The Rodding Roundtable
Site Content => Tech Archive => Topic started by: Pep on March 12, 2007, 06:48:29 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.
(http://pepsgarage.com/2005_1106Image0001.JPG)
(http://pepsgarage.com/2005_1106Image0002.JPG)
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.
(http://pepsgarage.com/2005_1106Image0003.JPG)
(http://pepsgarage.com/2005_1106Image0004.JPG)
Nice job. I think I may have a piece of wire, but I don't know if I can afford a box. :lol: Looks like the maker of your plumb bob copied the maker of mine.
Yeah Frank....no excuses for costly items..all up I'd say 50 cents :lol: