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C5 Harmonic Balancer Replacement

55K views 0 replies 1 participant last post by  RTGordon 
#1 · (Edited)
These instructions are really intended for the novice mechanic who does not have the factory service manual. I highly recommend purchasing a manual if you plan to perform any major repairs to your vehicle. Many of the instructions are my recommendations; they are not word-for-word from the book. I have given additional details not found in the service manual to help those of us who are not quite as mechanically inclined.

1. Lift the vehicle high enough to work. Unless you have an extremely low profile floor jack, I find it easiest to drive the front of the car onto some ramps to provide easy access to the front cross member. Place your floor jack under the front cross member to raise the vehicle. Make sure to use some blocks to prevent bending it; the cross member is aluminum. A couple of 2x4’s nailed together will do just fine. Support the car at the front frame supports (just behind the front wheels) using jackstands (and lifting pucks if you are concerned about appearance). The vehicle can also be supported on jack stands at the cross member, but you don’t want to do that for this operation. More on that later.

2. Disconnect the battery and remove the front wheels.

3. Remove both the main serpentine belt and the AC belt.

4. Disconnect the terminals from the starter. This will take a little patients with a 12mm box wrench and an 8mm box wrench.

5. Remove the two 13mm bolts that hold the starter on using a 13mm box wrench on the one nearest the passenger side and a 13mm socket with extension on the inboard bolt. The manual instructs you to remove the exhaust on the passenger side, but since the starter will not be replaced, this is not necessary. Simply slide the starter towards the front of the car where it can rest out of your way. Now, replace the starter with the flywheel locking tool, Kent Moore part number J-42386-A. You won’t find this tool at your local auto parts store, but you can usually get one from E-bay for around $40. Some people are able to simply keep their car in gear (or park) and have someone stand on the brakes to hold the engine, but I didn’t have any luck with this method. Anyway, the tool simply bolts on where the starter came off using the starter bolts. Make sure that you have it positioned so that the teeth on the tool positively lock with the teeth on the flywheel.

6. Now we’re ready to start removing parts up front. I started up top by removing the steering shaft. Center the steering wheel and secure it to the seat support using some bungee cords. You don't want it spinning on you.



Now, remove the 13mm (????) bolt that attaches the steering shaft to the steering rack. You should have enough slack to pull it free of the rack.

7. Remove the sway bar. There are (4) 13mm (?????) bolts holding the sway bar to the front cross member and two 18mm nuts holding the sway bar to the lower a-arms.



The 18mm nuts must be removed using a box wrench and a Torx bit to keep the joint from rotating.



8. Disconnect the tie rod ends from the steering knuckles.



Again, these are 18mm (???) nuts with a Torx bit. The manual instructs you to use a specific tool to break the tie rod ends free; a block of wood and a few taps with a hammer will do the job.

9. Place a drain pan under the vehicle to catch power steering fluid. Disconnect the two power steering lines that are visible through the driver’s side wheel well. One line goes to the PS reservoir, the other to the PS cooler. Make sure to use an 18mm line wrench; these fittings can easily strip. If they won’t break free with moderate pressure, tap the end of the wrench PARALLEL with the wrench to help free them up. Don’t tap perpendicular to the wrench; you will only round off the nut. Once removed, protect the fittings with a cap or some tape to keep them clean and free of nicks.
10. Remove the three 10mm nuts that hold the EBCM (that aluminum brick with all the brake lines going into it just below the alternator) on its mounting bracket.

Two of the bolts can be reached using a 10mm socket on a ¼” drive wrench, the third (nearest the driver’s side headlamp) requires a 10mm socket, 3” extension, and swivel on a ¼” drive - yes, I’m serious. Access that nut from the underside of the car. The EBCM rests on three bushings that reduce vibration. When you lift the EBCM upward slightly, you can pull the bushings off the bracket. You may wish to remove the EBCM completely from the vehicle, but I chose to simply pull it upward and tie it off to the alternator with some nylon rope.



As long as you are careful not to kink the brake lines coming out of it, this saves you some time bleeding brakes.

11. Moving under the car now, disconnect the two 10mm bolts that hold the PS cooler to the cross member and slide the cooler out of your way. Again, you can remove it from the vehicle completely, but I didn’t find that it got in the way that much.



12. Disconnect the (4) 13mm bolts that hold the EBCM bracket on, followed by the 18mm bolt that holds both the EBC bracket and the steering rack.



You should be able to jiggle the bracket free and remove it by rotating the top of it toward the center of the car. Now, disconnect the other 18mm bolt that holds the steering rack.

13. With the EBCM bracket out of the way, you should see a shielded pair of wires that goes into the steering rack on the driver’s side. This is the Magnasteer connection. The connector is clipped to one of the PS lines that you just removed. Slip it off the PS line and disconnect it. Now, look on top of the cross member and find the shielded wire that runs along it. Remove the two clips that hold that wire to the cross member. Remove the clip that holds the brake line to the cross member as well. The brake line and wire need not be removed; just let them hang free of the cross member.

14. Now comes the scary part of this whole operation. Remember early on when I mentioned that you need to support the vehicle on the frame, not the cross member? You have to lower the front cross member. Place your floor jack under the front cross member at the front of the vehicle, using a block of wood to distribute the load. Do not lift the vehicle at all; just brace the wood against the car gently. This will keep the cross member from dragging against the nuts so much as you loosen them. There are only four nuts holding the cross member in place, one pictured here at the left front.



A 15/16” spark plug wrench (or deep well) fit’s the bolts. Loosen them approximately 10mm. Make sure to loosen all four bolts equally so as not to bend the cross member when putting it back together. You may find that there is no load at all applied to the jack at this point. The cross member has locating pins at each corner that have a great deal of friction. Lower the jack out of your way now. You may have to use some sort of wedge at each corner of the cross member to free it from the frame. I used a large flat head screwdriver wrapped in electrical tape, but a hardwood shim or something similar would work just as well. The cross member should not drop so low that the locating pins become completely disengaged.

15. Once the cross member has been dropped equally on all sides, get back under the vehicle and push upward on the steering rack to free it. Begin pushing it out of the driver’s side wheel well. Once it begins to hang up, get out from under the car and finish the procedure from the wheel well. Rotate the rack clockwise as you pull it through the opening in the wheel well, being careful not to pinch any of the brake lines from the EBCM.

16. Now, time for some celebration. You can finally get a breaker bar on the damper bolt. Some people say they have been able to remove the bolt with an impact wrench, but my 450 ft-lb unit wouldn’t touch it. The easiest way to get some leverage on this thing is the stand on the passenger side of the car and put your breaker bar on from there. Don’t bother trying to break it free using just an 18” breaker bar. I added a 4’ length of pipe to the end and still had to basically hang from the end of it to get the bolt to break loose. Once you break the bolt loose, it can be removed by hand.



17. Mark the damper and the snout of the crankshaft with a wax pencil, Sharpie, or something else that will work on metal. The new damper must go on in the same orientation as the old one.

18. Remove the damper using a 3-jaw puller.



If you’re renting one from AutoClone, get the smaller of the two, not the 5-ton puller. The center bolt on the small puller is too small to rest directly on the end of the crank, so you will have to be creative here. I was doing this portion of the project late at night and was short on raw materials, so I took an old 3/8” drive extension and put some washers on it that were about the same size as the end of the crank. The end of the nut fit right in the female side of the extension, while the male end slipped into the hole in the crankshaft, keeping it centered. Like I said, had to be creative… There is a GM tool available for this operation if you want to spend the cash.

19. Installation is the reverse of removal.

20. Just kidding. Orient the two dampers, old and new, to the same position and copy the mark you made before removal. Observe the holes drilled around the perimeter of the old damper. Look for any that are filled. GM used one of three different weights that were pressed into these holes. If any of the holes are filled, you need to measure the depth of the remainder of the whole. Based on this, you can then find out which weight was used. The new balancer must be weighted the same way in order to ensure a balanced assembly. You'll need the info from the FSM to do this, along with the weights.

21. If you have no weights in the damper (as I didn’t), we can move on. Slip the new damper on the end of the crankshaft, remembering to line up the two marks you made earlier. Using either the GM damper installation tool or a modified harmonic balancer installation tool, begin pressing the damper onto the crank snout. The harmonic balancer installation tool that is available at many local auto stores must be modified - about 1.75" must be cut off the end of the threaded cylinder or else it will bottom out. Pressing the damper onto the shaft requires quite a bit of force, so don’t be too timid here. The damper is a friction fit and DOES NOT BOTTOM OUT, so you will not be able to feel when the pulley reaches its proper position. Continue tightening the pulley down until it starts to line up with the other pulleys. Stop a little bit short of where it looks in plane; you don’t want to press it on too far. Remove the tool and measure the distance from the end of the crank to the face of the damper immediately adjacent to it. The distance you are looking for is 2.40-4.48mm. I just used my dial caliper to make two marks on a small slip of paper to use as reference. When you take a measurement, orient your measuring device (paper) so that it is across the diameter of the crank snout. The end is slightly beveled, so the paper would slip slightly between the pulley and shaft if you don’t do this, adding error to your measurement. If you are between the two marks you made on the paper, congratulations - you have an incredible eye. If not, reinstall your installation tool and keep cranking. This usually takes a little trial and error to get just right. I actually had to use the old crankshaft bolt for the last couple of millimeters; the tool was on the verge of breaking and I could not apply enough torque to move it.

22. Now that the damper is in the proper position, reinstall the OLD BOLT and tighten it to 240 lb-ft. Immediately remove it and verify your depth measurement one more time. Install the NEW BOLT and tighten to 240 lb-ft.

23. Slide the steering rack back in the way it came out. Again, be careful not to kink any of the brake lines or damage the fittings on the PS lines. Before sliding the power steering rack back into place, this is a good time to loosely fit the EBCM bracket. Once the rack is on, it is difficult to shoehorn it back in. Torque the steering rack bolts to 74 Lb-ft. Torque the EBCM bracket bolts to (haven’t been able to locate torque spec for this, but estimate 25 lb-ft).

24. Untie the EBCM and lower it back onto the isolators. Tighten the 10mm nuts to secure it in place. You may have to push down on the EBCM slightly to keep it in place while you tighten the bolts.

25. Reconnect the PS lines and the Magnasteer connector.

26. Bolt the PS cooler back into place; remember, you’re attaching things to aluminum, so don’t strip out the threads.

27. Reattach the plastic clips that hold the brake line to the back of the cross member and the wires along the top.

28. Reattach the tie rod ends and torque them to 33Lb-ft.

29. Reattach the sway bar, being careful to center it. Torque the bolts on the cross member to 43 Lb-ft and the ones on the A-arm to 53 Lb-ft.

30. Replace your wheels and make sure that they are straight before reattaching the steering shaft.

31. Don’t forget the starter! Remove the flywheel holding tool and replace the starter and connectors. Torque the starter bolts to 50 Lb-ft.

32. Replace your AC belt and accessory belt as shown on the picture under the hood (or in your owners manual).

33. Now you can lower the car, refill your PS reservoir, and reconnect your battery. Make sure that you verify the fill level in the reservoir after a short drive to circulate all the air out of the system.

DONE
 
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