That !*~^%* air filter bracket - 1983 300SD
 

Well, wouldn't you know it, the wretched air filter bracket on my 300SD fractured again. The first one lasted 10k miles. The second lasted 130k - only because after it broke soon after installation, I had a Ruddy, Great Big Weld placed on it. When it broke it did so in 2 places, looking beyond redemption. The third broke in 2 places and one of the pieces was lost. That lasted 10k miles.

Now the fourth has gone - broken in one place. The fractures occur either at the trailing or leading mounting location, closest to the engine. This is a 1983 300SD with the big air cleaner mounted near the engine on the passenger's side. Car is about to roll over 200k miles.

So I'm having not one but four RGBWs put on it by the local welder - two atop, where they fracture, and two around the periphery to see if I can get some life out of this thing. I just hate that loud rattle when I start it first thing in the morning....

Am I the only one with this failure rate? The engine is well tuned, motor mounts are fresh, air filter rubbers are fresh, little shaking at any speed.

Thomas
Did Mercedes redesign the mount on the latter year SD's?
If so maybe they got it right and they don't break.

Or maybe it would be cheaper to buy a welder *G*

Dave

I just had another air canister bracket break. I studied why it might have failed and I believe I may have found the problem.
When I put the air canister in place I noticed the nozzle that slides into the oil drain would hang up, so that the nozzle was not down into that tube. Not only did it drip oil all over, but it broke the t shaped bracket.
The solution is to get your hand under the air canister everytime you remove and replace it. You should be able to feel that nozzle and then make sure it is not sitting on top of the drain tube. Then it is safe to tighten the nuts holding it in place.

Thomas,
I agree, the daggone air filter bracket has to be the most frustrating, under-engineered, POC on the entire car.

My TD ate it's first set of rubber mounts in a little less than 5000 miles and SWMBOs 300D broke (and lost) the back part of it's mount in a shade over 2000. These aren't abused, shaking monsters either.

There has to be a better way of doing this job that does not involve a misapplication of a K&N racing filter, hanging out there, exposed to the elements.

I'm contemplating a separate air box of some sort, mounted to the fender with flexible tubing running to the turbo intake.

Old Deis
 

I have always been very careful to insert the tube correctly, using my hand under the air filter canister, so that's not it.

No oil leakage, though that would not necessarily be a symptom, as I have minimum blowby....

Dave - I think on the 1985s (at least the few CA models I have seen) they moved the air filter closer to the right front passenger side, and the whole thing got a lot smaller. It may be fender mounted, so lower vibes, than the engine mounted variant I have. I am blessed (?) with the whopper on the earlier cars.

air filter mounts
 

Thomas,
First, please allow me to thank you for your various diy accounts on your website that is now listed as a sticky at the top of this forum section.:) I personally listed your site in my favorites section some time ago! Thanx.:cool:

Anyway, something that you may want to try.....................posted the other day, sorry to say that I don't recall who did the posting.........REPLACE your engine shock absorbers.:eek:
Best wishes always, and keep those diesels humming!
Spo out.

Why not bring the bracket and some strips of thick stteel to a local welder and have him/her stick them all over the bracket? Or insted of metal sheet you could use some reasonaby thick steel rod from the local hardware store?

Me, I just replaced mine with a PVC tube directly attached to the turbo, a K&N, and a homemade oil seperator. I love this mod. It makes the engine bay soooooo much less cluttered, I can hear the turbo real nice, and I don't need to buy any more of those FU**ING rubber stumps or the thinmetal bracket!

They have failed on both of mine. It's just a crappy design. Take a metal diving board that doesn't flex well and hang a lot of mass at it's end, then shake alot in the the wrong direction. There are a couple of things that can be done to improve it.
1. Lower the mass, not likely.
2. Beef up the diving board. Just a band-aid.
3. Add another support brace under the assembly.
4. Scrap it and start over.

I've been looking at the air cleaner in the Lincoln and wondering if it can be modified for the Benz. The only complication is the oil separator. While the 240 assembly would work, I want a little more elegant solution.

Jerry

Some folks take an extra rubber bracket bumper and drill the air cleaner cover on the side to attach it with a recessed bolt; to act as a vibration dampener/limiter between the air cleaner cover and the valve cover.

I too have fought with the stupid air cleaner design. I just replaced my engine shocks but the air cleaner still vibrates quite a bit. Remember the shocks keep the vibration from reaching the chassis but it is still happening! There are two solutions I see:
1. Replace entire assembly with a home-brew setup. K&N w/240 separator, etc.
2. Reinforce the metal bracket. I am planning on seeing if more supports could be added and additional rubber isolators used. If you could add three more mounting points with the same style isolators used then I think the aircleaner may be well enough attached to not bounce around so much. Just a thought. RT

Here's a picture with the RGBW....
 

Cost all of $10.

Here's the detailed close-up
 

I had the welder add a bead around the curve to stave off the inevitable.

New bracket by mail order? Over $60.

I use the heat shields (p/n 617 094 02 20) with the rubber mounts and find that these greatly extend the life of the rubber.

Though only one side fractured, I had both welded as past brackets have broken at both the leading and trailing ends.

Thomaspin -

First, let me also add my thanks for all of your good work on your site.

In looking at your pics on this post, I will bet that your next bracket failure will happen fairly soon. (Hope I'm wrong though.)
The heat from the welding probably made the metal in the vicinity of the welds somewhat brittle and that may lead to failure again.

I've don't seem to be having trouble with the brackets on my two '82 300Ds.... but I'm not sure why. They shake more than I would like, but not excessively.

Cheers,
Wes

Thanks, Wes. Actually, the last time I had one welded it ran 100k miles before breaking at the weld....let's hope I am as lucky this time.

I was told these brackets only fail because of idle time, not running.

I wanted to ask if you have a rough idle? Does your injection pump rack dampener need to be adjusted or replaced?

Thanks for your work on your site. Very helpful.

Haasman

Haasman
 

Idle is very smooth. New motor mounts. New rubber bumpers under the air filter canister. Engine shocks 30k old. Don't idle much....

The OEM bracket is simply an inadequate design solution.

The breakage is due to the twisting motion between the two manifold bolts which is caused by engine vibration-induced vertical movement of the filter cannister.

Since welding the bracket does nothing to address the movement of the cannister, I'm guessing that adding material at the location of the existing cracks (ie weld bead) will only marginally extend the life of the bracket.

Shame on you, Mercedes-Benz; no engineer his right mind would place that kind of weight on 10" of stamped steel lever arm and expect it to last any length of time without providing any additional bracing.

In practice, the design simply needs a knee brace added to it in order to inhibit the twisting motion between the two manifold bolts caused by the engine vibration-induced vertical movement of the filter cannister.

FWIW, we'll be screwing around with TO's 'Horse With no Name' over the next few days. I'll look and see if there's any place on the manifold to attach a knee brace and try to fabricate one.


"The horse with no name"

I had that bracket break two weeks ago. Didn't want to buy another just yet. Looked for some way to get the air cannister to quit shaking so badly with the broken bracket. I do have an idle miss, but that is another story.
So I connected a throttle return spring from the rear of the air cannister to a bracket on the intake. Not a very elegant solution, but it does work. The air cannister does not shake. The spring seems to act as a dampener to the rattling and shaking.
A temporary solution for the meantime. Maybe something like this would be of help here?

Thomas
I would have hoped this forum would have had the solution.
I can't help you. The bracket on my car is original from day one and i just looked at it. No cracks, marks, stress points, nada. 175,000 mi.
I actually did not keep up with the rubber mounts at times. And the motor mounts went a little long between changes. Head to a junkyard and try to buy another one cheap see if you can see a difference.

Dave

10kmi? Mine don't last 500 miles! I gave up and left it broken. I have the heat shields and new rubbers, no change in bracket life. Someone on the MB email list mentioned they had some bar stock welded underneath, and that fixed their problem with continual breakage. I hope to sell my 123 next summer (?) and be rid of the problem completely. :D :D That's one more thing on my list of dislikes, which was fixed on the 124/201 & OM60x models. (along with serpentine belts, 1-piece motor mounts with no shocks, no valve adjustments, simple AC plumbing, and a zillion other things...) ;)

I am currently running with only one of the rubber bumper things bolted down at both ends. Can't remember which one is still hanging in there but I think it is the front one close to the engine. The others are broken off on the bottom side but most of the rubber is intact. This gives some dampening to the motion of the air filter box, yet isn't likely to beat the bracket to death. The long coil spring to tie it down a little more sounds like a basically good idea. Just need a place to hook it and make it look like it should be that way. Oh, by the way the oil return line seems to be staying where it belongs also, so don't have a lot of oil exiting that way!

Wobble
 

My concern with too wobbly a mounting is that it might play havoc with the down tube in which the air filter container's central spigot locates.

Just wanted to revisit this. I need to purchase a new bracket - this thread seems a bit old, can anyone point me to the best possible bracket to purchase? They seem to be pretty cheap on most sites these days (non mercedes version). I saw that Mercedes Source was promoting their bracket kit with a re-enforced bracket - is this the same bracket being sold elsewhere?

thanks in advance!

The above mentioned store is over priced and over hyped, but I don't think you can go wrong.

yes the pricing on his products has me hesitating and if he is selling the same brand (MTC) everyone else seems to be selling then it definitely is way over priced. Are there any other after market brackets other than MTC - I am not really interested in the Mercedes Original because of how crappy it is.

Sorry to hear you're having issues with the stock unit/s.

I did replace one on a friends years ago, haven't heard back.

I am considering having a cnc aluminum bracket built...

Any interest?

If it will be more durable and not overly expensive I would be interested...

I haven't owned a W123 in about 10 years, but I'd cautiously suggest the bracket failures are a symptom of other issues, not necessarily a design problem with the bracket itself. (And, I'd be cautious about using any MTC stuff, many of their products have taken a severe turn for the worse over the past decade...)

:blink:

I end up getting rid of stock mess,and used a Mustang assembly and air filter.

Some drilled/bolted angle aluminum would probably work pretty well also.

Sent from my MB886 using Tapatalk

I cut down a piece of bedframe angle iron - put it in a vice and used a cutoff wheel to slice down one side of it but left enough of a ridge to give it strength/ prevent flexing. Drillled holes for the rubber pads and the two bolts that fasten the original bracket and mounted it over the oiriginal bracket wih the ridge facing up, on the valve cover side. Had to unbolt and carefully bend/ pry on the turbo oil feed so the new brace would slide up under there; also cut a couple of notches for clearance of the oil feed tube. It's a redneck solution but seems to be working - I did this on both of the OM617 cars I have after the ends had broken off. Having the valves adjusted and cleaning and balancing the injectors goes a long way too, for addressing the shaking that is at the heart of this issue.

Those in CA can get the 1985 frame-mounted air filter from a junkyard. I put that on my 1984 300D. Search for my post w/ photos. I used a silicone turbo hose for the inlet instead of the factory rubber bellows (usually rotten now) and ran an oil drain tube over to the normal drain tube, rather than into the turbo inlet (as 1985 CA did). I did have to cut the air filter outlet tube a bit shorter to make the 90 deg turn into the turbo. The 1985 CA turbo sits higher. At the same time, you might get the vacuum amplifier (blue moon) for better tranny shifting, as I did. I also found a Wix PN air filter that allows stacking 2, rather than the rare and expensive proper air filter (search post).

Anybody in Sacramento that needs another 1984- air filter bracket, I have 3 in the box (one new) and will sell cheap. But you can buy new ones for ~$17 I recall.

I went ahead and bought the after market one for $20... We'll see what happens, my current one had been welded before I bought it and that was before I did a valve adjustment so the idle is smoother now. Fingers crossed :)

Mine hasn't broken lately but the one on the parts car was trashed & I was thinking of something like what people do on a Cummins (BHAF).

https://www.google.com/search?q=cummins+bhaf+pic&tbm=isch&imgil=uoZFSajaOiRsMM%253A%253BfQfhZvMmpuTIoM%253Bhttp%25253A%2525 2F%25252Fwww.thedieselgarage.com%25252Fforums%25252F170-5-9l-cummins-12-valve-1994-1998-5%25252F103513-12v-cummins-air-filters.html&source=iu&pf=m&fir=uoZFSajaOiRsMM%253A%252CfQfhZvMmpuTIoM%252C_&biw=1280&bih=667&ved=0a hUKEwjnvqKy8NfJAhXIVyYKHVvEBqUQyjcIMA&ei=weNsVqfaI8ivmQHbiJuoCg&usg=__NcSu82Cv9BDSMWF5SwAIr9Aob2s%3D #imgrc=uoZFSajaOiRsMM%3A&usg=__NcSu82Cv9BDSMWF5SwAIr9Aob2s%3D

You'd have to do something with the down tube.

Let the hating begin
 

This is my solution. First, clear up the vibration through valve adjustment and vacuum repair. Then ....

Some say this is a "hot air" intake. I do not believe it to be so. The standard air filter box (all but California) is located directly above the exhaust manifold and turbocharger, a definite hot spot on the engine. In addition the underhood temperature drops almost immediately when the car starts moving.

The K&N filter works well when cleaned and oiled once/year. Use of a K&N on gassers may be controversial but the diesel is pleased to burn up any possible excess oil anyway. The breather is a two-stage system using two catch cans. The upper goes into the air cleaner vent tube, then to the lower catch can.

In any case, it offers vastly improved access underhood and an improvement in performance particularly when combined with the removal of the EGR system. I installed this about 10k miles ago. The only drawback is increased induction noise, a growl which some may like. I know I do.

Yeah my set up is nearly identical to yours. The oem intake design is a pain in the ass.

you can combine 2 merc solutions
air setup from 97 e300 turbo....

cheers

Now THAT is a nice solution!!!

:balloon2:

Wow... Aside from the green garden hose, that looks great.