Out with the stick

[blind]

Getting rid of the solid axle in my 1997 Mustang this weekend.


Installing an IRS from a 2003 Cobra, it has some goodies already, namely MM poly IRS bushing kit and a diff brace.

It came with the stock `03 cobra bilstein shocks, stock springs cut 1 coil, and a new in box ford racing 4.30 gear + master installation kit + 2 bottles of royal purple fluid + ford racing friction modifier.



Hopefully the install goes smoothly, I got it from a guy who had it in his `98 mustang so everything I should need came with it, basically being some long bolts for the quad shock mounting bracket to go through to the floor of the trunk.


Why am I doing this?
1-ride quality
2-I don't want to spend any more money on this car, and to get better performance out of the solid rear would take more money than getting great performance out of this IRS, and I should be able to resell all of the solid axle parts that I had for about what this swap will end up costing.
3-the solid rear has a really minor clunk, that drives me bat____ insane on my daily commute, on a track car it would be irrelevant but I'm very anal when it comes to noises that my cars make,

[Julie GT07CS]

Kevin, you are SUCH a gear head! I love it!!! Have Carli take pics while you work! LOL

Looking forward to seeing in action!

[Glenn_03Cobra]

Hope it doesn't rain. What time you starting? If I can, I'll drop by.

[SVTRonDogg]

So it has the MM Poly UCA and LCA bushings? Might be a good time to swap to Delrin if you can swing it.

Does it have the stock Diff?

[blind]

from what I can tell, it has the poly cradle bushings, and poly diff bushings, but the control arm bushings look stock rubber to me.

I think all I want to do in the short term is the aluminum diff mounts -IF- the pinion angle isn't correct when I bolt it in, I don't think the pinion angle can be adjusted with what's on there now.

I'd love to go to the fulltiltboogie complete delrin setup right now, but I just don't want to spend the money on the car, I've got a wedding coming up in July


Glenn, me too! I'll be out there from 9am on, I'm trying to get Christian and Matt to come down and give me a hand, they have my brake bleeder and fender roller and I'll likely be needing both to finish the job, I know the IRS is wider so I'm not sure if my 275's will rub.

[SVTRonDogg]

from what I can tell, it has the poly cradle bushings, and poly diff bushings, but the control arm bushings look stock rubber to me.

I think all I want to do in the short term is the aluminum diff mounts -IF- the pinion angle isn't correct when I bolt it in, I don't think the pinion angle can be adjusted with what's on there now.

I'd love to go to the fulltiltboogie complete delrin setup right now, but I just don't want to spend the money on the car, I've got a wedding coming up in July


Glenn, me too! I'll be out there from 9am on, I'm trying to get Christian and Matt to come down and give me a hand, they have my brake bleeder and fender roller and I'll likely be needing both to finish the job, I know the IRS is wider so I'm not sure if my 275's will rub.

Aluminum might be worth the switch early on. From what I've read the Poly tends to melt with the heat of the Diff. I never used Poly there I went from stock to MM Aluminum, so no experience there.

I've been running the Poly Subframe bushings for years with good results.

[blind]

(Unplug ABS connectors under the back seat and feed through this hole)



Out with the stick, this point took me 1 hour to get to

After this I removed the tailpipes, driveshaft, mufflers, muffler hangers, upper bumpstop, etc



The upper cradle brackets bolted into the old quad shock bolt locations

lower cradle/lower control arm bolt location had to be drilled out to 14mm (9/16") to fit the larger lower cradle bolts, this was a bitch and I nearly broke my arm when the drill snagged on me 4 times




I just have some minor ____ to do now, waiting on my H&R Race spring set.

After springs, just need to bend the brake hoses a little, add the shocks, raise the cradle and bolt it in to the upper bracket, then torque everything down

[SVTRonDogg]

Looking good man. I think I'm going to try and tear mine down in the next week or so.

[blind]

Looking good man. I think I'm going to try and tear mine down in the next week or so.

what are your planning to do to it?

[Glenn_03Cobra]

Sorry I couldn't get over there Kevin. Jackie came home; I took the kids to MB2 and lunch.
Who's going to do the 4-wheel alignment?
What's the plan with the brakes? Hopefully you don't have the same issue brake bleeding.

[blind]

Sorry I couldn't get over there Kevin. Jackie came home; I took the kids to MB2 and lunch.
Who's going to do the 4-wheel alignment?
What's the plan with the brakes? Hopefully you don't have the same issue brake bleeding.

camarillo alignment will be doing it for me, as always!

brakes are a non-issue, the p/o of the `03 IRS painted the calipers gold....so yeah I'm re-using my old cobra brakes, I just need to bend the brake hoses a little bit for clearance around the upper control arms.

got the H&R springs at 8pm last night, so I'm about to head out there and finish it up

[SVTRonDogg]

what are your planning to do to it?

Upper/Lower Control Arm bushings in Delrin, swapping the Cradle Bushings to something firmer, Toe Links, and I think that's it.

So far it has the Urethane Cradle Bushings, Aluminum Diff Bushings, MM Swaybar Endlinks and Urethane on the swaybar bushings.

Sorry I couldn't get over there Kevin. Jackie came home; I took the kids to MB2 and lunch.
Who's going to do the 4-wheel alignment?
What's the plan with the brakes? Hopefully you don't have the same issue brake bleeding.

I didn't get the Memo.

[Glenn_03Cobra]

[Glenn_03Cobra]

2 Questions -

• With the IRS mounted and rear jacked-up. Does the swar bar hit the top of the diff?
• What size socket/wrench fits the sway bar mount bolts?

[blind]

hmm I'll have to look at the swaybar for ya Glen, the swaybar mount on the cradle is very small, maybe an 8 or 10mm, the endlinks are a bit larger, probably 13mm.





Pretty funny driving it around with no mufflers.

time for a quick lunch break, then I'm going to swap the front steeda springs out for the H&R's.

one of my 275's rubbed on something when I left the driveway, but otherwise everything is good. that ____ under the car isn't a leak, it rained really hard last night and when I took the car down off the jackstands all the water that was up around the trunk came pouring out, lol

[Glenn_03Cobra]

Mine have some funky allen head bolt for some reason. Brian (at Vista) and I were trying to figure-out if the bar was stock, when it was up on the lift. Doesn't look any bigger but, he said it shouldn't hit the diff., when the wheels are off the ground.

[SVTRonDogg]

2 Questions -

• With the IRS mounted and rear jacked-up. Does the swar bar hit the top of the diff?
• What size socket/wrench fits the sway bar mount bolts?

Attachment 285

Swaybar should definitely not be hitting the Diff Housing under any circumstance.

It's mounted to the IRS Subframe in the middle, then to the LCAs on the outside.

[BigMike]

Sweet. You made it look easy.

[blind]

Did some more stuff to the car this weekend, I slapped in the H&R Race 03/04 cobra front springs, dropped the IRS (again, ugh) and swapped the fuel pump for a walbro 255lph, swapped the fuel filter (nobody warned me how much of a bitch the fuel filter is going to be to replace now with the IRS!!! there's seriously no way to replace it with the IRS in place, wtf?!), and swapped the gas tank filler tube gasket because there was a little moisture around it, that gasket was TOAST so I'm really glad I was able to do it now so the tank doesn't have to come down again for a long time

then I drilled and added the vertical bolts into the trunk floor for the upper IRS cradle brackets. I ran into an issue when I was tightening down the shocks at the top, I wasn't able to snug them down before the nut bottomed out on the shock shaft inside the trunk, I had to steal the rubber bushings off the tops of my old solid axle bilsteins and double stack the upper bushings before I could get the shocks tight, this seems pretty weird to me, maybe the teminator shock towers are taller than mine? Need to do some more research

Glenn, I took some pics of the swaybar mounting brackets for you when it was down, the allen head bolts are just part of the bushings, the actual bracket is above the bar.




(look how much nicer/thicker the $15/roll peel `n seal from Lowe's is than the $90/roll dynamat xtreme!)





Now that the springs are done, it's time to get that alignment taken care of!

[SVTRonDogg]

then I drilled and added the vertical bolts into the trunk floor for the upper IRS cradle brackets. I ran into an issue when I was tightening down the shocks at the top, I wasn't able to snug them down before the nut bottomed out on the shock shaft inside the trunk, I had to steal the rubber bushings off the tops of my old solid axle bilsteins and double stack the upper bushings before I could get the shocks tight, this seems pretty weird to me, maybe the teminator shock towers are taller than mine? Need to do some more research

Shock Towers are no different.

Are you using the 'Stock' IRS Bilsteins? I know the upper bushing is different than the normal ones. Per MM:

The OEM Cobra Bilstein upper rubber isolator is shorter and softer than the isolator that comes with an aftermarket Bilstein IRS shock. Because of this, the OEM Cobra Bilstein upper rubber isolator prevents the shock's upper retaining nut from being properly tightened when a MM Rear Coil-over Kit is installed.

I know you're not running Coil Overs, but there is a difference between the 'Stock' and 'Aftermarket' Bilstein upper mounts.

[blind]

yeah they are OE 03 cobra bilsteins, interesting, wonder why I ran into that problem without coil-overs - meaning still using the stock under the shock tower bushing as well.

[blind]

Picked up a catback a couple weeks ago, it's a flowbastard 2.5"

I think it's stainless but I'm not sure, waaaaay too loud for my taste, but I can live with it for now, it's quieter than no mufflers was! Unfortunately the muffler pipe is offset differently than the solid rear axle catbacks use so I can't swap my old dynomax mufflers onto it to quiet it down I have to buy new mufflers.

[blind]

Picked up a catback a couple weeks ago, it's a flowbastard 2.5"

I think it's stainless but I'm not sure, waaaaay too loud for my taste, but I can live with it for now, it's quieter than no mufflers was! Unfortunately the muffler pipe is offset differently than the solid rear axle catbacks use so I can't swap my old dynomax mufflers onto it to quiet it down I have to buy new mufflers.

[SVTRonDogg]

Those Tips aren't going to get all melty with the fascia are they?