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Subject: Replacing the woodruff key Author: elmoreandrew : member since February, 2004 : 619 posts Posted on: 2004-05-27 09:39:04

REPLACING THE WOODRUFF KEY

Symptoms of a broken key:
1. With the car running, the crank turns, but the main pulley located in the bottom middle of the engine. This is the pulley that all the belts spin off of. It is connected to the crank by the woodruff key.
- With out the main pulley spinning, you lose power steering, A/C and the alternator no longer spins. The lights in the instrument panel should light up when these go out. The BRAKE light comes on when the power steering pump dies because the pump is connected with the brake system i think

The Fix:
A. Tools needed (e28 specific--im not sure what other models this applies to but most likely the e23 and probably the e24(6 series i think)
1. 36mm socket to fit the crank nut-- preferably a 3/4 drive
2. a 3/4 drive socket wrench
3. a 300lbs torque wrench -- i found mine at harbor freight
I guess the torque wrench would work both ways for taking it on and putting it back on, but my dad had just a normal wrench and i didn't want to risk damaging the wrench.
4. Assorted screw drivers and smaller sockets.
5. An ice pick -- probably my most used tool while working with the car. Its good for sdtabbing oil filters to get them to turn, and it works very well for getting the broken key out of the crank.
6. Assorted parts needed for the job -- new key from the dealer and belts if you want to replace them.
B. Procedure

1. Drain and disconnect the radiator and remove from the car
2. Pull the fan schrowd out of the car (provides enough room for the socket to get in there without having to remove the fan
3. Optional--Remove the fan if you can get it off easier. It just makes things a lot easier space wise w/o it being in the way.
4. Remove all belts from the pulleys -- i'd suggest replacing them if they arn't new.
5. Put the car in gear and hope you have good compression to hold the engine while you try to turn the nut. I had mine in 4th or 5th and it worked fine.
6 Get the socket on the nut at the end of the crank and pull. I suggest getting an extension bar on the end of it and just turn it as hard as you can.



7. When you get the nut off it should look something like this: (pic of it is a little blurry i think)



8. After getting the nut off you can celebrate the half way point as i did so eloquently



9. Pull the hub off the crank and you should see a little tick mark in the pulley and on the crank. The half of the key is probably i nthe pulley and the bottom half is still in the crank

This is what mine looked like compared to the new one from the dealer



10. Pull the piece out of the hub and set it aside. Now go get your icepick and get under the car
11. I used the ice pick to remove the rounded half of the key from the crank. It takes a little working at it but you can get it out.
12. With that removed, place the new key in the crank., The top of the semi circle goes into the crank and the fla side goes on the buh. Put the key in and smash it in there as best you car so it doesn't pop out when you put the buh back on.
13. Line the tick mark and the key on the crank and slide the hub onto the crank
14. Put the nut back on and start tightening it down.
15. Get someone to sit in the car and stand on the brakes because it will want to move when the crank turns. You're pretty much turning the entire engine when you tighten the nut
16. Set the torque wrench and put on the entension and keep pushing till it clicks. It will feel like you arn't getting any more pressure out of it and it will want to snap back so be care full when tightening.
17. Once it clicks you've got it secured tightly and re assemble the blets and replace the radiator.
18. Refill the radiator and check all the nuts and bots to make sure everything is tight
19. Cross your fingers
20. Start the car. Mine worked the first time. Make sure you have plenty of ps fluid in the car. Have someone turn the key while you watch the front and make sure everything is spinning properly.

Good Luck with your Project
Andrew

• Replacing the woodruff key (pic) - elmoreandrew 2004-05-27 09:39:04 (5859 views)
  • Re: Replacing the woodruff key - spinedocab 2004-05-30 21:34:52 (906 views)
    • i was unaware of this small aspect so it was at 300lbs =\ - elmoreandrew 2004-05-30 22:22:20 (776 views)
      • Re: i was unaware of this small aspect so it was at 300lbs =\ - spinedocab 2004-05-30 22:33:29 (667 views)
  • Wow...surprisingly good post (nt) - Kevin Elmore '86 735i VA 2004-05-28 11:12:11 (767 views)
    • So your kid brother is one up on you for long posts.> - kff 2004-05-28 15:04:32 (802 views)
  • Good post! (nt) - DavidC 2004-05-27 15:00:51 (636 views)