M5 SLS issues...accumulators?
M5 SLS issues...accumulators?
Enjoyed my e28 M5 for about 7 years now and it still has the original self-leveling rear suspension. Recently thought the rear suspension very stiff and rides like a dump truck. Used to be intermittent, but now it seems to be raised as high as it can go at all times and no give at all when you push down on the bumper (trunk is empty). No leaks from system. I did notice the fluid level in the tank is fine, but color is very dark which was not the case before. Blown accumulator(s)? Car currently has 112,000 miles.
Re: M5 SLS issues...accumulators?
From service manual:
Fault:
Rear of vehicle rises when vehicle is unloaded and either does not fall to specified height or only after a long delay
Cause:
Sintered filter dirty
Remedy:
Remove hydraulic unit and clean sintered filter - 37 12 055
Check solenoid valve connections and control switch pulse
Check solenoid valve and replace, if necessary
or
Cause:
Control switch contact not working properly
Remedy:
Switch on ignition, detach control rod and move control switch towards "Lower" position
Solenoid valve opens
Replace control switch, if necessary
Fault:
Suspension harder than normal
Cause:
Loss of gas from accumulator
Remedy:
Check accumulator pressure 37 21 010
Replace accumulator, if necessary
Before I got rid of SLS, the rear end at max height happened to me once, but letting the car sit for awhile and turning it back on brought things back to normal and I never saw the issue again. I'd take a look if there's something going on with the height switch connected to the sway bar.
Seems like bad accumulators are the only cause of a stiff suspension that is sitting at the correct height, according to the manual.
Do some searching for e24 M6 service manual, should help explain all the troubleshooting steps.
Fault:
Rear of vehicle rises when vehicle is unloaded and either does not fall to specified height or only after a long delay
Cause:
Sintered filter dirty
Remedy:
Remove hydraulic unit and clean sintered filter - 37 12 055
Check solenoid valve connections and control switch pulse
Check solenoid valve and replace, if necessary
or
Cause:
Control switch contact not working properly
Remedy:
Switch on ignition, detach control rod and move control switch towards "Lower" position
Solenoid valve opens
Replace control switch, if necessary
Fault:
Suspension harder than normal
Cause:
Loss of gas from accumulator
Remedy:
Check accumulator pressure 37 21 010
Replace accumulator, if necessary
Before I got rid of SLS, the rear end at max height happened to me once, but letting the car sit for awhile and turning it back on brought things back to normal and I never saw the issue again. I'd take a look if there's something going on with the height switch connected to the sway bar.
Seems like bad accumulators are the only cause of a stiff suspension that is sitting at the correct height, according to the manual.
Do some searching for e24 M6 service manual, should help explain all the troubleshooting steps.
Re: M5 SLS issues...accumulators?
Thanks—mine did that a couple of times where if you shut it off it would eventually go back down on its own and return to normal ride but now never goes down and rides poorly. Right now as it sits ride height measures 14 1/2” from center cap to bottom of fender in front and 16” from center cap to bottom of fender in back. I really don’t want to ditch the SLS at this point if I can avoid it.