How To: Replace rear lower control/trailing arms.

Discussion in 'Tech Info' started by jimmbrooks, Jun 21, 2012.

  1. jimmbrooks

    jimmbrooks Member

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    So, forgive the fact that I was too much in a hurry today to take pictures of the process and it was 110 outside today so I wasn't thinking clearly, but here is a how to to help you out if your suffering from the all too common rusted out trailing arms.

    Side note: I am not a mechanic nor do I claim any automotive insight besides what I have learned on my own, and from trial and error. If you hurt yourself or your truck following these steps I am not liable.


    Step one.
    Gather the following tools.
    1. Breaker Bar
    2. Ratchet
    3. Metric and standard sockets (18mm to 24mm and 5/8 to 15/16ths)
    4. Rotary tool with cutoff wheel (zipo de roto) ;)
    5. floor jack
    6. jackstands
    7. face shield
    8. drift pin
    9. penetrating oil (blaster de PB)
    10. 5/8 x 18threads x 3.5 inch bolt (i only needed 1 as i reused 3 of the old bolts)
    11. Nut for the above bolt
    12. lock washer for above nut

    If you feel that jack stands are not a required tool, leave this page now. I refuse to go into detail on how important they are and the following steps are assuming you are adult enough and intelligent enough to perform this safely. Think about your family, pets, friends, drinking buddies, what ever you have when your deciding on whether or not you will climb under your truck without proper safety equipment.

    Step two through a whole bunch....
    Break the nuts loose on the driver's side rear wheel
    Jack the truck up under the shock mount on the axle
    Place the jack stand underneath the frame in the middle of the rear door.
    Remove the wheel.
    Because the gasoline tank is in the way, I suggest starting with the top bolt on the drivers side trailing arm. This gives quite a bit of frustration here so take your time and be patient.
    Using a breakerbar and ratchet loosen up that top bolt. You should spray some of your penetrating oil (blaster de PB) and let it sit for 5 minutes if you have difficulty with that, or any bolt for that matter.
    Once the nut is off of the bolt, push the bolt out until it makes contact with the gas tank.
    Don your face shield and using your rotary tool cut the head of the bolt off
    DO NOT REMOVE the bolt yet.
    Make your way to the bottom bolt and remove the nut the same way as above.
    At this point use your jack to find the sweet spot in the suspension where both the top bolts and bottom bolts are loose and you can wiggle with your hand the trailing arm. Using the drift pin push the bottom bolt out, and let that part of the trailing arm drop.
    Do the same to the remaining part of the top bolt and remove the trailing arm.
    Install the top of the trailing arm first. using either your replacement bolts or old hardware. (This time install the bolt from the outside)
    You hopefully will have the lower bolt hole line up. In the case like mine, some massaging of the hole with the drift pin allowed me to line up the holes to press the bolt in by hand. Try raising and lowering your jack in small increments to make it easier if your having a hard time. DO NOT BEAT the crap out of it to get it in there. You will bugger up the treads and have to take it out and start over again. What you can do is use tie down straps to move the axle if it is that far out of whack.
    Congrats you've installed a new lower control/trailing arm.
    Put the wheel back on and that side is done.
    The passenger side is the same except no need to cut anything. The two bolts on the passenger side are easily accessible.


    The above process was my exact procedure. The driver's side took me an hour and a half with removing the top bolt. and the passenger side 25 minutes.

    I hope my first post helps some of you out. Feel free to PM me if you have questions
    :sawzall:
     
  2. MarkIndy

    MarkIndy New Member

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    Expi Rear Control/Trailing Arm Replacement

    I am curious to know what type rotary tool you used. Also to anyone who was successful cutting that hardened bolt with a reciprocating saw, can you please post what blade you used.
    For me this info request is just to improve my knowledge for future reference because I just finished replacing my Expedition control/trailing arms yesterday. When it came to cutting the one driver side control arm bolt obstructed by the fuel tank I considered several options. First I dulled a couple of reciprocating saw blades during a bench test using one of the OE bolt I had already removed on the passenger side. Next I bench-tested a 22K rpm 3” pneumatic cut-off tool. It cut through the bolt fast and smooth and threw off sparks so small and cool I could not feel anything on my free hand that I had intentionally positioned close-in directly in the path of the sparks. I did that to determine what I would be dealing under the vehicle. Only problem was when I went to cut the bolt that needed cutting I found that due to gas tank skid plate and control arm bracket obstructing access to the bolt shaft, that tool with 3" disk could not be positioned to reach any more then about one-third of the way through the bolt. So my next choice was a 4.5" electric grinder with a cut-off disk. Since that tool only achieves half the speed of the pneumatic cut-off tool I bench tested again. There was a noticeable difference in the time and force required and fumes suggested I was generating much more heat than with the higher speed pneumatic tool but it did cut ok. However, through my jeans and shirt I also felt debris hitting me which caused me to glance down at myself while cutting only to discoverer that my flannel shirt was on fire. The part of the shirt that was burning was the double layer buttonhole area, so I was not burned. However, with elevated concern about catching my clothes on fire in tight quarters under the vehicle I resorted to using a hacksaw. What ensued was a rigorous upper body workout that I estimate to have taken about an hour but the bolt is off, the job is done and I am happy to not be posting this from the hospital burn unit.
     
  3. jimmbrooks

    jimmbrooks Member

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    I used a roto-zip with the largest diameter cut off wheel. Can't quite remember the size now. Glad you didn't get hurt! Good job
     
  4. TRTLSLO

    TRTLSLO Active Member

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    I had the same problem of the cut off wheel not being big enough. I cut about halfway thru the bolt and then whacked it a couple times with a BFH to snap it off. YMMV
     
  5. 98EXPY 5-0

    98EXPY 5-0 Full Access Members

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    I used an angle grinder with a 4inch cut-off wheel. I cut as far as it would go in, rotated the bolt, cut in as far as it would go again, and repeated all the way around. Then I put the nut back on and tightened it until it snapped the head. Then I pulled it out with the nut.

    I need to get my top arms done. Not sure if there are any pitfalls. Most times I have searched, all the info online is about the lowers.
     
  6. AVERY CONFER

    AVERY CONFER Active Member

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    What arms did you buy? I need to find a 97 set. I heard all of the trailing arms after 98 have larger bolts so I would have to drill out my frame and most sets are marketed as 97-200X.... Not so confident as to be taking a hand drill to my expy and causing hundreds of dollars in damage lol. Where can I find a set of legitimate 97-98 lowers that fit my vehicle?
     

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