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1997 S500V
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272 Posts
Discussion Starter #1
HI Ya'll,

As W140 owners, there are a lot of things that can go wrong and my PSE finally stopped working after some intermittent operation and final failure of remote door locks, trunk, and gas tank cover along with rear head rests, etc. But close assist is still working since the other pump is OK for now.

After researching the PSE here, I decided to disassemble to PSE unit and inspect it. I determined one of the electric motor stator brushes had completely worn out leaving the Cu spring as a temp electrical contact until it wore out too.

In a nut shell, I was contemplating just replacing the Johnson manufactured electric motor with another but it seems very difficult to find an EXACT replacement. The closest motor I found was Johnson HC683LG-011.

Without further ado, here's the W140 p0rn...with captions.
 

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Registered
1997 S500V
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272 Posts
Discussion Starter #3
Reassembled everything back after a thorough cleaning of all black dust and plugged it in with crossed fingers...it's alive! Not having fully functional remote door locks with passengers is a real pain in the ass! Just wondering how long this temp fix will last?????:rolleyes:
 

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Premium Member
1997 S600 (sold)
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4,660 Posts
That's pretty cool. I'm not an ee, but the only comment I have is my understanding is that electric motor brushes are made of graphite for the reason that the graphite wears out before the copper contacts on the rotor do. That's by design because brushes are easier and cheaper to replace than the whole rotor. Your bit of steel replacement for the brush could be problematic in destroying the rotor contacts. Maybe you can find some cheap graphite electric motor brushes to reshape to fit this motor.

This does confirm what I've suspected all along, that the brushes wear out and cause the pump to die.

Brett
 

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1986 560SEL, 1986 560SEL, 1992 500SEL, 1999 S500
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473 Posts
You have created a self destruct mechanism. Graphite also is used because of its self lubricating properties. There are lots of places selling generic replacement brushes and assortments online.
 

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1997 S500V
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272 Posts
Discussion Starter #6
Yep, ya'll are right about the non-optimum material selection! I'm gonna try some carbon brushes from my non-working dremel tool...
 

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1997 S500V
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272 Posts
Discussion Starter #7
PART DEUX:
Found an old non-working dremel with easily replaceable carbon brushes that worked perfectly. The first attempt ended up getting crushed on my workbench vise. Its like hardened pencil lead but much easier to shape. Cut and shaped the other brush with a file instead of a hacksaw. Since it is soft compared to steel, the tapped screw hole didn't hold up so I snaked some copper wire thru both holes and blobbed some solder to hold it down.

It works perfectly! :thumbsup:
Should last a while, I read somewhere that most DC motor brushes wear unevenly, drag vs. push since this motor has to reverse direction for either creating pressure or vacuum...
 

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Banned
2008 C200K (W204) & 1998 SL500 (R129) Imperial Red
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3,373 Posts
wow im very impressed with this thread..

My PSE pump died just the other day.. I kind of saw it coming, thanx e-bay.. this was a replacement pump I bought from someone in San Diego California off e-bay..

Recieved it on February 14, and it died on 29 April :( DAMMMIT! Oh well, its atlest repairable because I am quite sure the eletronics are still fine, has to be this motor. (When I press the remote, the green and orange lights still light up on the door handles, and my alarm system still works, thats why I assume the electrics are fine. I used to hear the pump working, but now no sound..)

I will try this repair, maybe the old motor from the PSE pump which I pulled out in the first place might have some life on it.. I will open both of them up and see if I can build one up from all the "good condition" parts..

Thanks for the motivational tutorial, will update you on what happens..
 

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2008 C200K (W204) & 1998 SL500 (R129) Imperial Red
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3,373 Posts
I have to say, much respect and thank you sooooo much for this write up!!

It trully inspired me to take on the job since my pump died about 2 weeks ago..

So I followed all the instructions, and stripped the pump which was reletively easy. But then It took me about 2 hours to open up the bottom part of the "dc motor" lol, but oh well.. Was beeing diffecult and I didn't want to break anything. (Pump was in excellent condition in terms of electronics) when I did get the motor open, it was clearly visible that the strata brushes were beyond depleted, clearly in need of replacement.

So here's my contribution to thread..

I found good "strata brush" replacements! If your motorised radio antenna does not operate anymore (like mine was) I just took out the mechanism from the antenna mast and put the everything back to normal. The antenna is still plugged in and operational, the black box still supports it, all I removed was the cogs and dc motor. (I'm going to replace the whole antenna mast anyway, so no loss either way.) This antenna mast is obviously located on the left hand side of the trunk behind the carpet lining ;)

The electric antenna motor is slightly smaller than the pse pump motor, but the "Strata brushes" were in great condition and possible as replacements in the pse pump! Had to get abit creative in terms of fitting the strata brushes into the pse housing, but secured them eventually..

Rebuilt everything back the way it was, and obviously cleaned all the parts. (My hands were pitch black from the original strata brush residue from all over the inside of the pse pump housing.)

The circuit board also got a good clean with turps and fitted it into my S320.. Crossed my fingers, then tried to lock the door... YES!!! It works now!!! All my PSE functions restored back to normal, if not even smoother!!

Many, MANY thanx for this motivational and informational thread! It really did help me repair my PSE pump!
 

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1998 S600 LWB 2011 GLK 350 4matic 2013 Sprinter 2500
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412 Posts
Great job. Many components in our cars are of a repairable quality. With my 2006 Chevy van, they are mostly throwaway. You can't make chicken soup out of chicken shit.
 

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Banned
2008 C200K (W204) & 1998 SL500 (R129) Imperial Red
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3,373 Posts
Heres a pic of the Ariel mechanism that I removed from the aerial mast, and used for parts to repair the PSE pump.. It didnt work anyway, so no loss by taking it out.. (The strata brushes were thick and made a perfect replacement)

Second pic is the "Donor" strata brushes fitted on my PSE motor.. Not a great pic, but you get the idea.. I would think that 90% of PSE pump failure would be due to this reason.. If it works intermittently before eventually dying, and you alarm still works, aswel as the little lights on the door handles (but not the central locking) then the chances are that your motor in the PSE pump is in need of repair.. Replace the Strata brushes and you back in business lol!!

Thanks again "MOS500" you really helped me out..
 

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Banned
2008 C200K (W204) & 1998 SL500 (R129) Imperial Red
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3,373 Posts
Could some one "PDF" this repair and upload it to the "Knowledge Database"?????

This trully will help MANY W140 owners, because this is usually the first thing to go wrong on a PSE pump, and sooo many people have bought new ones when they could have just replaced these "Strata Brushes" in the motor.. I found this thread REALLY helpful, and used it just as a guideline to do the actual repair. not only is it informative, but also motivating since it is a DIY repair and costs are virtually none..

This thread could save countless people, Thousands of dollars!
 

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1997 S500V
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272 Posts
Discussion Starter #15
Thanks for all the constructive feedback and I have more to report!
My temp repair only lasted about 2 months before my PSE motor died again. The solder eventually melted off and the copper brush broke in half.

The next solution which is a hell of a lot more reliable and a better method was to order a Johnson replacement motor that appears to be very similar in specs to the stock one which I measured in terms of shaft size, motor size, etc: 12VDC compatible, 5 pole, identical mounting tapped screw holes for the pump, rotation reversible and motor diameter.
See 9167AK/66430/3H1644
https://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001CID=HPCATALOGCID=HPCATALOG_2082177_-1

Best of all, it only cost $2.49 but with a minimum order of $10 otherwise they surcharge you, I ordered 2 motors and a nice pair of Xcelite snips for about $11 and $8 shipping= $19 clams.

My previous repair was OK in terms of getting the locks to work but was a bit slow and lazy to move. I noticed the pump would run for about 10sec. each time which may be the time out limit. My remote double pump would still not remotely open the trunk.

One modification is required: you must file the shaft down flat on one side and file off the splines in order for the pump vanes "D" shaft lock to fit and secure the rest of the pump assembly. See pix below.

Now, it's night/day difference. The locks respond instantly and swiftly, and the pump only runs for about 1-3 sec. Very snappy operation including restoration of the remote double pump to open the trunk which is super convenient when I got my hands full!

Here's a couple pix of the new motor. Sorry didn't take additional pix since there is nothing new to share but the motor is marked with a red circle near one of the electrical post to indicate to solder to the red wire which should be positive and result in proper motor rotation.
Good luck everyone!



 

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Premium Member
1997 S600 (sold)
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4,660 Posts
Second pic is the "Donor" strata brushes fitted on my PSE motor..
Mafiadon,

I'm confused by your use of the phrase "strata brushes." Do you mean "stator brushes?" May just be an English translation thing, since English may not be your first language. "Stator" is the stationary part of the motor that includes the brushes. Is that what you mean? Just seeking clarification.

Thanks,
Brett
 

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91 500SL, 93 600SL, 95 S600 coupe, 97 S320, 99 ML430, 2003 CL600, 94 SL600, 97 Kawasaki 1100 STX
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135 Posts
MOS500,

Great info. Thanks for sharing. I ordered two motors to replace in my pump. Awesome job finding replacement motor that fits.
 

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'93 300E 2.8, '95 S320, 99 S320
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40 Posts
Wow, between this inexpensive fix for the PSE and Brett's classic writeup for the close-assist pump, we all should have fully functioning doors, locks and trunks! Great info gentleman.
 

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Timeship, see you yesterday, but you already knew that.
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4,103 Posts
I give it two thumbs up, just for repairing instead of replacing.
 
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