Mercedes shops I talked to all charged about the same labor rate.

Neil and Jeff, I found the thread on replacing the hydraulic fluid. It sounds easy. Do you think it would be all right if I did the fluid and filter change myself after the new accumulators and valve are installed or should I have it done at the same time? Or maybe I should do it before the car goes into the shop?

UW

Just have them do it, because it can be messy. Be sure to print out the procedure, because it really doesn't exist in any of the MB books. I would pay to have about 1.5 qts. new fluid flushed through, and leaving you enough for fill.

Also, as Preventative Maint. (PM) replace the hose between the resevoir and the pump (don't ask me how I know).

:-) neil