Rear suspension - while you're in there questions

[kyngfish]

So yesterday I was in the garage and I noticed that my rear end was sagging weirdly. On closer inspection you can't see any space between the passenger rear tire and the fender, the fender is sitting about a third of the way down the sidewall - and on the driver's side, you can barely see the sidewall. I suspect something is up with my torsion bars.

So since it looks like I'm tearing my torsion bars out - aside from spring plate bushings, and trailing arm bushings, new torsion bars and new shocks, what else should I be replacing in there.

If I'm making any incorrect assumptions about the sag also, let me know.

Thanks

[Flojo]

yep, looks like an issue of a ripped torsion bar.
dead shock allone don't do that effect.

add to list: new rubber and coupler for the spring bar
maybe trans and engine mounts while you're at it?

[911tracker85]

I encountered this years ago. was at a DE and the car handled terribly. noticed the drivers side was sitting just slightly lower than passenger. figuring I needed a good alignment and corner balance ... again.

going to dinner that evening the drives side torsion bar snapped. when we replaced it, looked like it had cracked a bit before finally snapping. no rust or corrosion so no idea why it snapped.

ironically when this happened the first car that stopped was my instructor for the event. when I told him what happened I could see the WHOA in his eyes thinking about what would have happened if on the track at speed.

good luck.

[1979-930]

How many miles on the car?
A torsion bar can be changed pretty easy without all the bushings.
If everything is worn and deformed then I see a slippery slope.
The front won't be much different and might as well do a full refresh.

[kyngfish]

Originally Posted by 1979-930

How many miles on the car?
A torsion bar can be changed pretty easy without all the bushings.
If everything is worn and deformed then I see a slippery slope.
The front won't be much different and might as well do a full refresh.

Honestly not that many. Still under 100. But it’s still a 35 year old car.

[rokemester]

I’m in the middle of a complete suspension refresh on my Targa. No problems really, just figured after 170K miles it needed some love. The insanity of Porsche ownership! If it ain’t broke, go ahead and take it apart to learn more about the car, challenge yourself and maintain it. Fortunately for you there are some awesome threads on the subject. The rear suspension is a ball buster IMO. I couldn’t manage to remove the torsion bar chassis mounting bolts. Too much interference! Rather than go the sawzall route and hack the bolts out I dropped the drivetrain. You’ll also have fun knocking out the wheel hubs and wheel bearings.

While the drive train is out, I’m tidying up the tranny, powder coating the engine tins and having the fuel injectors serviced. I’m also going to pull those nasty little heater valves, blast and powder coat them. Access is so much easier! I’m also going to tidy up the engine bay a bit.

Have fun! Good winter project for me in NEO.

[NYNick]

Originally Posted by 1979-930

How many miles on the car?
A torsion bar can be changed pretty easy without all the bushings.
If everything is worn and deformed then I see a slippery slope.
The front won't be much different and might as well do a full refresh.

Not to hijack, but I've been contemplating "a full refresh" on my 72. Pretty much would need everything, but one doesn't always have to change sway and torsion bars, does one? ER has packages, but they're pricey, even just DIY.

Is ER's the price of admission for redoing a suspension: $4-5K? Holy smokes.

[Driven97]

Originally Posted by NYNick

Not to hijack, but I've been contemplating "a full refresh" on my 72. Pretty much would need everything, but one doesn't always have to change sway and torsion bars, does one? ER has packages, but they're pricey, even just DIY.

Is ER's the price of admission for redoing a suspension: $4-5K? Holy smokes.

As always, the best answer is "it depends."

Some cars just need a fresh set of shocks. Some cars legitimately need everything replaced. Most cars are in-between, and replacing certain things wouldn't hurt, but it's by no means necessary. Unfortunately, you can't tell through a forum post.

I think the OP's problem of a broken torsion bar is rare, but not unheard of. I don't think I've heard of a sway bar failing ever, sway bar end link maybe.

There's not a lot more expensive phrases than the title of this thread.

[1979-930]

Originally Posted by NYNick

Not to hijack, but I've been contemplating "a full refresh" on my 72. Pretty much would need everything, but one doesn't always have to change sway and torsion bars, does one? ER has packages, but they're pricey, even just DIY.

Is ER's the price of admission for redoing a suspension: $4-5K? Holy smokes.

I don't think it's a must do unless the car feels soft and has a lot of body movement when driving aggressively. New shocks will only help so much with weak torsion bars.

My car only had 80k on it, but it didn't drive like a sports car to me. So I upped the torsion rates a little per Steve Weiner's recommendations.
I'm very happy with the firm but not harsh ride of the sport type suspension I ended up with.

[NYNick]

Originally Posted by 1979-930

I don't think it's a must do unless the car feels soft and has a lot of body movement when driving aggressively. New shocks will only help so much with weak torsion bars.

My car only had 80k on it, but it didn't drive like a sports car to me. So I upped the torsion rates a little per Steve Weiner's recommendations.
I'm very happy with the firm but not harsh ride of the sport type suspension I ended up with.

Could you point me to Steve's recommendations? Are they on PP?

[KTL]

At this point in our cars' lives, I think age trumps mileage. I have known my '86 Carrera since the late 1990s when my friend Mark (RIP) bought it. I bought it from his widow in 2015 and it has only 77K miles on it. Mark got it with like 54K miles I believe. Pretty clean car with a bit of annoying rust. Nothing major but it's got small rust in numerous locations throughout the car. Plus it didn't help that it sat in a detached non-climate controlled garage for around ten years.

I decided that if i'm going to enjoy the car to the fullest, and be safe, I better look into refreshing the suspension. I tracked my previous 911 and figured i'll probably take this one to the track every once in a while. Well, what I found was pretty ugly and dangerous. The front suspension bushings were all deformed and the torsion bars looked really nasty

So since the front looked bad, I knew the rear wasn't going to be much better. The rear was a bit of a struggle to get the torsion bars out of the spring plates, as the splines were slightly rusted. Had to drill a hole in the end cap and drive the torsion bar out of the spring plate tube with a hammer and punch. I also had one of the spring plate bolts frozen/corroded into the trailing arm pass-through hole- took a lot of heat and hammering to knock that sucker free. Spring plate bushings were also deformed quite a lot. So it all came apart to put in new bushings and clean up all the crud and minor rust. Given how bad my torsion bars looked, those obviously had to be replaced.

While you're in there can start the snowball effect quite easily when you start looking at other things like fuel lines (these are getting scary on a lot of these cars....), seized brake line fittings, surface rust that keeps spreading.......... and it only makes sense to do these other things while you already have major pieces like the suspension out of your way.

Oh, and I already had the drivetrain out of the car for an engine top end (known/witnessed bad valve guides long ago, then also found a broken head stud while I was in there.......) that turned into a complete teardown that isn't back together yet.

[RWebb]

700 miles on this car







torsion bars don't last forever either...

[Larmo63]

My rear Tarrett sway bar finally ripped the stock mount out of the car and I will be welding in solid mounts soon. In the meantime, I am collecting parts to do a full front end re-build to include alloy S calipers, new drilled rotors, all bearings and seals, new A arm bushings, ball joints, sway bar bushings, clean, inspect possible new turbo tie rods too + plating, powder coating.....it never ends.

Then, the rear end gets the treatment.

[fanaudical]

Something I wish I had done when I had the engine/trans out and rear suspension apart: replace the tunnel fuel lines.

[911tracker85]

.....it never ends.

nope..... 6 yrs and counting.

[chrismorse]

I'm into my dad's 74 probably 25K and 6 years off the road, so you might want to take my ramblings with a grain or two of salt.

One of the first considerations is do you stay with stock, or do you want to "improve" the car for more sporty driving, an occasional auto X, or track days, or hard core track days. There is a huge range between extremes. This is where an honest discussion or two with guys like Chuck at Elephant, or John at rennsport will help define what you want for the car.
Are you going to just clean good old parts, or plate or paint stuff - you are starting down the slope.....
The next approach is to get a thorough assessment of the condition of the existing components to see what "needs" to be replaced. You can benefit from experience here too, regarding things line tunnel fuel lines, is it time to pack the CVs, etc. is there any damage or rust that makes sense to repair now??
Make a plan, kind of back to the goal here. You need the upgrade parts to work together to achieve your objective. If you are going to upgrade the rear T bars a bit, you might as well do the fronts, because the car will need another cornerweighting and alignment and there is little point in duplicating the expense. This leads to more bushings, parts painting and "legit" stuff like steering rack overhaul.
lastly, the dreaded consideration, Budget. This will likely trim your plan, or more likely, make you trim the plan into phases. Keep in mind that you will always find more stuff that absolutely needs to be done while you are in there.

Good luck,
chris

[aoncurly]

I had a complete refresh done by Elephant Racing a few years ago. They found my torsion bars to be shiny due to rubbing and replaced them with used bars. I was surprised at others mentioning in another thread that they reused abraded torsion bars without issue. These things are under tremendous cyclic stress and depending on the wear they may have a notch or microcrack which can fatigue and fail over time. Best to replace with new or clean used ones.

[rokemester]

Great point! Just hate to replace them all because of one bad actor. If you replace one you’re really stuck replacing them all unless your lucky enough to find a single used in good condition OEM torsion bar. The spring rates need to match. Damn this hobby is expensive!

[kyngfish]

So I finally got into the car tonight. I didn’t have to remove the caliper or rotor because I was able to access the last spring plate bolt from behind. But looking at my axles I think I’m going to go ahead and knock those out so they’re going to have to come off anyway. Oh well. Anyway getting the torsion bars out was fairly easy and I’ve never been happier to see a shattered part in my life. Quick question. There’s undoubtedly some debris in the torsion bar tube. Best way to get it out? Blow it out?

[rokemester]

Good for you getting the torsion bar out! At least you didn’t have to pull it out with a ratchet strap and other vehicle like I’ve seen in other threads!!