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Wednesday, August 10, 2011

Priming the Exterior Floor & Unisteer Rack & Pinion Teaser

It’s hot!  When the heat goes up, the enthusiasm ‘round here goes down in a hurry.  But somewhere in there, I managed to piddle just enough to get a few things accomplished in the last few weeks.  Most importantly, I was finally able to concentrate on getting the lower floor surfaces in primer in preparation for the installation of the subframe connectors and Heidt’s 4-link suspension mounts. 
As with much of the under body preparation, I decided to sand-blast the rear subframe rails and axle tunnel to remove the surface rust.  I am very lucky that the rear subframes are in excellent condition in spite of the fact that the trunk floor is a mess.  Once I had this work complete, I was able to better assess the next steps in the preparation to install the 4-link suspension mounts and plan ahead for the trunk floor repairs this fall.
On the cooler evenings, my dad and I scuffed the entire underside of the new floor and surrounding components to prepare the surface for a new coat of PPG primer/sealer.  Since I knew I would be welding the subframe connectors in, I taped off the weld areas at the same time I masked the floor flange edges.  There is no point contaminating the weld areas with primer if you don’t have to and hopefully this will minimize heat-blistering from the welding process and thereby reduce the work required to get everything primed after installation.
Priming was an absolute dream on the rotisserie and I was finally able to use the “faster” DP402 catalyst which really worked well.  In fact, I will be trying to stay with this catalyst in all future priming jobs if at all possible.  Good stuff.  The finished job looked very good and I was happy with how uniform everything looked.  Now, the stage is set for the subframe connector and 4-link mount installation……….and I LOVE any opportunity to fire up my welder for just this kind of thing!
The teaser for this entry is the preview of the Unisteer power rack and pinion steering kit that will be going in to the car along the way.  The kit is very nicely made, but as with most aftermarket “kits”, it follows exactly Pruett’s Restoration Rule #1:  If it says “bolt-in”, it isn’t.  While there is nothing major at play, the modifications that will be required to make the kit fit a 1970 Mustang chassis properly will be fairly numerous, but I will do what is necessary and correct (in my opinion anyway) to make this system work correctly.  On the “up” side, the Unisteer rack unit looks very clean in the car and should allow tremendous extra room to fit headers and vastly improve the feel and performance of the steering system.  Yes, it’s a lot more work than I had hoped, but I have become tempered to these necessities to get what I want.  Like they say, “If it was easy, everybody would be doing it!”
After draggin out the dreaded sand blaster, I cleaned up the axle tunnel and rear frame rails in preparation for the future suspension and trunk floor.

Passenger rear frame rails is in excellent condition in spite of the rough surrounding trunk floor panels.

Driver rear frame rail is equally good!

Rear bump stop brackets are in great shape on both sides of the car.

After a few hours with Scotch Brite pads, the lower surfaces of the floor pan were ready for primer.

In addition to masking the edges that didn't need primer, I also masked the general areas that were going to get welded when the subframe connectors and rear 4-link mounts are installed.


Floor ready for primer/sealer ("Before" shot).

Amazing how a simple coat of primer makes everything look complete even when the primer is still tacky! ("After" shot).

Another look at the primed floor pan from the front.

Here is a look at the front subframe connector "weld" areas after removal of the masking tape.

Rear subframe connector weld locations after masking tape removal.

I didn't mask all of the places that will require welding on the rear 4-link mounts due to uncertainty in location of the welds in a few spots, but the few places that were nailed down were masked as shown here.

Unisteer Rack & Pinion Mock-Up
I settled on the Unisteer power rack & pinion conversion for my Boss.  There were many reasons for this, not the least of which was the fact that I could get them on the phone for answers and they were willing to work with me on some small requests I had regarding some details of the kit components.  Here you can see the rack assembly mocked up in position.


Because the 69-70 front lower control arm mount wings are flared out compared to earlier Mustangs, the Unisteer kit is not a straight-up "bolt-in" as advertised.  Thus, it meets Pruett's restoration rule #1:  "If it says "bolt-in", it isn't going to".

Here you can see the passenger side interference in more detail.  I'm noodling on how I want to address this in a manner that I feel appropriate.  Grinding and hacking on the mounting bracket is not currently a consideration.

Here is the same area on the driver side.  Looks like the same "fix" I come up with should work on both sides.

The small tabs on the rear camber bolt reinforcement will probably require some modification to get the alignment that will be required for the rack mount.

Here is an idea of how tidy the system is relative to where the original steering box was located.  The system opens up TONS of room and reduces steering system complexity by a huge margin.


Another look at the relative simplicity of the system on the "busy" side of the steering equation.

One complaint I had with the kit is the interference between the inner tie rod boot and the pressure line loop on the right side of the rack.  No excuse for this oversight, but fortunately a delicate tweak of the bend is all that was required to correct this.

Thought it appears the fluid line fittings will work fine, there may some adjustment required to get the lines to enter and exit the rack smoothly.  We'll see.

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