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Manicmechanic
11-26-2017, 08:14 PM
Rebuilding BC Racing Z-01 Front Coilover Assemblies
The tools you will need to complete this task will be:
1.Tape Measure, pen and paper.
2. BC Coilover wrench set (came with coilovers when new.)
3. 10mm 13mm, 14mm, 16mm and 18mm wrenches and 11/16”wrench.
4. 18mm and 22mm ½” drive sockets, 6 inch extension and ½”ratchet.
5. 5 mm hex key (allen wrench) and Metric Crescent wrench.
6. Paint Pen or Permanent Marker in other than black.
7. Your choice of jack and stands.
https://s26.postimg.org/vmagy5zyt/IMG_0767.jpg (https://postimg.org/image/vmagy5zyt/)
This should take you about an hour each side to complete and have a level of difficulty of about a 2.
First you have to place an order for new shock cartridges from BC Racing and it takes 3-4 weeks to get them. Also depending on the age of your units you might want to order 20mm bump stops and new dust boots too.
Dodge Charger/Charger SRT-8 Shock Cartridge (https://store.bcracing-na.com/shock-...t-8-p4774.aspx)
https://s26.postimg.org/7jtn3ajbp/IMG_0751.11.jpg (https://postimg.org/image/7jtn3ajbp/)
After you have received and inspected the new cartridges (Don’t let the GM part number scare you) your ready to start the process of removing yours and rebuilding them.
First thing I suggest is that you check your current adjustment level on the units on the car.
The factory setting is -8 from full hard, if yours is different be sure to write down the setting, clockwise is harder and CCW is softer.
Next you want to measure your current ride height at the fender, I placed a piece of masking tape on the fender and drew a line at the point I measured from so I could make sure I was checking in the same spot.
https://s26.postimg.org/mkqdgj2ad/IMG_0750.jpg (https://postimg.org/image/mkqdgj2ad/)
I measured to the ground before I moved the car for this job (If you need to move it into a garage or work area to complete this job) and record the numbers.
https://s26.postimg.org/82t68jaz9/IMG_0754.1.jpg (https://postimg.org/image/82t68jaz9/)
Now you can raise the car and support it (I did one side ata time) with a stand, remove the wheel and get ready to measure again. Since the unit has to be dissembled to complete the process you have to know where the preload is on the coil spring. I measured between the lock rings at the top of the lower strut housing and the one under the spring perch so I could get back to that setting upon re-assembly.
https://s26.postimg.org/orum4g7kl/IMG_0766.1.jpg (https://postimg.org/image/orum4g7kl/)
Notate that reading and using the BC Racing wrenches back off the bottom lock ring and the lock ring under the spring perch while not allowing the cartridge to rotate. Now mark the threads at the top of the lower mount and just under the spring perch ring. Now your ready to remove the strutfor rebuild.
https://s26.postimg.org/sphvtuudx/IMG_0769.1.jpg (https://postimg.org/image/sphvtuudx/)
You need to take the preload off the coil spring and now is the best time, you might have to run the bottom lock nut back down into position to help lock and hold the cartridge. Turn the spring mount nut down until the spring looses all tension on it and can be move freely between the lower nut and upper plate. Now you need to remove the Sway bar mount from the lower strut mount, you’ll break the pressure off the nut then will have to hold it at the end of the stud with a 10mm wrench and finish backing off the nut with a crescent if you don’t have a 17mm wrench. Support the lower arm under the lower strut and then remove the lower strut bolt thru the lower arm with an18mm wrench on the bolt head and 22mm socket on the nut(s) (there should be two as sent from BC when strut was installed new) and work the bolt out of the strut. At this point there are two methods to removing the assembly, the factory recommends removing the connection between the knuckle and upper ball joint for factory units. Since the BC units are adjustable I simply screwed the unit to the lowest setting (down into the lower mount) until it freely came out. You can either remove the top place mounting nuts before or after you screw the unit together, using a 13mm wrench on the nuts.
https://s26.postimg.org/e0xsraf6d/IMG_0755.jpg (https://postimg.org/image/e0xsraf6d/)
Also you can decide if you want to remove the adjuster knob at this time using a 14mm wrench and backing it off the top of the cartridge stud and set it aside. You could possibly leave the top plate in place and usethe 5mm hex key and 16mm and back off the nut holding the rod to the top plate and lower the strut out or remove the top plate nuts and lower the whole assembly out. I went the latter as this was a first time and I wanted to document and inspect everything. So once you have screwed the assembly down into the lower mount you can lower the jack under the lower arm to allow you room to remove the smaller unit without breaking the upper ball joint. With your assembly removed from the car now it’s time to disassemble the parts off of it for install on the replacement cartridge. If you left the top plate on now is the time to remove as describe earlier, then remove the coil spring keeping the top and bottom in check so it goes back together the same way.
https://s26.postimg.org/kpzqtkb4l/IMG_0761.jpg (https://postimg.org/image/kpzqtkb4l/)
https://s26.postimg.org/m1c3frw45/IMG_0762.jpg (https://postimg.org/image/m1c3frw45/)
Now unscrew the cartridge from the lower mount and remove the lower spring mount, lock nuts from the old unit and the strut upper boot and bump stop, keeping everything in order until you have a bare cartridge.
https://s26.postimg.org/ip978qez9/IMG_0760.jpg (https://postimg.org/image/ip978qez9/)
Now take you old cartridge and place the rod end on the ground and press down on the other end to see how bad your old unit is (you probably won’t be able to compress the new units, but should the old ones) by how far it goes. Inspect everything for any signs of damage and laying the old unit beside the new unit transfer the marks you made for on the old cartridge to the new one for the spring mount nut and how far you had the cartridge screwed into the lower receiver so you can get back to the same height you had before +/- 1/2”. Screw the assembly together to the lower setting so you can get it back into position between the lower arm and top mount, raise the top into position and place the 3 nuts back on the studs to support it and unscrew the assembly back to the mark you made for the lower mount position. Jack the lower arm back up until you can place the lower mounting bolt thru the mount and hole in the arm. Install but do not tight the nut(s) on the bolt. You cannow tighten the 3 top mount nuts to 20 ft lbs. and install the adjustment knob if you haven’t already. Now you have to screw the lower spring mount nut up to set the spring preload, running it up to the mark you should have made on the new cartridge.
After you have set the spring preload run the lock nut upand tighten it against the lower spring mount. Make sure your lower strut mount housing and marks are right and lower the lock nut down to the top of the housing and lock it into place. Check your measurement between the two nuts and check them against the ones you took before you started the job. If there is any real difference loosen the lower nut to the housing (Do not adjust the spring preload nuts) and screw the cartridgein the direction needed to get back into spec. Install the sway bar end linkand tighten to 95 ft lbs. using the 10mm wrench and crescent/17mm wrench.Before you can tighten the lower strut mounting bolt you have to load the suspension by either install the wheel and lowering the car to the ground or jacking up the lower arm and until the suspension compresses and the car start to raise off the jack stand and tighten the nut to 128 ft lbs. Now you’re ready to do the other side! After all the work is done set you ride adjustment knobs back to your original setting or -8(default) from total hard and lower the car down and take a short test drive to help thing settle, measure your new ride height and make any changes you need/want too. Also don’t run down to the alignment shop just yet, drive it a few days and recheck your ride height till your satisfied and then have an alignment done.
A few things I discovered doing this write up was, I am the original owner of the coilovers and upon disassembly of the Drive vs. Passenger side I was missing the bump stop on the drivers unit, But a quick note sent to BC Racings sales office about it got mein touch with Tony in sales who promptly researched my owner status and sent me a no cost replacement, I just have to redo the drives side unit, if your not the original owner of your set a new 20mm bump stop is $5 at the time of this writing.
https://s26.postimg.org/8qxfdqkb9/IMG_0770.jpg (https://postimg.org/image/8qxfdqkb9/)
I also noticed the one of the old units was a tad longer that the other and new units, not sure if that indicated an internal issue or aQA thing. I had 50K miles on these units and they were 6 years old, I noticed a ride quality issue which led me to rebuild the units.
https://s26.postimg.org/tgf7ddm51/IMG_0772.jpg (https://postimg.org/image/tgf7ddm51/)
https://s26.postimg.org/h6mzv8n6d/IMG_0771.jpg (https://postimg.org/image/h6mzv8n6d/)
The new ride affirmedmy findings.
Also check out the rear rebuilding thread here:
http://www.lxforums.com/board/brakes-suspension-and-wheels/394840-rebuilding-bc-racing-01-rear-coilover-shock.html

netnathan
11-30-2017, 03:47 PM
Nice detail...thanx

These coil overs will also make a "clunking" sound when bad. I know because I ran my settings all the way up for 3 months while I was waiting to get my fenders rolled.
When I adjusted them back down, I started having the "clunking" sound.
I already bought replacement shocks for the rear ($125.00 each). Now that I saw this I will rebuild the fronts.
Lesson learned.....these shocks SHOULD NOT EVER be run at the max settings.