Need help diagnosing frustrating steering/suspension issue
 

Hey everyone.

So I posted here a while back about some strange vibration and sloppy steering from my 02 986S (85k miles, bought it at 78k). Anyway, the consensus was get to an alignment shop and look at tie rods. I ended up bringing to a Porsche specialist here in the Bay Area. A week and probably too much money later he did a full diagnostic of the car down to every single last detail... I really just wanted to find out what was wrong with my suspension, but it is nice to kind of have a laundry list of things to address slowly.

What he noted (pertaining to suspension) was:
Tie rods (inner and outer) were shot
Rear trailing arms shot
Shocks shot (only passenger right is leaking, but he thinks they're all pretty beat - passenger front is missing bump stop)
Strut mounts are bad

So, I decided to tackle the work myself because I was sick of paying someone to not fix the problem - I had brought into my usual Porsche place, they said they couldn't feel anything and sent me on my way. I took it to another place, they recommended changing the tires and balancing them - which I did with Continental ExtremeContacts (PSI is 29 front, 36 rear) - didn't solve the problem, and then this last guy.

I bought OEM inner and outer tie rods and front swaybar endlinks and changed those out over the weekend. Yesterday, I took the car to a highly recommended alignment shop and got it all aligned.

The steering feels a bit tighter than before, but I can still feel vagueness or sloppiness in it. It's kind of hard to explain, but it feels like I turn the wheel off of center, and then a half second later the car responds. It kind of feels like its rolling over on itself / swaying, but if I take a turn sharply it feels fine, grips and makes the turn, it just doesn't feel stable/planted in a straight line.

I also still feel this frustrating and annoying vibration/rapid clunk through my steering wheel/front wheels.

I'm really not sure where to go from here. I have considered the engine mount being bad, but I don't know if that would really cause the problem. I know the struts/strut mounts are worn, but would it really cause a problem like this? Any support would be greatly greatly appreciated. Also, if there's anyone in the Bay Area with some experience who would be willing to go on a short drive with me and the car to see if they can feel it as well or shed more light on what it might be, I would be 100% down and willing to compensate with beer/food/money or whatever.

Thank you guys again.

Those mechanical items listed if the are shot/loose will all contribute to the issue. The tie rod ends helped with only 1 part of the system. The next to replace are the strut mounts, and then work your way thru the full list. The rear trailing arms are also hurting the front end feel. The car looks to just have a worn out suspension and it needs a rebuild and then an alignment. As you work away at the list, things will continue to improve.

definitely some additional parts in the front end to replace, from strut mounts, to ball joints to potentially even wheel bearings.

Also, I think 29 might be a bit low and is causing the steering response to be a bit mushy

No reputable shop would consider aligning a car with shot trailing arms. You start the alignment in the rear with aligning the rear to the centerline of the car, if there is any sloppiness in the bushings or trailing arms you can not get an accurate reading and moving to the front is pointless.

If you are going to replace those items, you may as well replace the coffin (lower control) arms as well, as those can contribute to the feeling you are describing.

Did you say you did or did not replace the control arms?
That's what got rid of the thumping noise over bumps for me.....

Ok - I know my rear passenger strut is leaking, so I was going to replace the shocks anyway. I'm pretty confident in being able to do the fronts myself - the rears look a little daunting. Also, do you if a garage would compress and move the springs from the old struts to the new ones if I paid them? That's what I'm most scared about.

The door jamb has 29 F / 36 R, but I could play around with the pressure.

I have not replaced the control arms - the guy I brought it to said the rear trailing arms were shot but didn't mention anything about the fronts. The noise doesn't really happen over bumps - it's really just driving straight at any speed over 30 and its like a rapid jitter / vibration more than a clunk I guess.

I should be able to do front and rear track arms without re-doing the alignment, right?

There's a huge difference between the Porsche part ($400 each!!) and OEM from URO / OCAP / Beck Arnley (about $90 each). Do you have any experience with the OEM parts?

I used non-Porsche parts, I can't remember exactly what brand. I believe they are actually the supplier for Porsche, so they are the same parts that you would get from Porsche.

Meyle coffin arms are popular. Avoid URO.

Track arms should be TRW

These ones? https://www.****************************.com/products/porsche-control-arm-rear-lower-911-boxster-cayman-4160500000?ads_cmpid=352578679&ads_adid=2297821783 9&ads_matchtype=&ads_network=g&ads_creative=852288 16639&utm_term=&ads_targetid=pla-66292848145&utm_campaign=&utm_source=adwords&utm_m edium=ppc&ttv=2&gclid=CjwKCAiA1uHSBRBUEiwAkBCtzUFu IafDl1b2uSOiuOyzfdRwumvKCrI5Y49-E04l4toaqqr4uksJoxoCDRAQAvD_BwE