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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Discussion Starter #1
This is a Bosch ( 0 280 140 017) Auxillary Air Valve or Air Slide Valve from a D-Jet fuel injection system. There is a similar valve on the early K-Jet system. It was stuck in the closed position and could not be fixed. I decided to cut it open to see how it worked. I found that the brass bulb on the bottom had a rubber diaphram in the center and was filled with a liquid, not a waxy substance as had been previously stated somewhere. The liquid looked, felt and smelled like motor oil.

Heat causes the liquid to expand pushing on the diaphram which in turn pushes the rod up.

Hope someone finds this interesting.
 

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Rowdie, this is a superb sypnosis of the innards of an AAV and it is exceedingly praiseworthy the time and effort you undertook to dissect the AAV to provide a better visual understanding on the workings of this outrageously expensive item, so often the culprit of the high idle from hell syndrom!. I was quick to file a copy of pics on my temporary folder (pending favourable consideration outcome of copyright granting approval):D to be able to refer to it when the occasion arises. Very many thanks for sharing your findings!!!> :bowdown::thumbsup:
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Discussion Starter #3
No copywrite problem. I took the pictures. I posted them on a public forum. They may be copied and used by anyone as they wish.
Thanks for the compliment.
 

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2010 Mercury Milan Hybrid, 1993 BMW 325i convertible
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Some really energetic and desperate Porsche owners posted a piece about swapping the bottom bulb with one liberated from a thermostat. I don't think I'd want to do that. All in all, I'm happy with my KJet system.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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This is a Bosch ( 0 280 140 017) Auxillary Air Valve or Air Slide Valve. It is stuck in the closed position and could not be fixed. I decided to cut it open to see how it worked. I found that the brass bulb on the bottom had a rubber diapram in the center and was filled with a liquid, not a waxy substance as had been previously staed somewhere. The liquid looked, felt and smelled like motor oil.

Heat causes the liquid to expand pushing on the diaphram which in turn pushes the rod up.

Hope someone finds this interesting.
Thanks a lot for that Jim. I had been thinking of doing same with my old AAV, but it is still sort of functional - just closes at too high a temperature and tends to stick. Luckily the used one I purchased works fine.

I read on a Jag forum about dismantling their AAV, cleaning, adjusting and then reassembling. Looks like everything is press fit. Do you think the the unit could be taken apart without destroying it?
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Discussion Starter #6
It is a press fit but I can't see how to disassemble it without destroying it.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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It is a press fit but I can't see how to disassemble it without destroying it.
I was wondering if the upper cylinder could first be pulled out, or more likely the outer housing pushed down off the upper cylinder. Maybe with some dry ice or heat to loosen the fit?

Now I see what it looks like inside, I would like to try (friend has a hydraulic press)

Here is the Jag link:

http://www.jag-lovers.org/xj-s/book/AAVdisassembly.html
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Discussion Starter #8
The piece with holes in it in the Jag pics is thicker than the one in ours and ours only has a hole in the center.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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The piece with holes in it in the Jag pics is thicker than the one in ours and ours only has a hole in the center.
Yes - we couldn't separate the parts the way they suggest - I think it will be necessary to either push down on the outer casing or pull up on the cylinder. Once the cylinder is out, then the bottom plug would be pressed out to expose the piston.

Will put on my to-try list!
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Discussion Starter #10
I have another bad one to experiment with.

And from what I can find the early K-Jet also had one. Don't know if it was the same part number. Still checking.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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I have another bad one to experiment with.

And from what I can find the early K-Jet also had one. Don't know if it was the same part number. Still checking.
If I hadn't found a good used AAV, I was going to buy one off a Saab.

barri on Peachpartts has used them on his SLs. It is electric with reversable motor. With a two way switch on dash, it can be opened or closed at will. Used ones cost next to nothing in junk yard or under $100 on eBay. Sort of works like a manual choke.
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Discussion Starter #12
Interesting.
The early K-Jet did have one. PN 000 141 05 25. The D-Jet PN is 000 141 03 25. The difference looks like the inlet and outlet tube position.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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Interesting.
The early K-Jet did have one. PN 000 141 05 25. The D-Jet PN is 000 141 03 25. The difference looks like the inlet and outlet tube position.
I came across some of those when searching:

DJET


KJET


Not sure if this is the right one, but the 3-wire Saab valve looks something like this.
 

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Interesting.
The early K-Jet did have one. PN 000 141 05 25. The D-Jet PN is 000 141 03 25. The difference looks like the inlet and outlet tube position.
Yes, the D-JET and K-JET have different angles and height of inlet/outlets


 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Discussion Starter #17
Well that answers the question.
 

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Meh, all well and good taking them apart etc or replacing with a modern one. But you don't need to, all you have to do to fix one if its letting too much air in at first start-up is to put the bottom bulb in a vice and squeeze it a little(or find a crimper large enough). Put it back in the car and see if its idling slow enough, squeeze it again if its still idling too fast, try not to go too far as i have no idea how to go the other way, might have to wait another 10yrs :)

Mine when i first looked at it was almost 100% open at like 20degrees Celsius and the car would idle at 1600, my mothers 350SL with a normal ecu kept going so high when out of gear it would reach fuel cut and oscillate. To get the car to idle at 1100-1200 when first started i squeezed the bulb enough that it was only 2-3mm off been fully closed.
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Discussion Starter #19
That would be fine for one that is stuck open or won't close enough. The one I cut open was stuck fully closed.
Soaked in PB for days could not get it open.
 

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Always Remembered RIP
1979 280sl 4 sp w/ac 1957 MGA 1998 volvo xc/70 2004 F150
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Cool, I love to take things apart to see how they work. Now what did I do with the rest of the parts?
 

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