Front Subframe (K-Member) Centering

[aleccolin]

My car aligns fine, drives fine, but there is a little more lateral fender clearance on the right than the left - as if the front subframe is not perfectly centered, but shifted slightly to the left. The difference is probably 3/16", but enough to affect tire clearance and noticeable if you know what to look for. The rear is perfectly centered now after installing Steeda's kit, but there's nothing similar available for the front.

Has anybody else experienced this issue and tried loosening the front subframe bolts to shift it over a bit?

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[BMR Tech]

This is a great topic, and one of the reasons I am not so quick to suggest everyone "center" their rear IRS subframe. When people ask me (daily), "do I need IRS centering sleeves" I usually reply with, are you going to center the front of the car too?

There can be a difference between centering the subframe assemblies to the chassis and centering the subframe assemblies to the body panels.

There can also be a difference (slight) in the centering of the front mounts that hold the front subframe, versus the mounts that hold the rear subframe.

Ford put variance in their part assemblies to ensure the cars can be assembled straight and drive straight down the road.

For those who want to center both the front and the rear subframes to the body panels/fenders - you hang a plumb bob from fenders, loosen all the bolts and measure to the plum bobs.

 

[aleccolin]

 

[Albertcado]

Did you ever re-align your front subframe?

 

[aleccolin]

Did you ever re-align your front subframe?

Yes, when I got my car re-aligned again after this the race shop that did it centered up the front subframe. I didn't even ask them to, but I checked my measurements before and after and it's dead nuts in the middle now. I continue to go to this place because they're thorough, and don't shy away from aftermarket, adjustable suspension setups.

I've got camber plates and oddly now that my subframe alignment and fender gap is perfect and the camber is even side to side, the strut nut is almost touching the ID of the hole in the tower on one side, and has about a 5mm gap on the other side. I'm going to ignore that because everything else is bueno.

It does make me think that since there's no factory camber adjustment (not really) that they may use the centering of the subframe to even up the camber left-to-right, to make up for any variances in the body construction. A small movement could make a big difference, since it's inversely affecting both sides at once.

I also have roll center correction control arms which reduces the scrub radius and adds positive camber, so with camber set back to -2 deg the lateral fender gap at the top is enough to get my fingers in to the knuckles, whereas before it was just shy of rubbing. I could really use another 10mm or so of negative offset, but I don't want to put bigger spacers on the front so I'll just wait until I order some wheels. Still better than stock as-is.

 

[Dana Pants]

I have shifted my subframe to center camber. it’s easy peasy.

 

[ZeroTX]

Good alignment shops will align subframes. I've had it done on a Mustang (SN95) and even on a Toyota Matrix. But it's an ALIGNMENT SHOP not a generic shop who happens to own an alignment machine. My shop has 6 alignment machines and nothing else... it's all they do.

 

[Albertcado]

Yes, when I got my car re-aligned again after this the race shop that did it centered up the front subframe. I didn't even ask them to, but I checked my measurements before and after and it's dead nuts in the middle now. I continue to go to this place because they're thorough, and don't shy away from aftermarket, adjustable suspension setups.

I've got camber plates and oddly now that my subframe alignment and fender gap is perfect and the camber is even side to side, the strut nut is almost touching the ID of the hole in the tower on one side, and has about a 5mm gap on the other side. I'm going to ignore that because everything else is bueno.

It does make me think that since there's no factory camber adjustment (not really) that they may use the centering of the subframe to even up the camber left-to-right, to make up for any variances in the body construction. A small movement could make a big difference, since it's inversely affecting both sides at once.

I also have roll center correction control arms which reduces the scrub radius and adds positive camber, so with camber set back to -2 deg the lateral fender gap at the top is enough to get my fingers in to the knuckles, whereas before it was just shy of rubbing. I could really use another 10mm or so of negative offset, but I don't want to put bigger spacers on the front so I'll just wait until I order some wheels. Still better than stock as-is.

Do you know how exactly they properly adjusted and aligned the front subframe? Are there holes to line up by eye? Markings? or what was the correct way they went about it? I may need this info in case my alignment guy isn't 100% sure how to move and align the front subframe.

I have IRS alignment sleeves in the rear so that is a no brainer since bolts can only go in at one exact spot through the sleeves, but how is the front aligned? I just got my car back from the dealership with a new short block and the tech moved the front subframe to work on the motor. He put it back as close as what it was before (probably by eye based on the markings it left), but now my steering wheel is not centered and driver side wheel is "very slightly" closer to the front fender, but before it was DEAD center. I'm getting an alignment next week, but was wondering if messing with the subframe was even worth it for such a slight correction or to just get a 4 wheel alignment + steering wheel re-centered and call it a day.

 

[ZeroTX]

Do you know how exactly they properly adjusted and aligned the front subframe? Are there holes to line up by eye? Markings? or what was the correct way they went about it? I may need this info in case my alignment guy isn't 100% sure how to move and align the front subframe.

I can't speak for the S550 or for how his guy did it, but when I've had it done before (on other cars, not S550), they basically loosed the subframe bolts and man-handled it into position, measured, and then checked it again on the laser alignment machine.

 

[Dana Pants]

Do you know how exactly they properly adjusted and aligned the front subframe? Are there holes to line up by eye? Markings? or what was the correct way they went about it? I may need this info in case my alignment guy isn't 100% sure how to move and align the front subframe.

The front subframe is attached by ~8 bolts. You loosen them and use a pry bar to shift it to the side you need it to go before tightening it back up. It only moves a few mm. Again, it’s easy-peasy.

 

[Albertcado]

The front subframe is attached by ~8 bolts. You loosen them and use a pry bar to shift it to the side you need it to go before tightening it back up. It only moves a few mm. Again, it’s easy-peasy.

But what do you use to determine which side it should move or that it's centered? For example, if the front wheels camber or toe is off to begin with, it can "look off" when it's just the wheel and not the subframe.

 

[Dana Pants]

But what do you use to determine which side it should move or that it's centered? For example, if the front wheels camber or toe is off to begin with, it can "look off" when it's just the wheel and not the subframe.

I shifted my front subframe because one side had more camber than the other and I had maxed all camber adjustments.

 

[aleccolin]

Do you know how exactly they properly adjusted and aligned the front subframe? Are there holes to line up by eye? Markings? or what was the correct way they went about it? I may need this info in case my alignment guy isn't 100% sure how to move and align the front subframe.

I have IRS alignment sleeves in the rear so that is a no brainer since bolts can only go in at one exact spot through the sleeves, but how is the front aligned? I just got my car back from the dealership with a new short block and the tech moved the front subframe to work on the motor. He put it back as close as what it was before (probably by eye based on the markings it left), but now my steering wheel is not centered and driver side wheel is "very slightly" closer to the front fender, but before it was DEAD center. I'm getting an alignment next week, but was wondering if messing with the subframe was even worth it for such a slight correction or to just get a 4 wheel alignment + steering wheel re-centered and call it a day.

Unfortunately I don't know exactly, I didn't realize it until after the fact, otherwise I would have asked them.

 

[Albertcado]

I shifted my front subframe because one side had more camber than the other and I had maxed all camber adjustments.

so did you use alignment readings as your reference point of which way and how much it should move or did you do it by eye?

 

[Dana Pants]

so did you use alignment readings as your reference point of which way and how much it should move or did you do it by eye?

The alignment imbalance was very bad. After full subframe shift to one side it was just bad. Yes I measured camber before and after.

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