#1: Bump steer checker Author: Pep, Location: Sydney, AustraliaPosted: Mon, Mar 12 2007, 5:48 pm This is what I made when I was building the 37. I have taken this from my web site. I have now driven the rod for a few miles and can confirm it works well. You could have the rack in a slotted mount and raise and lower until you achieve the correct position.
This is my primitive bump steer checker. I used a stiff wire rod cut to 14" and attached it to the stub with the castellated bearing nuts. I chose 14" as it would be about the radius of a wheel. I then used my primitive plum bob to mark a vertical line on an old cardboard box. I centred the steering rack then attached the tie rod ball joint into the steering arm. I then adjusted the ball joint until the stub axel was close to straight ahead. I also leved the chassis. Once I was happy with the positioning, I then jacked the lower control arm up to full height. I then moved the box in front of the pointer. I then lowered the jack slowly and observed the deviation. I expected the movement to be in a shallow arc, after all, the arm is pivoting around a mounting bolt. What I hoped to see is at the lowest point of travel, the pointer should come back to the marked line, and to my delight, it was spot on.
This is the moment of truth. With the suspension at its lowest point, it is still pointing directly at the line This is the extreme as I have not fitted the bumps stops, so the travel is more than normal. Still, I believe a slight toe in at the highest point is acceptable. The last pic is to confirm the line is still vertical. This may be wrong, and I would like to find out if there is logic in my thinking. As it stands, I feel confident that the rack is in the optimum position and I should not suffer from bump steer.
#2: Author: enjenjo, Location: Swanton, OhioPosted: Mon, Mar 12 2007, 6:37 pm Nice job. I think I may have a piece of wire, but I don't know if I can afford a box. Looks like the maker of your plumb bob copied the maker of mine.
#3: Author: Pep, Location: Sydney, AustraliaPosted: Mon, Mar 12 2007, 6:56 pm Yeah Frank....no excuses for costly items..all up I'd say 50 cents