SLS shock reseal

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cjarvis
Posts: 26
Joined: Wed Apr 13, 2016 11:02 pm
Location: Michigan

SLS shock reseal

Post by cjarvis »

Morning all,

I am knee deep into the SLS on the 745. Both shocks have leaks, but only the left is still available. So I have to reseal the right. Disassembly was simple. And it seems all the seals should be available. But I am having trouble getting at one of them. The first pic is of the disassembled shock. The second pic is of the top shaft seal, shouldn't be a problem. The last pic is of the problem seal. So far, I haven't been able to remove the disk (with the 4 holes). I tried grabbing it with snap ring pliers and pulling, twisting. No movement. Before getting more aggressive, I am hoping someone here has seen something similar and knows how these seals can be removed and replaced. Based on the design, the lower seal seem to be the one dealing with the weight of the car. So ignoring isn't an option. The top shaft seal (wiper) isn't going to hold oil back.

Any ideas?

Thanks!!
Disassambled Shock
Disassambled Shock
E23 SLS Shock - 1 sm.jpg (812.11 KiB) Viewed 6969 times
Top wiper seal
Top wiper seal
E23 SLS Shock - 5 sm.jpg (719.52 KiB) Viewed 6969 times
Lower main seal
Lower main seal
E23 SLS Shock - 4 sm.jpg (831.57 KiB) Viewed 6969 times
Craig in MI
85 745i
85 M635CSi (gone but not forgotten)
71 F-250 (gone but not forgotten)
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sansouci
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Joined: Mon Jul 08, 2013 10:52 pm
Location: Southampton NY

Re: SLS shock reseal

Post by sansouci »

You may want to check Shogun on bimmerforums.com. He seems to have a lot of experience with both LAD and SLS on the E32. He's very responsive.
--Ken
Last edited by sansouci on Tue Dec 05, 2017 10:23 pm, edited 1 time in total.
Sansouci
84 E24 633Csi Auto, Bronzit/PearlBeige 6997510
93 E32 740il M60 Auto, Alpenweis/Ultramarine
60 528i M30 5-speed Green/Beige (crushed)
71 240Z 4-speed White/Blue (rusty & sold)
65 396 Chevelle 4-speed, Marina Blue/Black (stolen)
cjarvis
Posts: 26
Joined: Wed Apr 13, 2016 11:02 pm
Location: Michigan

Re: SLS shock reseal

Post by cjarvis »

Thanks Ken. Shogun's site (http://twrite.org/shogunnew/systems/lad.html) is exactly where I landed. Have the seals out and am trying to source them now, hoping to find what I need at the o-ring store.
Best!
Craig
Craig in MI
85 745i
85 M635CSi (gone but not forgotten)
71 F-250 (gone but not forgotten)
User avatar
sansouci
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Posts: 1850
Joined: Mon Jul 08, 2013 10:52 pm
Location: Southampton NY

Re: SLS shock reseal

Post by sansouci »

Let us know how you make out. Shogun is a god to us E32 owners.
Sansouci
84 E24 633Csi Auto, Bronzit/PearlBeige 6997510
93 E32 740il M60 Auto, Alpenweis/Ultramarine
60 528i M30 5-speed Green/Beige (crushed)
71 240Z 4-speed White/Blue (rusty & sold)
65 396 Chevelle 4-speed, Marina Blue/Black (stolen)
cjarvis
Posts: 26
Joined: Wed Apr 13, 2016 11:02 pm
Location: Michigan

Re: SLS shock reseal

Post by cjarvis »

Looks like I am at a road block. The rod seal (below) doesn't seem to be available in the 17mm size needed. 16 and 18 are readily available but not a 17. Since the inner ring is not rubber, a 16 won't stretch over the 17mm shaft. Tried that, not even close.

Left shocks are still available from BMW, I may have to buy two lefts and flip the bushing to make it into a right shock. Painful for the lack of simple seal :(

I am open to any ideas on sources for the rod seal. I've tried a local shop, 6-8 web sources, shogun, Jay S(looking). Same result so far, 16, 18, no 17.

The wiper seal is another story. I don't think it is intended to be replaced. But it's likely OK to replace the other two seals and leave the wiper alone.
E23 SLS Shock - rod seal 3.JPG
E23 SLS Shock - rod seal 3.JPG (489 KiB) Viewed 6908 times
Craig in MI
85 745i
85 M635CSi (gone but not forgotten)
71 F-250 (gone but not forgotten)
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JCS
Posts: 999
Joined: Wed Sep 22, 2010 11:06 pm
Location: Santa Ana, California, USA

Re: SLS shock reseal

Post by JCS »

Craig,

Is this wiper, or bushing/buffer, in the middle or at the end?
The material in the center of the bushing is probably PTFE, and I have found that this material does not ware out easily if it glides on a polished surface.
And when its lubed with hydraulic fluid, there is hardly any friction, to even measure.
And it is not as affected by normal heat/cold cycles, as the NBR rubber o-rings.

Unless it is leaking or broken or damaged, I would re-use it.
Then there is the outside NBR rubber o-ring around the perimeter, this provides cushioning, and it might have hardened over the years and lost its elasticity. And its cross sectional size may have changed from round the oval/egg shaped.
Do you know if this outside o-ring is detachable from the inner ring PTFE? Or molded into the PTFE?
And then maybe, can it be replaced.

I searched and could not find a 17.0 mm bushing/buffer.

Good luck,
Jay
'88 M6, Red/Tan
My NEW Website https://www.jaysbmwparts.com/
Smoky540i

Re: SLS shock reseal

Post by Smoky540i »

Has anyone had any luck finding the wiper seal yet?

cjarvis, how did you get the seal out of the seal body?
cjarvis
Posts: 26
Joined: Wed Apr 13, 2016 11:02 pm
Location: Michigan

Re: SLS shock reseal

Post by cjarvis »

Hey Smoky540i, I was not able to source either the wiper seal or the rod seal. The rod seal is the likely source of leaking, as it is the only seal that is effected my wear. The others would only fail due to age. As for the wiper seal, the bore it fits in is knurled in at the top. So I don't know how you would get the old one out and a new one in without undoing/redoing the knurl/taper. I decide they did not intend for this to be serviced. If the rod seal could be sourced, you could change it and the other seal and leave the wiper alone. I gave up on that though and ordered two left shocks, and installed the internals out of one in the original right shock tube. Also replaced the accumulators and hoses. All back together and riding nice again. BTW, the hose from the pump that goes through the trunk floor was NLA. So I left that alone.
Craig in MI
85 745i
85 M635CSi (gone but not forgotten)
71 F-250 (gone but not forgotten)
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