Vehicle: Merz 2002 S500 W220.175 -owner since Oct.2008
Location: The Great White North - Canada
Posts: 26
Hello Skylaw, the brass valve's angle definitely makes one think "if it is pressed down, it may break at the thread point", and I can see why the mastic (original black resin/sealant) may have the intention of "holding" and dampening the brass valve. However, the amount of thread the valve has, in screwing into the hole on the top part of the strut, makes it pretty solid anyway - and probably why the repair kit for the metal cap leak doesn't call for new mastic (shops leave everything open). Also, given that the top horizontal half of the valve sits above the mastic, I think that the mastic really doesn't do any real damping or holding of the brass valve. The mastic is very hard, relatively weak and brittle, so any vibrations will surely make it crack (!).
From the removal of my passenger side mastic, I do notice that it does act as a sealant, even if it is not intended as such, and I am considering doing the same removal of mastic and testing (and resealing with multi-metal epoxy) of my driver's side front strut - which currently doesn't show leaks, but does show a few cracks in the works. I will be sure the record on video that second "fix", and I theorize that the removal of the mastic on the strut that currently does not show leaks, will actually leak, and probably through the same place as my passenger's side - in between the gap of the steel ring that holds the original steel cap. I realize that I will be "fixing" something that is not broken (yet), but I want to avoid having to stop and restart the car to reinflate the struts when i am going somewhere in a hurry.
By the way, the epoxy I was recommended at the hardware store (Canadian Tire) by an "off-duty" mechanic was the PermaPoxy-multi-metal-4min stick (more info from their web site): http://www.permatex.com/products/Aut...poxy_Stick.htm
This two part, hand kneadable, putty type epoxy has contrasting colored materials that are mixed together to form a uniform color to indicate thorough mixing. Eliminates the need for welding or brazing. Holds in four minutes, useable in 30 minutes. Dark grey appearance. Temperature range -40°F to 350°F (-40°C to 176°C). When cured, can be drilled, sanded, threaded or filed. Resistant to fuels and solvents after full cure. Permanent strength up to 3500 PSI.
It is interesting to note that this stuff is recommended for sealing cracked blocks, castings, etc, which is subjected to high temps and pressures. This experiment may prove useful, since I believe that if the surfaces are properly cleaned, the applied multi-metal epoxy when fully cured is actually above specs of the original factory install, or the fix kit. If I am wrong (it is possible!) I'll be the first one to admit that I need the $120 kit for each side, plus the special tool - and will get that done and recorded for the forum.
Vehicle: Merz 2002 S500 W220.175 -owner since Oct.2008
Location: The Great White North - Canada
Posts: 26
Okay, second-last update. The battery on my mobile died while recording so I lost the full video while fixing the driver side strut. I can confirm (with all due respect) that the original black resin/sealant (aka "mastic") does act as a sealant, since when I removed it from my non-leaking driver side strut, the underlying steel cap which is in perfect condition did leak via the 1 cm gap of the steel ring that holds the cap in place - same thing as seen on the video of my passenger side strut. I strongly believe that the original steel cap design is flawed - and I wonder why doesn't Merz do a recall. I bought my Merz second-hand, and the warranty doesn't cover that.
I have gone ahead and sealed the driver side strut with the epoxy, and waiting to cure. Both my front struts now have the epoxy seal, after having removed the original black sealant/mastic, and having sanded the surfaces down to remove paint, etc. I will go ahead and test during the next few days (of vacation left!), and let you know here how it goes.
Below I will also post pictures of the final look of the epoxy - which is not exactly pretty, since it looks like grey putty, but I am not too concerned with mechanical looks - just function, and I can't complain for 1 hour work and $5 total material cost per strut.
This $5 + 1 hour per strut alternative is definitely for those of us who feel that $300-$500 is way too much to fix the leak when the underlying steel cap, strut and valves are okay and that the "putty-look" is also acceptable, vs the steel-look.
I don't recommend this for those that want their Benz to be great-looking in the engine. In terms of safety, I think (with no warranties) that this fix exceeds the specs of the original black mastic, since it is stronger, adheres perfectly, is usable under the temps and pressures it experiences, and it does not crack like the original mastic.
Anyway, last post on this will be my road test results!
Carlos,
Per your request, I've attached the pictures of MB W220 Front Strut Repair Kit with the Brass Valve. I'm going to put this kit into my car over weekend. Also, I found "strutmasters.com" has 4 wheel Coil Spring conversion kit to eliminate the troublesome of air shocks on this car which might be my alternative solution when I encounter problems on air shock next time.
what exactly is that yellow stuff in the small white container? I got the kits myself and will be doing this myself this weekend. I did not get any instructions. I have not had a chance to research more yet.
Also, do you have the special tool needed to do the job? I ordered mine from ebay and should receive it in the next few days. paid $99 plus $15 shipping. I plan to sell it when done.
Vehicle: Merz 2002 S500 W220.175 -owner since Oct.2008
Location: The Great White North - Canada
Posts: 26
Hello dko888, thanks for the excellent close up pics of the kit.
Before I start, a quick update on my epoxy fix of both struts - i drove 30km of hwy and main roads, and a parking lot with speed bumps, always with sport setting 2, and alternating hieght of car up and down. No low car warnings - and the ride was excellent. My car never responded so quickly with the raise and lowering button. By the way, all this hassle is worth the sophisticated air suspension of the S500 - I too have thought about the conversion kit, but have decided to forget that. In my opinion, this air suspension system only has one problem - keeping the air in, especially the really bizarre design of the front strut connections to the hoses. The back struts have a different design, and hence never give any problems. Few cars can have the versatility of the S500 airmatic system - I encourage everyone to stay with it. some of us will do kits, others epoxy!
Okay, so getting back home, I checked the epoxy for leaks on both struts, and the epoxy is unchanged - it probably slept through all those pot holes I did NOT avoid. The leak I had with one of the valves at a mid-joint, was also fixed since I also epoxied that point of the brass valve (see pic for location). The only thing I notice NOW is a very slow/small leak at the point where the brass valves screws into the strut. I have not applied epoxy to this joint, in order to make it easy to replace the brass valve, if necesary. However, in looking at the original black sealant setup, I have noted that this brass valve connection to the strut was ALSO under the black sealant - so the engineers at MB "knew" this was a potential leak point - c'mon there is no washer or anything between two metal parts! The thread of the valve has a little bit of wax, but its more for avoiding it "unscrewing" from vibrations (I believe), not sealing the point. Given that the brass valve looks very solid, I have decided to epoxy that to the strut as well - which will seal the connection point. After this, the air form the hose cannot escape from the strut - as it should be. I've quickly tried adding a washer between the strut and brass valve, but it just gets squeezed out. The air hose connection to the brass valve is a great design - it has a washer and the valve holds it in place during tightening.
Anyway, that all for now. here are a few picts to follow my story above.
wow, i did not know you can ge a strut conversion kit from Air Suspension Kits | Air Ride Suspension Parts | Air Bag Suspension for so cheap. I may look into it down the road but only if my car requires all new struts. By that time my car may only be worth $5k so it will not be worth spending few grand on new air struts.
I wonder if anyone actually converted them and what the results are. Of course the air ride is much nicer and preferred, that's one thing that makes the s500 what it is but there comes a point when enough is enough with the crappy suspension design on these cars.
Hello Detcomm,
The yellow stuff in the small container is grease paste for the new sealing ring. I'm going to pick up the tool from www.kingtonytools.com. $89 plus tax and will sell it after the repair job.
I only can repair one leaking shock, another air shock (passenger side) has air and fluid leaks, so that is not repairable.
Repair instruction is attached.
Vehicle: Merz 2002 S500 W220.175 -owner since Oct.2008
Location: The Great White North - Canada
Posts: 26
Okay, as mentioned before, I have gone ahead and sealed with epoxy the brass valve to the strut, to avoid leaks with the metal-to-metal contact of the brass valve at the strut.
I have uploaded two videos - hope they prove useful to think about what anyone may want to know of what I did.
I have also included below some pictures of the finished epoxy application. Tomorrow Friday, i will be testing the whole thing, and will let you know how it goes.
With this last chapter, I hope to have duplicated and surpassed the sealing specs of the original black sealing mastic that MB placed at the factory.
By the way, if anyone changes a strut entirely, be sure that they apply the kit-fix, or whatever, to avoid the eventual mastic cracking and leaking.
Cheers
Last edited by carloslameiro : 01-09-2009 at 06:20 AM.
Vehicle: Merz 2002 S500 W220.175 -owner since Oct.2008
Location: The Great White North - Canada
Posts: 26
Hello dko888,
Those instructions are great. the idea of the bolt to close the upper hole of the strut once the brass valve is removed is nice (step 8)
I do notice that the removal of the casting compound if pretty delicate (using hot air) - i used to good old screw drive and hammer approach!
What is step 18 referring to? "Glue upper center console of air suspension
strut in the engine compartment" - to place glue on the new plate cover? What type of glue? What's the purpose (sealing?)
What is interesting is to see that the STAR system is "supposed" to be used to remove and refill the strut with air.... yup, didn't to this either in my case.
The checking of the bellows for wrinkles (step 23) is something I will be doing....
Thx for the manual - excellent stuff - even for me, using epoxy!
Cheers
Last edited by carloslameiro : 01-08-2009 at 02:08 PM.
Carlos, you have done us all a service with the discussion and the photos. Extremely useful, and I would love to hear that it worked out over time.
However, I go back to what I said in the first place about the mastic (epoxy); its purpose is NOT as a sealant. While any "sticky stuff" may hold a leak for a while, it will give way eventually against pressure. Its primary purpose is as a vibration damper to avoid metal fatigue and cracking in the smallest portions of the brass valve (and the connection it screws into).
The early production S-Classes did not even have the mastic. The seal was expected to hold, as I indicated above. If the brass valve broke, it was usually toward the bottom; but more often, the failure was at the seal itself (below the valve) or because of metal fatigue in the top of the mount, causing cracks (the latter is what happened in my '00 S-Class; I could see the circular cracks in the stamped metal).
__________________
2005 S500 4-Matic
with Gateway 500 iPod integration
1978 450SL restoration project
Formerly: 2000 S500
with Ice>Link iPod integration
Moto V710 phone with MikBox
Upgraded Voice Control
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