So I was doing some pretty serious whipping back and forth of my 1980 rx7s tail end. I took off a bit briskly in first whilst steering a bit to aggressively. Needless to say I accidently redlined the absolute **** out of the engine. That is the least of my worrys because honestly the engine is very solid and takes 8000rpm elegantly if only for a few seconds.

However I've examined my suspension components in the rear end and not everything seems 100% straight. I'll post some pictures in the morning, but my main concern is the lower link seems to be bent on the drivers side.
It isn't bent side to side like what would happen if you slide into a curb but rather it is bent upwards. By that I mean the center of the bar is pushed slightly upwards in the direction of the frame, but the bend is in alignment with the mounting of the bar so that the brackets and every thing are seemingly normal.
It's just concerning me a bit, but the car still drives straight as ever to the point where if I'm on a good straight flat road I can let go of the wheel and stay exactly where I am pointed.
Also I'm not entirely sure that the bar was straight in the first place, but the fact that the passenger side is makes me wonder.

Any help is appreciated, pictures of stock rear suspension for comparison would also be helpful.

 

I have seen plenty of them bent and most were by dumb owners jacking the car up on lower control arm

 

Yep should be straight.

 

It looks exactly like someone tried to jack it up there... the previous owner was a moron. There are several underbody dents cause by his stupid *** trying to jack it up improperly, nothing serious but it ticks me off. Not that hard to jack stuff up properly...

So should I replace it? I mean it wouldn't be difficult for me to but I just don't know that it's necessary.

 

If its bent you may experience some weird handling at the limits I would expect. Up to you.

 

From your description, it sounds like the lower trailing link arm is bent - there are 4 trailing links; 2 at the top which are shorter, and 2 at the bottom, which are longer and nearly parallel to the ground where they come off the body mounts. In addition, there's a locating assembly on the rear of the differential which ensures no side-to-side movement (like a panhard rod setup).

On the lower links, if one side is bent and not the other, you're going to get binding on that side at some point of suspension travel while the other bushings in the 3 other links are still moving smoothly - this could result in weird handling at the limit, as posted above by another astute member here. Unless it's bent significantly (like more than 1/2" in deflection at the bend), then I wouldn't think it would cause problems in city driving, but personally, I'd replace it.

Also, check the bushings on the links while you have it out as unless they were replaced by the PO, they're probably ~30yrs old and likely in need of replacement. Good luck,

 

I'd say it's a total average deviation of about .4". It's not bad, I will probably replace it over the winter as it will be in storage. Any recommendations for buying replacement suspension parts? Or do I need to take apart a parts car? Either is fine, but obviously it would be easier to just buy the piece.
Also is binding just when a certain part of the suspension runs out of range of motion, before other parts, comparatively?

 

Apply a BFH to that thing and straighten it out.

Yep binding is just the movement is restricted compared to other parts of the suspension.

 

You could probably remove that one link, hammer it out - or an arbor press would work better - and be just fine. The same part from a donor car may have worn bushings and they wouldn't act the same, if limits of adhesion handling are important to you. Again, for a street car, you'd probably never notice the difference.

I used an arbor press to straighten a tie-rod on a 80-series LandCruiser which is about 1-1/4" diameter hollow steel tube, and it's been fine ever since. This isn't exactly a high-stress part on your lower trailing link arms.

New = MAZDATRIX for Mazda RX7, RX8, Rotary Engine Parts and Accessories = $$$

 

I have successfully straightened out a lower trailing arm with a BFH. It works just fine.