chaadster

All,

My rebuilt rack is showing unacceptable "on-center" play. I don't know if this is the right term for the play or dead space I feel in the steering wheel, so correct me if I'm wrong.

When straight ahead, or turned, the steering wheel wheel will move about an inch or so (measured on the outside rim of the steering wheel) before it exhibits any resistance and the wheels start to move.

Additionally, the car is tram-lining or darting all over the road when the surface is irregular.

I checked for play myself in the ball joints and for slop in the wheel bearings, but came away without any obvious problems, so I relented and took it to my service tech.

After checking it out, he decided that, in addition to some shaft wiggle on both ends of the rack, that the "over-center adjustment" might be incorrect, a situation that he described as the the gears inside the steering rack not being firmly interlocked. If it's too snug, apparently the wheel won't return to center because the rack is binding.

Furthermore, he's saying that he may be able to adjust the slop out by snugging up the over-center adjustment.

So, out of curiosity, has anyone had success with performing this adjustment? I'm trying to weigh whether or not I should try it, or should just go ahead and R&R the rack again. Besides being a messy PITA, there is no guarantee that a new rebuilt will be any better, so I'm leaning towards trying this.

Thoughts?

Mrmerlin

from your description i would say that the rack bushings may be suspect.
The best way to check them is with the wheels on the ground and a helper turning the steering wheel back and forth with the engine running while someone looks at the rack.
The pinion preload is adjusted with shims.
Also of concern is the steering shaft rubber coupler and the U joint connection either of these could also cause a loose feeling, my bet is on the bushings

Mrmerlin

BTW where did you get the rack??
I got one from 928 International ( rebuilt) and it looked new and went in with no problems and has been trouble free

porsche 928 RI

sounds like a woren knuckle to me

Lizard928

Inspect the rubber isolator in the steering shaft. This connects the column that the wheel attachs to to the rack and is in the engine bay.

Jim M.

Also inspect the four rubber mounting bushings. These are where the rack is mounted to the frame crossmember. If they are oil soaked they get spongy and will cause the rack to move before the rack starts turning the wheels.

chaadster

I'll confirm with the service tech, but he checked it out and concluded the slop was originating, largely, in the internal mechanicals of the rack. He said he did a visual inspection of the mounts, and so I assume he'd have checked to see if the rack was shifting in situ when activated, but I'll double check.

The rack was a new rebuilt from 928 Int'l that I installed, and has only been in about 3 weeks and probably fewer than 300 miles. I did speak with 928 International, and in addition to graciously allowing my tech to check over-center adjustment without voiding their guarantee, they also said they'd replace the rack, no problem, if I just wanted to go ahead and replace it. So let this not cause any concern with 928 Int'l; they're standing behind their product and showing me great customer service.

Once I get this problem sorted out, I'll post back on cause and cure.

Mrmerlin

Check the rack bushings with the wheels on the ground.
If its a 928 Intl rebuild i would be surprised if the rack was the problem based on the one I installed, it looked brand new. that said I guess the R/P could have play in it.
If it does i would return it and get another one

Chuck Schreiber

Chaadster,
Did you get this problem resolved??
If so, what cured it?

Jerry Feather

I suspect that after his service tech snugged up the over center adjustment, he repacked the muffler bearing and then cleaned the whole mess up with prop wash and he was good to go.

Landseer

Mine's all in the rack saddle area. Tramlining until I can buy the rack.

Chuck Schreiber

I put in Delrin bushings with Roger yesterday and it totally improved my vague steering feeling.
(What you described Chad, is what mine felt like)
I'll start a new thread here in a minute.