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300TD rear suspension level control valve

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familydieseldr's picture
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Hi,
I think the rear hydraulic level control valve may have failed on our 1983 300TD.

It is the original valve, has 352k miles on it.
The back of the car is sagging at all times/loads.

I checked that the linkage is intact on the valve and on the suspensions attachments.
I checked that there is a good volume of oil flow through the filter when running.

The oil is dark, and is was changed w/ filter a few months ago so something has polluted it.

Thus my conclusion.

I searched the forum and found that DIY rebuilds don't seem to last very long.
I checked my usual suppliers and no one sells the p/n "1233200158 rear height control valve"

Now what????

Familydieseldr

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1983 300TD = old clacker 370,000-retired parts donor
1985 300SD = Son's Diesel cruiser 332,000
1985 300TD = Dad's Diesel wagon 183,000
1992 Kubota Diesel tractor = mutant lawn mower 390hrs
2000 Ford Powerstroke Diesel = Wife's Toyota crusher 253,000
2004 Chevy Blazer = Daughters gas SUV 80,000
2010 BMW 335d = new clacker toy 56,000
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Tom Hanson's picture
Arrowhead Farms, CA
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4793

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1970 300SEL 6.3
Re: 300TD rear suspension level control valve

Where do you normally buy your parts? There are still plenty of these valves available, and rebuild kits for them as well.

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Tom Hanson
Supervisor, Parts Operations
Mercedes-Benz Classic Center USA
MBUSA, LLC
thomas.hanson@mbusa.com
949 598-4842 direct.

Prior MB cars: 2010 ML350 Bluetec, 2003 C320 Coupe, 1986 300SDL, 1971 300SEL 6.3, 1973 450SE, 1959 220S, 2011 C300

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Biodiesel300TD's picture
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Re: 300TD rear suspension level control valve

If the oil is dark then your SLS pump is leaking. If the valve is leaking it will be greasy. I don't believe the SLS valve rebuild kits are available from the dealer anymore. I have o-ring sets that will reseal the valve. There are 5 o-rings inside the valve. Unfortunetly you have to buy the o-rings in large quantities. I bought a ton of then so that I could rebuild my valves. I have more than enough and have been selling them off to other leaky SLS folks. If you are interested send me a PM. Also There is a guy here named George Murphy that sells rebuild kits for the pump.

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Andrew  <> 1978 240D ~ Flo ~307k mi <> 2004 VW Jetta Wagon TDI ~ Her Car ~ 115k mi <> 1982 300TD ~ Winnie ~ Sold at 178k mi <> 1977 300D ~ Sold

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Maxbumpo's picture
Mount Pleasant, SC
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1995 E300 Diesel
1987 300TDT
Re: 300TD rear suspension level control valve

I agree that you SLS control valve is probably failed.

I see three choices: New, rebuild your original, get used from salvage yard.

You may want to try to find a used valve; if you can inspect in person you can verify if the system is still holding pressure and have some assurance that the valve is good. Swap out valves, rebuild your original and you'll have a spare.

Far less hassle but far more expensive is to get the new valve (that was were I ulimately ended up).

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Max Dillon
Charleston SC
'87 300TD, 334k miles (head is off, getting ready to install a different used head...)
'95 E300 Diesel, 348k miles (daily driving duty)
'73 Balboa 20

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pch2021's picture
Rockledge, FL
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Re: 300TD rear suspension level control valve

Level control valves on these cars tend to be a bit funny.

However, I have had some luck with rebuilding them. A friend of mine who ahd the same problem on his TD fixed it by some precision machine work:

heres how it was done:

the main shaft where the levelling rod attaches had some wear in it where its o-ring seals it. The leakage was between the shaft and the o-ring. The leveller also contains a check valve. By machining the o-ring slot as bit bigger, a larger o-ring was installed. so far, this ahs worked well for the last 2 years. the rebuild kit can be ahd for $96.00 and my friend [over in metro west] actually has a rebuilt unit that he prepped for himself, or anyone else that needs it.

The leveller can be had new from mercedes, also, for about $600.

Used ones from euro cars seem to be available. I have one that worked from a 1985 500SEL [somewhere]

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Pierre Hedary
...happily servicing vintage Mercedes-Benz in sunny Florida...
1972 280SE 4.5 252K
1970 280se 3.5 coupe 108K
1971 300sel 4.5 121K
1991 420SEL TMU, but looks brand new!
Mercedes technical advice: 407 765 2867

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familydieseldr's picture
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Re: 300TD rear suspension level control valve

Thanks for all the tips & advice.
The 300TD is being used by my daughter to get to work & school, so the
weekends are the only time I can take it off the road.

So the fix has to be quick and low risk.

(and still have to listen to "when can I have the car dad?? Will it be ready soon??"

I sent e-mails to Duval and Arizona Autohaus to see if they can get a new one.

I also send an e-mail to a boneyard locally to see if they have one.

I'm not averse to buying a new unit, as I believe this car has at least 10 years more life in it.
(Even more if there is no fuel to drive it)

I have a machine shop and can take the core and try to rebuild and/or modify as Pierre described.

Familydieseldr

__________________
1983 300TD = old clacker 370,000-retired parts donor
1985 300SD = Son's Diesel cruiser 332,000
1985 300TD = Dad's Diesel wagon 183,000
1992 Kubota Diesel tractor = mutant lawn mower 390hrs
2000 Ford Powerstroke Diesel = Wife's Toyota crusher 253,000
2004 Chevy Blazer = Daughters gas SUV 80,000
2010 BMW 335d = new clacker toy 56,000
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pch2021's picture
Rockledge, FL
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Posts:
2780

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Re: 300TD rear suspension level control valve

I beleive I found a valve that I had rebuilt. I don't know how well it functions, though.

__________________

Pierre Hedary
...happily servicing vintage Mercedes-Benz in sunny Florida...
1972 280SE 4.5 252K
1970 280se 3.5 coupe 108K
1971 300sel 4.5 121K
1991 420SEL TMU, but looks brand new!
Mercedes technical advice: 407 765 2867

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familydieseldr's picture
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Re: 300TD rear suspension level control valve

More clues and mysteries.

My daughter says that she witnessed the 300TD rear suspension "event"
- car was parked, she was standing behind it, hissing noise, rear of
car lowered all the way down on the springs.

I replaced both accumulators 25k miles ago, but they were not OE, and much
of the aftermarket I have had is junk, so perhaps one or both leaked.

What other events could cause the above behavior?

Also, this morning I put the car on jack stands, under the rear control arms
so that the suspension is compressed as normal.

Disconnected the rear hydraulic level linkage to the axle hubs.

Started the engine and manipulated the control arm.

- moving the arm up causes the body to lift from the suspension
- moving the arm down causes the body to from on the suspension.

So while the valve might have an internal leak, it is still functional.

Based on a post about the linkage adjustment, I am going to experiment with a
small change in the length and see what happens.

I would really like to find out what the source of the problem is before spending
$1k on throwing random rear hydraulic parts & pieces at it, comments please?

Familydieseldr

__________________
1983 300TD = old clacker 370,000-retired parts donor
1985 300SD = Son's Diesel cruiser 332,000
1985 300TD = Dad's Diesel wagon 183,000
1992 Kubota Diesel tractor = mutant lawn mower 390hrs
2000 Ford Powerstroke Diesel = Wife's Toyota crusher 253,000
2004 Chevy Blazer = Daughters gas SUV 80,000
2010 BMW 335d = new clacker toy 56,000
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familydieseldr's picture
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228
Re: 300TD rear suspension level control valve

Hi,
Just finished the job before the rain starts! (I work outside, under a canopy)
And the car is level now, does not sag.

The factory original rear hydraulic level valve had 352k miles on it.
I attribute the longevity to regular hydraulic oil & filter changes, and replacing the
accumulators whenever one popped. Also it was designed well to begin with....

I was surprised to find when I scraped off some of the dirt that the valve housing was light alloy.
Fear. Steel fittings that have been threaded into Aluminum for 25 years and subjected to road spray are always challenging.

Soaked the fasteners with Kroil and another penetrating compound. Three of the four hydraulic fittings came out easily, #4 would not move until I applied heat from a Oxy-Acetylene torch to it.

http://i180.photobucket.com/albums/x257/fish1_07/valve_pn.jpg
http://i180.photobucket.com/albums/x257/fish1_07/old_valve.jpg
http://i180.photobucket.com/albums/x257/fish1_07/new_valve.jpg
http://i180.photobucket.com/albums/x257/fish1_07/finished.jpg

I'm going to try Pierre's suggested method of rebuilding the old valve, I might be able to recover a tiny bit of the $600 the new one cost someday!!

Familydieseldr

__________________
1983 300TD = old clacker 370,000-retired parts donor
1985 300SD = Son's Diesel cruiser 332,000
1985 300TD = Dad's Diesel wagon 183,000
1992 Kubota Diesel tractor = mutant lawn mower 390hrs
2000 Ford Powerstroke Diesel = Wife's Toyota crusher 253,000
2004 Chevy Blazer = Daughters gas SUV 80,000
2010 BMW 335d = new clacker toy 56,000
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Biodiesel300TD's picture
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Re: 300TD rear suspension level control valve

Rebuilding the valve is pretty easy. Just make sure you pay close attention to how it comes apart. There is a cam inside the valve that can go on a few different ways. If you are interested in an o-ring set let me know. I have enough to do more valves then I will ever do.

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Andrew  <> 1978 240D ~ Flo ~307k mi <> 2004 VW Jetta Wagon TDI ~ Her Car ~ 115k mi <> 1982 300TD ~ Winnie ~ Sold at 178k mi <> 1977 300D ~ Sold

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pch2021's picture
Rockledge, FL
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Posts:
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Re: 300TD rear suspension level control valve

I want to see this 352k wagon one day (:

__________________

Pierre Hedary
...happily servicing vintage Mercedes-Benz in sunny Florida...
1972 280SE 4.5 252K
1970 280se 3.5 coupe 108K
1971 300sel 4.5 121K
1991 420SEL TMU, but looks brand new!
Mercedes technical advice: 407 765 2867

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