I was hoping there would be some great ideas out there on my problem. I have installed Scott Danforth's cross member and have a GM metric front suspension, with JEGS 2" lowered spindles. I finally got around to welding up the F-body rack and pinion only to discover that when placed on the cross member, the tie rods are not low enough to make it to the underside of the spindle. Even if I lowered the rack mounting point, there still would not be enough travel to make it driveable. My thought is to drill out the spindle so that the tie rod can be mounted from the top. Any other ideas out there?
Hi, not that clear,are the steering arms in front? if so you will have issues when cornering (Ackermans angle stuff) If its ok,you will need to make threated extentions. JW
more pictures. Not sure what you are asking with the steering arm question. The arm where the tie rod end mounts to the spindle is ahead of the rack, if that's what you are asking
What about heating up the spindle to RED HOT and bending it to where you need it to go? Might want to ask some of the experts on here about that but just a suggestion. Good luck with it.....
The first and second pic in the latest pics, looks like that side tie rod can fit... what am I missing? anyways, an IFS needs to have the original designed tierod pivot points at the same place, to prevent bump steer. If those pivots are too low, too high, or out too far or in too far, as you go over a bump, it will cause that wheel to steer by itself. Worse yet, it could change what is called "toe out at turns"....sort of another name for ackerman angle. So, even if an IFS was originally a coventional box with 2 short tierods and a centerlink, a rack system of the exact same specs of where the joints are, will work fine. But if a rack is not matching, it won't work correctly. Or if it is not mounted with the joints in the correct planes, it won't work right. If you don't understand what I mean about tierod pivot points; those are where it pivots at the spindle arm end, as well as the inboard end which can be at a rack or at the inner joint on a centerlink style.
Those arms being in front and inboard like that will give very bad toe in when cornering (you need toe out on curves) and this will cause one tire to break traction (NOT GOOD!!!). You need to find out about Ackermans Principal and understand it.The steering arm will need to bent OUT so the ball joint centre, the king pin centre and the centre of the rear axle align in a tangent. Hope this gives an insight into your problem. Cheers, JW
The biggest thing I see right off is that the rack is about 6" too wide to work with wha you are doing. Is this somebody's kit? If you are running an A - G bodied front suspension, why the rack and not the steering box and linkage designed for the front end? Where a rack is placed makes all the difference in the world. Where your inner pivots line up should fall within an imaginary line between the upper and lower inner pivots. right now where your at those intersections seem to be about three inches per side outside that line. We aren't going to get into the Ackerman problems that others have pointed out so far, nor the unsupported or gusseted upper control arm "hat" welded to the side of the frame rail. Sorry, I promise I'm not just a troll trying to piss on your parade, I have been involved in designing aftermarket suspension systems for many years now, but you really need to drop back and look at what you are putting together here from a safety standpoint.
When I see those upper arm digging into the frame rails, I see a poorly engineered kit. The crazy angle of the lower arms tell me they were never engineered to work with a rack and pinion steering.
I'm starting to wonder the same thing. The notch in the frame rail? for an upper control arm? at what point does this become unsafe. Your frame is now structurally unsound because even if boxed has a flex point on the top of the frame rail which could at worst snap causing some serious damage. I'm not far from Park Ridge and often drive through, i would attempt to help if i could, the point is we would like to find a solution for your problem not bash this design issue. I'm hoping scott will chime in but i'm not hopeful.
I agree with the others concerning the safty issues etc and am not thinking of the rack as it just cant work with your suspention setup,however due to the angle of the steering arms the tie rod setup for those hubs must have been behind and not in front.Either the whole unit is back to front or the hubs have been changed over.There are so many systems that need to come together in order for your front end to work as a unit. JW
I dont believe even the "manufacturer/designer" has even had a working setup. Looks like a boat with a hole in the hull for the mast to go through.
Something with the way you have the rack mounted just flat doesn't look right. Is that done the the way Scott suggested? Have you contacted him to ask what he suggests? Last I read there were none of those crossmembers being driven on the road yet and unless I just flat missed it he never tried one on an AD truck to see how it drove. You are in essence his product development department. It looks to me that the rack is to high an too close to the crossmember. The centerline of the rack needs to be on the same centerline through the eyes in the steering arms with the wheels straight ahead. Unless it is an optical illusion your rack is at least two inches behind that centerline and maybe more. The fix is most likely cutting out the engine mount portion of the original crossmember and moving the rack forward to get it in line with the steering arm ends and dropping it down some so that The angle of the tie rod s matches the angle of the lower control arm. In theory and practice the tie rod should pivot at the same spot the lower control arm pivots to avoid bump steer. Look under any production vehicle with an independent front end and that is what you will see. The pivot point of the tie rods being the same as the pivot point of the lower control arm and the tie rods running parallel to the lower control arms. After taking the top middle photo in post 3 and blowing it up on my computer it appears that the rack may be the right height but is just too far back behind the eyes in the steering arms. That truck still lacks about three or four hundred pounds of it's final weight on the front end that will settle the suspension a bit.
Not sure about the whole configuration, but a couple of points I see in the pics. The angle of the input shaft on the R&P appears to be straight up, this could cause a problem with the steering shaft. The brackets holding the R&P appear to be 1/8" thick, I would use nothing less than 1/4" material.
NO. That is how GM gets their Ackerman, the center link is behind the outer tierod ends. They have built millions of cars this way. Moving the rack forward, or back, changes the degree of Ackerman.
Over a number of years I aligned the front ends on a lot of GM front steer cars and I don't remember one being set up with that much angle from the center link to the steering arm eye. The tie rods were pretty much in a straight line with each other pivoting on the center link at the same spot as the lower control arms. This example is obviously a custom suspension but it shows what I was saying above. The rack and it's tie rod ends work in the same manner that a solid tie rod would on an I beam with their own flexibility built in.
Aside from the rack being too long, creating bump steer, most OEM racks are designed for short steering arms. Using them with long steering arms, slows the steering ratio way down, and kills your turning radius.
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