Sorting out instability
#1
Rennlist Member
Thread Starter
Sorting out instability
Hi,
when I jack up one front wheel, I can rock it side/side, a lot. This causes instability in the car.
Both ball ends of the tie rods are good.
At the inner tie rod ball ends, I see a up/down movement. It appears that the "piece" that comes from the internals of the rack, and connects to the tie rod, is not sleeved properly to the rack housing.
It's hard for me to explain this for me, limeted by school English as I am, so I've attached a photo.
There is no horizontal movement, all the looseness at the road wheel comes from the vertical movement at the inner end of the tie rod. I guess there ought to be some sort of bushing at the end og the rack, that would prevent this.
photo
when I jack up one front wheel, I can rock it side/side, a lot. This causes instability in the car.
Both ball ends of the tie rods are good.
At the inner tie rod ball ends, I see a up/down movement. It appears that the "piece" that comes from the internals of the rack, and connects to the tie rod, is not sleeved properly to the rack housing.
It's hard for me to explain this for me, limeted by school English as I am, so I've attached a photo.
There is no horizontal movement, all the looseness at the road wheel comes from the vertical movement at the inner end of the tie rod. I guess there ought to be some sort of bushing at the end og the rack, that would prevent this.
photo
#5
Rennlist Member
Pull the boots back from the rack to expose the inner tie rod end. Manipulate the tie rod shaft in all directions - there must be no free play in the inner joint. If there is, replacement is necessary.
Push up/down on the steering rack: if there is noticable vertical movement, either the 4 mounting bolts are loose or the bushings are worn ( as Dave mentioned).
Push up/down on the steering rack: if there is noticable vertical movement, either the 4 mounting bolts are loose or the bushings are worn ( as Dave mentioned).
#6
Rennlist Member
Thread Starter
Garht S: I have basically done what you suggest, and the answer is that the play takes place inside the rack, unfortunately. It may turn out that the recent rebuild was focused on hydraulics only, since the 4 rack mounting bushings vere toast too.
#7
Rennlist Member
Originally Posted by gruffalo
Garht S: I have basically done what you suggest, and the answer is that the play takes place inside the rack, unfortunately. It may turn out that the recent rebuild was focused on hydraulics only, since the 4 rack mounting bushings vere toast too.
However, even if this were the case, it is difficult to see adequate movement between the rack and housing to allow the degree of horizontal movement that you have at the wheel(s). The rack rod is ~ 80cm and has ~ 4 cm of solid inner ball joint tightly screwed into each end. The maximum deflection would be 2 mm over half this length (44 cm) - the hypotenuse of this triangle equates to a fraction of a mm change in effective length: not enough to permit significant steering angle changes.
I'm guessing that the large movement is due to the four mounting bushings: if your rack assembly is not leaking , try replacing the bushings. If I had to do that now, it would be attractive to lathe cut them from polyurethane rod stock. The diameter is ~25mm, and OEM height is 25mm - but 20mm would bring the rack closer to the crossmember, and it would be firm!