n13
Member
Had the car over 3 years now and only for a short spell of me having the car have the dynamic seats and pneumatic bolster adjustments actually worked. Once it failed, investigations ensued; hit the pump in the boot with a hand, it kicks back in… so every time I went back to it, I gave it a hit, this only worked if the demand was onto the pump so not a very reliable fix…
Remove pump open it up and have a look. Carbon pump parts look good, can’t see brushed etc… test motor on pc power supply (current draw above my bench tops capacity >2A). Motor runs… test on/off a few times… motor eventually won’t start…
Turn motor shaft a little or hit motor. (With 12v on) motor starts: suspect motor internals…
To open motor: using various chisels and screwdrivers files etc.; undo the crimping.
Pull off NDE end cap (spherical bearing housing)
Plastic brush cap now visible, rest a socked up against the commutator (approx. same O/D as commutator) and slide brush cap off (socket to prevent brushes popping out or smashing into each other)
Now the commutator is visible! Start to measure resistance across opposing commutator contacts readings should be a few ohms.
Notice that one set of commutator contacts are 0.5Gohms. Mark them off.
Test motor; notice that the motor won’t start when brushes are in contact with high resistance commutator contacts.
Options: rewind motor rotor? I’d rather not.
Measure resistance on one of the bad pair to its neighbouring commutator contact; test both bad ones to isolate which is the culprit.
Find single culprit and measure resistance on commutator contact to enamelled wire winding behind (a bit fiddly) and also to opposing commutator contact.
Notice that there is a nice low resistance between winding and opposing commutator contactor, and still high on the commutator contactor which it should be connected to…
FIX IT TIME: gain a nice flat bladed screw driver and squeeze the commutator tab a little harder on winding wire or flux and solder if you want.
Measure resistances once again and re assemble.
Now my seats work. after 2 years without….
savings: about £600 for a new pump and hoses etc.
Remove pump open it up and have a look. Carbon pump parts look good, can’t see brushed etc… test motor on pc power supply (current draw above my bench tops capacity >2A). Motor runs… test on/off a few times… motor eventually won’t start…
Turn motor shaft a little or hit motor. (With 12v on) motor starts: suspect motor internals…
To open motor: using various chisels and screwdrivers files etc.; undo the crimping.
Pull off NDE end cap (spherical bearing housing)
Plastic brush cap now visible, rest a socked up against the commutator (approx. same O/D as commutator) and slide brush cap off (socket to prevent brushes popping out or smashing into each other)
Now the commutator is visible! Start to measure resistance across opposing commutator contacts readings should be a few ohms.
Notice that one set of commutator contacts are 0.5Gohms. Mark them off.
Test motor; notice that the motor won’t start when brushes are in contact with high resistance commutator contacts.
Options: rewind motor rotor? I’d rather not.
Measure resistance on one of the bad pair to its neighbouring commutator contact; test both bad ones to isolate which is the culprit.
Find single culprit and measure resistance on commutator contact to enamelled wire winding behind (a bit fiddly) and also to opposing commutator contact.
Notice that there is a nice low resistance between winding and opposing commutator contactor, and still high on the commutator contactor which it should be connected to…
FIX IT TIME: gain a nice flat bladed screw driver and squeeze the commutator tab a little harder on winding wire or flux and solder if you want.
Measure resistances once again and re assemble.
Now my seats work. after 2 years without….
savings: about £600 for a new pump and hoses etc.
