How to change the upper rear shock mount on a Mazda3

"DasWauto" (DasWauto) 01/07/2016 at 15:50 • Filed to: DIY, let's play mechanic, tag_you're it

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On a friday night a bit over a year ago my brother was driving home and something began rattling around in the rear suspension of our 2004 Mazda. Upon inspection at a gas station, the problem was easily spotted, the mounting tabs on either side of the upper shock mount had broken off around their bolts. Fun times.

Here are some step by step instructions to fixing this issue:

Park the car in a heated shop because this is November in Canada and it is therefore somewhere between -Nope°C and absolute zero. Also, it’s snowing, obviously. (After parking, promise to yourself that you will work on the e30 sitting next to the stricken Mazda after you’re done with that. You probably won’t but that’s beside the point.)

Grab some WD-40, PB Blaster or other penetrating oil of your choice and soak the nuts holding the broken remains of the old shock mount. This will hopefully make them easier to remove through all the gravel dust, road salt, beaver guts, maple syrup and other debris encountered on Canadian roads.

After work the next day, call the nearest parts store 20 minutes before they close. Be surprised to hear that they’ve got the new shock mount in stock and hustle on over there. Arrive 2 minutes before closing time and pay the nice man who’s already grabbed the part for you. Good guy parts store clerk.

Celebrate this victory with some Tim Horton’s. While the staff is refilling the machine they need to make your beverage, enjoy your doughnut and chat with the increasing number of fellow caffeine addicts in line behind you.

Machine filled, take your drink back to your car and set off for home. Be sure to almost immediately scald your tongue with your freshly brewed cup of Joe, this will serve to entertain you on your way.

Upon arriving home, grab your floor jack and place the bit that goes up under the rear subframe of the car. Before lifting said car, chock the front wheels, set the e-brake and grab a large ratchet and 21mm socket to break loose the lug nuts. Four of them will give way with a solid twist, the fifth will stump you.

After failing to find something suitable to use as an impromptu breaker bar, say ‘fuck it’, bust out the electric impact and have at that stubborn bastard. Observe as one metric shit-ton of dust and other assorted garbage falls out of your wheel well while the gun rattles away. That nut will come off, eventually.

Place the wheel under the car to stop it from falling on you in the rare event that the jack/stands fail. Place the lug nuts in a neat pile nearby so you don’t lose them.

Remember the bolt at the bottom of the shock absorber that you soaked in WD-40 the day before? Good, neither did I. Accidentally kick your lug nuts across the shop floor as you struggle to wrestle that 17mm bolt loose.

Retrieve your lugnuts (one of them will probably have ended up in your toolbox, somehow) and resort to the rattle gun to remove that damn bolt at the bottom of the shock.

Wrestle the shock and its broken mount out of the top of the control arm or trailing arm, whichever one it was attached to.

Grab the ratchet and loosen the 12mm nuts holding the broken tabs left behind by the shock mount. Once free, zip them off with the electric gun (don’t use it initially as you want to be careful not to break those studs, fixing them would require welding).

Pull down the dust boot and lightly clamp the piston shaft of the shock in a vice. Loosen the 14mm nut at the top, remove the remains of the old shock mount, install the new one and snug it down. Push the dust boot back up and into the new mount and the assembly is ready to back on the car.

Using lessons learned from the removal, slide the shock absorber back through the suspension and onto the waiting studs at the top. Zip those nuts back on with the rattle gun and just snug them up with your fingers.

Realize that the shock absorber is now apparently too short for the bottom mount to line up with its holes and the suspension in full droop. Attempt valiantly to pull the shock down (it will move a bit to give you some false hope) and struggle to get that bolt through the holes.

Give up, loosen the nuts holding the upper mount to allow the shock to drop down and meet its proper mounting place. Reinsert that bolt, tighten it with all your might and snug everything back up on the top mount as well.

Clean any corrosion off the hub with a wire brush and put the wheel back where it belongs. Throw the lug nuts back on with the rattle gun and tighten them in a nice star pattern.

Go for a test drive and enjoy a job well done.

DasWauto > DasWauto 01/07/2016 at 15:50

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I originally made this post a bit over a year ago but never ended up publishing it. I’ve done so now in light of Takuro having the same problem (even though he probably doesn’t need the DIY help).

Party-vi > DasWauto 01/07/2016 at 15:54

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Y’all keep fuckin up Mazda3’s around these parts.

PotbellyJoe and 42 others > DasWauto 01/07/2016 at 15:56

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Here’s how most consumers would fix it.

Justin Hughes > DasWauto 01/07/2016 at 16:00

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Genius. This is exactly how most of my wrenching projects go down.

Takuro Spirit > DasWauto 01/07/2016 at 16:00

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This post is relevant to my interests.

Takuro Spirit > DasWauto 01/07/2016 at 16:05

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Pfft, I have air tools at home in my unheated garage. And a lift at work in the heated garage if I so desire.

And I don’t drink coffee.

Or live in Canadia.

DrJohannVegas > Party-vi 01/07/2016 at 16:06

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Does one fuck up a Mazda3, or simply stop it from fucking itself up?

S62B50daily > DasWauto 01/07/2016 at 16:08

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About the part where the shock being too short for the bottom mount: could you have used your floor jack to raise the trailing arm just a tiny bit?

I sympathize with the E30, I have one in a serious state of hibernation occupying a 1-car garage, meaning working on the other cars is done outside, usually when the weather is 1/optimal

Highlander-Datsuns are Forever > DasWauto 01/07/2016 at 16:09

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I’m bookmarking this for future reference. BTW my right front strut is leaking oil so I’m thinking that is a good spring project. Should I stay with OEM? My car has no suspension mods considering I need all the ground clearence for the snow and rough forest service roads I frequent.

DasWauto > Party-vi 01/07/2016 at 16:17

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Half correct. They’re a bit fucky from the factory, we’re only keeping them going.

DasWauto > Takuro Spirit 01/07/2016 at 16:18

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I pity the fool who doesn’t have Time Horton's.

DasWauto > S62B50daily 01/07/2016 at 16:20

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You could, but I think I still had the jack under the back of the car because I’m lazy and didn’t want to move it and have to put it back later.

My e30 occupies some space in my parents’ shop. Much to their (and my) shagrin. I’ll get to it, eventually. Maybe this weekend actually, I need a new bottle of gas for the welder.

vicali > DasWauto 01/07/2016 at 16:24

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french vanilla IV stat!@

DasWauto > Highlander-Datsuns are Forever 01/07/2016 at 16:27

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I wouldn’t get the part from the dealer, I’d just go to a parts store and ask for the whole strut assembly (usually not much more than the strut itself and much easier to change as you don’t need spring compressors). They’ll probably have a couple of options, if the car’s not too new and they have a semi-reputable brand go for that (a forum search might help to get good options for the specific car).

It’s also good practice to replace the struts in a pair to ensure you have predictable handling.

DasWauto > Justin Hughes 01/07/2016 at 16:29

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For me it’s either a comedy of errors or an expletive filled struggle as stuff refuses to cooperate (at which point I just leave, and finish later), sometimes both.

64Mali > DasWauto 01/07/2016 at 16:31

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I just did shocks on my MILs 3. I cross threaded the stuff while removing it. Yay New England rust. In all fairness it still is an easier bracket than the rear shock bracket on a 04-08 Mazda 6.

Highlander-Datsuns are Forever > DasWauto 01/07/2016 at 16:42

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Good advice, the closest mazda dealer to me is 143 miles away.

If only EssExTee could be so grossly incandescent > DasWauto 01/07/2016 at 16:50

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Bitch I have Marylou’s.

Tiramisu iced coffee, anyone?

DasWauto > vicali 01/07/2016 at 16:55

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I don’t actually go very often anymore as I don’t have to commute but I do love me a cafe mocha when I do.

gmporschenut also a fan of hondas > DasWauto 01/08/2016 at 20:32

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I got one of these. worth the 15 bucks. and shows those nuts whos boss.

DasWauto > gmporschenut also a fan of hondas 01/09/2016 at 09:14

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What am I looking at here? Does it split the nut?

gmporschenut also a fan of hondas > DasWauto 01/09/2016 at 09:43

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Correct

Great when a breaker bar cant fit, or you cant get heat near an area. Though an impact usually does a great job.

Viggen9er3 > DasWauto 02/12/2016 at 16:47

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Amazing Mazda3 story!

What year is it, I might have missed it? I sold my wife’s 2008 mazda3 due to the same issue 4x broken shocks. I didn’t want to fix it before selling, so I dumped the damn rusty broken shock mazda for a low price.

Thankfully, my family gifted my wife a mint 2009 Toyota Matrix, which she loves.

DasWauto > Viggen9er3 02/12/2016 at 17:03

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It’s an ‘04 and has been in our family since ‘09. It’s not worth much anymore but it has served us well and is still a good car to drive.