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am an idiot, crushed rear pinch weld, other jacking stuff

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Old Apr 23, 2017 | 09:01 PM
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am an idiot, crushed rear pinch weld, other jacking stuff

hey all, was changing the 8 over to its summer shoes, and went to jack up the rear. pumped it halfway up, suspected the wheels on the jack were stuck (it's not perfect asphalt), pumped it once more and - surprise - started to roll the pinch weld over. put it down real fast.

so i guess a few dumb questions.
1) this isn't really something worth fixing, right? banging the pinch weld back to vertical isn't doing much since it'll roll again as soon as i jack it again. i heard about some people who have 1x1 steel tube welded to reinforce it. i might do that. what would/have you done

2) what is the correct place to jack for the corners? it's supposed to be at the pinch weld, right? i know the rear diff is the center jack point but i hate center jacking because it's more weight on the jack and i'm a *****.

3) with these flattened, what's the best option now? should i just do it on the moderately crushed pinch weld?

i learned the correct jack stand placement is on the rear frame rail earlier today. should be easy enough to find. is there enough space on the frame rail to both jack and get a stand in?

thanks in advance. yeah, i know, this is dumb **** but jeez i hate jacking cars up even when done safely.
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Old Apr 24, 2017 | 12:02 PM
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Originally Posted by yudkib

thanks in advance. yeah, i know, this is dumb **** but jeez i hate jacking cars up even when done safely.
You have the wrong car, my friend.

As to where the best places are to jack up the car, there's a ton of info on here about that. I've used this thread for a while, as it has a nice infographic.

https://www.rx8club.com/series-ii-te...icture-242250/

All the best.
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Old Apr 24, 2017 | 01:40 PM
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From: 2017 Miata RF Launch Edition
Jacking points
Ideal:
Middle of the front subframe (just behind the undertray) and the differential. If you can't get the jack under the car to get there, roll the car up onto 2x4 or similar. I made myself a set of ramps two 2x4s tall to make this easier.

Adequate:
You may notice that the notch in the scissor jack's saddle is deeper than the pinch weld. The weight of the car rests on the hard point inboard from the pinch weld. To simulate this, place a small cutting of 2x4 (a few inches long) on your jack saddle and maneuver it into the scissor jack location. Make sure that the 2x4 is just inboard of the pinch weld so that the car's hard point rests on the wood rather than the pinch weld.


"You're going to have a bad time":
Placing the jack saddle directly beneath the pinch weld. But you already know this.
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Old Apr 24, 2017 | 03:21 PM
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Originally Posted by TheWyvern
You have the wrong car, my friend.

As to where the best places are to jack up the car, there's a ton of info on here about that. I've used this thread for a while, as it has a nice infographic.

https://www.rx8club.com/series-ii-te...icture-242250/

All the best.
heh. this needs to get jacked up A LOT less than the domestics i've worked on, trust me. thats a good diagram and i've seen similar ones, though i am not crazy about putting the stands on the LCA's, even all the way towards the center. also, that recommends the center jacking positions, which, i get it, i just don't want to do it.

You may notice that the notch in the scissor jack's saddle is deeper than the pinch weld. The weight of the car rests on the hard point inboard from the pinch weld. To simulate this, place a small cutting of 2x4 (a few inches long) on your jack saddle and maneuver it into the scissor jack location. Make sure that the 2x4 is just inboard of the pinch weld so that the car's hard point rests on the wood rather than the pinch weld.
Ah, I don't have the factory scissor jack, so I didn't know that. So I guess hammer this ****** back to plumb with a deadblow, route out about a 1/2" slot in a 2x piece of lumber, then straddle the pinch weld with the slot and i'm good to go? I have a full accompaniment of woodworking tools so that would be easy and preferred for most routine stuff.

As for makeshift ramps, tragically that's a no-go because I'm working on the street in NYC. Makes larger projects fun. So I might invest in a better / lower profile jack. Anyone around here have the Harbor Freight / Snap-On clone?
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Old Apr 25, 2017 | 04:33 AM
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You don't need to get fancy for a pinch weld adapter. Just a 4-inch length of 2x4 will do it. Like I said, just but it up against the back side of the pinch weld and you're good.
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Old Apr 25, 2017 | 10:45 AM
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so the centerpoint of the jack is like 1.5" inboard of the pinch weld? man that just feels weird, but is probably why i crushed my pinch weld
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Old Apr 25, 2017 | 11:21 AM
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From: 2017 Miata RF Launch Edition
Pretty much. If you get under the car you can see the ribbed hard point that the OEM scissor jack touches. The scissor jack really only contacts the hardpoint inboard from the pinch weld. The slot in the jack is just to help you position the jack properly using the pinch weld.
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Old Apr 25, 2017 | 02:58 PM
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So I've also been jacking my car up on it's pinch welds like an idiot. Any real lasting damage that this might've caused?

heh. this needs to get jacked up A LOT less than the domestics i've worked on, trust me.
Really? I feel like I have to jack the car up to do just about everything. Except maybe change the battery. The best access for a large majority of things on our engine is through the wheel wells.
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Old Apr 25, 2017 | 04:23 PM
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From: 2017 Miata RF Launch Edition
Originally Posted by Reoze
So I've also been jacking my car up on it's pinch welds like an idiot. Any real lasting damage that this might've caused?
You tell us. If there's significant damage, it will be structural so you'll probably know about it.
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Old Apr 25, 2017 | 05:51 PM
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Well I have noticed that the front shock towers seem about 1/4-1/2" closer together based on the previous paint wear on the strut bar from the nuts. I assumed this was due to the recent coilover install/lowering. Beyond that everything seems perfectly fine to me.
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Old Apr 25, 2017 | 08:30 PM
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Sounds like you're fine. If the front end collapses, let us know.
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Old Apr 25, 2017 | 08:49 PM
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Originally Posted by NotAPreppie
Sounds like you're fine. If the front end collapses, let us know.
Yeah, the front's not meant to fall off.
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Old Apr 25, 2017 | 09:51 PM
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I'll make sure to keep an eye on it.

If the rear falls off, that's fine though right?
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Old Apr 26, 2017 | 09:21 AM
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Well, I mean, the car will stop so it's sort of a self-correcting problem as far as safety goes.
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