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Jaya Perera
09-09-2001, 01:30 AM
Hi all,<br>After hering about the woos regarding the stepper motors I removed the radio and the OBC to check mine. The two stepper motors were broken from the mounts. I am thankful to the descriptions given in the archives for repairing the mounts. My question is I have another problem. In trying to remove the right stepper motor from the actuating rod, the rod got loose from the bottom. I think the connecting arm to the flap on that side jumped out from its hold. I removed the rubber cover from the vent door and could see a plastic arm at the end of the rod. Cannot take it out of the vent.<br>Please let me know how to fix it back. Have I got to open the heater box and if so how?I am planning to mount the two motors. <br>Thanks a lot in advance.<br>Jaya Perera 735i/A 88 74k NZ

Max Fretter (NZ 87 735i)
09-09-2001, 07:08 AM
Hi - in the same boat here with broken mounts, but haven't yet moved into the new house to get a workshop going to do anything in yet (grrrr!!)<p>Just moved to Christchurch...<p>Max <br>(mines done >230K **grin**, but otherwise sounds really familiar!!)<p><i><br>Hi all,<br>After hering about the woos regarding the stepper motors I removed the radio and the OBC to check mine. The two stepper motors were broken from the mounts. I am thankful to the descriptions given in the archives for repairing the mounts. My question is I have another problem. In trying to remove the right stepper motor from the actuating rod, the rod got loose from the bottom. I think the connecting arm to the flap on that side jumped out from its hold. I removed the rubber cover from the vent door and could see a plastic arm at the end of the rod. Cannot take it out of the vent.<br>Please let me know how to fix it back. Have I got to open the heater box and if so how?I am planning to mount the two motors. <br>Thanks a lot in advance.<br>Jaya Perera 735i/A 88 74k NZ<p></i><br>

Jaya Perera
09-09-2001, 02:34 PM
<i> Hi Max, To tell you the whole story, I had a look at the s/motors about two weeks back. They were broken from the mounts. I attached two aluminium strips wrapping round the motors and fixed them to the lower end of the heater box. Since cold air was coming from the drivers side grill despite the heat setting, I removed the radio and had a look. The motor in question was moving from the alum mount when working thus reducing the opening of the heater vent flaps. It is then only I removed the motor again. The plastic sleeve which goes to the actuating arm came out attached to the actuator rod. While trying to remove it by levering the rod, the lower end got detached from the heater control flaps inside the heater box. There is no way by which this end can be attached to the heater flaps without removing the cover of the heater box.This is what I think. I think the dash and the centre console has to go for this job and I wanted to get some information on how to remove the heater/AC box. Unfortunately information is not available despite my post. If it is a case of draining the coolant or discharging the AC, I will not attempt it.<p>I also found that hot air comes when the actuator rod is pulled out to the top (may be when the heater flap is fully open. By pushing the rod gradually in, the temperature of the air get less and less. Actually this is what the control dial does when you turn it for a high setting to a low setting by moving the motor arm. With the top of the rod disconnected and the starter switch in position two, you could see the movements of the motor arm for different settings. It always goes to the default setting when switched off, which is the the rod at the lowest position. The amount of force exerted by the motor is considerable and I think there should be some free movement in the axis of the motor. If the motor is mounted rigidly, there is a hell of lot of strain on the motor mounts. My feeling is this is why the mounts break in time combined with the altered state of the plastic mount due to heat and cold. There is no oil dripping from the motor as BMW suggested. I think it is a design fault. The motors should have been mounted on a metal frame. <p>I have removed the HVAC control unit and cleaned it well. There was a hell of a lot of dirt in the sensor vent. Thanks for your excellent photos.<p>I also found two of the bulbs in OBC fused and replaced the the whole lot (to be on the safe side 4 of them). Bought from TM Auckland. By the way the right end of the lever which should be pushed back to eject the OBC was found broken (by some one previously). The other end (left) of the lever was ok.<p>I also designed a plastic/wooden centre console plate (where the gear lever is) and glued it to the board, thus replacing the cream leather one I had. Now it matches with the in side wood trim. I also replaced the plastic belt through which the gear lever goes. Bought from TM.<p>It was herculine task to remove the inside wood trim especially the one in the middle. To access the plastic nuts it took a couple of hours. While putting back I used 5/32" butterfly nuts bought from hardware store. It would be very easy to remove them next time.<p>Sorry for the long post but my experiences may be of help to you and others. Any way my problem remains. How am I going to fix the lower end of the acuating rod to the heater control flap. A warning to others not to lever the rod outwards. If you do it the lower end may get dislodged and then you are in a big soup.<p>Regards<p>Jaya 735i/A 88 NZ<br> <br></i><br>

David F
09-10-2001, 10:46 AM
Jaya:<p>I did read all of the below message due the length. However, you did not mention whether or not you provided for the stepper motor travel limit stops in the aluminum support you fabricated. Basically, the stepper motor arms will continue to travel in a complete circle if they do not encounter resistance (i.e. limit stop). If this is allowed to occur, it will probably break the vent flapper (or attachment thereof). The reason the mounts break is due to the very strong motors constantly exerting pressure against the stops built into the plastic mounts. After time, the plastic gives and breaks, proabably due to age and heat.<p><br> Hi Max, To tell you the whole story, I had a look at the s/motors about two weeks back. They were broken from the mounts. I attached two aluminium strips wrapping round the motors and fixed them to the lower end of the heater box. Since cold air was coming from the drivers side grill despite the heat setting, I removed the radio and had a look. The motor in question was moving from the alum mount when working thus reducing the opening of the heater vent flaps. It is then only I removed the motor again. The plastic sleeve which goes to the actuating arm came out attached to the actuator rod. While trying to remove it by levering the rod, the lower end got detached from the heater control flaps inside the heater box. There is no way by which this end can be attached to the heater flaps without removing the cover of the heater box.This is what I think. I think the dash and the centre console has to go for this job and I wanted to get some information on how to remove the heater/AC box. Unfortunately information is not available despite my post. If it is a case of draining the coolant or discharging the AC, I will not attempt it.<p>I also found that hot air comes when the actuator rod is pulled out to the top (may be when the heater flap is fully open. By pushing the rod gradually in, the temperature of the air get less and less. Actually this is what the control dial does when you turn it for a high setting to a low setting by moving the motor arm. With the top of the rod disconnected and the starter switch in position two, you could see the movements of the motor arm for different settings. It always goes to the default setting when switched off, which is the the rod at the lowest position. The amount of force exerted by the motor is considerable and I think there should be some free movement in the axis of the motor. If the motor is mounted rigidly, there is a hell of lot of strain on the motor mounts. My feeling is this is why the mounts break in time combined with the altered state of the plastic mount due to heat and cold. There is no oil dripping from the motor as BMW suggested. I think it is a design fault. The motors should have been mounted on a metal frame. <p>I have removed the HVAC control unit and cleaned it well. There was a hell of a lot of dirt in the sensor vent. Thanks for your excellent photos.<p>I also found two of the bulbs in OBC fused and replaced the the whole lot (to be on the safe side 4 of them). Bought from TM Auckland. By the way the right end of the lever which should be pushed back to eject the OBC was found broken (by some one previously). The other end (left) of the lever was ok.<p>I also designed a plastic/wooden centre console plate (where the gear lever is) and glued it to the board, thus replacing the cream leather one I had. Now it matches with the in side wood trim. I also replaced the plastic belt through which the gear lever goes. Bought from TM.<p>It was herculine task to remove the inside wood trim especially the one in the middle. To access the plastic nuts it took a couple of hours. While putting back I used 5/32" butterfly nuts bought from hardware store. It would be very easy to remove them next time.<p>Sorry for the long post but my experiences may be of help to you and others. Any way my problem remains. How am I going to fix the lower end of the acuating rod to the heater control flap. A warning to others not to lever the rod outwards. If you do it the lower end may get dislodged and then you are in a big soup.<p>Regards<p>Jaya 735i/A 88 NZ<br> <p></i><br>


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