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Any tips on shifting the subframe to correct uneven camber/caster?
So i've had uneven camber for a while but didn't really look into it until my driver's side went out of spec recently. I believe it was from the header install when they had to loosen the subframe. I believe they didn't torque it back to spec as i re-torqued the bolts to spec and the suspension feels tighter than it did. I tried to move the subframe but couldn't really figure a way to "pry" it over such as a good spot to get a good point of fulcrum to shift the subframe a little. I have a lifetime alignment with firestone but i went to a "frame and alignment" shop and they got a different reading on some of the aspects of the alignment. They said they couldn't adjust the subframe, but rather suggested i needed to replace all 4 struts and quoted me a ridiculous price. I declined to do that at this time. The firestone alignment was done on 8/12/17 and the "frame and alignment" shop that is more detailed was done on 08/15/17. I do have the Figs LCA bushing and have an offset for the caster as the caster was way off before i even installed them, not knowing it might have been a subframe issue until recently.
I'm wanting to get this fixed before i put on new tires as the front passenger inside edge is wearing down similar to the toe wear issue. I had to "rotate" that to the other side so now the unaffected tire that was on the driver's side is wearing out like crazy on the inside edge now pretty quickly on the front passenger side where that -1.6 camber i believe is wearing it out quickly.
I'm sorry but I cannot tell you how to make the adjustment. But I can confirm that it IS possible to do. My dealer did it for me on my 2008 back in 2009. The subframe was not aligned properly from the factory. The ISx50 cars have locating pins so they are always properly aligned up. The ISF does not have these and that is where the problem lies. Back in 2009 my dealer did not know the ISF did not have these pins and argued with me that they could not be moved. Good luck to you! Once it is correct, make sure to make the subframe and frame so it lines up easier next time.
I'm sorry but I cannot tell you how to make the adjustment. But I can confirm that it IS possible to do. My dealer did it for me on my 2008 back in 2009. The subframe was not aligned properly from the factory. The ISx50 cars have locating pins so they are always properly aligned up. The ISF does not have these and that is where the problem lies. Back in 2009 my dealer did not know the ISF did not have these pins and argued with me that they could not be moved. Good luck to you! Once it is correct, make sure to make the subframe and frame so it lines up easier next time.
I've never had an issue manipulating the subframe by hand into the poisition that I had marked with a paint pen at the beginning of a header installation. I would imagine that loosening all of the bolts plus the brackets at the back of the subframe (LCA #2 shares this bracket) and then cycling the steering wheel may help if you can't miniplute the frame by hand. Once you get to the point of torquing the bolts back down be sure to leave the 14mm bolts of the brackets I referenced as your last step.
I'm sorry but I cannot tell you how to make the adjustment. But I can confirm that it IS possible to do. My dealer did it for me on my 2008 back in 2009. The subframe was not aligned properly from the factory. The ISx50 cars have locating pins so they are always properly aligned up. The ISF does not have these and that is where the problem lies. Back in 2009 my dealer did not know the ISF did not have these pins and argued with me that they could not be moved. Good luck to you! Once it is correct, make sure to make the subframe and frame so it lines up easier next time.
Ummm. No. No pins on any 2IS. Whoever told you this was either mistaken or ignorant.
Your subframe is biased to the right hand side. You (or someone you can trust) needs to loosen all the subframe positioning bolts and hammer or lever the subframe to the left of the car (right and left as if you were sitting in the driver's seat). It will likely correct a multitude of alignment sins and may require you ditch the (very poor bandaid) caster "correction" rear lower control arm bushings.
Your subframe is biased to the right hand side. You (or someone you can trust) needs to loosen all the subframe positioning bolts and hammer or lever the subframe to the left of the car (right and left as if you were sitting in the driver's seat). It will likely correct a multitude of alignment sins and may require you ditch the (very poor bandaid) caster "correction" rear lower control arm bushings.
Are there any markings to make sure its perfect or just a visual ?
thx
Are there any markings to make sure its perfect or just a visual ?
thx
there are no markings. Just basically adjust, throw it on the rack to measure, and then adjust again if needed. There are old fashioned ways of measuring camber with a string and ruler and other tools without needing to throw it on the rack. You'll find stuff on google if you really want to find out how.
only explanation i have for the weird toe reading for the rear is that i changed the tire pressure to 34 psi as my Indy 500 tires run narrow and looking at the contact patch scrub of the tire, felt it wasn't getting the full width that i thought where it should be... I know tire pressure plays an important part in the alignment, but think about it, depending on how far away your shop is, the PSI will get higher as the tires heat up and may not heat up evenly, unless of course if you have nitrogen filled tires, then it won't change...I have a leaking strut in the rear passenger which i thought would've caused more negative camber as it should be sagging more but not sure why it's more on the rear driver's side instead...
I had a nasty subframe bolt that was loose and thought it was tight since i torqued it down but the LCA bracket that connects with LCA bushing was actually still loose... the bolt was shredded...
i was scared the frame threads were farked... so bought another bolt... had a little difficulty getting the threads to bite... after a couple of tries, the last try where i went super slow to tighten the bolt, it finally bit... torqued to spec and the LCA bracket was tight...
I had sikky headers installed... I would suggest to make sure all 4 subframe bolts are torqued to spec while the suspension is LOADED... most shops have your 2 post lifts where the suspension is UNLOADED and i doubt they will take the time to find out what the correct torque for each bolt is... Pretty sure having a loose subframe was the issue with my uneven camber... So after any install from a shop, double check all the bolts are torqued to spec properly...
someone should make subframe alignment dowels, they are fairly simple. 15+ Mustangs have a lot of slop in the rear IRS, subframe alignment and stiffening mods help out a lot. Modern production needs generous tolerances in the subframe holes so its quicker to manufacturer, but detrimental to precision and performance when the subframe is off due to these generous tolerances.
Dowels are simple, but they're difficult to position correctly unless you align the subframes - both front and rear so that the wheel base is equal on both sides, any side to side measurements are as equal as is realistic and they are both square to the chassis centerline; then match drill the subframe to the chassis and locate your dowel in the match drilled holes. It's a whole lot easier said than done. Thankfully, you only have to do it once.
This is the first step in setting up a sprint car - make sure the axles are square with each other and the frame.
Spoon Sports makes a product that aligns the subframe to the unibody and holds it there; it's called the rigid collar kit. It solves the subframe - bolt mismatch by centering the bolt and increasing the surface area on which lateral forces are transferred. Lots of different JDM guys run them and across the different marques and their forums, they seem to get really good reviews. Cheap as far as suspension products go.
I can see where that might limit subframe shifting, but I don't see how it ensures good alignment. The whole reason for the slop in the system is to allow the subframe to be mounted and positioned where it needs to be. The collars just freeze it in one spot. If your chassis isn't quite straight, that could cause as much pain as it solves.
08-17-17, 10:23 AM
Any tips on shifting the subframe to correct uneven camber/caster?
