Tlaloc75

As a winter project I want to replace all the bushings and ball joints in my rear suspension.

Question for the experts - would you do all the bushings in sport hardness or would you do just the trailing bushings ala RS suspension? In other words, is there a reason Porsche left the forward bushings softer, or am I better off going sport hardness everywhere?

Bill Verburg

In a 993 the rear A-arm leading leg has a sealed mono-ball, can't get stiffer than that. They do get loosey goosey w/ age.

Buy new RS rear A-arms, this is the best way to get new outer ball joint new leading mono-ball joint and new stiffer rubber bush for the trailing leg. Only the KT arm needs to have a stiffer bush, best to buy 2x RS KT arms to accomplish that, again you get new outer ball joints and new stiffer rubber inners.

The other arms are the same on RS and normal, so replace any that are worn, the one that goes first is the toe arms, for track use mono-***** on these for street use you can fit stiffer rubber here too, though it's not absolutely necessary stiffer here does add precision.

complementary front will be stiffer rubber on at least the trailing A-arm leg, both leading and trailing is a bit more precise

Tlaloc75

Thanks for the quick response Bill. Your advice on the rear suspension makes sense. Sounds like you do not recommend getting sport bushings for the other arms (e.g. Toe arm), right?

For the front, can you explain what you mean? I did sport on both leading and trailing control arm legs for front suspension. Are you suggesting that's less precise and I should have done sport on the trailing arm only?

I really appreciate your help, you are awesome.

Knight

I'd be curious if you can even get the RS k-arms, for the longest time they were on back order with no timeline when I was shopping.

Do exactly as Bill stated. I went with Tarrett for the rear toe arms.

Tlaloc75

If I can't get the RS k-arms maybe I can get elephant to sell me a stock arm with sport bushing installed. Should be pretty close to the same thing, right?

Why did you go with solid rear toe arms?

Knight

Tarrett was priced well, good reviews from locals using them and it offered extra adjustability when doing the alignment.

Tlaloc75

I've read up on them now, they sound great. I'll add to my list.

Do you know if TRW is ok to use for the stock links or should I stick with OEM?

Knight

I've kept everything OEM except for the Tarett toe arm. I'd think that is best route in addition to the RS A-arm and K-arm. If it's not being used for track then closer to OEM is best as it's more than adequate for the street and you get longevity too.

Tlaloc75

Makes sense, thanks.

Bill Verburg

On the front A-arms, leading/trailing
loosest is stock, soft/soft
RS tightens, soft/sport
Elephant tightens more sport/sport

RS also used a stiffer bush on the tie rods, you can use the RS inner(sport rubber) w/ stock or RS outer, RSR(mono-ball) is the most precise. Currently the RS is available oe and the RSR from Tarret

A lowered car(RS and under) will want RS wheel carriers and outer tierods in front and solid sidemounts in back, stock or above RS height will want to skip this.

For street use the stock rear toe links are fine, you can tighten up the rear w/ sport rubber here or nail it down w/ the Taret or Rennline toe links. Some find this last to be too tight on the street, It transmits much more feel to the driver, some find this disconcerting or uncomfortable.

Any of the links w/ mono-***** will have a shorter life than rubber

Tlaloc75

Great explanation, thank you. If I went with RS stiffness on A arm and on KT, then did sport bushing on toe link, that leaves just the camber arm in stock hardness. Is there any value in doing camber arm with the sport hardness bushing as well?

For the front I've already done sport hardness on both control arm bushings, RSR inner tie rod and stock outer. I'm at RoW M030 height.

Bill Verburg

On a stock RS the camber arm is the same on both base and RS models.

when I had RS suspension I used new stock camber arms, new stock RS kt arms new stock RS A-arms, new stock toe arms at first, then because it was 99% track changed the toe arms to Tarret. Sport rubber on both legs up front, RS wheel carriers, RSR mon0-ball tie rods, solid rear side mounts, very low car. Handling/ride for mostly street is probably better w/ the stock rear toe arms handling for track use is infinitely better w/ the mono-ball toe links.

It sounds like your use is mostly street, for that purpose either stock or sport rubber on the rear toe links and stock camber arm, w/ the RS kt & A-arms.

Tlaloc75

Thanks Bill. Yes, I understood from reading your previous comments in other threads that RS uses same bushings as stock on toe and camber arms. From your statements earlier in the thread it sounds like its worthwhile to use Elephant sport bushings on the toe arm, so I was wondering if its worth using sport bushings on the camber arm as well. Sounds like you are recommending leaving the camber arm bushings at stock hardness?

Yes this is a spirited street use car.

pp000830

Is there a test procedure to test arm bushing softness before going to the expense nd trouble of replacing them all?

Tlaloc75

From what I've gathered, this is more art than science. If you are experienced and have seen lots of cars you can pry on the bushing and tell that it is deflecting more than is 'normal'. If you don't have that experience I think you have to make assumptions based on age and usage and choose when to refresh based on that.

Front suspension control arms are more obvious, you can look at the leading bushing (which is quite large) and see if its cracked and sloppy. All the other suspension bushings are quite a bit smaller and harder to inspect.