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'76 280SE

Started by chrismsullivan, 02 May 2010, 10:10 PM

chrismsullivan

#45
Thanks Koan. Yeah, I'll see what I can do about fabricating some new pins.

Just spoke with Murray at MBSpares and ordered the kit. He confirmed that it comes with high pressure o-rings.

chrismsullivan

Guys, how on earth do I get this bit out???




oscar

#47
Pretty much like that as shown above, with a screw driver, being careful not to gouge or mark the hole's bore.   However, the first time I did one I picked the seal out with needle nose pliers and small screwdrivers only to find, or rather not realising, I'd left the metal outer casing of the seal in the bore.  From memory I then inverted the pump body and used the screwdriver and hammer to knock the seal out.  They're very stubborn.

This particular seal below was an early or alternative version and was a combination of two individual single lip seals with two individual metal casings back to back.  New ones should be a double lip seal with only one metal casing as shown in the third pic of one of sclass' strip downs.  The seal is on the bottom left which is the best pic of one I could find.  If you saw a side on pic of one the profile would be more obvious but for the life of me I can't remember if the metal casing end goes into the bore first or the other way round.  Anyone ??? I'm assuming the metal casing faces the rear.  s class' pic also shows how clear the bore should be when all parts of the seal is removed compared to mine which still shows the metal casing in situ.









1973 350SE, my first & fave

chrismsullivan

Great, thanks Oscar...

I'll wait until the seal kit arrives and then go about trying to remove it with minimal damage.

s class

If you look at that last pic oscar posted, showing one of my pumps, just above the bronze bushing, at the 12 o clock position is an oil way.  This would be obstructed if the seal was inserted with the metal side first.  I therefore concluded that the metal ring must be towards the rear of the pump, ie upwards in this pic. 


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

koan

Quote from: s class on 08 June 2010, 07:44 AM
This would be obstructed if the seal was inserted with the metal side first.

I've always put the seal in metal side first, pretty sure that's the way I've always found them (see first pic).

If the seal is positioned depth wise so the metal edge is flush with the back of the pump there is sufficient clearance for the oil feed hole.

The seal being double lipped handles pressure on either side unlike a normal seal so a reversed seal should be OK.

koan
Boogity, Boogity, Boogity, Amen!

s class

Quote from: koan on 08 June 2010, 04:14 PM
I've always put the seal in metal side first, pretty sure that's the way I've always found them (see first pic).

If the seal is positioned depth wise so the metal edge is flush with the back of the pump there is sufficient clearance for the oil feed hole.

Yes, that would work too I imagine.  The double lipped seal looks to have equal sealing properties in each direction. 


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

chrismsullivan

#52
Thanks for the banter guys. Love it!

Firstly, I can confirm that the double lipped seal you're talking about was inserted into my pump with the metal ring facing upwards, as in lined up flush with the rear of the pump.

MY SLS seal kit arrived today. In the pic below you can see the rear of the pump on the bottom left, with the old gasket still attached. Just above that you can see the new gasket, which is considerably different to the old one. The new one lines up with the mounting holes, but doesn't cover the recesses on the front of the engine mount as the old one did. Should I just use the old gasket or do you think it'll be OK to strip it off and use the new one? On that note, the new one doesn't seem as robust as the old one, it's esentially just a piece of thin cardboard, or thick paper if you like.

Next in this pic you can see the new o-ring and double lipped seal on the top right. I know where these go, so it's all good.
On the bottom left are 3 more o-rings that came in the kit. They don't seem to fit anywhere that I can see would be useful. Are they just spares for a different car or application?



Next I tackled the job of fabricating new pins for the reaction band. In the image below you can see the new pin I made centre middle of the shot and the head of a nail that I'd cut off above it. Kind of a before and after for you.
It required a fair amount of trimming and filing, but it's a good fit. not bad for $3.50 that the packet of nails cost me. I doubt genuine parts would cost less or a metal fabricator could do a better job for less.



chrismsullivan

Oh balls...

Just noticed this:



The plastic band that sits around the main piston has cracked and can come off. It does sit quite nicely in its mount and when the piston is back in place it's so tight in there that I seriously doubt that it will come off.
It also looks as though this isn't any kind of seal.

Do you thin it will be OK to leave it on there when re-installing it all, do you think I should remove it altogether and run it without the plastic band?

The only real fix is to get a new piston with a band that's not broken.

Cheers,
Chris

oscar

One of the rings goes into the base of the outer casing as shown in these two koan pics.  This is the one I didn't realise existed coz I didn't take out the piston block.


That leaves one largeish thin ring and the medium sized fat one which I can't remember if it was in my kit.  Does one of those rings in the kit replace that cracked plastic one?  Is there one there with a rectangular profile? 
Nice work on the pins too BTW.

1973 350SE, my first & fave

chrismsullivan

Great, that covers one of the extra o-rings.

There isn't another one that has a rectangular profile to replace the cracked plastic one. I'll have to have a dig around and see if there are any other locations taht will accomodate for the remaining ones. It's a mystery, but I'll let you know if I find anything.

The pins.. they were a bit of effort to fabricate, but I'm glad I did it.

chrismsullivan

Any thoughts on my gasket question above??

Cheers,
Chris

oscar

#57
Completely missed that sorry.  Just went out to the shed to check the wrecks and neither had a gasket on the rear of the pump nor on the cam housing. The red 280S in particular was in really good nic when I got it in 2006.  No leaks from anything and the SLS was working before I started dismantling it. The square gasket in your picture definitely goes on the V8 but I'm wondering now if the m110 of the 280 doesn't need this gasket at all.  If there is no m110 specific gasket your options would be to use that square one anyway, cut out something that would suit, use a sealant of some kind from loctite or permatex like hymolar or just clean the mating surfaces and forget about using anything.  If it were me I'd be tempted to use the square gasket or use hymolar but I'd be keen to hear what others think or what other have used on the m110.
1973 350SE, my first & fave

chrismsullivan

Thanks Oscar. That all makes sense.

When I removed the pump, that rear of the pump was just sitting there with no evidence of any sealant being used. I wouldn't be surprised if it doesn't specifically require one. The existing gasket that is still attached to the back of the pump isn't in bad cindition, so I'm wondering if I should just use this again, with a combination of a sealant.
With the layout that the rear of pump bolts onto, using the square gasket would be almost useless? Maybe a combination of both gaskets can be used?

oscar

So there is a gasket on the back already. I can see it now on your photo now that you mention it and it does look pretty good and dry.  I'd probably reuse that rear gasket as is and don't bother put anything else with it.   There's no pressure there and if sls fluid works past the new seal one day it'll flow back into the engine via the cam housing.  Besides, although it's ideal to replace gaskets, this one is just like cam cover gaskets, I'm not going to replace them every time I take the covers off when I play with valves unless they're damaged.

FWIW I found that particular gasket in the head gasket set on autohaus.Link. I would guess it's available by itself from a dealer or others.  Note the picture below where the pump gasket is next to the square gasket.  I'd assume the square gasket is for the blanking plate of non sls equipped cars which is square.  Note the three triangular gaskets at the bottom.  The three other camshaft ends are covered by triangular plates, one in the front and two at the rear.



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1973 350SE, my first & fave