Desperately seeking advice with rear suspension!

[911T70]

I need help in determining the best compromise in keeping my rear suspension together until I have time to fix it properly. I noticed a while ago that the spring plate covers were in bad shape and that the bushings were tired. I ordered new covers and Neatrix bushings and did some research on the forums on how to refresh the rear suspension. What I found worried me, realizing I would not have the time nor the patience this winter to adjust the position of the spring plates by re-indexing the torsion bars by trial and error. I would also need to remove the s-trim rocker covers before I could remove the torsion bar access panels and, from what I’ve read, that’s also a frustrating and time-consuming job.

The car being in storage in my garage for the winter, I decided to remove the spring covers and they are in much worse shape than I thought. The original bushings are quite distorted with the upper portion compressed, allowing the springplate tube to practically come in contact with the springplate cover.

Please help me in deciding what to do:

1. Put everything back together until next winter when I drop the engine, which will give me better access to replace all of the suspension’s old bushings. I’ll know what to expect and will take the time to do it properly. As far as I could tell, the car’s suspension worked well enough. Maybe I just don’t know better!

2. Install the new covers over the old, distorted bushings, even if the covers seem slightly loose over them? The old bushings and covers aged together so they mate better. I’d hate to reinstall the rusted covers but would the new ones allow too much movement of the springplate tube?

3. Remove the old outer bushings, replace them with the new Neatrix and intall the new covers. In my forum searching, I found comments that this is not recommended because it puts unequal loading on the springplate tube. Although not perfect, is this the better option?

Any advice would be very appreciated. It’s been a long winter and I can’t wait to get the car ready for spring!

[Trackrash]

FWIW. Many years ago, I replace only the outer bushings. At the time I used poly graphite. At any rate, I drove the car like that for decades. It worked well for me.

As long as your torsion tube is OK, I would not hesitate to do #3.

[fanaudical]

I rebuilt the suspension on my '75 last winter. If you're not ready to tackle the project, I recommend putting the old covers back on and doing lots of research before next winter.

[HaroldMHedge]

It appears that right spring plate cover is cracked. I would do at least #3 if the cover is cracked.

[fanaudical]

I didn't notice the cracked spring cover (thought that was just "shiny"). I agree - replace at least the cracked spring plate.

[Evans, Marv]

If I remember correctly (from a loooong time ago), the Neatrix bushings came with a curved scraper for removing the old bushings. It's been so long I don't remember how easy it was to use it to help remove the bushings, but if it were me I'd get those old ones off and replace them with your new ones and new covers. I had a '72 a long time ago that had the spring plate tube bumping the upper part of the cover like yours seems to do or be close to doing. I didn't like that. If you replace the outers, you can drive it until you want to do the inner bushings. At any rate I wouldn't use the old, cracked covers.

[1979-930]

Outer bushings only may put all the load on the studs which are known to crack and fail. I would just install the new covers.

But I think you should just replace the bushings and install new plates.
I think you’re making a mountain out of nothing. It’s only February and even a first timer should be able do get this done in a weekend.
Mark the spring plate at the two upper studs with it disconnected from the arm. When you reassemble make sure the marks line up so it’s at or close to the old angle. Worst case you’re off by a tooth. The process reads more complex than it is if you have to re-index.




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[911T70]

Thanks for all your replies - really appreciate it. I was all set on starting to remove the outer bushings when I read Derrick's reply. Looking at it, I can see how a lot of weight would be supported by the studs that the cover plate bolts onto.

This puts me back into analysis paralysis! I guess the safest option now is to just replace the cover plates, which is what I'll probably end up doing.

[wrxnofx]

Having just removed the bushings from my spring plates this weekend on my’87, I don’t know how you’d get the outer bushing off the plate with it installed on the car.

I think it would make sense to remove the spring plates entirely from the car, remove the old bushings, throw the new ones on, and reinstall. Just make sure you mark the plate angle before pulling it off the torsion bar so you get the angle correct on reinstallation. If you don’t remove the torsion bar then I don’t think you need to mess with the rockers. Someone else may chime in.

[Superman]

I'm a fan of doing this all at once. Take stuff all the way off and replace with new bushings. Harbor freight sells a tool which can measure your spring plate angle. Bushings can't be that spendy, if you're looking to save $. Suspension is important.

[911T70]

I probably would have finished this job by now if I just stopped thinking about it and got off the internet!

Looks like the the rockers do need to come off to remove the access panel to allow the springplate assembly to be slipped off the torsion bar. Have a look at this video from fellow Pelican Kav - skip to 4:50 for the spring plate removal.

https://www.youtube.com/watch?v=7eFLfdl5uyU

[wrxnofx]

Originally Posted by 911T70

I probably would have finished this job by now if I just stopped thinking about it and got off the internet!

Looks like the the rockers do need to come off to remove the access panel to allow the springplate assembly to be slipped off the torsion bar. Have a look at this video from fellow Pelican Kav - skip to 4:50 for the spring plate removal.

https://www.youtube.com/watch?v=7eFLfdl5uyU

Hmmm, looks like you’re right

[gtc]

While you're at it, buy some adjustable spring plates so you can save some time during alignments. Factory style are fine and affordable.

[piscator]

Today was my first time disassembling the rear suspension on my 1979 Targa. I finished one side. Working slow, marking and measuring; it took me about 6 hours. It wasn't a bad job. Good to have air tools, though.

I bought Rennline's adjustable torsion plate that already has the bushings in place. I'll install that and start working on the trailing arm tomorrow.

I don't think you need to sweat this job. Just get in there and do it.

This video did a great job of walking me through the process.

https://www.youtube.com/watch?v=7eFLfdl5uyU

[911T70]

Originally Posted by gtc

While you're at it, buy some adjustable spring plates so you can save some time during alignments. Factory style are fine and affordable.

That must be good advice because others have suggested I do that!

Originally Posted by piscator

Today was my first time disassembling the rear suspension on my 1979 Targa. I finished one side. Working slow, marking and measuring; it took me about 6 hours. It wasn't a bad job. Good to have air tools, though.

I bought Rennline's adjustable torsion plate that already has the bushings in place. I'll install that and start working on the trailing arm tomorrow.

I don't think you need to sweat this job. Just get in there and do it.

This video did a great job of walking me through the process.

https://www.youtube.com/watch?v=7eFLfdl5uyU

Yes, I should just force myself to start this job, 'just get in there and do it', as you said! The Rennline adjustable plate is very tempting. The fact that the bushings are already in place (I assume glued in) means one doesn't need to decide whether to glue them or not, which is another great debate on this forum.

That video is the same one I posted above. I'm a big fan of Kav's - love how he documents and shares his work.

[juanbenae]

Originally Posted by gtc

While you're at it, buy some adjustable spring plates so you can save some time during alignments. Factory style are fine and affordable.

^^^ this. with an adjustable you can set the adjustment in the middle and have a good 1/2" height in either direction upon alignment time. you can at times find a set of the sway away adjustable spring plates with a WTB add in the classifieds and that's the best of both worlds because no special tools are required to adjust height after reassembled.

if originality is important to you than all bets are off. ive only indexed with adjustable units so having the leeway of getting it with in a few degrees takes a bunch of the frustration out of it id imagine.

[911T70]

Here's an update on my rear suspension. I decided to do this right and took everything apart. After reading countless threads about this, I was expecting problems and that's exactly what I got. The rocker trim came off no problem and I didn't find a rusty mess hidden under them, which was a huge relief. Starting with the passenger side, I measured and marked the position of the springplate, unbolted it from the trailing arm and proceeded to pull and pry on it. It was really stuck but after a lot of effort, it started coming out, along with the torsion bar, which is what I was hoping wouldn't happen. I went out and bought a puller, removed the end cap off the springplate and off it came.

Moving to the other side, the springplate came off much easier because this time the torsion bar stayed in the chassis. It stayed because it was really stuck - I wiggled, pounded and pulled on it for a long time until I came back to these forums and found an old post where I learned that the torsion bar tube was open all the way through so that the bar could be pushed out from the opposite side. I used a rebar to pound it out, which only took a few hits.

Next week I'll order Rennline adjustable springplates. Hopefully the installation will be easier than the dismantling!

Thanks for all the advice - much appreciated!

[Superman]

Nice car! The splines inside can be cleaned up if you have the right LONG brush strategy. The bars including splines can be greased. Corrosion protection and perhaps installation ease.

You are doing the right thing.

[911T70]

Originally Posted by Superman

Nice car! The splines inside can be cleaned up if you have the right LONG brush strategy. The bars including splines can be greased. Corrosion protection and perhaps installation ease.

You are doing the right thing.

Thanks! I will clean inside the torsion tube meticulously and spray with Fluid Film. I found rust flakes in there but it cleaned up quite well. The ends of the tube where the bushings sit are rusty so I will clean them up and seal them with a thin layer of POR15.

The torsion bars are in surprisingly good shape, probably because they were coated with a thick layer of grease. I will clean them up and re-apply grease.

Is there a particular type of grease that I should use?

[brighton911]

Good show Michel, nice not to have found any rust or other unwanted surprises. As far as coating the T bars, I have used a wheel bearing type grease with apparent success. I also spray the inside of the torsion tube with a Krown oil as a rust inhibitor. Part two should be fun, good luck.

Dave