Doctor Diff Viper-Style 13" Front Disc Brake Kit

[JR_Charger]

Kind of what I figured, but I haven't run a bearing I've packed myself yet, so why not ask?

Wheelhubs installed -

Found a bag of washers in the Dr. Diff kit. Clearly these guys didn't make it where they needed to be, but it's not too late. I'm guessing two go under the caliper bolts, two go on under the caliper bracket bolts, and two go under the nuts holding the spindle to the knuckle arm? I do wish I'd spotted these sooner.

Finally, if you were wondering if the 13" Viper rotor will fit under your 14" rim, it will!

 

[RemCharger]

The shims are for centering the caliper to the rotor.

 

[Kern Dog]

I didn't need those when I installed the kit.

 

[RemCharger]

Perfect scenario . If checked properly.

 

[RemCharger]

I didn't need those when I installed the kit.

View attachment 1916480

Are you comparing the viper fixed calipers to your floating pin sliders ?
Maybe I'm missing something

 

[Kern Dog]

Ooops!
Mine are the FORD Calipers.
That was a boo boo on my part.

 

[JR_Charger]

From my research on the SN95 Mustang rims in post 27 that this kit is supposed to be designed for -

Offset is 30 or 32mm and backspacing is 5.72 inches. Some Cobra rims have 6.12 inches of backspacing.

Going by my measurements, the regular Mustang rim shouldn't fit either, at least not without rubbing, and preventing the steering from reaching its full travel. Yet those rims are out there, on b-bodies with this kit. So those cars are either not fully functional, or I'm missing something.

 

[JR_Charger]

Does the Borgeson box have greater travel than the factory box? Could there be some other steering component that limits travel, which I forgot to reinstall?

 

[JR_Charger]

Testing clearance with the 14" slotted mags.

So it turns out the tightest point is at the front. Keeping in mind that nothing on this steering has been adjusted, and even the kmember could be a bit out of whack - but I imagine this is in the ballpark. Only about an inch of clearance.

 

[Kern Dog]

The lower ball joints have “stops” in them to limit the steering box. At full turns, the nubs on the lower ball joints contact the LCA.
It is better to bump them than to hit the internal stops of the steering unit itself.

 

[JR_Charger]

I think we've got our winner. I pulled out a factory LCA and lower ball joint. I see the stop on the lower ball joint, and where it contacts the LCA. That stop isn't going to hit anything on a QA1 tubular lower control arm. Lots us of have QA1 tubular lower control arms - how is everyone else dealing with the steering travel issue?

 

[64fury74charger]

Kind of what I figured, but I haven't run a bearing I've packed myself yet, so why not ask?

Wheelhubs installed -

View attachment 1916454

Found a bag of washers in the Dr. Diff kit. Clearly these guys didn't make it where they needed to be, but it's not too late. I'm guessing two go under the caliper bolts, two go on under the caliper bracket bolts, and two go under the nuts holding the spindle to the knuckle arm? I do wish I'd spotted these sooner.

View attachment 1916456

Finally, if you were wondering if the 13" Viper rotor will fit under your 14" rim, it will!

View attachment 1916457

Looking at this picture I am wondering where the caliper will go?

 

[JR_Charger]

Looking at this picture I am wondering where the caliper will go?

I think it clamps on to the tire?

I'm measuring things now - the rotor will space the wheel out a little, so I'm putting it on. I also want as many car parts as possible on the car, instead of taking up space in my garage. This has gone on for too long.

 

[64fury74charger]

I think it clamps on to the tire?

I'm measuring things now - the rotor will space the wheel out a little, so I'm putting it on. I also want as many car parts as possible on the car, instead of taking up space in my garage. This has gone on for too long.

The rotor fills up the rim diameter really close to the edge. The caliper is centered on the rotor and needs some space to mount up over the rotor. This requires additional space to clear the caliper inside the wheel. I hope this makes sense the way I am explaining this.

 

[Kern Dog]

The general rule that I've found is that you need a wheel diameter that is 3 inches larger than the rotor size.
11" rotor, 14" wheel.
12" rotor, 15" wheel.

I see the stop on the lower ball joint, and where it contacts the LCA. That stop isn't going to hit anything on a QA1 tubular lower control arm.

Regarding your issue about steering travel, my own tires rub the frame rail before the steering range reaches it's limits.
Be a baller. Run a wide tire. Mine are 275s.

 

[Mopar Hunter]

Finally, if you were wondering if the 13" Viper rotor will fit under your 14" rim, it will!

With the caliper mounted, it fits under a 14 inch wheel?

 

[JR_Charger]

The rotor fills up the rim diameter really close to the edge. The caliper is centered on the rotor and needs some space to mount up over the rotor. This requires additional space to clear the caliper inside the wheel. I hope this makes sense the way I am explaining this.

With the caliper mounted, it fits under a 14 inch wheel?

It was a joke. The caliper does fit under this rim -

(Dr. Diff 13" Viper brake kit not installed at the time this picture was taken)

I'm doing tests now to figure out if this rim will work or not. My research said it would, but reality isn't cooperating again. So I have to figure out what reality's problem is this time.

 

[JR_Charger]

Here's the steering travel limiter Kern mentioned -

And here it is with a QA1 LCA -

Sorry for the poor lighting, but hopefully everyone can see the limiter isn't going to contact anything on the QA1 LCA. These QA1 LCA's are on lots of b-bodies - how did the owners solve the steering travel issue?

 

[JR_Charger]

Regarding your issue about steering travel, my own tires rub the frame rail before the steering range reaches it's limits.
Be a baller. Run a wide tire. Mine are 275s.

View attachment 1916901

I have a feeling this is the solution 99.9% of the people running QA1 LCA's came up with - the tire is the travel limiter.

I was far more worried when I thought the strut rod was going to get hit before the frame rail. The QA1 adjustable strut rod is just an aluminum tube. It might fold if pressed hard from the side. However, if the frame is being hit, not such a big issue. Autocross might call for that much steering at speed, but most of the time it would happen in a parking lot situation, where I could back off as soon as I felt the tire hit, and there'd be no damage.

 

[Kern Dog]

I've never touched the strut rods but the paint is worn off the frame rails behind the suspension on both sides.
See post #88. You can see the red paint gone but some original green paint remaining.