Jim Clark

I've read all the threads I can on the control arm and ball joint issues for the aluminum arms I can find. I'm considering some custom fabrication of steel arms by lengthening to fit. Presently the aluminum arms on the car are 14" from the center (pivot point) of the front mount to center of the ball joint. Can anyone tell the the length of the steel arms with the ball joint attached that would bolt into the 87 944na cross member, as well as the caster block? Any and all help would be appreciated.

Thanks,

SidViscous

Er ah

Aren't the steel arms from the early cars (VW part) a direct replacement?

Heard of race cars swapping them out.

FormulaOne10

The steel arms are certianly shorter...that is why the wheel offset is different on the early cars.

Jim Clark

Right on both accounts. I'm going to fabricate a set of arms out of 4 early year stampings and have them seam welded as well as modified to take the newer sway bars. I'm looking for the longest length steel arms I can find.

Thanks for the responses

Travis - sflraver

You also have to take into account why porsche changed to aluminum. The steel arms had too much flex in them. I ran reinforced steel arms on my 86 for a while, modified to fit the sway bars, and you can tell the difference.
If you are going to make some longer ones than the stock (short) length may I suggest you do some major reinforcing. Longer arms means even more room to flex.

Jim Clark

I totaly agree......I was going to just rebuild the aluminum with the "Rennbay" or "SSI" kits but I'm a bit leary that they would still have the failure point at the ball joint. I Have not heard of a steel arm with a standard ball joint pulling out. Any thoughts.......Are you still running the steel arms? Do you track the car?

Travis - sflraver

I switched back to the aluminum arms when I started making the "rennbay" kits. I have not heard of one kit rebuilt arm being loose yet and I know a great deal of them get autox'ed every month.

The failure at the ball joint only comes from running the arms with worn bushings or lowering the car substantially. A worn internal bushing lets the ball hit the aluminum pocket during cornering. This room to move and impact the aluminum is what causes it to crack. The other way they break is by lowering the car. What happens there is that the ball reaches the end of it travel and the pin binds with the outer lip. This creates a great deal of leverage on the pocket and can cause the ball to break out of the top of the aluminum.

The ball joint bushings that come with the Rennbay kits are made from Nylon which is impregnated with a fine Teflon powder after manufacture. They new bushings have almost no wear and should last almost 2x as long as the OEM ones but still offer the same shock absorbtion properties you can only get from a plastic bushing.

Salesman mode off

If you are really worried about a ball joint coming loose you may want to look into some of the aftermarket options such as charlie arms and the such.

tifosiman

Hey Travis,

Isn't this really more of a problem with cars that have been lowered to the extreme that have somewhat soft springs and more travel, than a car that has been lowered the same amount and has high spring rates and less travel?

Manning

Franky I see the idea of peicing together a bunch of pressed steel A-arms into on set of longer arms as kind of, err, cobbled. If you are set on replacing the aluminum arms with steel, and you're doing the fabrication yourself, why not go all out and craft something out of tubular steel like Turbo Tim proposed a while back, or like Markus is offering (not his reinforced pressed steel arms mind you).

M758

Steel arms have advantages.

1) Cheap to aquire stock
2) cheap easly replaced ball joints.
3) bend, but not break

They have disadvantages

1) Flexible
2) Only for early offset suspension
3) could bend at the track

I guess you could make steel arms for late offset, but I am not sure how much you gain from it. I my case (84 944 spec) the cheapness, and bend, but not break is huge for me. I have not bent them from normal driving duty and have early offset suspension. So that leave flexing. Since the car is light 2450 lbs and we run a realtily narrow and not so sticky tire 225/50 R15 Toyo RA1 it does not seem to be too bad.

If you do decide to make you own arms plase think about load paths and whay sees load and what does not. I had some concern about they way a rod end was being loaded on Turbo Tim's arms. They might have been strong enough, but it was one of those brute force over good design concepts.

Jim Clark

Travis,
Your stating a lowered car is creating the issue only. So your suggestion, salesmanship aside, is rebuild the aluminum with the Rennbay Kits, and have a high spring rate to hold the angularity. At present I have adjustable sport Koni's with Hypercoil 400lb springs with adjustable perches and a stayrod with fully adjustable caster camber plates. Also have 30mm bars in the rear. Car sits 5" at rocker panel seams and handles like a dream.
I've looked at the kits and they look pretty good. Any deals out there?

Thanks,

Travis - sflraver

Jim and Tifo,

Something you guys may want to wait for, if you can stand it, is our geometry correction ball joint kit. It should be released in the next few weeks, I am just waiting for parts to get sent back from heat treat.

The geometry correction kits will come with everything the deluxe ball joint kits have with the addition of a system designed to stop the binding issue on lowered cars. They were designed with the 1.5" lowered cars in mind but will work with cars lowered up to 2". It is the perfect solution to the binding problem even if you dont have a high spring rate. The only comparable kit out there is well over $600 and it doesn't even rebuild the ball joints.

I am aiming for a price range of less than $200 for the complete kit but I will not know details until the last minute. As with all the Rennbay stuff there will be an initial 24 to 48 hour sale on them with awesome discounts so keep your eyes on the list.

Travis - sflraver

Yes, lowered cars and not checking for play in the ball joint. A worn bushing in the ball joint that causes play is just as bad over time as a binding issue. You should check them at least twice a year for a daily driver and before every event for the autox/DE crowd.

M758

Jim might need to check into SCCA rules... They may not allow a "Geometry correction kit". However they may allow "new" ball joints. See where I am going travis!

Just a little FYI...

Travis - sflraver

Do they alow "bump steer" kits? Believe me, this is as close to a standard ball joint as you can get. Most people would not even be able to tell the difference with it in stalled on the car if they looked from one to the other.