Printer-friendly copy Email this topic to a friend
Top Interior / HVAC topic #11347
View in linear mode

Subject: "Seat Motor Repair Tips (long)" This topic is locked.
Previous topic | Next topic
billcuWed Jul-21-10 11:15 AM
Member since May 20th 2003
2744 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
"Seat Motor Repair Tips (long)"


          

My 94 passenger's seat wasn't moving forward or backwards properly. It was getting so bad that I had to push it with my hand while pushing the button, to make it move. I figured I better fix it because if the seat won't move at all, it's almost impossible to remove the seat bolts then.

I took photos while I did the work as a sort of "how to" guide for anyone else that might want to do this. I'm not an expert at this, so this should be used as general information only. If anyone sees any errors in this please let me know.

This might not be a do it yourself job for some people, but if you've ever rebuilt a small electric motor before, you should have no problem. I'm an antique model railroader and I've rebuilt many of the electric motors, so that experience probably helped me a bit.

First you need to remove the seat from the car. There are two bolts in the front and 2 nuts in the rear that hold the seat to the floor. You'll need to remove the plastic cover from the bolt and the two covers on the nuts first. You'll need to move the seat forward and back to get to these bolts and nuts. After the bolts and nuts are out, disconnect the seat wire plugs from under the seat.

When the seat is out, set it on the floor upside down. I just put 2 new garbage bags on my living room floor and put the seat on them to protect the seat leather.

This first photo shows what the bottom looks like. The memory module and bracket for it, is on the left and the 3 motors are on the right.


The memory module needs to be removed to access the motors. Remove the 2 nuts and 1 screw circled.



You'll see that some wires are connected to the bracket on the right, with wire hold downs. The black one needs to be compressed with needle nose pliers, then it comes out. The other 2 will come out with a screwdriver or push pin removing tool.



Let the module and bracket hang down as shown in the next photo.



Remove the 2 screws from the cover on the bottom of the motors as shown below and remove the cover.



This part on the end of the motor is the encoder or motor position sensor. It is used to tell the memory module what position the motor is in. The passenger's seat only has one sensor and it's used for the Autoglide feature. The driver's seat has sensors on all the motors for the seat position memory feature.



The sensor is removed by using a tiny screwdriver to push in 2 holding latches and gently pulling the sensor out. The photo after this one shows a close up of the latches. Be careful not to rotate the sensor shaft.



Here is a close up of the 2 holding latches on the sensor. Actually there should be 3 latches on the sensor but one of mine was broke off.



I numbered the motor cases and snouts with a paint pen to make sure that I put them back together correctly.



Next, remove the long bolts holding the motors together.



Next, remove the brush plate. This one peice holds the brushes and armature shaft bushings for all 3 motors. When you remove it you'll hear the little clicks of the brushes coming off of the commutator. Notice the shaft bushings are still on the armature shafts on motor 1 and 2 in this case. If you see this on any of the motors, just pull them the off of the shaft and put them back in the brush plate where they belong for reassembly.



Note how the commutator on motor 2 looks very dirty. This is the motor for the forward and reverse movement of the seat.



Here's a shot comparing the dirty commutator with one of the others , which worked fine. I think I'm onto something here.



At this point it's important to mark the end of the armature shafts with a paint pen to make sure that they are put back together in the same position. I just marked them on the top at the 12:00 position. This is important for reassembly and to make sure that the position sensor (s) are put together in the original position.



Then remove the motor case and armature by sliding them out in the direction of the arrow. The armature will be stuck to the field magnets in the case. Notice the thrust washer (circled) stuck to the bushing in the motor snout. Just remove it and put it back on the shaft for reassembly.



Here is a photo of the shaft coming out of the motor. The shaft is a square shaped spring. If it slid out, just push it back into the armature.



Remove the other 2 motor cases and armatures. Then work on them one at a time. Don't mix up the parts. Pull the armature out of the case. It will be stuck to the magnets but it will come out. I cleaned the commutators using Q tips and some brake cleaner. I spray a little bit of brake cleaner into the cap and dip the Q tip into it. I was careful to not get the brake cleaner all over everything. I kept cleaning the armature using clean Q tips until the Q tip stayed clean. It's important that the commutators be completley dry before reassembling. I dried them using new Q tips and let them air dry for an hour too.

Once I had all 3 commutators cleaned I cleaned the brushes. I used Q tips here too and cleaned the brushes and the area around them of all the grease. These must be dried completley too.

Once they are all clean and dry, it's time to put the armatures into the bushings in the brush plate.Look at the paint marks that you put on the end of the shaft and make sure that it is in the same position that it was in before. I started with number 1 and worked back to 2 and then 3. You put the shaft into the bushing but the brushes will hold it from going all the way into the bushing. I just used a tiny screwdriver to slide the brushes back away from the commutator while gently lowering the armature into the bushing. It's a little tricky but it will eventually lower all the way and the brushes will be contacting the commutator squarley.

When you have all 3 armatures installed it should look like this.



Then you need to slide the motor cases down around the armatures. The magnets will stick to the armature while doing this so I used one finger inside the case to hold the armature shaft shaft down while I slid the case down. Sorry I don't have photos of this but I needed both of my hands to do this. It's really not difficult and if for some reason the armature pulls out of the brush plate, you can just put it back in.

When you get all 3 cases back on, it should look like this.



Now you're ready to put the motors back together with the motor snouts. First look for your paint marks on the ends of the shaft. You can see them when you tilt the motors/brush plate assembly down to the position where they should be to go into the motor snouts. If the paint marks aren't in the same position that they were before, just turn the armature a bit until they are in the right position.

Just line up the shafts to the bushings in the snouts and push the motor/brush plate assembly in all the way. It should go right together easily. If not, you might need to pull it back out and rotate one or more armatures just a small bit so the square spring shaft lines up to enter the snout.

Once it's together replace the long screws that hold the motors together, and replace the shaft position sensor (sensors if working on the driver's seat). Then replace the rest of the parts in reverse order of dissassembly.

My seat works great now. Hope this helps.

Bill, Charter Member of Club 16
1998 White Collector's Edition 109K
1994 Red Garnet Glaze 200k miles
1994 Deep Jewel Green 183k miles

  

Alert Printer-friendly copy | Top

Replies to this topic
Subject Author Message Date ID
RE: Seat Motor Repair Tips (long)
Mar 29th 2008
1
RE: Seat Motor Repair Tips (long)
Mar 29th 2008
2
      RE: Seat Motor Repair Tips (long)
Mar 30th 2008
3
           RE: Seat Motor Repair Tips (long)
Mar 30th 2008
4
RE: Seat Motor Repair Tips (long)
Mar 31st 2008
5
RE: Seat Motor Repair Tips (long)
Apr 15th 2008
6
RE: Seat Motor Repair Tips (long)
Apr 25th 2008
7
RE: Seat Motor Repair Tips (long)
Mar 16th 2009
8
RE: Seat Motor Repair Tips (long)
Apr 13th 2009
9
      RE: Seat Motor Repair Tips (long)
Dec 28th 2009
10
           RE: Seat Motor Repair Tips (long)
Dec 31st 2009
11

rdstevensSat Mar-29-08 09:36 AM
Member since Feb 29th 2008
74 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#1. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 0


          

Very well done! I only wish you could have also gone into the parts that are driven to make the seats go forward and back. Alas I fear the only option is replacement when you have trouble there, as I do.

RD Stevens
Two Mark family in Texas
95 pearl base
98 SF

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

    
Mark of DistinctionSat Mar-29-08 04:30 PM
Member since Aug 05th 2004
3539 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#2. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 1


          

Excellent write up and photos. One of the best instruction set I have seen on the board.


MOD aka "another Craig"
Mark of Distinction
1993 Light Mocha

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

        
MGroveSun Mar-30-08 06:24 PM
Member since Apr 30th 2005
647 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy listClick to send message via AOL IM
#3. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 2


  

          

Bill,

That was amazing. Thanks for taking all the time and effort to provide us with such a complete set of instructions.

M

'95 Mark VIII : Midnight Black/Saddle Tan

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

            
billcuSun Mar-30-08 11:11 PM
Member since May 20th 2003
2744 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#4. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 3


          

Thanks guys, glad to help out.

It's really not that difficult. It took me longer to write that up than to rebuild the motors.

There's not a lot of bolts, just a bunch of fiddely stuff.

I actually just took my time while I was watching TV, and took a lot of pictures.

Bill, Charter Member of Club 16
1998 White Collector's Edition 109K
1994 Red Garnet Glaze 200k miles
1994 Deep Jewel Green 183k miles

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

neontail97Mon Mar-31-08 10:28 AM
Charter member
2280 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#5. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 0


          

Excellent work Bill. Starting to see more posts on failing seat motors so am sure that info will come in handy to others as time goes on.
This is one example of what makes this site so great. Things like this really help make these cars practical to own for those who can do the work themselves.

Jason Z
Pittsburgh PA

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

slow84lxTue Apr-15-08 09:11 PM
Member since Sep 22nd 2005
28 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#6. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 0


          

Awesome write up and documentation. Thanks for taking the time to do that. My '93 needs this done to it. How long did it to from start to finish?

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

    
odannyFri Apr-25-08 05:24 PM
Member since Jun 10th 2007
59 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#7. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 6


          

Absolutely OUTSTANDING write up!

You might know that a Google search brought this thread up first, and I should have thought of checking into the forum for some information on this topic.

My search query was "drivers seat memory module Mark VIII" as my memory module is bad and I am looking for a replacement.

1995 Mark VIII 4.6L 32V - 125K

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

firestoneMon Mar-16-09 10:53 AM
Member since Apr 05th 2008
59 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#8. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 0


          

this is an awesome explanation. I am having the same problem - everthing works except forward and reverse movement - it will move if I push really hard while activating the motor control.

I was wondering, the only part that looked dirty was the commutator on motor 2, which you note is the motor for the forward and reverse movement of the seat. Do you think it would have been sufficient to just clean that end of the asssembly and skip the rest of the procedure? the rest looked a LOT more difficult.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

    
billcuMon Apr-13-09 06:08 AM
Member since May 20th 2003
2744 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#9. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 8


          

You really have to take all that apart to get to the commutators. Once you have the brush plate off, the armatures and cases just pull out.

It would be a pain to try to put the brush plate back on with all 3 armatures and cases still in place. It was easy one at a time when they were removed.

Bill, Charter Member of Club 16
1998 White Collector's Edition 109K
1994 Red Garnet Glaze 200k miles
1994 Deep Jewel Green 183k miles

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

        
eunospeedMon Dec-28-09 12:53 PM
Member since Jul 12th 2007
44 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#10. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 9


          

Guys, I'm new just getting my 98 LSC on Saturday. Its clean but has a list of the usual problems. First job is to get the drivers elec seat f/r travel fixed. I did the cleaning but this didn't help, to be honest everything was already very clean. I can hear the motor/switch trying to get things moving but it just won't budge. I read another post talking about the gear-train possibly having broken teeth..... I'm going to try and dig into this today but wanted to get more input on what else it might be.

FYI, I was able to move it forward enough to get to the rear bolts by sitting in the back seat and pushing with my legs while my son pushed the switch. It would move a few inches then stop, I did this about 3 times to get the clearance needed.... nnot sure if this tells anything or not?

Thanks,
John

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

            
eunospeedThu Dec-31-09 04:37 PM
Member since Jul 12th 2007
44 posts
Click to send email to this author Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#11. "RE: Seat Motor Repair Tips (long)"
In response to Reply # 10


          

OK, I know the problem..... I can freely spin the gear when the middle motor is out of the way. The other two will not move at all by hand, So it looks like the teeth are broken on the f/r protion of the seat travel. Looks to me like there's no good way to replace the black box of gears easily, I guess I;ll have to replace the entire seat bottom mech.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

Top Interior / HVAC topic #11347 Previous topic | Next topic
Powered by DCForum+ Version 1.27
Copyright 1997-2003 DCScripts.com
Driving, racing or working on cars can be hazardous. The procedures and advice on this website including the message board are opinion only. www.markviii.org and its webmasters do not guarantee the correctness of the advice and procedures. www.markviii.org and its webmasters assume no liability for any damage, fines, punishment, injury or death resulting from following these procedures or advice. If you do not have the skills or tools to repair your car, please consult a professional. www.markviii.org recommends that you only race your car with proper safety equipment on an approved supervised track. By using this site you agree to hold harmless www.markviii.org, its officers, its authors and its webmasters from any resulting claim and costs that may occur from using the information found on this site.