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Art Love

Australia
6226 Posts

Posted - 05/18/2011 :  03:26:24  Show Profile  Reply with Quote
I looked this up this morning but didn't have time to post a reply. I'm a bit intrigued by what I found in my M100 Parts Manual. The O ring is shown in Group 13. It's Part 56 way over on the left side in front of the power steering pump.





But when I looked it up to provide you with a Part Number which is 001 997 72 45, it lists it as only applicable to the 100.980 motor used in the 600, not the 100.981 in the 300SEL 6.3. Don't know if you can read it in the <80Kb image, but it is the third number down. I haven't had an air pump and power steering pump from a 6.3 apart in recent memory, so I don't know if this is correct or not, but that is what my Parts Manual clearly says.




Art
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pjtigger

United Kingdom
153 Posts

Posted - 05/18/2011 :  04:29:44  Show Profile  Reply with Quote
The 6.3 pump does have that "O" ring. For info to overhaul the PS pump you need the following "O" rings

2x64 O ring
2x23 (2) O ring
3x47 O ring
2.5x13 O ring
2x8 O ring

When i purchased the rings there was a minimum order so i have a number of "Kits" - i did think about putting them up on Ebay but have not got round to it yet
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Art Love

Australia
6226 Posts

Posted - 05/18/2011 :  05:19:53  Show Profile  Reply with Quote
Paul,
Justin may be interested in a "kit" or two. Send me a PE artlove@bigpond.net.au with prices.
Thanks,
Art
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Kai McRae

Australia
390 Posts

Posted - 05/18/2011 :  08:40:13  Show Profile  Reply with Quote
Having just done this job and calmed down a bit I concur. The O ring in question is part 56, roughly 3 or 3.5 x 45ish if I remember. I sourced mine locally after checking with Tom re. availability.

The ring is not available separately from the Classic Centre. It comes in a kit for the PS pump I think. I wasnt breaking mine down and didnt want to buy the whole kit for the o ring.

It wasnt a dual lip seal simply a round profile O ring. I can post the kit part number from Tom tommorow if need be.

1971 6.3 - #5417 -
(LPG)
1982 230E - W123 (M102)
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tjryan

USA
25 Posts

Posted - 05/18/2011 :  13:13:12  Show Profile  Reply with Quote
The PS fluid (red ATF) is looking a little murky/brownish. So I suspect that the engine oil is getting in there.

Is this a classic center type part, or can I get this seal anywhere? I haven't had the pump off yet, not sure of its design. Thanks

Tim

TimRyan
71 300sel6.3
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tjryan

USA
25 Posts

Posted - 05/18/2011 :  13:17:12  Show Profile  Reply with Quote
sorry, didn't see the second page of replies before my question. All is clear.
Thanks
Tim

TimRyan
71 300sel6.3
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Chris Johnson

USA
3751 Posts

Posted - 05/18/2011 :  13:18:57  Show Profile  Reply with Quote
Hi Tim,

I think it is very unlikely that engine oil is getting into the PS system as there is a drain back to the engine between the compressor and the PS pump. The PS pump generates much higher fluid pressures than the engine ever will, so if there was a leak you would see PS fluid in the engine.

More likely is that the PS fluid is very old and the filter has never been replaced. Dump all the PS fluid and replace the filter, operate the system again, and dump the PS fluid again. Then fill it again.

Chris Johnson
If you aren't constantly impressed with your car, then it needs fixing.
100.012-12-000790
100.012-12-000867
www.300SE.org
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Ron B

Australia
11612 Posts

Posted - 05/18/2011 :  18:20:45  Show Profile  Visit Ron B's Homepage  Reply with Quote
Chris, as a matter of interest I have changed a lot of these seals where the engine oil has reached the powersteering reservoir. I have done two for Robert Fulton on both of his 6.3's and he can attest to the fact that the engine oil goes everywhere as the pressure builds in the reservoir and covers the left hand side of the car.
The high pressure side of the vickers pump is below the reservoir and the engine oil comes through the pumps seal because it is designed to hold a lower pressure in ,not stop higher pressure coming for the other side.
It's not unusual on a 6.3 and the symptom is a lot of black oil in the reservoir and dripping under the car.
The two O rings are simply low pressure seals and basically just seal the pump to the compressor. They wont prevent the oil leaking from the compressor to the power steering because they are on the power steer pump flange,not the compressor shaft.
The EPC incidentally doesn't list he lip seal which is why I seem to be getting stick from others here. i am not sure if the seal kit# A000586 26 46 contains this, because I simply go to the local seal place here and buy a new one for $8. But,be aware,if you dont replace it ,the oil WILL go from the compressor to the power steer reservoir.

quote:
12-14-2004, 11:49 PM #8
Tom Hanson
MBCA Member

What the heck, try to stuff a MB 6.9 liter V8 in it. What a machine that would be..
__________________
Tom Hanson
Orange County Section

Edited by - Ron B on 05/18/2011 18:42:37
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Chris Johnson

USA
3751 Posts

Posted - 05/19/2011 :  01:50:08  Show Profile  Reply with Quote
There simply is no seal on the rear of the compressor.

There is a seal in the front of the PS pump shaft, but there is also an oil passage way straight back to the engine sump between the compressor and the pump, so there is no oil pressure there on the compressor side of the pump seal.

Of course, all this is predicated on the passageway for return oil flow being open so that the oil can actually flow. If that return path is blocked then the front of the PS pump might see full engine oil pressure. I'll have another look at a PS pump tomorrow, but right now I remain of the opinion that the pressure on the pump side of the pump shaft seal is higher than any pressure that might be in the engine sump.

Chris Johnson
If you aren't constantly impressed with your car, then it needs fixing.
100.012-12-000790
100.012-12-000867
www.300SE.org
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Chris Johnson

USA
3751 Posts

Posted - 05/19/2011 :  17:37:01  Show Profile  Reply with Quote
I looked at the PS pump. The oil pressure on the pump side of the shaft seal is equivalent to whatever the amount of oil in the reservor imposes. Not a lot.

Since there is a large drain between the compressor and the PS pump that goes back to the engine sump and the sump is ventilated back through the air controller, there wouldn't be a positive pressure between the compressor and the pump unless the drain path was blocked. Blockage seems quite unlikely considering the size of the path.

Chris Johnson
If you aren't constantly impressed with your car, then it needs fixing.
100.012-12-000790
100.012-12-000867
www.300SE.org
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Art Love

Australia
6226 Posts

Posted - 05/19/2011 :  18:17:01  Show Profile  Reply with Quote
I checked with Tom Hanson regarding what Kai posted about the availability of that O ring - 001 997 72 45. Tom replied that it IS available as a separate part. I've asked him for a price and shall post it when I have it. Tom commented that the odd seal in the PS pump is the "radial seal between the two pumps", which is what I presume Chris is referring to as the "seal in the front of the PS pump shaft". Air compressor kit 000 686 01 13 that Albert posted a picture of is $155 and the PS pump kit 000 586 26 46 that Ron referred to is $53. I presume that 000 586 26 46 includes the radial seal which I guess from what Ron is saying is the seal he buys locally for $8. I'm happy to be corrected on any of my presumptions.
Art
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Ron B

Australia
11612 Posts

Posted - 05/19/2011 :  19:00:17  Show Profile  Visit Ron B's Homepage  Reply with Quote
Art,radial seal is what the lip seal translates in english from German and it's the seal which I am refering too. I would be most interested to see the compressor which runs without one as Chris is so adamant about. If you dont replace it ,and it needs replacing every so often you get the oil running into the power steering. Going back through the archives ,one could find several instances of it here,including I think Mike getting one replaced at a Lodestar meeting.
I wouldn't pay those prices for the vickers pump seals when they are available locally at several places within 5 minutes of me. The design of the vickers pump means that it is extremely rare for the fluid to run from the high side out of the drive pulley side of the shaft.But,as i have already said. it is common for the oil from the compressor to be pumped into the power steering from the air compressor when the lip seal fails.
Looking at a picture in the manuals I can see that it doesn't show the seal ,a generic picture in fact used across the range... now I know why everyone is trying to tell me that there is no seal there. If you dont pull one apart you wont see it will you ?


quote:
12-14-2004, 11:49 PM #8
Tom Hanson
MBCA Member

What the heck, try to stuff a MB 6.9 liter V8 in it. What a machine that would be..
__________________
Tom Hanson
Orange County Section
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Kai McRae

Australia
390 Posts

Posted - 05/19/2011 :  19:24:09  Show Profile  Reply with Quote
The only seal between the pump and compressor on mine was a single O ring with the dimensions already posted.

Tom did advise me that the seal only came in the kit, however there may have been some confusion about which seal was being discussed.

Ron,

Where exactly does this mystery lip seal sit?

Alberts 10th picture down is the only one which shows this area.

The O ring I replaced mounted to the PS pump body (in the channel)and sealed against the smooth inner face of the compressor body in this pic. This was the only seal on mine.

To replace this other seal you speak of, does this involve opening the PS pump?

1971 6.3 - #5417 -
(LPG)
1982 230E - W123 (M102)
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Chris Johnson

USA
3751 Posts

Posted - 05/19/2011 :  21:15:43  Show Profile  Reply with Quote
quote:
I would be most interested to see the compressor which runs without one as Chris is so adamant about.


Ron, please post a photo of this rear compressor seal. I will bow down and kiss your feet (figuratively, anyway). Of course, if it isn't there, then reciprocity is appropriate.

Also, please address how the engine is pumping oil into the PS pump while there is that drain back bore into the engine sump between the pump and the compressor. I've only been doing this stuff for 35 years, as opposed to your 40 so I'm still quite willing to learn something new.

Chris Johnson
If you aren't constantly impressed with your car, then it needs fixing.
100.012-12-000790
100.012-12-000867
www.300SE.org

Edited by - Chris Johnson on 05/19/2011 21:28:07
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Art Love

Australia
6226 Posts

Posted - 05/20/2011 :  02:57:20  Show Profile  Reply with Quote
Nothing like a bit of a stoush to stimulate my education. As one of the moderators, I have decided to put everything into perspective to avoid any genuflexing. Tim's question has raised a point that Albert really did not cover in his excellent posting, and that is the rear part of the air compressor crank and its lubrication and sealing. The mechanics among you who already know all this do not need to read further. This is written for the mechanically ignorant like me.

Firstly, to follow up on my last post, the price of 001 997 72 45, the O ring between the air compressor and the power steering housings is $5.50 retail. Now to how a moderator will deal with this issue. Firstly, go into the garage and get a few examples of the items under dispute. Take an intact pair and pull them apart to demonstrate that the moderator is not biased and not a magician. This pair are clearly not from a 6.3, but they will do for the sake of the argument.





Take trusty Allen Key wrench and separate the two components in question.













Now here is what you see if you look at the front of the power steering pump.





Here is a different one off a 6.3 to show they are the same. The radial seals are "shot".





I believe that the rubber seal around the drive shaft is the radial seal/lip seal that Tom Hanson and Ron are talking about - Ron, correct me if I am wrong.

Here are a couple of angled views showing 001 997 72 45 which is flattened by use and age. This seal between the two housings stops oil around the drive coupling from leaking to the outside world.









The radial seal prevents oil around the coupling and power steering fluid in the power steering pump from mixing. I have no idea which would be at higher pressure and shall not get into that argument, because I would not have a clue.

Now here is the rear of the air compressor, an area only shown once in Albert's pictures as pointed out by Kai amd previously noted by me when I also looked for the same reason.





There is a drive coupling between the two shafts which obscures the view.





So, I have taken it out.





Now you can see the rear of the crank in its bearing shell and the oil return hole that Chris is talking about on the right hand side, and I'll come back to that later.





Here is a similar air compressor pump body (sump) with the crank out.





Here we are looking at the bottom of the air compressor sump to show the large drain hole for the sump oil with its surrounding O ring for return of the air compressor sump oil to the engine sump via the hollow mounting bracket that the air compressor sits on.





This picture shows an outide view of one of these air compressor sump bodies and you will notice that the high pressure oil feed line from the top of the oil filter on this body is on the opposite side to where it is in the 6.3 and 600, explaining one reason why M-B list more than one version of the air compressor. The one I pulled apart for this dissertation is similar.





Now this is what I found interesting. Knorr who make these pumps don't make a different casting for the sumps for inside or outside feed, they make the housing so it can be drilled and tapped from either side to reach the rear crank bearing.





So the high pressure oil input to the air compressor sump feeds to a circular groove in the housing where the rear bearing is mounted. From there, it feeds through 3 small holes in the bearing shell, set at 120 degrees apart. This is the same type of lubrication used in the fan coupling that Justin and I rebuilt off the M189 and used elsewhere. If these tiny holes or the circular groove become plugged with rubbish, the lubrication of the pump crank will fail. I don't think Albert covered this. The same would apply if the channel between the holes in the crank shaft bearing surfaces became blocked. I could not see any other holes for entry of oil into the air compressor sump from the high pressure line.

You can see one of the 3 holes here at 12 o'clock.





And by turning the housing upside down, the other 2 here at 10 and 2 o'clock. Note also the groove in which these holes lie which lines up with the small hole in the rear bearing face of the crank shaft.





So, unless I missed something (which is quite possible), the oil all feeds in via this route and can spread equally either forward through the hole in the crank into the sump via the front bearing surface or rearward into the coupling housing. That which feeds rearward returns to the sump via the large hole set at 3 or 9 o'clock, depending on whether the feed line comes from the outside of the pump or the inside respecively. The hole is opposite the side of the inflow fitting and channel to the bearing. To my mind, the position of this hole would mean that the coupling housing would always be half full of oil, whereas, the sump itself would have very little oil because its drain is in the middle of its bottom side.

Here are a couple of air compressor housings to show the opposite set up of the oil input line and drain holes.





So, in a sense, Chris is totally correct in saying "There simply is no seal on the rear of the compressor." But, if you count the coupling chamber as part of the compressor sump which it is from the oil's point of view, then the seal that Ron is talking about is between the compressor and the PS pump. Strictly speaking, it is in the front of the PS pump, not in the air compressor, but it is in direct contact with the air compressor sump oil. The front of the PS pump acts as the rear of the air compressor in this set up where the PS pump drive is from the rear of the air compressor, otherwise oil would just spew out everywhere because there is no back wall on the air pump over the rear bearing.

Did I get this all right and does it settle the argument?
Art
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