[260e crusier]

There was a stain on my driveway yesterday. It was from my 2003 E320 wagon at the right rear wheel. It appears to be light petroleum with no odor. My guess would would be SLS fluid.

I check the SLS reservoir and the level seems fine. Not absolutely sure as driveway is sloped and fluid was maybe 3/8 - 1/2" below max mark on the front of the tank. I topped it off to the maximum line and will check again tonight when my kid return home from work.

I jacked up the car and removed the wheel. It appears fluid is dripping off the subframe mount and down the front lower control link. EVERYTHING else was dry. I see no fluid spray. It almost appears as if the subframe mount was fluid filled and sprang a leak!

All lines (brake & SLS) are dry and also the following: the accumulator, hydraulic ram, fluid control valve, top and bottom of subframe and the area above the subframe mount!

I measured the fender lips on both side and they were within 1/8" of 27 1/2''. Any guess/insight were this fluid is coming from?

 

[Kajtek1]

It looks more like gasoline leak on the pictures, but you are the one who can stick your finger in it, smell and taste
Leaks with cross air flows in engine bay can travel mysterious ways. Wrap the parts with paper towels and see where the wet will reappear.

 

[tabijan]

Brake fluid?

Sixto
98 E320 wagon 197K miles

 

[Deplore]

It almost appears as if the subframe mount was fluid filled and sprang a leak!

That's because it is. Check the surrounding area, and if there is no other obvious source of leak, either from SLS or brake lines, it's your subframe mount.

Good luck, that is a total pain in the ass job.

 

[260e crusier]

Damn!! I was in the process of typing this when you posted!

This is starting to drive me crazy 🤪

95% sure its SLS fluid. Definitely not gas or brake fluid. Kind of blackish (dirt?) when it hit the driveway. Brownish yellow with a very light pinkish tinge when droplet is hanging on the subframe mount. Cleans up easily with a RTU all purpose degreaser.

There is no fluid migration due to air or car movement. I have double check all gas, brake and SLS lines and there are no leaks. The valve body, hydraulic rams and accumulators are also dry.

Fluid is dripping off the bottom of the right front subframe mount at the rear of the car. The top of the subframe mount is dry as is the external surface of the subframe!

Logically......... this must mean fluid is either inside the subframe or it is migrating down from the bolt. Question is how did the fluid even get there? As I stated the top of the mount is bone dry

 

[Deplore]

Well, subframe fluid is black. I mean, BLACK. Blacker than diesel oil, if you've ever handled it. Black black black.

If its anything other than black, most likely SLS. If you're not sure, dip your finger into the SLS reservoir in the engine bay and smear it on paper towel. Then drag your finger on the wet spot on subframe and wipe on towel. Compare the two.

If you have borescope camera, now would be perfect time to look at the space above subframe mount, so you're not fighting a flashlight and mirror, or anything.

 

[260e crusier]

Its black when it hits the driveway.......wouldn't call it super black. It did cleaned up fairly easily like motor mount fluid. Going to have to investigate it further. If it is the subframe mounts, how critical is it to have them replaced? Can one be changed or does the whole subframe have to be dropped and all replace?

Is there a pathway for SLS fluid to get inside the subframe. I would think it would take a noticeable drop in reservoir level for it to migrate to the subframe mount. Is it possible for the hydraulic rams to leak at the very top into the interior car (while remaining dry underneath the car) and then down to the subframe mount bolt?

Thanks Deplore!

 

[Deplore]

Is there a pathway for SLS fluid to get inside the subframe.

That's the problem, the subframe is bolted directly to the chassis, and then the mount is pressed into the hole, and then bolt goes through the mount and then chassis. No way for the SLS line to go through it. Around it, yes. That's when you should be touching the SLS line and just follow it with your hands until you feel some wetness. If you don't....its the subframe mount.

If it is the subframe mounts, how critical is it to have them replaced? Can one be changed or does the whole subframe have to be dropped and all replace?

One can be changed, but like shocks or motor mounts, usually its better to replace them in pairs. Spring has to be removed, then you're lowering the subframe on one side.

There's a youtube video about replacing the subframe mounts by some dude in a garage with the car on jackstands. It's pretty clear....but it's a total pain in the ass. I absolutely do not envy you, that one is the harder mount to press out.

Is it possible for the hydraulic rams to leak at the very top into the interior car (while remaining dry underneath the car) and then down to the subframe mount bolt?

Possible, but doubtful. SLS fluid when mixed with the interior foam or fabric or stuff makes some potent smell....you'd have to have a non-functioning nose not to notice it....plus I bet your wife would've definitely said something about it. The SLS line doesn't exactly go into the interior...

View attachment 2641356

Notice the line, that one is on the outside, not inside.

 

[260e crusier]

The stain on the driveway is smaller today. Guess if it stops in the next couple of days, I can assume its the subframe mount as there is a finite amount of fluid in it.

Time to watch some YouTube videos and do some searching....

Thanks again Deplore

 

[Deplore]

This is the video I was referring to.

 

[260e crusier]

Booked mark!

Looks doable, but pain in the arse. At least I won't have to be on my back like doing motor mounts.

My car is corrosion free so hopefully the old one will come out easier. Maybe cutting/slicing the metal sleeve with a dremel will help? Heard there was a special tool also. Will have to look into that also.

 

[260e crusier]

After looking at the video and parts online, it appears not necessary to remove the metal sleeve. I don't even see a part number for that piece unless it comes with the replacement bushings. Job shouldn't be that bad if that's the case!

 

[Deplore]

No, but you might need a propane torch, or lots of lubricant, or both, plus lots of sockets and washers of varying size that you can use as a poor man's pressing tool.

The subframe tool for W210 (211 and up use different tool) is like $300.... Given that the subframe bushings are like $50, it seems too much for one time job.

 

[khomer2]

No, but you might need a propane torch, or lots of lubricant, or both, plus lots of sockets and washers of varying size that you can use as a poor man's pressing tool.

The subframe tool for W210 (211 and up use different tool) is like $300.... Given that the subframe bushings are like $50, it seems too much for one time job.

Is it possible a tool like this can be (rented) or borrowed? I hear good things on the W163 forum about those south of us, have options to borrow these types of automotive tools out of the big box tool/supply shops, for personal use.

 

[260e crusier]

The subframe tool for W210 (211 and up use different tool) is like $300.... Given that the subframe bushings are like $50, it seems too much for one time job.

Reading the "Stickies" and other previous posts now for additional information. Hope this is a one time job, but with three W210s.............

 

[260e crusier]

UPDATE: Confirmed.........its the front rear subframe mount.

That's because it is. Check the surrounding area, and if there is no other obvious source of leak, either from SLS or brake lines, it's your subframe mount.

Never knew they were liquid filled like motor mounts. You can easily miss this unless your driveway is oil free. It will only drip for about two days.

Well, subframe fluid is black. I mean, BLACK. Blacker than diesel oil, if you've ever handled it. Black black black.

If it's anything other than black, most likely SLS. If you're not sure, dip your finger into the SLS reservoir in the engine bay and smear it on paper towel. Then drag your finger on the wet spot on subframe and wipe on towel. Compare the two.

When I first saw the black stain on the concrete, I briefly wondered why it was so dark as I changed all the fluid on the car last year when I bought it. I assume it was from a hydraulic ram as I don't thing fluid circulates thru it. I did not flush the SLS/steering system, but just did multiple fluid exchanges at the reservoir.

Miss this hint: The stain easily cleaned up with a water based degreaser just like motor mount fluid.

The stain on the driveway is smaller today. Guess if it stops in the next couple of days, I can assume it's the subframe mount as there is a finite amount of fluid in it.

Time to watch some YouTube videos and do some searching....

Thanks again Deplore

A new adventure awaits in the future............ You hear/see a lot of posts on motor mount symptoms and replacements. Very few on subframe mounts. It you don't see the leak/drip while it's occurring, I guess you wouldn't know there is a problem until there is enough wear to cause noise or handling symptoms. Anyone know how long this will be (procrastinating now)?

 

[tabijan]

Is rear suspension thumping a symptom of dry subframe mounts? I thought it was collapsed spheres but they pass Uncle Kent’s stick depth test the ride is fine. There’s just audible thumping on abrupt drops.

Sixto
98 E320 wagon 197K miles

 

[260e crusier]

Is rear suspension thumping a symptom of dry subframe mounts? I thought it was collapsed spheres but they pass Uncle Kent’s stick depth test the ride is fine. There’s just audible thumping on abrupt drops.

Sixto
98 E320 wagon 197K miles

With close to 200K on your wagon and being a 1998........yours are probably due. My wagon is a 2003 with only 125K.

 

[Deplore]

Is it possible a tool like this can be (rented) or borrowed? I hear good things on the W163 forum about those south of us, have options to borrow these types of automotive tools out of the big box tool/supply shops, for personal use.

I wouldn't know, I never found someone willing to rent it. Tool is expensive and almost no one buys it. There are various places that sell it, but you have to read the fine prints very carefully, the tool is NOT interchangable with W211 or W220, or even W203/202. W210 stands alone in that regard, the subframe bushings are a size unique to W210 only. At least 211 shares it with 220 or even 203.

Never knew they were liquid filled like motor mounts. You can easily miss this unless your driveway is oil free. It will only drip for about two days.

HCB Auto Tools - H.C.B-A1341 Mercedes-Benz (W210) REAR SUBFRAME BUSH EXTRACTO

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Rear Subframe Bushings - MBWorld.org Forums

W210 AMG - Rear Subframe Bushings - Five weeks or so ago I took my car on a 500+ mile roundtrip which is the furthest I've driven it since I bought it. About two-thirds of the way to my destination I started noticing what felt like the rear suspension wasn't working properly. It wasn't riding...

mbworld.org

DIY - W210 Rear Subframe bush replacement

As time passes by you may notice that your beloved no longer handles quite the way that she used to . She may feel a little wayward in a straight line, lurches around corners and jumps sideways when surprised by bumps on bends. In all she's not quite so composed with her rear end as she used...

forums.mercedesclub.org.uk

BENZ CHASSIS REPAIR TOOLS : H.C.B-A1341 Mercedes-Benz (W210) REAR SUBFRAME BUSH EXTRACTOR / INSTALLLER

 

[khomer2]

Lol - When you have to call for pricing, I guess they want to know how many generations down the line you have to carry on the payment plan. Sheese.