Replacing LAD accumulators: DIY for amateur?

[warton]

Bentley makes it sound reasonably easy... can I get "Pentosin CHG 7.1 hydrolic fluid or equivalent" at Autozone or the like? The back end of the Touring is bouncing like 2T Dodge flatbed...

Thanks,
Peter

[winfred]

dead bombs usually make it not bounce, as in no suspension at all. it's easy to swap em, when done installing refill the tank with 7.1 and with the backend still off the ground, start the motor and let it idel about 5 minutes to bleed out, at least that's how it was explaned to me and how i've done all the ones i have worked on

[warton]

dead bombs usually make it not bounce, as in no suspension at all. it's easy to swap em, when done installing refill the tank with 7.1 and with the backend still off the ground, start the motor and let it idel about 5 minutes to bleed out, at least that's how it was explaned to me and how i've done all the ones i have worked on

I guess "bounce" is the wrong word... it's very stiff in the back, like an unloaded 2T flatbed. ;-)

Thank you Winfred, I'm going to give this one a shot.

Peter

[George M]

yup an amateur's job. Break the accumulator rubber hose hex's loose before unbolting the accumulator from the bottom of the car, then unbolt the accumulator and rotate it off. Spend accumulator bladders introduce no pneumatic pre-load on the fluid, so no need to crack the bleeder screw on the LAD height reg. valve which is good news because it is hard to access. I would refill "only" with Pentosin 7.1 and adhere to Bentley's procedure for rebleeding the system which is a bit tedious but necessary to purge the air after installing fresh accumulators.
Peter, you will be amazed at the difference in ride quality...night and day...no more pogo action :-)...been there.
George

[George M]

actually dead accumulators make it bounce a lot Winfred because the nitrogen bladders have collapsed and the rear struts which are basically hydraulic slave cylinders are riding on the incompressible Pentosin fluid without the nitrogen gas compressibility which gives LAD its damping. Result with dead accumulators is a high frequency bounce.
George

[Bill R.]

pressure still, so i would put a pan underneath and then when cracking the fitting loose expect some fluid.. And No, autozone doesn't have pentosin but almost any import car parts place should.. That sphere literally contains a bag of nitrogen and you don't always lose all the nitrogen out of the bag.







Bentley makes it sound reasonably easy... can I get "Pentosin CHG 7.1 hydrolic fluid or equivalent" at Autozone or the like? The back end of the Touring is bouncing like 2T Dodge flatbed...

Thanks,
Peter

[ryan roopnarine]

deal with any of that big car/touring crap, i can suggest two pages of background to peter without adding much, from sean and johan's useful page


http://bmwe32.student.utwente.nl/sean750/LAD_dust_cover/ReplacingLADdustcover.htm


http://bmwe32.student.utwente.nl/gavin/LAD_strut_rebuild.htm

[George M]

that big car/touring crap you mention, i.e. LAD was standard on the flagship car for this message board...the E-34 M5...lol.
Sean and Johan's site you reference like Bruno's board is a must bookmark...first rate...have exchanged many an e-mail with Sean across the pond...a wonderful guy.
George

[warton]

I'm going to give it a try. I'll photo-document it, so we should end up with a comprehensive record of everything that can possibly be screwed up on this particular job... :-)

Thanks again everyone. Knowing you all are around makes me FAR more willing to try stuff like this.

Peter