Mustang II spindles on stock control arms

[Super73]

I am working my way towards a little more weight savings. I don't want to spend the $3,500 on a front suspension right at the moment, so I am growing in pieces.

I have a set of MII spindles and started looking at things.

CPP Drop spindle weighs 24lbs
MII spindle weighs 7lbs

Current 11.75" rotor weighs 28.8lbs with bearings and dust shield

Current caliper weighs 11lbs

My current CPP drop spindles are 8" 11/16" tall where the MII ones are 7" 5/8" tall. At my current ride height the upper control arm is slopes down towards the frame (higher at the upper ball joint) where the lower is level. The reduction in spindle height will likely flatten out this slope.

Next is ball joints. The upper looks like it might have the correct taper and enough thread to see the nut/cotter pin. But.. QA1 makes aftermarket upper/lower ball joint that are rebuildable.

They make an upper housing for our GM arms and a MII taper in standard length +.1" +.5" +1" ball joints.

Part numbers for upper:
1210-101 = Standard height
1210-201B = +.5"
1210-238B = +1"

The lower needs to be done in 2 pieces as they don't sell a complete unit.
Press in housing for our arms 1210-510
Ball Joint for lower MII that fits that housing is 9029-229

The next thing that will need to be addressed is the steering linkage as the MII is a bottom tie rod feed where the truck is a top tie rod feed. I am going to drill the spindle square and run a rod end. This may require me making some form of threaded rod to accommodate the current adjuster.

[Fatherof3]

Please keep us posted on how this works out with pictures.

[KQQL IT]

Ream the spindle to your ball joints?

[Super73]

I'd rather keep as much meet on the that area of the spindle as possible.

[Super73]

Summit called me on Friday to advise they loaded the part numbers that were missing.

I have been slammed getting things ready for my mothers services this weekend, but should be ordering parts in the next day or two. Will not be doing much on it until next week, but please stay tuned.

[Super73]

Ordered lower ball joint stuff this morning. I think my stock uppers will work on the m2 spindle.

[KQQL IT]

Don't mustang II use a screw in ball joint?

[Super73]

If the shaft has the proper taper and depth, it doesn't matter how the ball joint attached to the control arm.

[KQQL IT]

I was thinking you could weld the threaded part to your current A arms, and the lowers would be done.

[KQQL IT]

This



And that.

[franken]

What did (since hopefully none still exist) a Mustang II weigh and what does a 67-72 truck weigh?
2700 vs 4000 pounds?
Or in different words, do I want tiny car parts on a truck?

[Super73]

KQQL IT,

I didn't honestly see the weld on female threaded sleeve. But if these fit, I don't plan on taking them out often.


Franken,

My truck last time out weighed 3,200 with me in it.

This mod might not be best suited for a daily driver. For guys like me though that drive the truck to the store and are making every attempt to loose weight to go fast. This creates an in between option, >$2500 for a full front end at roughly 180lb loss or <$1000 for a 75-100lbs loss in spindle/brake combo. My cross member has already been modified providing a 25lb loss.

Keep in mind that this spindle is used on a lot of roundy round cars which are taking a beating in the dirt. No, they don't weigh what our trucks do, but they are getting abused none the less.

[KQQL IT]

I was more thinking of the low friction qa1 joint.
Wonder what the camber/toe change will be with the geometry of the new spindle?

[Fatherof3]

Originally Posted by franken

What did (since hopefully none still exist) a Mustang II weigh and what does a 67-72 truck weigh?
2700 vs 4000 pounds?
Or in different words, do I want tiny car parts on a truck?

Keep in mind that the stock truck spindle was designed to carry the truck with an abusive load and not fail. Bearing life would likely be the first weakness to show up if they are much smaller but again the original bearings size was designed to carry an insane load too.

[Oldtruckfanatic]

What you guys are talking about weight wise and engineering wise is the difference between a stock pickup truck designed to hold up to what pickups do for as many miles as possible. The standards are different for a drag race vehicle/ short trips to the quickie mart. The only concern id have is with the caster and toe change because those two things are what is going to determine a stable and straight driving race car or a darty dangerous one. Frankly the strut front ends on the tube chassis cars scare the hell out of me just looking at them. We run mustang II spindles on a couple of imca cars here and havent had any durability issues at all banging wheels and retaining walls. I wish I could say the same for swedged tie rods.

[Super73]

I agree camber and caster needs to be looked at and could be of concern. One thing though, there is a possibility that this spindle will actually help my camber curve through out travel and here is why.

At my ride height, my lower control arm is level. My upper arm however is not. The ball joint end is higher than the frame side. If I were to have the camber set at 0*, then the camber would go positive as the upper control arm passes through the level point and then would go back to 0*, most likely becoming negative at full suspension travel. The upper control arm would technically get longer before it got shorter again.

By using the shorter spindle, there is a good chance the upper arm will be much more level or even possibly sloped the opposite direction. If this is the case, 0* camber at ride height would equate to only negative camber as the front rises simply due to upper/lower arm lengths.

Now caster, won't probably know until it goes on an alignment rack.

Bumpsteer, all together another thing to look at too. But I will say, with the 11" or so of travel I have in the front right now, I have never had a scary bump steer moment. I would think I would have a lot of change in tow through out that travel, just have not measured it. I plan to compare the C10 and MII once one side is put together.

[Oldtruckfanatic]

As long as your lower control arm and inner tie rod pivot at the same place and the arm and tie rod are parallel to one another bumpsteer shouldnt be a problem. I like the idea.

[Super73]

From what i understand if the length from center of lca pivot point to center of the ball joint is the same length as the inner to outer tie rod length the arc or radius would be equal. But if the starting angles differ they wont follow each other well causing tow in/out. Best way I can describe it right now.

[Operatorfailure]

I have been thinking of a similar thing to this but making my own upper and lower control arms. Some dom tubes, heim joints and those screw in ball joint sleeves and you would probably cut down another 10-15 pounds off each corner.

[Operatorfailure]

I was also wondering about the mustang spindle. How much drop does it give compared to a stock truck spindle? I'm debating using these for a drop in height and weight but I don't have a mustang spindle laying around to measure.

[Super73]

That are comparable to stock height. You would need a drop spindle.

[Super73]

So the qa1 ball joints have allowed the spindle to fit the control arms.

Notice the spacer required on the lower control arm. The lower ball joint is a bit long. After taking to qa1, this is the only option, I am ok with the spacer to properly seat the nut so the cotter pin can pass through.

The next thing I noticed is the rotor for the Willwood brake ever so slightly contacts the lower control arm. I am planning on cutting the tip of the lower arm to make it clear. I will take pics of that as I do it.

[Super73]

Duplicate post.

[IIGW]

they make aftermarket big brake kits for the mustang ii as well.

ditch them big heavy control arms for some wieght saving tube ones will help also

[Super73]

The big brake kits do not fit a15" wheel. I opted for the Willwood drag brake.

The bolt in tubular arms for our trucks are actually heavier than stock.