Mytbtruck
What about the caster on the IRS? Do you need to worry about that?
Thanks
Scott

 

No, caster helps the front wheels return to center after making a turn. Since the rears don't steer there is no way to measure it.

 

I know caster is probably not the correct term on an IRS, but the rear suspension has up and down travel. Do you need to be concerned with the actual orientation of that travel? Should it be straight up and down or should it lean slightly forward or back? Then the next question is how do you measure that? Do you base it on the orientation of the axis of the lower control arm?
Thanks
Scott

 

The Cougar/Tbird IRS's have camber adjustments, ideally (and it looks like they do) when they sides go up an down they move 90* to plane.

Is that what you're referring to?

 

Thanks Mike!

 

The T-bird IRS has camber and toe adjustment. You adust camber at 0 at ride height and toe probably doesn't have to be adjusted unless you tear it apart to paint the pieces individually. It is probably not that critical anyway just as long as you are very close. You could use a framing square against the back wheel to the floor of you shop and be close enough.

 

Like Cobraguy said caster is the angle that helps the front wheels try to straighten back out after you turn. The more caster you have the harder it is to steer because it will be fighting you to straighten the wheels. Newer cars, especially front wheel drive cars have a lot more caster than older cars and trucks that had solid axles. The rear end does not have caster.

 

Actually the rear does have caster. It is not usually provided with any adjustment.
When swapping in an independent rear suspension you are more concerned with the pinion angle than with caster because it is not critical.

 

This is a great thread. Nice job on the mounts Dave. Looks like I need to find a Mark VIII rear. I'm going with the 03-07 Crown Vic IFS and until now I hadn't decided on what to do for IRS. I really like the ride height on your 56 shown in the photos Dave. I'll definately be contacting you for those mounts once I find a good deal on the IRS. Great thread!

Mike

 

Hi there; I'm new at posting so please bear with me. I purchased a set of installation brackets from Dave@truckirs.com and I have installed them in my 55 F-100. The installation was sweet and simple, no glitches or hangups. I had a Jag set up but decided that this is a better setup because it is a stronger way to go. It will be a while until my truck is road ready as money is everything these days. The good part is that I'm retired so I have a lot of time to study on it and do it right the first time. Dave sells a quality product, which is refreshing in this day & age. NO JUNK & 100% AMERICAN. Iwill keep you folks posted as I can.
Tbucket

 

Thanks for the information. I too am retired and I just completed the total boxing of the frame and now I move on to the radiator (Dakota) mount, transmission x-member and the motor mounts. I hear you load an clear on budget. When and If I get some "extra" money then I can start back working on the F1.

 

Tbucket
How about some pictures?

Scott

 

I would love too post some pics and I will as soon as I figure out how to downsize my pics. I am working on it though. Thanks for your reply.

 

can't see anything

 

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