Author Topic: Power steering reseal  (Read 2427 times)

oscar

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Power steering reseal
« on: 09 March 2010, 10:56 PM »
Trying my best at the moment following a few threads and the following link of a 126 box rebuild which a few others have posted up before
http://www.davidpetryk.net/Mercedes/Steering.htm

but I'm at a standstill.  I've got the pitman/pinion shaft out.  Then I started winding the steering shaft a little then extracted the rack.  On inspection of the casing I find a steel ball inside sitting in the left over ATF.

Shown in the pic now sitting in that spanner, it's about 7-8mm diameter but I'm not sure if it's come out of the ball cage or is supposed to sit in that dimpled bit on the rack piston part to the left of the ball cage.  If it goes there then that means I'm missing a ball since I only found one yet there's another dimple on the reverse side.

I'm hoping it's one of the recirculating balls and if it is, how do I get it back in?  I wasn't planning on pulling that section apart.

« Last Edit: 09 March 2010, 11:06 PM by oscar »
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koan

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Re: Power steering reseal
« Reply #1 on: 09 March 2010, 11:37 PM »
The ball has come out of the ball nut, there are 24 of them (I think). No other loose balls in there.

koan
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oscar

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Re: Power steering reseal
« Reply #2 on: 09 March 2010, 11:53 PM »
Definintely only one ball.  By "ball nut", do you mean it has to go back in the "U" shaped thing and if so can it be worked back in through the worm shaft without having to undo anything else?

As far as I could tell it seems the leak was occuring through the steering shaft spline.  Without the proper four pronged large socket I'm having a bit of difficulty taking that end cap off to get to the shaft seals but will get there eventually.

One other thing, I've got the the circlip off the valve section but can't seem to get the cap out.  Do I just lever this thing out pictured below or does it screw out?

1973 350SE, my first & fave

koan

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Re: Power steering reseal
« Reply #3 on: 10 March 2010, 12:23 AM »
The ball can only have come out of the ball nut, the square bit with the "U" shaped guides, it would have fallen out when you unscrewed the worm shaft. Should be a lot more balls somewhere.

Getting the balls back in requires one half of the "U" guide to be removed and the balls dropped in one a a time as the worm shaft is turned.

Should use the the proper tool, a C-spanner or a hook-wrench but I used a brass drift and a heavy hammer to crack the four-slot nut free then a pair of circlip pliers undo the middle piece.

The cover on the spool valve just pulls or prises out.

koan
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s class

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Re: Power steering reseal
« Reply #4 on: 10 March 2010, 12:34 AM »
It is my belief that the recirculating unit should have a total of 24 balls - but it is just my belief, I've never seen anything in a manual about it - and have seen several that I'm certain had only 23, and one with 25  ???  The units that had only 23 balls may have been previously 'overhauled' - and I'm guessing 1 was lost at that time. 

It is tricky to get the balls in - good luck!

'77 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '76 350SE, '80 280SE -parts, '75 280S Man -parts, '80 450SL, '94 C180, '00 C240

oscar

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Re: Power steering reseal
« Reply #5 on: 10 March 2010, 12:54 AM »
Awsome, thanks fellas. 8)

I think I may have undone the steering shaft too much at first but not completely, hence only one ball fell out. 

The good news is that I wound down the worm enough to see other balls emerge, popped the ball in and screwed the worm back up and it joined the rest of the crew.  It was a bit more involved than that and required a bit of jiggling but no big drama.  With doubt over how many balls there should be I'm kind of tempted now to see how many balls there really are.  But, judging by the bash marks on the four slotted nut on the steering shaft I'm guessing this box has been opened before.  To be honest I always thought for a high mileage car the steering was surprisingly fantastic.  Clearly it's been replaced or rebuilt at some stage but there's no guarantee that the ball count is as per ex factory.  I'm dead certain though that I haven't lost any more.

Also conquered that four slotted nut by placing that rack part back in the box with a couple of bolts to hold it there, put my weight on the box, then large pipe wrench on the nut was hit with a mid sized sledge hammer once only and that was enough.  Would've used a vise if I had one, but it's broken from doing something similar a while back.

Oh and got that valve cap out ok in the end.  Needed a lot of prodding and levering from all sides but it slid out eventually.
1973 350SE, my first & fave

goldacre

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Re: Power steering reseal
« Reply #6 on: 10 March 2010, 10:02 PM »
I take my hat off to you Oscar on doing this job in house  :-*

I had a good hard look at my leaking steering box and surrounding paraphernalia then looked at my shabby tool box collection (Holden Torana beginnings) and farmed it off to AutoMac.

You will be $795 better off than i was  :(

G

PS how much was the re seal kit????
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s class

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Re: Power steering reseal
« Reply #7 on: 10 March 2010, 11:40 PM »
You will be $795 better off than i was  :(

 :o  :o  :o

For that price I hope they rebuilt, machined/ rehardened and rechromed the teeth of the sector shaft.

A reseal kit is about ZAR250 here - which is somewhere around A$37.

'77 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '76 350SE, '80 280SE -parts, '75 280S Man -parts, '80 450SL, '94 C180, '00 C240

oscar

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Re: Power steering reseal
« Reply #8 on: 11 March 2010, 12:36 AM »
Damn, $795.  Seal kit cost me $16.91US in Sept 08 which I see now they cost $20.23 USD https://www.autohausaz.com/search/product.aspx?sid=hddi3i2izskvek55tabuipax&partnumber=1074600061

You gotta adopt the w116 DIYer motto goldacre.  Fix it or f*#@ it trying.  8)
If you don't succeed, then you go spend the big $ on a guaranteed part.  The discovery process in trying and potential saving outweighs the cost of paying a pro plus the part you couldn't fix.  If you do succeed, it's a good excuse to buy good tools with the savings.  I basically had nothing 5yrs ago apart from cheap spanners and screw drivers.

This was my first reseal and although it seems daunting at first, after a while the parts look simple when you visualise what goes where.   And that link for the w126 box is almost identical to ours.   I started taking pics and realised soon that it wasn't worth the effort when that link is good enough for a first timer or pro.  It just doesn't deal with the worm and balls but I didn't plan on going that far either. 

From the time I jacked the car up till the time I closed the box up was about 12hrs with quite a few breaks.  It still needs a thinners wash prior to painting and bolts torqued for bearing caps.  Still waiting on new tie rods and damper before I'm on the road again but fingers crossed there'll be no more leaks.
« Last Edit: 11 March 2010, 12:38 AM by oscar »
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s class

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Re: Power steering reseal
« Reply #9 on: 11 March 2010, 12:48 AM »
Oscar I've resealed several MB boxes now and all have been leak free since.  The only trick to watch for is the locking nut that secures the sector shaft adjustment on top of the steering box - the nut is usually not included in the rebuild kit, but should be replaced as it has an integral rubbery seal ring on its back side.  Even with a new one of these nuts, I had leaks initially, and I was surprised at just how tight I had to torque this nut to prevent leaks.  Fortunately, I did all this learning on the 280SE, which has good access to the top of the box when its in the car.  On a V-8, you want to get it right first time. 

'77 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '76 350SE, '80 280SE -parts, '75 280S Man -parts, '80 450SL, '94 C180, '00 C240

robertd

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Re: Power steering reseal
« Reply #10 on: 11 March 2010, 01:37 AM »
Good on you Oscar,

I,m with you, I've just had to redo a job that was done by a qualified mechanic for a roadworthy on the 280S I've recently acquired.

I find that most times mechanics don't take the time to get it just right, instead they bang away with the attitude " she will be right mate".

The job entailed unsticking a front brake caliper, I had to take it back three times with no satisfaction.

I've since discovered that he had incorrectly installed the heat shield on the inside of the piston causing the brake pads to be pinched to one side making a real mess of it.

Fun and games

Rob
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oscar

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Re: Power steering reseal
« Reply #11 on: 11 March 2010, 07:09 AM »
sclass thanks for that tip about the locking nut.  I tried for ages to get it to take the thread again and ended up shaving a bit of that nyloc or rubber with a stanley knife.  I didn't realise the importance of that seal until now.  It's the only thing stopping oil coming out of that hole.   

Your'e dead right about the V8s too.   It's one thing I love about the m110 with more space to swing spanners.

So I'll have to source a new lock nut and I don't reckon they'll have one at the local engineering shop.  I tried to get a replacement pitman arm nut and despite the huge range of nyloc nuts they had, they didn't stock halfnuts nor were any of the same pitch size.

Rob that would've been annoying, got a couple of those stories too.   As much as we'd all like to find a bit more time to work on our cars we're not under pressure to get one job out of the way to get another car up the hoist before knock off time. It's a luxury for DIY to be able to sort things out even if it takes a few hours here and there over a few weeks.  So long as there's another means of transport of course.  I couldn't survive as a mechanic, I just couldn't work quick enough.
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Big_Richard

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Re: Power steering reseal
« Reply #12 on: 13 March 2010, 03:57 PM »
modern cars are quick and easy for mechanics to keep turning over - its the 30 year old cars we play with that always have hidden surprises waiting to turn a 5 minute job in to a 6 month nightmare ;)

oscar

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Re: Power steering reseal
« Reply #13 on: 16 March 2010, 04:29 AM »
Right now I'm thinking spending money on a professionally resealed unit might have been worth it.  My first attempt at a reseal has failed miserably.
 
Today I took all the balls out, 24 of them, because the worm would bind in one direction.  I found that the last ball I put in last time was one turn above the rest and wasn't going into the ball nut.  I managed to feed them all in through the end of the worm gear making sure they all disappeared and once all in I could turn the steering shaft from lock to lock without any binding.  

Once I did that I gave it a clean and applied magic black spray and made it look new.  Refitted the box and aligned the steering shaft to centre.  Put the lines on and the last picture shows the result.  Big leak out of the pitman shaft seal.  Prior to removal the leak was in the steering shaft seal.  Somehow I've damaged the pitman seal I think when hammering it in with a socket though I thought I was careful.  I might enquire locally if I can get the seal by itself and try again but in the short term I'm just going to swap out the 280's box with this one to get the car on the road again.

Last week before disassembly,


After reseal  and magic black paint


Reseal fail at idle.
1973 350SE, my first & fave

s class

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Re: Power steering reseal
« Reply #14 on: 16 March 2010, 05:06 AM »
Don't give up Oscar - I know that this kind of 'learning the hard way' is backbreaking.  But its usually worth it in the end.  Those main lip seals are all available individually from MB. 

When you pull off the sector shaft cover again, examine the shaft and seal first before just digging out the seal, to try and see if there is an obvious reason for the leak. 

'77 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '76 350SE, '80 280SE -parts, '75 280S Man -parts, '80 450SL, '94 C180, '00 C240