Upper control arm positioning.

fastmonkeywheel · Aug 18, 2006

I'm in the process of replacing the control arms on my 78 Coupe. I just bolted one Upper arm in and noticed that one of the two holes that go through the bushing shaft allow for the control arm to piviot. The rear hole in the frame is rectangular cut instead of square allowing the control arm to piviot. My Haynes manual doesn't say anything about this so I'm a little lost as to where I should position the control arm.

I know many of you have replaced these arms and I'm curious if yours had this pivioting action or if I'm just special.

Thanks for the help, soon to have another II on the road...this one turbo charged.

THE COBRAMAN · Aug 18, 2006

The arm should have in/out travel at both bolts where they pass through the unibody structure. This is how caster/camber is adjusted. I suspect that one of the slots is full of... ahem.."crud". If you didn't make a note of where the arms were before, you'll just have to hit the middle of the slots and get it aligned as soon as it's back together. Good luck finding somebody that will take the time to do it properly. It's a PITA without the OTC tool set (LONNNNNNG out of production).

fastmonkeywheel · Aug 18, 2006

Oddly enough only one of the holes provides for travel. I've removed all loose crud that could be blocking the hold. I have some pictures of the reassembly that I'll put together in a pdf tutorial so someone contemplating this job can see it done. Took me damn near an hour just to get the passenger's side spring in, I hate doing springs. I still have the driver's side to do tomorrow so maybe my procedure could use some fine tuneing.

I attatch the upper control arm to the frame and the spindle to that. I connect the lower control arm to the spindle and put a bolt through the shock absorber hole to provide a place for the jack to catch on. The spring gets allighed in the lower arm and positioned in the frame at the top. I push the whole assembly under the car, slightly compressing the spring and position a tire underneath, I fit the jack on the tire, under the lower control arm and start jacking it up. I see where the control arm bushings are in relation to the frame holes and lower the jack again to relieve some tension in the spring to slide the tire around with the jack to position myself for my next attempt. I put screwdrivers in the lug hole in the tire to keep the jack from sliding around.

I played around with many different attempts doing this part of the job, I spent a good 2 hours just trying many different things, and finally the tire thing seemd to work. I ran into issues with the car raising off the jack stands before the lower control arm was still an inch away from the frame, but positioning the jack under the control arm further towards the bolt holes helped, but I still had to put some weight on the car.

I still have more work to do before the car's road worthy, but an alighment is deffinitially the first place I'm going, then the exhaust shop. I'll check around and see if any place in town can adjust the chamber/castor of these cars. Is there a specific question I should ask? I'm sure if I ask if they can adjust the castor/chamber for a 78 mustang they'll say yes but possibly not do it.

Thanks for the responce, I'll post some pictures when I'm done. I sandblasted and painted everything that isn't being replaced and am replacing the control arms, rotors, all bearings and seals...it's looking really good, I'm doing my best not to bang these parts around getting them on so the paint doesn't chip...but it's holding up really well.

THE COBRAMAN · Aug 19, 2006

Well, they really won't have much choice since you had it all apart. Frequently, they just set the toe and call it good, at least at the cheapie places. Old saying in the biz..."set the toe, collect the dough, let it go".

One issue to be aware of..I have found that often you have to double up on the strut rod bushing washers (install 2 washers, then the bushing) to get the ball joint far enough forward to be able to get both caster and camber in spec. Seems that as the cars age, the bushings that hold the strut rod mounts allow the mounts to go back slightly. This results in the outboard end of the lower control arm being too far back. It's apparent on many IIs in the form of the wheel being rear of center in the well when viewed from the side.

I use later fox body springs in mine as I find the OE spring rate too low for my taste. I generally use a 4 cyl '84 or so spring. The rate is quite a bit higher, the spring diameter is within a few hundredths of the II spring, and a side benefit is that they are usually slightly shorter, which makes installation easier. I generally install the upper arm/spindle, then install the lower arm into the crossmember, then jack the outboard end up and install the nut on the stud. I do have access to a lift, so that helps as opposed to rolling around on the ground.

Oh yeah, ALWAYS ask for a spec sheet (printout) of the before/after settings (at the very least, the after) when you drop the car off. Make sure to ask before they do the alignment. Many shops routinely print them, but most do not, unless you ask. If they won't provide one, find another shop.

Lastly, don't assume that everybody understands the concept of the angles in an alignment. The local Goodyear store has no clue whatsoever, nor do most franchised tire dealers (Tires Plus, etc). There are exceptions of course. We had to teach the shop that we use at work how to diagnose suspension problems as they relate to collision repair. You wouldn't believe how many times I've heard "frame damage" when the actual problem was a suspension part. Got so bad at the last shop I worked at that we bought the equipment and (I) started doing them in-house.

Wart · Aug 19, 2006

Monkey,

Your doing this with a BOTTLE JACK??

You have a bigger set of Cahones than I. A floor jack with the ball in the lifting pad is MUCH easier, and lots safer.

Cobraman,

By what your stating we would be further ahead setting our own front suspensions at home with a machinest protractor, steel rule, chalk and tape measure instead of taking the car to many shops.

fastmonkeywheel · Aug 19, 2006

We have one shop around here that specilizes in alignments, it's all they do. I had them do my 90 GT when I replaced the ball joints. They even took the car for a road test to check steering wheel alignment. Their normally 2 weeks booked, so these guy keep buys...oh and they charge $35 for the same alignment other shops charge $50.

...

Oh, and I'm not sure where you got the idea that I was using a bottle jack, that's just crazy...lol...I used 2 2-ton floor jacks. One more centered on the lower control arm and the other used at the end to help allign the bolt holes.

...

Maybe my springs are taller that yours, Cobraman, but there's no way I could get the spring into bother perches if the lower control arm was bolted to the frame like you make it sound like. I should try the 4cyl Fox springs, I have a 4 cyl in there now anyways, and have the 6cyl springs that were original in the car.

fastmonkeywheel · Aug 19, 2006

The driver's side spring install went like clockwork using yesterday's method. In 3 hours we completly installed everything on the drivers side (minus strut bar and sway bar, still waiting for bushings) and everything spindle onward on the passenger's side. Here's a picture of the completed drivers side

<a href="http://photobucket.com" target="_blank"><img src="http://i101.photobucket.com/albums/m64/fastmonkeywheels/Suspension_Drivers.jpg" border="0" height=50% width=50% alt="Photobucket - Video and Image Hosting"></a>

Also here's a picture of the engine compartment, I still have a few things to do but it's about 90% done, it starts and runs too...

<a href="http://photobucket.com" target="_blank"><img src="http://i101.photobucket.com/albums/m64/fastmonkeywheels/EngineComp2.jpg" border="0" height=50% width=50% alt="Photobucket - Video and Image Hosting"></a>

Wart · Aug 20, 2006

fastmonkeywheel said:
...

Oh, and I'm not sure where you got the idea that I was using a bottle jack, that's just crazy...lol...

My misread, when you wrote about putting the shock bolt in to use as a lift point, I forgot there are floor jacks with small enough pads to fit inside the lower arm.

Looks good. Have fun!

78CobraII · Sep 16, 2006

Fastmonkey,

Any progress?

The suspension looks great, I can't wait till mine gets to that stage.

I would think that an option loaded 2.3L car would weigh about the same as a stripped 2.8L car, so the V6 springs might not be that far off. If the front is in the air after you get it drivable, then they are too strong. Otherwise, no worries.

What about using an "inside" spring compressor to install the spring? I figured that I'd have to chase one down as I could never get a set of externals to compress the spring enough to get the front end dissassembled. One thing I learned is that you can forget about getting the spring back in with a floor jack unless the engine is installed to hold the nose down!

I saw the OTC MII alignment kit on eBay a few years ago. It seemed to go pretty high, now I know why. I bet that the MII used parts guys have a few. They could probably make some bucks renting them out!

The upper control arm mount is less than perfect. A lot of cars with similar designs bolt the pivot shaft to a vertical flange and use washers to set camber. The advantage is that you don't need the specific adjusting tool to move the arm (just a big hammer ), and the settings can't slip.

Upper control arm positioning.

fastmonkeywheel

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THE COBRAMAN

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fastmonkeywheel

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THE COBRAMAN

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Wart

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fastmonkeywheel

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78CobraII

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Upper control arm positioning.

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