Dear Welder Series…
I recently came across your MII installation instructions, and I am really impressed. A great tool for a builder!
I have few questions; (The more I study it the more I have questions!)
1. Am I correct in saying that your instructions will only establish the desired ride height, if on assembly, the lower control arm is positioned as you assumed it would be when you wrote the instructions? What position does the lower control arm need to be in? (The old method of placing a straight edge under the cross member and the control arm resting on it?)
2. I see on your web site you answer questions about maximum outside frame width to avoid frame notching to clear coil springs. You point out that the maximum varies depending on ride height… understood.
I am looking at installation of an MII in a 1934 Chrysler which will need the frame narrowed considerably because it “flares” out to 36 inches- outside width (the existing frame runs to the outside of the existing coils spring.) I am looking at narrowing the “flare” to 29-1/2” (outside) to match the existing frame dimension on the firewall side of the “flare”. I would like to narrow the frame sufficiently to avoid any frame notching for spring clearance. I am not building the car to be super low… a car that will allow me to roll a floor jack under the cross member.
Will 29-1/2” be a fairly safe number to avoid frame notching for MII coil springs on a 56”or 58” system?
3. If the frame dimensions and the cross member dimensions are such that the cross member gets welded to the underside of the frame and the OUTSIDE of the frame, doesn’t the section of the cross member outside the frame interfere with the springs?
4. I see you recommend longer tie rod ends for the 58” system. Does this not create bump steer because it changes the relationship of the hinge points of the control arms relative to the tie rod hinge point?
5. The Internet tells me that the tubular lower A arms are failing where they extend to the rear of the cross member. Do you have experience with this issue?
Thanks in advance for your help.
Keith, what a great list of questions.
1. At ride height, the Mustang II suspension is designed to have the stock spindle 3-1/2″ higher than the lower arm pivot bolt center. This is the dimension used in our crossmember and tower design. Dropped spindles would be 5-1/2″ higher than the pivot bolt center and this is referenced in the instructions.
2. 29-1/2″ will be fine for either the 56″ or 58″ kits.
3. The 56″ crossmember is 30″ outside the “wings”. The spring almost always clears the crossmember wings, even when they are on the outside of the frame. We used to taper the outer edge of the wings up and in towards the frame more for cosmetics than clearance. Although the 58″ crossmember is wider than the 56″ (32″ vs 30″), the upper towers mount 2″ farther apart when the 58″ crossmember is used so the clearance stays the same.
4. The geometry does change, but in the “real world” the bump steer if not noticeable. I try very hard to steer clear of discussions about this because the difference MIGHT be noticed by Tony Stewart, but not by me. Rack extensions are the correct way to go.
5. I have read about this on the internet but have no personal or business experience with this issue. I do believe the people who say they had a problem, did have the problem. I have tubular lowers on our ’40 Ford with about 50,000 miles on them over all types of roads.
Thanks very much for your questions. I hope we can help with your project.