April 29, 2011

Delrin Upper Control Arm Bushings

Mazdaspeed sells some amazing delrin bushings for the front upper and lower control arms made by SpeedSource. Since my class rules specify that I can change the material, but not the type of bushing (aftermarket bushings for the lower control arm change them from cylindrical to spherical), I only picked up a set of upper control arm bushings.

, If there is a DIY on here that I seriously disliked performing, it would be this one. I think doing the rear differential was easier than dealing with these things! Heck, even SpeedSource said to Mazdaspeed when we called for help, "haha...Oh man, I wouldn't wish that job on anyone." That being said, make sure you have a lot of patience and time for this job. Each bushing without torching, took us between an hour to two hours.

Tools & Materials
  • Torch
  • Gloves that will handle very hot temperatures
  • A Breathing Mask
  • Goggles
  • Vice Clamps
  • Pry Bar
  • Hard, Flat, Raised Surface or Work Bench
  • 4 or 5 lb. Hammer
  • Rubber Mallet
  • A strong metal pick or bit
  • Reciprocating Saw
  • Brake Grease (we used some copper colored brake grease that worked nicely)
  • Penetrating Oil
  • Beer and Friends to enjoy the smoke show that will take place

Process Please note, this guide assumes you have the upper control arms removed already, but if not, there are a few DIYs out there. It's relatively straight forward, just be cautious when installing the ball-joint back into the knuckle after, as that took me quite some time to figure out a way to get enough load to press the upper control arm down into the knuckle to prevent the ball-joint from spinning when tightening the nut.
  1. Start by getting your torch and safety gear ready, and in a very open area outside, torch out the bushings. NOTE do NOT breath this stuff in... you WILL feel like you're dying for the next week
  2. Once you get the bushings melted out, try using the bit to scrape off as much excess rubber as possible
  3. Once you do this, you'll see the problem that, makes this a tricky task. The OEM rubber bushings sit inside a metal cylinder that is separate from the control arm...and yes, it needs to come out
  4. Using your reciprocating saw, cut into the thin metal of the cylinder, cutting into sections like a pizza
  5. After cutting the sections, take the bit to the cylinder, and start hammering away at the bit with your 4 or 5 lb. Hammer. The goal is to collapse the cylinder on itself so you can just hammer it out after. Spraying penetrating oil between the cylinder and control arm will help once you start making enough of a dent into the metal cylinder
  6. Once you deform the cylinder enough, you should be able to use the pry bar to pull it out, or hammer it out
  7. If you used the penetrating oil, be sure to clean inside the control arm as much as possible
  8. Here comes tricky part number 2. Using the rubber mallet, with no lube, hammer in the delrin bushing into the control arm, but NOT the same way as OEM as it will not fit. Instead, hammer in the bushing from the inside, out. Notice the picture below
  9. Once the bushings are in, grease the metal sleeves that slide inside the bushings with the brake grease and hammer those in
  10. Make sure the cylinders and bushings are as flush as can be, otherwise you will be fighting a losing war. We had to frequently pull out the control arm and keep hammering down the bushings, then check fitment again and again before we somehow managed to pull it off.
  11. Once this is done, reassemble the suspension, torque down the necessary bolts to proper specifications, and then go for a test drive!


shadycrew31 said...

You literally just saved my hair as I was about to rip it all out. I even took the control arms to a machine shop and after 3 hours they gave up. My only issue is I need to reuse the inner sleeves but I think a bath in some paint remover should soften the rubber up enough.

Thanks man!

Marc Monnar said...

No problem, anytime! I'm glad to hear my DIY helped you out. Yeah as mentioned, that job really is just very time consuming.