Build Thread Dusty is at it again...

[90sickfox]

This IRS is going to be rough on the ground. Last time I did this I had a lift. I decided to do the rear because I have to drop the tank for the new fuel pump.

I know people love the bushing kits, but I've had really good luck with the factory set up. The cover brace is about the only thing I can get done right now.

This stuff needs to go in so I can finish dealing with the layout for the front and for the full length subframe connectors.

Its coming together...slowly. Lol

 

[FoxMustangLvr]

Sweet build bro! Which diff cover brace are you going with? What year IRS did you get your hands on?

 

[90sickfox]

Sweet build bro! Which diff cover brace are you going with? What year IRS did you get your hands on?

I went with Steeda...its an 04. I've had this rear for a long time...since about 08. Don't laugh at my Monro shocks they worked great on my vert with this thing. I did this swap before anyone was really doing it. Back then there wasn't a lot of info available.

 

[90sickfox]

One thing I did was to take the emergency brake bracket off a 98 v6...drilled the spot welds out and used 1/2 bolts to bolt it in my tunnel. The 98 also donated the emergency brake cables and e brake handle as well.

 

[90sickfox]

The brace came in today. I want to clean up the axles and the carrier before install. Gear oil and friction modifier on its way.

 

[90sickfox]

I'll be putting my old grant steering wheel in today. Its kinda cool being able to use stuff I have memories with. This thing was on my vert when I sprayed it the first time....thought my finger marks would never go away. This thing has seen a lot of "white knuckle rides". The SRT 4 that whipped my ass made me beat the hell out this thing. Lol. ;shame

 

[90sickfox]

Got it done in the rain...who said we can't do it in the rain. No, this wheel isn't the best but its MINE. Its been with me for a long time. I used a puller to take the old wheel off. I forgot about the little spring under the factory wheel...that thing gets ditched with the grant. Once wheel is tightened down the grant spring goes under the horn button....and....voilà

 

[90sickfox]

I did get some work done to the IRS. Took the axles out. The front bushings for the center section have a little play...never heard anything weird. I'll be sanding and painting this weekend.

Included is a pic of my SRA flange on the IRS. I didn't do anything special to swap them. Actually, I just took it off the old rear and impact gunned it on the IRS. A lot of folks aren't as lucky as me so I can't endorse it...but mine has done well for years and bunches of miles.

 

[90sickfox]

The two bolts that hold the back of the cover kicked my butt. They were a pain in the 8ss. It took me a while to figure out that I had to take the front brace loose and then raise the front of the diff, remove the top halves of the bushings, remove the vibration damper, and then remove the brace....in that exact order.

The inside of this thing is black but the fluid was still golden. The 3.55 gears and the spider gears still look awesome.
The only special tool I needed was the bucket its sitting on.

The stuff Ford used to glue this thing together is garbage. Literally, I could see where the seal failed. Clean up tomorrow....can't paint because of the cold snap on its way. [emoji20]

 

[90sickfox]

@FoxMustangLvr I've had a 306, and a built 347 in front of this rear. The horsepower rating was for the latter. The 347 destroyed my stock axles, studs, axle tubes, torque boxes, ripped the trans tunnel, tore up the passenger side firewall, ripped the seat mount point out, and did everything but kill me with a dry shot an slicks. Didn't help that it was a convertible. Thats how the 10 point cage found its way in it....and the IRS.
After tearing the car down and finding all the problems I decided to go IRS and give up the quarter mile. Back then I thought gas was it. Didn't nave the money to really fortify my suspension for the power, or the brakes. Just motor, nitrous, clutch, and et streets. I'm glad I survived but my car didn't.
Everyone wants a 10 sec car. Wish I would've done things differently.

no, that isn't me in the pic.

 

[90sickfox]

Got some stuff done. Just FYI finding axle seals is a PITA !!! Three trips and three wrong seals. Wanted something from somewhere local. Have a seal on order...we'll see how that goes.

My axles were black with dirt. Cleaned up OK. I want to wire wheel them and clear coat.

The rear brace is on and bolts torqued to 24ft lbs.

 

[90sickfox]

Everything on the rear is back together. For any one else going "el cheapo " I used 3/4 in. washers to space the bushings at the front of the diff. Its like a layered cake, the front brace, lower half of bushing, diff., washer w/ edge shaven, top half of bushing, rear cradle, then nut. The washers ( one per side ) are the zinc plated thin ones from Lowes. I had to shave about 1/4 in. from the edge because of how the diff is cast in that area. Wish I had pics but my phone was dead.

I used about 1 ⅓ qt 75w140 synthetic and 4oz of friction modifier.... Motorcraft of coarse.

I found the right axle seals at Advance Auto they're National seals part # 714569

 

[FoxMustangLvr]

So you added a washer to the top side of the diff mount? I thought you were supposed to add the washers to the bottom side of the diff to raise the diff? Isn't the idea of this is to increase the pinion angle?

 

[90sickfox]

So you added a washer to the top side of the diff mount? I thought you were supposed to add the washers to the bottom side of the diff to raise the diff? Isn't the idea of this is to increase the pinion angle?

No, not in my case. The bushings had a little up and down play. The bushings themselves looked okay.

 

[90sickfox]

Ordered new rear cobra calipers today. The strange thing is they were cheaper than regular gt calipers. The only difference between the two is the bracket.

If gt calipers were cheaper I would've ordered them and reused my brackets.

Fixed dinner for the family tonite...tomorrow, after work, the project continues. [emoji14]

 

[90sickfox]

My calipers came in today but one was missing a bracket. They were rebuilt cobra calipers and brackets....but with the missing part issue I opted to get brand new rear calipers without brackets. My cobra calipers and the regular mustang all have the same cast calipers with the number 38 on them. Reused the old brackets and installed the calipers.

 

[90sickfox]

Thought I was going to have an issue. I found this exhaust hanger welded on with a bolt hanging out of the quad shock hole. I just knew this thing was stripped.

To my surprise it was just sitting in the hole...threads are fine....I'll retap them tomorrow. Ground off the welds and surface rust.

And primed...still too cold for paint.. Guess I might as well tub it @Davedacarpainter

 

[90sickfox]

Today I tapped the bolt holes. They're 12 x 1.75. Hopefully, I'll drop the rear and give some attention to a couple surface rust areas.

I'm trying to get the rear in by the end of the weekend. I've got to drop the tank for the new fuel pump.

I don't have the time or money to do the job that way I'd like to, but that just means I'll get to do it all again. Lol

 

[90sickfox]

The rear is out...only took about 45 mins. I've got some surface rust to deal with on the drivers side but the passenger side looks like the day it rolled out the dealership ( if you look past the dust )

 

[90sickfox]

You guys keep me motivated. I got the rear in the car today. Just need to drill and bolt the four bottom holes in the frame. A couple thing were different from my 89 vert. First, the rear most quad shock hole didn't line up with the bracket. I drilled with a 7/16 bit and tapped for a 1/2 by 13 1in bolt. Second, I had to bend the edge of the wheel well on the passenger side.

I had to drag this behemoth out of my shed. Don't ask how I did this by myself....guess I was determined.

Tomorrow I plan to get those 4 bolts done, emergency brake cables, e brake handle, and 5 speed trans tunnel hump installed.

The cross member brace got bent and a couple spot welds ripped out when the car jumped off the trailer. I'll attempt to get that welded up, too, but no promises.