Okay, might have solved the DIY corner balance/alignment
 

The issue for most of us doing the corner balance and alignment in our garages is a level place to put the car, and more importantly, access to the adjustments under the car.

Here is my solution:

Start with a set of these bottle-jackstands placed under the control arms up front, and the trailing arms in the rear. The key is they are under the suspension, not the body.

http://www.alltradetools.com/catalog...jack-stand.jpg

Now, you have to level the car. I used the bucket water level trick for this. Fill a bucket sitting next to the car with water, and using a length of tubing long enough to reach each corner, add water until the level reaches any repeatable point on the wheels. I used the bottom edge of the wheel. This eliminates tire pressures as a variable. Don't forget to put your weight in the driver's seat.

Using the individual bottle jacks, set all four corners level.

Now you can measure ride height from the water level to the torsion bars front and rear, with similar measurements side-to-side giving a good indication of balance. Using the factory ride height measurements as a ratio can be translated to a lowered car, and maintaining the ratios front-to-rear should yield the correct front/rear weight bias.

From here, I use the strings to set toe, and a simple digital level for camber.


This method should get you very close, and it is repeatable in any garage, regardless of slope issues. I found the access to the adjustments to be the biggest hindrance to performing alignments at home. These simple jackstands address the issue without breaking the bank.


EDIT: placing the jackstands under the trailing arms and control arms will not result in accurate ride height. Place them under the hubs as shown later in the thread. Also, after plenty of feedback, this method should be converted to the tripod method for accuracy when corner balancing, so the opposite corners do not affect the measurements. Simply jack the car at the center of each end, and lower the jackstands from the hubs to provide the trianglulation.

I can't stop looking at your avatar :)

I think that's a clever sounding idea. Would it be possible to use a laser straight edge to set toe? That would eliminate strings, and seems like it could be pretty accurate.
Thanks,
Dave

Interesting concept. Wont the jack in the rear being placed under the trailing arm hinder movements for any adjustment? Especially toe.

Any toe measuring method should work.

I placed the jack near the drain hole in the trailing arm, plenty of access to the adjustments. I'll snap some pics later today.


edit: I misunderstood your comment. It may indeed hinder movement for toe adjustment. I'll take a closer look. I have not adjusted toe yet, as I'm still dialing in corner balance. It seems that the small amount of movement needed at the rear for toe should not be hindered by the presence of the jackstand under the trailing arm.

Great try but it wont be super accurate because the Force is acting through the control arm where the jack makes contact instead of the hub/wheel/tire. This shortens the moment and the force on the T bar so it wont deflect as much. If you removed the wheels and used it on the brake disc (not sure this is a good idea?) it would be closer. Still have the same toe adjustment problem. Maybe you could set them on two greased plates....might mess up the stability.

I think I want to get one of those jacks.

The amount of movement required is going to be very small, so I think the adjustment will work. In any event, if rear toe is the only adjustment I have to compromise, I think it's a win. I can adjust rear toe on the ground with greased plates. Being able to do the corner balance, front toe and camber is worth the setup.

I dont think it will work for ride ht either if you are under the control arm. Might be up as much as an inch? And if the ride ht is elevated that much it wont be in the right spot to set the camber. You could probably figure out the ratio but it would be easier to mount it to the lug studs somehow then it would apply the force the righ distance from the T bar.

I am suprised no one makes one of these with an adapter to the wheel studs. That would be trick but limited applications I suppose.

Ride height measurements taken from the bottom of the wheel (water level) to the center of the torsion bar. It would not be different if the tire was on the ground. The key is that the car is on it's suspension when measured.

Zoa,
What an avatar!
I'm probably six months away from corner balancing/aligning my RST project so your thread is most appropriate.
To take Erik's point, could you not do the corner balancing on the rotors and then the toe/ camber adjustments as you have described? BTW, I think that the rotors are plenty strong to take static weight if you use open lugs to tighten in the rotors (depending on what brake system you have). I would put on some old ones for this purpose as extra insurance prior to installing the calipers.
Where can I get those jack stands?
Cheers,
Johan

I got the jackstands at a local auto store. I think I've seen them at O'Reilly's, Autozone, etc.

Erik has me thinking about the jack point in the rear, and I can't see where putting the jack under the rotor, or even attached somehow to the lugs would change the readings, since the whole assembly for the hub and axle attachment is rigid. Shouldn't matter where you lift. It wouldn't be very difficult to make a pair of adapters that fit into the jackstands to attach to the lugs though.

what if you put a 1" or 1 1/2" spacer on the lugs, slide it just off the hub, and use the bottom of the spacer as your jack point??

That would probably work. It might be easy to weld up a circular disc with lug holes in it to a post that fits into the jackstand. I'm not sure it would be necessary though. The car is currently sitting with the jackstands under the trailing arms, and I think it will work. I'll know more when I've finished setting the ride height and can start adjusting the toe.

Maybe think about it like this. If you have a 1 foot lever and apply 100 lbs of force to it you are generating 100 ft/lbs of twist at the end. If you shorten the lever to 6 inches and apply the same 100 lbs you are only generating 50 ft lbs. So if you have the jack stand 1/2 the distance from the tire to the mounting/pivot point of the lower control arm you are only putting half the twist on the torsion bar that it sees from the tire so the car wont set down to its ride height.

I disagree. Rideheight can be correct and balance way off on the diagonals.

For example, lower RF and LR, then raise LF and RR to the same height. Balance will be way off.

Maybe I'm missing something here, but this seems like it will get you set on your base ride heights, but not corner balance.

My understanding is that once the initial heights are set, you check the weights and make minor height adjustments to get the cross weights equal.
I'm sure others will chime in here to help clarify.

Erik, I see your point now that I'm home and looking at it. Back to the drawing boards, but I'm close! The jackstands give great access to the adjustments, and allow leveling. I just need to made adapters to mount to the hubs.

Right, but if you have no scales, this method is similar to the tripod method by using ride height measurements at the corners.

We use "HubStands" at the race shop. Also have alignment rack w scales. No difference in end result between HubStands and alignment rack. HubStands much easier to travel with.
Check their website, may give you some ideas.

Matt

We use "HubStands" at the race shop. Also have alignment rack w scales. No difference in end result between HubStands and alignment rack. HubStands much easier to travel with.
Check their website, may give you some ideas.

Matt

Sounds so nice, I had to say it twice.
Sorry for double post.

Just so we are clear - this will give you an excellent ride height setting but will not give you a corner balance. Corner balance is all about finding an equilibrium between the two cross weights by adjusting the ride heights not equalizing them. I don't know of a way to do a corner balance without scales.

jittsl look up the "tripod method" its not scale perfect but its pretty good, especially for a street car and you can do it in your garage.

Actually I think these jacks would allow pretty good tripod corner balancing but not ride ht unless you can adapt them to the hubs.

OK, a simple resolution. Drilled a steel plate to fit over two lug studs, creating a block for the saddle of the jackstand so it won't slip off the hub. Viola!

http://i109.photobucket.com/albums/n...8B6BAA1902.jpg

The front hubs are already sloped inwards.

http://i109.photobucket.com/albums/n...5DD3EED5F3.jpg


Now I can set level right at the center of the hubs with the water level, and the toe and camber adjustments should be much easier to reach. Toe and camber measurements can be taken right off the surface of the rotors.

Lot of creativity and ingenuity her. Best solution I came up with was going in with another pcar guy and buying a set of used Longacre scales for $500 from dirt track guys. Or you can get a set of proform scales new for under $700....not pro a quality but fine for hobbyist.

Now we are cooking with gas.

Ok let me take it one step farther - this is out there in the ether a bit......what if you bolted a simple plate to the side of the jack with holes for the lugs and....and....bolted a big caster on the bottom of the jack stand! then it would not bind when you were adjusting toe and camber and you wouldnt have to bounce the car etc.

I think they sell those big casters at HF for cheap.

Oh wait they would just roll out from under the car. Have to attach the jack stands to each other and they would not move freely.

Dern it....this jack stand jack is really greasing the wheels though. My Tractor Supply has them on sale for $39.

Can you show a pic with the water level attached?

Thanks Jim, that's exactly what I've wanted to avoid. I wanted a repeatable method I could use for my race car, but at home in my shop. I plan to set the car up using this method, and then get it on a set of scales and verify the method.

yeah, I was thinking the exact same thing, but it starts to get silly. I think there is enough movement on the jackstand saddle that it shouldn't bind too much when adjusting. I'll run back out to the shop and grab a pic of the water level setup....


Here's the bucket sitting on the lift table i use to drop the motor:

http://i109.photobucket.com/albums/n...6C1FEFF37A.jpg

and a closeup on the tubing showing the water level at the hub:

http://i109.photobucket.com/albums/n...3B62ACABCB.jpg

OK new Crazy idea

What if you attached a large bolt facing up through the saddle of the jack stand. Then made a simple plate assembly that attached to the hub that had a spot for the end of the bolt to rest in. Essentially each wheel is then resting on a point so you could adjust camber and tow with out much binding.

Would that be secure enough to work under or could that roll off? Nahh that wont be safe either

The only binding I see here is gonna be caused by the saddle of the jackstands as I adjust toe, but I'm only gonna want a sixteenth toe in on each side. Camber shouldn't be a problem as it leans, and the spring plates are ride height adjustable with a single large hex head set screw.


Thanks for making me rethink the jackstand location. I think the method got better.

I was thinking of an inverted angle iron piece on top of the jackstand post instead of a saddle, so that the hub rested on a single edge, allowing full movement, and maybe a large round plate that overhangs the lug studs all the way around instead of just the plate covering two.

Okay, I've spent some time measuring, and I've had to massage a bunch of numbers because my car is race-prepared, so it is significantly lower than factory. Front spindles raised 19mm were causing my math to be skewed, but I managed to finally remember that. So, the factory method of ride height measurement calls for 16mm of delta between the rear hub center and the torsion bar center, with the t-bar above the hub. Mine is 60mm below the hub, yielding a total drop of 76mm.

The front factory numbers show 108mm delta, with the t-bar below the hub. Mine are 198, but once you factor in the 19mm raised spindles, and the 76mm drop, I'm sitting at 103mm, which is 5mm too high in the front. This is when I realized I don't have a full tank of gas per the Bentley instructions. :)

Once I get the fuel load onboard, this method should yield reasonably accurate corner balance and ride height. Then I can begin the toe and camber settings.

I like your idea, and you could have a little lip on the angle iron so if the car tried to roll forward the plate would rest against it. It will be interesting to see if the spindles can move in the saddle when you do the toe adjustments. I suspect they will move plenty and it will work briliantly. How accurate is the jacking mechanism? Can you make fine adjustments ok to get the car level?

The jacking is typical of a bottle jack, which is very fine. Definitely within a millimeter accuracy.

What I need to do now is to clamp a 16 inch long straight edge across the rotor to take my toe measurements. The camber will be easily read with a digital level against the rotor surface.


When all is said and done, I believe this will be a very accurate DIY method, for the cost of four of these jackstands, a bucket and some tubing. Far less than a set of scales.

Did I miss the balance part of all this?

The balance is achieved through equal measurements side to side, and maintaining the same ratio front to rear as the factory numbers. Same theory as the tripod method, but more accurate, IMHO.

Still not seeing how you balance anything here.

Then re-read it.

Level the car with the jackstands at the hubs.

Measure the deltas to the t-bars at the corners. Set the heights per the factory ratios. Balanced.


There is no magic here. Corner balancing is performed by adjusting ride heights at the corners. This method merely provides a method of leveling the car, and access to the adjustments.

Except that you are making assumptions that are just not true. A perfectly level 911 is not very likely to be balanced. If a 911 was a perfectly rectangular solid object made of one material with consistent density, your method would work. But, that is not the case.

Yes, corner balancing is performed by adjusting ride heights at the corners. But, weight is not distributed evenly side to side along the longitudinal centerline of the car. That is why some sort of real balancing needs to done.