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View Full Version : nylon hydraulic seal for LAD - sources?



shogun
04-13-2006, 09:19 PM
I got an inquiry from someone in Germany.
He has disassembled the shocks as per Johan's page
http://bmwe32.masscom.net/gavin/LAD_strut_rebuild.htm

The piston rod has a diameter of 17 mm.

The O-rings he could get easily in Germany.

But he has some probs with the sealing of the piston rod. The nylon seal is in Germany as standard only available in 16 or 18 mm, but not 17 mm.

Or is there any nylon seal available in inch size and where to find?
Any address or email/URL? Exact part number?
For details about the seals see the link above.

Edit: just found an old posting from 2002 on roadfly:

If the LAD struts are leaking at the top piston rod seal they can't be effectively repaired. If the leaks are in the valve assembly at bottom the repair is very easy. You do not have to remove the strut to do the repair. Bleed the pressure from the system using the bleed valve on the side of the leveling valve. Remove the large hex nut at the bottom of the valve on the side of the strut. This is the one with the small plastic plug in its center. I believe this takes a 32mm socket. (I had to put the socket in a lathe and reduce the OD for a distance back of about 3/16")
Remove the hex nut and the entire valve assembly comes with it - as well as about a pint of Pentosin oil.
Once the valve is out, remove the plastic plug and insert a 4mm hex key into the stem of the valve assembly to hold it, and remove the nut on the top. Carefully lift off all the springs, washers, and discs from the stem, keeping track of their order and position. You now have the base body with the stem it it. The stem is held in by a small stamped steel hat section which is staked into the body. This is very easy to snap out, even without grinding out any of the stakes. Once the hat section is out, pull out the stem and there is a 1/2" quad-ring seal and a teflon backup ring. The quad-ring seal is a metric size but a U.S. standard size -112 is within a couple of thousandths of the same size and works just as well. The replacement quad-ring should be Buna-N (nitrile) material. You may also want to replace the o-ring on the base body. This is a U.S. standard size -119. Also get this in Buna-N material.
Install the new quad-ring seal and snap the hat section back into place. Re-install all the springs, washers, and discs onto the stem and replace the retaining nut. When you disassemble this make note of the amount of stem projecting through the retaining nut and reinstall the nut to the same depth.




Thanks for your input.