Bump-steer problem

[yetibone]

I've just installed '86 944 spindles, struts, and brakes on the front of our '71 1302. I got a pair of '75 lower control arms to work with the Porsche spindles. The sway bar is stock, as are the tie rod ends, and the rest of the steering geometry.
Since the tie rod ends on a 1302 mount from the top with the stud pointing downwards, and a Porsche 944 mounts it's tie rod ends from the bottom with the stud pointing up, this is setting me up for some dangerous bump-steer.

Anybody know what to do to correct this?


Yetibone

[yetibone]

Problem solved!!! :hehehe: I reworked the tie rod end holes on the spindles with a conical burr and a die grinder to allow for topside mounting. Still looks like it will have some bump-steer, but not as drastic as before.


Yetibone

[SprintStar]

Originally posted by yetibone
I've just installed '86 944 spindles, struts, and brakes on the front of our '71 1302. I got a pair of '75 lower control arms to work with the Porsche spindles. The sway bar is stock, as are the tie rod ends, and the rest of the steering geometry.
Since the tie rod ends on a 1302 mount from the top with the stud pointing downwards, and a Porsche 944 mounts it's tie rod ends from the bottom with the stud pointing up, this is setting me up for some dangerous bump-steer.

Anybody know what to do to correct this?


Yetibone

Is your car lowered or stock height?

[yetibone]

Currently, I think it is about 2 7/8" lower. I'm using some sport springs for a 1302 from Mid-America Direct that I cut two coils from, and reworked the perches so they would fit right. As far as I know, 1303, and 1302 springs will work in pre-87 Porsche 944 struts, as mine did. I will probably eventually go lower, but I need to build the engine and get it in the car first so I can see what rake the chassis will sit at with the car at full curb weight. I want to keep it as level as possible.

The only geometrical difference I can see is the steering arms on the spindles are straight on a Porsche (for the most part), and are curved up, and inward slightly on a 1302. Not sure of the differences between Porsche, and 1303 spindles.

I don't think that I can lower the center steering arm either because the frame head is in the way.

Oh well... we shall see how it drives as-is.:rolleyes:
Yeti

[SprintStar]

Originally posted by yetibone
Currently, I think it is about 2 7/8" lower. I'm using some sport springs for a 1302 from Mid-America Direct that I cut two coils from, and reworked the perches so they would fit right. As far as I know, 1303, and 1302 springs will work in pre-87 Porsche 944 struts, as mine did. I will probably eventually go lower, but I need to build the engine and get it in the car first so I can see what rake the chassis will sit at with the car at full curb weight. I want to keep it as level as possible.

The only geometrical difference I can see is the steering arms on the spindles are straight on a Porsche (for the most part), and are curved up, and inward slightly on a 1302. Not sure of the differences between Porsche, and 1303 spindles.

I don't think that I can lower the center steering arm either because the frame head is in the way.

Oh well... we shall see how it drives as-is.:rolleyes:
Yeti

I have a early '03, which means mine shares the same suspension as your '02. I tried the 944 springs that came with the brakes and manz... Too stiff! My friend gave me some lower springs and while the car looks ok, there is still some bump-steer as the steering tie-rods are not exactly parallel. Since the Porsche spindles allow the tie-rod ends to mount upside-down, I didn't bother to convert it... Hehe, that means I can go even lower in future! :D

[Superman]

Topline Parts (http://www.toplineparts.com) sells a "bump steer bushing kit" that allows you to remount the tie rod ends and help correct the angle. Give them a call as it's a new item.

[yetibone]

Thanks for the info, Superman. I'll give them a call!


Yetibone

[SprintStar]

Originally posted by Superman
Topline Parts (http://www.toplineparts.com) sells a "bump steer bushing kit" that allows you to remount the tie rod ends and help correct the angle. Give them a call as it's a new item.

How much does the kit cost? Do I have to remove the spindle from the car to press it in or can I do it on the car?

Thanks!

[Superman]

Not sure of the price, that's why I said give them a call, it's not too much though. The spindle has to be removed and drilled before the kit can installed.

[SprintStar]

Thanks!!!