Need Help With My Fox Body Irs Swap !

Jan 1, 2018
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#1
Okay so this is my first post to the forum and I’m not quite sure how to go about my situation. I’m in the middle of swapping a 2003 or 2004 IRS in my 1991 hatch back. The car was a father/son project and my dad has recently passed so I’m kinda stuck. From what I know and have been told by my dad before he passed, I’m pretty sure he did some kind of fabrication and bolted the irs into the car. However for some reason once the irs is in and wheels are on, the passenger side wheel sticks out an inch or two and on the driver side the wheel hangs inside the fender well an inch or two. Thea is causing the wheel on the driver side to hang up on framing on the inside of the car. From the few articles or posts I can find on the swap, they say it’s a pretty straight fit. So I’m pretty nervous as to why it’s not lining up. At the moment I’m in Colorado and will be back home to Kansas in the next day so I can get any specific details or pictures one may need. I’m sorry I’m advanced I know I should have them now but don’t always have the time to sit down and type this stuff up. Any help would be grately appreciated I really wanna finish my dad and I’s project so I can have my car back on the road and move on to our Saleen car.
 
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bird_dog0347

I really enjoyed seeing your rear end up close
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#3
Sorry to hear about your loss! As for the car, can you post some pics of it showing what you're describing as well as possibly from underneath it? For it to be that far offset, I'd be worried that the chassis is WAY out of whack given the IRS subframe bolts into the lower control arm pivot points and directly to the frame rails in the rear. The only other thing I can think of off hand is that the axles aren't properly installed or perhaps there is a spacer on the passenger wheel but not the driver's side?
 

Hoytster

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#4
Sorry to hear about your loss! As for the car, can you post some pics of it showing what you're describing as well as possibly from underneath it? For it to be that far offset, I'd be worried that the chassis is WAY out of whack given the IRS subframe bolts into the lower control arm pivot points and directly to the frame rails in the rear. The only other thing I can think of off hand is that the axles aren't properly installed or perhaps there is a spacer on the passenger wheel but not the driver's side?
Hey man, really sorry to hear about your loss. I can totally understand wanting to get this projected completed now as it was something you were doing with your dad.

I'll second what bird_dog0347 said, try to get some pictures of underneath the car, specifically the torque box areas and the rear frame rail where the IRS mounts.The IRS is designed to mount to these areas so if the IRS is sticking out on one side and not the other, I would suspect something on the frame is tweaked, the mounting is somehow off, or there is a spacer in the wheel or you somehow have a wheel with a different offset then the other. From looking at my IRS, I don't think you could install the axle wrong and change how far the wheel mounts as the location of the knuckle is dictated by where it mounts to the upper and lower control arms. Also take a picture of the knuckles on the IRS if you could.
 

2000xp8

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#5
Probably one front and one rear wheel on the rear.
 

90sickfox

I didn't really have an issue with the stink...
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#6
Sorry to hear about you Dad. Its a great thing that you're completing it.

I'm with the others. The wheel of set may be different. The IRS is a bolt in job. There's no adjustment of the subframe left or right.

However, the top bolt that goes through the aluminum knuckle and the upper control arm adjusts....that bolt moves the top of the wheel in and out ( camber adjustment ). Loosen the nut and turn the bolt with a wrench. That usually doesn't give an inch of movement...more like 1/2 inch.

I've noticed that as an IRS is compressed it moves the wheels out and then back in. If the ride height isn't the same from side to side it could add to one wheel poking out.

Pics would really help straighten this situation out.
 

Mustang5L5

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#7
Couple good YouTube vids detailing the install. This is one of them. You can watch and see if something jumps out at you


The only part of this vid I don't agree with 100% is the way the rear irs mounts are bolted up and not using the bottom bolts or welding it into place.
 

bird_dog0347

I really enjoyed seeing your rear end up close
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#8
Also @FoxMustangLvr or @RacEoHolic330 might have some ideas? I think most of us also have some decent pics to compare in our build threads or if you need I'll be happy to take any pics of anything specific or measure something if you need.
 

FoxMustangLvr

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#9
Sub'd. Seems like a lot of good advice has already been given. I'll wait for OP to return.
 
Jan 1, 2018
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#11
Thank you all for the good information I can have some pictures posted this weekend. Sorry for the late reply I’ve just gotten my wisdom teeth out and have some house keeping to do before school starts. I was worried about the frame being tweaked that was my dad and I’s hypotheses. Hopefully these pics will help us out should have them before this weekend is up. Also thanks to all for the condolences for my father he was an awfully cool guy and if it wasn’t for him I would never have gotten the Fox body bug !
 
Jan 1, 2018
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#12
Okay so these pictures start from the passenger side where the wheel would stick out. Then as the pics go on I work my way over to the driver side where there is not enough clearance. To show the tight fit I included a picture of the driver side with the wheel on. If any other pics are needed just let me know. Sorry for the delayed response school has been busy and haven’t had much time to get out in the garage. Hope this helps !
 

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FoxMustangLvr

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#13
Honestly from looking at the last picture of tire clearance it looks like you need to adjust the camber on that side. Adjusting camber can move the top of the tire in/out at least 1/2"+

camber cross axis.jpeg
 
Jan 1, 2018
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#14
Okay I will check into that, if that is the case should I adjust the other side also, because the wheel sticks out the passenger side the same amount of distance the wheel sits in on the driver side.
 

FoxMustangLvr

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#15
Okay I will check into that, if that is the case should I adjust the other side also, because the wheel sticks out the passenger side the same amount of distance the wheel sits in on the driver side.
All I can say at this point is that it's a possibility. The upper control arm has a horizontal slot in it and the bolt has an oval head to it which adjusts the rear camber. It's possible that it was bolted up without any consideration to camber position. Good luck.
 
Jan 1, 2018
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#17
All I can say at this point is that it's a possibility. The upper control arm has a horizontal slot in it and the bolt has an oval head to it which adjusts the rear camber. It's possible that it was bolted up without any consideration to camber position. Good luck.
I will check it out thank you very much I hope it’s a fix !
 

bird_dog0347

I really enjoyed seeing your rear end up close
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#18
When you have the wheel at full droop it's going to be VERY close to the mount but it's not near as bad when you have the car on the wheels. Have you gotten it aligned yet?
 

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