Hi RobRob Plummer said:I understand that there is an internal memo stating that some seepage of fluid from EDC dampers is perfectly normal (!?!).
Does anyone have a copy they can post here or email to me?
Many thanks in advance.
It's SI 37 02 88 (1713) Oil Leakage from Rear Shock AbsorbersM5touring reg said:a light 'sweat' (not leak) from the rear-dampers is a result of the construction
of the dampers when the car is lifted up n down, f.ex. during a wheel-change
for winter-tyres, I believe there is no such 'memo', what there is however (and I do have it at home somewhere in 'german') seems to be a print-out from a TIS CD (TIS=technical information service system) supplying 'internal' service-information to the BMW-authorized dealer-workshops - :typing:
MODELS: All (equipped with self-leveling suspension)
Situation: The high system pressure inherent in the self-levelling suspension system can cause oil to seep past the piston rod seal of the shock absorber, and this film becomes even more apprent as it tends to collect dust.
This seepage is normal and is not to be considered a defect Excessive oil leakage will be evidenced by distinct drops forming on the shock absorber body.
Also, when the vehicle is raised on a lift with the wheels hanging free, it is possible that there will be an overflow from the reservior, due to the unusual amount of oil being returned to the reservior. This is also considered normal"
Hello Mike,London Mike said:Garcia, do you fancy trying to rebuild some of these units for members?
Mike,London Mike said:Garcia
I think you'll find a big demand for this if you could achieve it. So far the only option seems to be sending them to Brazil.
I for one have a '95 with 4 knackered shocks, and I know there are a quite a few more floating around too. Don't think there would be any trouble getting you a front and a back to experiment on....
Mike,London Mike said:Do the front dampers work in the same way as the rears? Are they repairable in the same way?
Both are basically unbalance actuators connected to a hydraulic systems that's controlled by some type of servovalve (which is controlled by a computer.) The next time you're flying on a large commercial aircraft/jet,
sit next to the wing, when the aircraft is performing some type of manuever (i.e. roll, bank, pitch). Stare the aft portion of the aircraft wing and you'll see large surface movements on the wing (flaps, spoilers, or ailerons), under those movable surfaces you'll see components somewhat similiar to the dampers, they're called roll actuators, spoiler actuators, or ailerons, the same type of components. One great thing about aircraft technology, they always seem to find a way use the same components/systems on cars (fuel injection, overhead cams, horizontally opposed engines, antilock brakes, multiple valve engines, superchargers, turbochargers), most were developed for aircraft use but found their way to the good ole hotrod. Guess that's why I have a passion for planes and cars (especially fighter aircraft and sport cars)
"cut them in half, replaced the seals and welded them back together", WOW, that's scary considering the cylinder and piston are machined parts with polished external and internal surfaces (for smooth seal movement during retraction and extension.) In the book "BMW M-Series" on page 28, it's a black and white picture of the Boge Damper and it's internal components.Rob Plummer said:Garcia - many thanks for your input onto this thread.
As far as I understand it, the dampers are sealed units and when the guy in Brasil had his rebuilt, they basically cut them in half, replaced the seals and welded them back together.
Is this what you anticipate doing?
I've got a "seeping" rear, so although BMW claim this is OK, I'd rather it didn't seep at all! But having said that, I certainly don't want to be rushing out spending £1500 on a pair of dampers.
Before I even discovered my "leak" I was thinking that there MUST be someone in the UK who can rebuild these damned things, rather than being kicked in the knackers by BMW.
Pedro, thanks for the information/photos, based on the pictures I'd say there's a least two different ways to separate the cylinder end cap from the forward body section for access to the internals ( and it will not required welding or cutting.) London Mike and all, I'd gladly accept the unserviceable dampers for an experimental, but please understand I'm in the middle of preparing my 1995 M5 for shipment to the US, plus I'm also preparing myself and family for the move to the North Carolina. Send the unserviceable dampers (only need 1 for the experimental repair) to: Mr. Brown, 50 Sycamore Drive, Beck Row, Mildenhall, Bury St Edmund, Suffolk IP288ST.yewcorner said:Hi All,
LondonMike just called me to let me know about this thread. I have two rear EDC units which 'Garcia' can be used for experimental purposes. One was leaking really badly. Let me know how we want to proceed, postal address etc.