Need help diagnosing what to refresh on suspension...

[sugarwood]

I would like to attempt a suspension refresh this year, and am ready to start diagnosing and scoping out the project. Right now, I barely know what all these parts are even called, never mind what they actually do. Most suspension refresh threads don't really talk about diagnosing what needs to be replaced and what can be left alone. Most seem to just replace everything "while you're in there"

Many suspension build threads seem to take 4 months to 2 years or more (because of "while you're in there)" I don't want to lose an entire driving season after storing the car all winter. (Doing a suspension project off-season is not viable in sub zero temperatures) I am not in any rush, but I really don't want this to become a "2 birthdays" project. So, I prefer to keep this project down below 80 hours (2 vacation weeks) Normally, I agree with the "while you're in there" mindset, but since I am not an expert mechanic, I would like to avoid over-complicating this project that leads to major roadblocks and massive delays. In this case, do you think maybe it's smart to avoid the stuff that is a real headache for a beginner (pressing bearing races?) If my bearings are fine, maybe it's just best to leave them alone, etc.

So, for my first time, maybe I am looking for the most bang for the buck AND the labor. Replace the most common wear items. Can all parts be diagnosed from visual inspection? Or from a physical test, like a shock bounce test? If a part can't be inspected unless you remove it, then I would rather just replace it. Can you guys help me make a list of parts to diagnose, so I can start building an order ?

Here is some info on my car. My service records indicate the suspension is mostly original. Just front shocks, turbo tie rods, and a few alignments (which are by now 15-20 years old anyway)

Car currently has 82,000 miles.

New front shocks
(1992 at 43,000 miles)

Alignment
(1995 at 53,000 miles)

Alignment
(1999 at 67,000 miles)

Turbo Tie Rod Kit
Replace R/Rear Sway Bar Console
Raise car 1 inch
Alignment
(2000 at 67,000 miles)

[sugarwood]

I tried the classic "shock bounce" test, and there is none of that repeated bouncing (yet my shocks are 20-30 years old)

[sugarwood]

The only other thing I've diagnosed so far is the spring plate bushing.

My round torsion bar caps are off center, right?


Mine seem to have a gap of a few mm's, but left side's gap is noticeably smaller than the right side's gap.

[tirwin]

Two schools of thought.

(1) If you just intend to drive it "normally" then identify the things that need maintenance and replace with suitable factory parts.

(2) If you want to do DE/AX then look at upgrades.

From personal experience, some of what takes the longest time is cleaning/prep and sending stuff out. I sent my rear Bilsteins to Chuck at ER to be re-valved. That's 3-4 days there and then the same coming back (I'm on the east coast and he's on the west) plus the time for him to do the work. Cleaning up the spring plates is no fun at all. Then getting them re-plated adds more time. If you had everything brand new and all you had to do was R&R, you could easily do the rear in a weekend (not including the alignment). I haven't done the front yet but I'm told it's even easier. It also depends on how anal you are.

Anyway, I don't think the actual time spent turning a wrench is that bad. If you end up having to make a couple of trips to the auto parts store that can kill your productivity. The first time you change your oil is really slow. After the 3rd time you're a pro. The problem with suspension stuff is you may not do it again for 10 years and the first time you're learning so it is what it is. Cleaning and prep... That takes me the longest.

In my case my rear struts were gone. T-bars were fine and the spring plate bushings had more life in them. I just decided to upgrade the t-bars and go ahead and do the bushings in one go. The bushings were original -- with over 30+ years I was operating under the premise that time, not use, was eventually going to be my enemy.

The spring plate bushings becoming more oval is an indication that they need to be replaced. At least that is my understanding.

[stlrj]

Originally Posted by sugarwood

The only other thing I've diagnosed so far is the spring plate bushing.

My round torsion bar caps are off center, right?


Mine seem to have a gap of a few mm's, but left side's gap is noticeably smaller than the right side's gap.

That's normal for all 911s and does not indicate a need to repair or refresh the entire suspension either.

Do you have the printout from the most recent alignment? That's likely the best place to start. Also, when the alignment was performed, the technician would have mentioned if anything needed attention as part of his inspection.


Cheers,

Joe
87 Carrera w/ over 200k and original suspension

[sugarwood]

Tirwin, I realistically might only ever do DE/AX a few times (not very convenient or local for me), and at a very casual "Sunday fun" level. It's quite firm already for basic street driving. So, I think keeping the suspension stock is best.

I think I will skip the replating, ad the car is low miles and pretty clean. (That rusted right spring plate sticks out like a sore thumb, and might have been replaced)

I will come back with some more questions in order to narrow down what to replace.

[Smoove1010]

Originally Posted by sugarwood

Tirwin, I realistically might only ever do DE/AX a few times (not very convenient or local for me), and at a very casual "Sunday fun" level. It's quite firm already for basic street driving. So, I think keeping the suspension stock is best.

I think I will skip the replating, ad the car is low miles and pretty clean. (That rusted right spring plate sticks out like a sore thumb, and might have been replaced)

I will come back with some more questions in order to narrow down what to replace.

You may find that the rust on the inside surface of that cover is worse than on the outside. I'm on the back-half of a rear suspension refresh on my 87 cab having done the front suspension last Spring. The front refresh included all the "while you're in there's" and the improvement in ride and handling was very noticeable. I stayed with new stock-performance Sachs shocks, ER a-arm bushings, turbo tie-rods, new ball joints and swaybar bushings. The front end feels much more responsive and lively.

My rear spring plate bushings, like yours, were shot. My spring plates are now cleaned, and I'm in the process of deciding whether to rattle-can or plate (if I can get a plater to return my call...) I'm really not interested in plating for the bling, it's more for the functionality and corrosion resistance on the plates and the hardware.

I also replaced the trailing arm bushings, which many on the forum opt out of. Once it's all back together I'm done for life suspension-wise.

The while-you're-in-there syndrome exists for good and valid reasons especially on cars with 25 to 30 year-old components, but we all need to act within constraints of time and budget. In my case, I really should have done the rear refresh two years ago when I did the rear brakes, CV joints and bearings, but I decided to defer the suspension refresh. I love working on the car so doing some double-work isn't so bad...

Good luck!
GK

[911 Rod]

This is a very slippery slope you are about to begin.

Being a low mileage car that you don't track, I would say shocks should be checked and unless parts are very worn, I'd leave them.

Take it for an alignment and they will tell you if parts are within spec.

It was a great car from the start and upgrades are not really necessary.

You can change the torsion bar covers with out re-indexing the t-bars if you are careful.

Or go nuts like the rest of us.

[Jesse16]

I'm about to embark on what I hope will be a 2 or 3 week activity to renew my front and rear suspension. (got about one month before driving anytime happens here). The car has significantly more miles than yours though at 240k. I'd guess that if its something you want to do, focus on rubber/resiliant parts. ie, bushings, shocks, maybe ball joints if the rubber boot isn't good. I'd guess all the metal parts, including the ball joints are good at only 82k.
There really aren't that many bolts and if the car is garaged mostly, then alot of wait time on plating can be avoided. Just clean a little and/or paint. You could tackle the front now and do the rear in the fall. What complicates is extreme cleaning, cosmetics, and fancy suspension mods.. I don't do any of those things.

[usedcat]

I replaced my bushings a few months ago when I put in the new turbo tie rods and the new bushings will center up your torsion bar in that spring plate opening...

I originally replaced them with a harder race bushing that sounded like the entire car was falling apart every time I hit a bump. Took those off and went back to the OEM rubber bushings and it was perfect...so get the OEM rubber ones (I got them from Elephant I believe) not the polycarbonate/hard plastic type...

[3literpwr]

I'm in the middle of mine... Started mid winter, but it was so cold that I didn't focus too much on it.

Hotbits adjustable dampers
23/31 T-Bars (wanted a bit softer, but found these used for less then one set new)
Powerflex bushing front and rear
New sway bar bushings
Turbo tie rod kit, rack boots, regrease etc.
Re-zinc or powder coating everything that cam off
Lower rear to match front
Rack spacers
Ball joints

[tirwin]

FWIW, I'm about to attempt to do my own zinc plating. I'll let you know how it turns out. I'll probably start a thread to share my experience.

[Jeff NJ]

I just finished my suspension refresh last week. My car is an 88 930 and as far as I can tell all suspension parts were original. I did the following:
Replaced all front and rear swaybar bushings. (easy and cheap)
Replaced front control bar bushings (cheap, but a little more difficult)
Replaced ball joints and tie rod ends. (easy and not too expensive)
Replaced rear control arm bushings (cheap, but royal PITA for me)
Replaced spring plate bushings (did this last year and it was a PITA)
Replaced rear sway bar drop links.
Replaced front strut caps.
Sent shocks/struts to Bilstein to rebuild. Cost just over $100 per and they look brand new. Took like 6 weeks though. See pic below.

This is pretty much all the rubber suspension parts in your car.

Yes, you can go upgrade with monoballs, polybronze bushings and higher end components, but if you are nearly all street, all you will get is a harsh ride with no benefit for the street, IMO. Every single part was sourced from our host and the only non Porsche parts were the control arm and the rear trailing arm bushings (elephant racing).
I still have my motor out, so I haven't tested it yet, but I expect a tighter, more precise suspension that handles like it did out of the factory without breaking the bank.

Except for waiting on the shocks and getting the parts in, everything else was done in about 2 weeks of me working at night and tackling one task at a time.

You can also refinish the control arms, spring plates, etc. if you have the time and patience. I don't.

My only suggestion would be that if you decide to upgrade to monoballs and the like, work with a specialist that knows how to put a suspension kit together for your car the way you drive it. All the parts must work together and if you just upgrade some components, you may well be disappointed with the result.

[sugarwood]

Originally Posted by Jeff NJ

Replaced all front and rear swaybar bushings. (easy and cheap)
Replaced front control bar bushings (cheap, but a little more difficult)
Replaced ball joints and tie rod ends. (easy and not too expensive)
Replaced rear control arm bushings (cheap, but royal PITA for me)
Replaced spring plate bushings (did this last year and it was a PITA)
Replaced rear sway bar drop links.
Replaced front strut caps.
Sent shocks/struts to Bilstein to rebuild. Cost just over $100 per and they look brand new. Took like 6 weeks though. See pic below.

This is pretty much all the rubber suspension parts in your car.

I don't really know where to begin.
So, thanks for this list, that gives me a starting off point to think about what to do.

It sounds like the rear is a lot worse than the front.
Maybe it's smart to break this project up into 2 stages, front then rear.

I am going to jack up the car and try to jiggle the wheels.
If the wheel doesn't move, that means ball joints and bearings are fine, right?

I will go try to test the shocks today also.
Put my knee on the bumper and try to bounce it?

[tirwin]

Just a suggestion on where/how to start.

In your shoes, I might do the front and rear separately.

On the rear I would consider replacing the the spring plate bushings. Look at the ER rubber. That seems to be a popular choice. Clean up the spring plate cover. If your rear shocks are tired (mine were), you can get them revalved. Chuck at ER offers this as a service and he can digressively revalved them to match your t-bars. Take a look at your sway bar drop links bushings and replace if necessary. Those things are reasonable and quite do-able. Cleaning up the spring plates is not a fun job but it is not the worst job either.

After you do that then tackle the front. Look at control arm bushings, strut mounts, tie rods and ball joints. Again, look into re-valving your struts. Depending on your ride height preference you might want to look into something to address bump steer.

[sugarwood]

To summarize the parts in the front suspension:

1) Sway/stabilizer bar bushings. 4 total. (91134379203) $6/ea.
What happens when these bushings are totally shot?

2) Control arm bushings (2 per arm, 4 total)
In another thread, someone suggested (91434142200 @ $15/ea) but these seem to be for early 911's.
I'll need to explore alternatives to $225 ER bushings, which seems a bit high.
Control arm bushings seem like the hardest part of the front suspension job.
If I remove the control arm, I can probably get a local mechanic shop to remove and press the new bushings, correct?

3) Front ball joint. 2 total. (91134104901) $70/ea.
Besides a torn boot, is there a simple way to test them while still on the car?

4) Tie rod ends (Turbo 91134732200) $30/ea
Since my car got the turbo tie rod upgrade (15 years ago, 15k miles ago), my tie rod ends should be fine, right?

5) Front strut mounts. What is this? Is there a rubber stopper or something at the top bolt? Anyone know the part number?
Is this part? 91134101800 Do you replace the entire metal mount /rubber bushing combo, or do you just replace the rubber bushing?

6) Front strut caps. Anyone know the part number?

[Jase77]

At the moment I cannot offer you any advice other than split it into two seperate projects, front and rear. Take what you learn on the front and apply it to the rear etc.

I will be keeping an eye on your progress though as I am planning on doing my suspension overall later this year when the winter and cash comes back my way.

I have performed similar replacements/upgrades to other cars that I used to own and although the new 'upgrades' looked cool and had bragging rights in the pub they nearly always made street driving more uncomfortable for me.

My car is from 77 and has 147k on it and I have noticed that most of the bushings need replacing. I changed the damper inserts last year and just this made a huge difference. At the moment my cars sways a little at higher speeds, so I definitely to to put this on the list.

I have already decided to replace with factory standard bushings etc but the only upgrade will be turbo tie rods.

Good luck and please keep us up to date.

[tirwin]

On the front you may want to also look at the rubber where the top of the strut comes through the top of the wheel well.

I think the ER control arm rubber bushings kit comes with a tool so you can press on the new bushings. (Edit: after looking into this I think you have to buy the tool separately). Chuck has a couple of videos posted on his website or YouTube on how to do it. Basically you just heat the old rubber with MAP gas and pry it off and use a press to install the new ones. You can do it yourself, no need to pay someone else.

Edit: Here is the link to one of the videos.

http://youtu.be/MX5jgsMiuFw

PS - I have no affiliation with ER other than being a satisfied customer.

[tirwin]

As I understand it, the normal turbo tie rod kit comes with new tie rod ends.

[TheSt|G]

I'm about to refresh mine as well, and my list is as follows(currently waiting on the last of the OE hardware to arrive):

Front:
Porsche OE Front strut top mounts
Porsche OE Front strut top mount hardware
Koni Yellow front struts
Lemforder Ball joints
Porsche OE Ball joint hardware
Porsche OE Ball joint specialty socket
Porsche OE Front sway bar bushings
Porsche OE Front sway bar hardware
Elephant Racing Front A-Arm bushings
Elephant Racing Front A-Arm bushing tools

Rear:
Porsche OE Rear shock mounts
Porsche OE Rear shock mount hardware
Koni Yellow rear struts
Elephant Racing Rear spring plate bushings
Elephant Racing Rear spring plate hardware
Porsche OE Rear sway bar bushings
Lemforder Rear sway bar drop links
Porsche OE Rear sway bar hardware
Elephant Racing Rear trailing arm bushings

Powder coating of all suspension arms and such.


That should pretty well cover it, but I will probably be back in there again to do a steering rack rebuild and turbo tie rods. Undecided if I want to Quaife the rack. My advice would be to assemble all of the parts first, organize them by section, and then start the project. Given the delays in getting factory parts these days, I wouldn't start without the complete kit. Ideally, this will take my roughly a week including the turn around on the powder coating.