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Power steering reseal

Started by oscar, 10 March 2010, 01:56 AM

TJ 450

I'm with s class... I went through the same process with the 6.9's transmission. After MT's assistance with the incorrectly assembled servo, the tranny still had to be pulled apart again...

The satisfaction is well worth it in the end.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

koan

Annoying when that happens.

I've got spare blue seals here if you want them oscar, but the reason for that is I was told they aren't very good and to use standard black seals.

koan
Boogity, Boogity, Boogity, Amen!

oscar

Thanks fellas.  It's amazing how quicker you get at removal and refitting when this kind of thing happens. ::) Though still annoying, I don't think years ago I would've had the patience.  I saw this leak and I think I just said "Damn!".  Nah, I'm sure I said the "F" word too, but ya get on with it.

I agree it will be worth soldiering on.  Especially now that I'm confident I've found the cause, ie hitting the seal in with a socket too small which has bent the lips downwards so only the outer lip is contacting the shaft.  The inner lip that would hold the pressure in isn't doing anything. 

I did what you suggested sclass and could see the error once the shaft was out.  Ended up taking the seal out too and although it's intact, it's no use now.  I'd take a photo but imagine a cross-section of the seal looking like this below.  Normal on the left, rooted on the right.

Shocking drawing I know, plus it's not that pronounced but I'm sure you lot will get the gist of my error. 

Thanks for the offer koan. Closest MB stockist is two hours away so I'll see how I go locally and if nothing, I might just go for a drive to get it and some other supplies from Wagga, then maybe pull an all-nighter tomorrow. I should buy a press too. 8) Failing that  I may be in touch.



1973 350SE, my first & fave

oscar

Any thoughts on using single lip seals as opposed to the double lip?  Have your alternate seals been double or single lip koan? I assume the the second lip is like a dust seal and helps the reverse side of the inner lip to be lubed but none of the shops here had them. I might just coat the reverse side of the seal with some rubber grease as a protective measure.

Here's what I've got, two seals, one's got a metal outer case but I think I'll use the one without.

1973 350SE, my first & fave

TJ 450

The outer lip is for protection. The standard procedure is to pack it with grease... I just used GP grease for the transmission and crankshaft seals.

IMO, the single lip may be an issue, because the steering box is positioned so that it cops a fair bit of dirt.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

koan

Agree with TJ450 on the double lip seal and grease.

Offer of blue seal is still there, I'll be going to the local bearing place this week, I can pick up a another seal of the black type if you have trouble locally.

Ken
Boogity, Boogity, Boogity, Amen!

oscar

If you don't mind koan that would be great and I'll keep it for the next seal attempt.

As it is now, I ended up putting the seal on the right in and smothered it with rubber grease.  So far so good.  Put the new tie rods and damper in.  With all the movement of the lines to the box I also had to replace part of the return line and the old supply line just before the box.  The return line had been seeping for ages but the supply line hasn't flexed in who knows how long and it developed many cracks.

The new hoses work great, though the downside is the new return line is red, no one had black. The supply line is just ugly compared to the original sleek hose and fittings.  The steel line from the box to the hose had only one nut and when undone had this huge nose screwed into the hose end.  I liked it but the shop didn't have anything like it.  They ended up cutting the end off and making and soldering adaptors to fit.  The advantage of the setup now is that you can just replace the hose when it leaks rather than take the hole lot off the box like what was needed to replace it.  Though when it does wear out I'd like to get something that looked more original, not a mix of imperial and metric adaptors.

Got it all fitted, went back and forth in the driveway, lock to lock trying to get any air out of the system. There was a bit of a groan returning from full lock but the alignment is way way out.  I reckon it's just the tyres scrubbing the ground with massive toe out and at crawl speed.  Went for a quick drive around the block and it feels good, no groans when doing u-turns.   The toe out feels obvious though, hopefully an alignment tomorrow will  shore things up.

Last thing, I've got a cap or guard around the pitman nut.  Hadn't seen it on any other car but it's always been on the 350.  They supposed to be there?  Although it's painted black it was just gal sheet or thin pipe as you can't see a join but it goes on the shaft after the pitman arm and before the nyloc nut.

Pitman nut gaurd


Old supply line


Box end of the flex supply line with steel  line to the box removed


The replacement flex supply line


Not quite original, ugly yet functional
1973 350SE, my first & fave

s class

Oscar, I have seen a few steering boxes with that cover/guard around the pitman arm nut.  In the case of steering boxes that don't have it, I assume its because they get discarded during rebuilds/re-seals - and after 35 years there aren't many steering boxes around that haven't had some sort of intervention. 

I can only presume the function of the cover/guard is to act as a heat shield to protect the nylon part of the nylock nut.  So perhaps certain models were equipped with this, and others not, depending on the proximity to the exhaust?


[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
I can only presume the function of the cover/guard is to act as a heat shield to protect the nylon part of the nylock nut.  So perhaps certain models were equipped with this, and others not, depending on the proximity to the exhaust?

From memory I think the manual says only certain models have the heat shield.

koan
Boogity, Boogity, Boogity, Amen!

oscar

Never thought of it being a heat shield but it has to be.  Too thin to be a guard and it makes sense that it would only be on models where the exhaust is closest.  It doesn't surprise me either that some have probably been discarded.

Report back from the wheel alignment.  Dropped it off at the local Bob Jane T-mart who usually do our tyres etc.  I get a phonecall from the bloke who did the alignment who said he was amazed how good the steering was compared to other old mercs they get through the shop that need up to a quarter turn of the wheel before the car changes direction.  Let me at em I thought.   :D I would guess that most have neglected bushes and joints and a box that could do with some adjustment.  It reminds me of povo when I first got it.  Box wasn't too bad but the car would fall from left to right, was good around corners and with decent camber in the roads it would track ok but otherwise it was hard to keep in a straight line.   Yet it was driven like that for a few years by a Uni student.

The 350 though feels great.  A little bit stiffer than before but very smooth and freeplay is negligible.  I reckon there's more of a power steering whirrrr sound than before especially when revved at a standstill but I'm honestly not sure if it's a perceived difference or not.  It's not that kind of loud whirrr that you'd be popping the bonnet for to check the fluid level, which is ok BTW and I don't notice it whilst driving.  It might be due to my adjustment of the box but I'm happy enough with it to just leave it.
1973 350SE, my first & fave

koan

Quote from: oscar on 17 March 2010, 04:34 AM
If you don't mind koan that would be great and I'll keep it for the next seal attempt.

On their way. Couldn't get black seals at short notice due to them being odd sizes so I've sent blue MB seals for both shafts.

koan
Boogity, Boogity, Boogity, Amen!

oscar

Much obliged, thanks koan. 8)
1973 350SE, my first & fave