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Rear torsion removal- not sure what to do next

I have removed the rear bolts holding the radius arm to the trailing arm and the assembly is hanging loose. I've removed the camber bolt. The toe in bolt is missing. I priced it at the dealer and they are $46 each! I measured the free hanging angle and it is at 32 degrees. I've calculated that I need to reduce this to 22 degrees to account for the stiffer 28mm torsion bars I hope to install one day.

I have the cover plate off so the outside bushing is visible. I thought the remaining assembly should pull off using two screwdrivers, but it's not budgeing. Do the two large adjustments bolts need to come off? If not, any advice on getting the assembly off is desperately needed. I don't want to damage anything out of ignorance.

I'm about this close to reassembling the entire thing and driving it to my mechanic.
Old 03-27-2003, 07:14 PM
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As ong as you removed the alignment bolts (or their missing) and you remove the 3 bolts that connect the rear of the swing arm to the banana arm, there are no more bolts holding it in place. I suspect just years of sitting have caused the torsion bars to get a pretty good grip. You do not have to remove the ride height adjustment bolts. Tru wiggling the torsion bar up and down, back and forth and it will free itself.
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Old 03-27-2003, 07:16 PM
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Sounds like you have all the bolts out. Your tbar is probably just stuck in the splines, unfortunately at both ends.

Try being more forcefull with the screw drivers.

Failing that, try taking the other side off. Once off you can reach into the torsion bar tube with a rod and know the tbar out from the back side.
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Old 03-27-2003, 07:17 PM
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I just finished this job on my 69. It took alot of wrestling to get the spring plates off.It's best to use a pry bar at the locations of each of the 4 bolts you have removed.Try to get the bushing to come out a little by working at each of those locations a little at a time. I t takes some patience but they will come out....also I blasted the inside of the inside bushing with Releaseall and let it sit overnight,this helped to loosen the torsion bar from the splines on the spring plate...
Good luck...
Old 03-27-2003, 07:55 PM
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Thanks. At least I know it's not some bolt holding it in place. After 24 years, I guess it's just frozen. I'll try soaking the bushing overnight and try again tomorrow. I have a feeling the other side is just as tight so I'll just work from this one side. If this doesn't work, I'll turn it over to my mechanic. This just might be the first job I've tried on this car that I couldn't complete.

However, using Wil Ferch's article I do think I have calculated the correct angle to set the ride height back after the new torsion bar is installed.

1) Using a level to form the top of the triangle and a protractor, measure the current angle of the radius arm hanging freely . This came out to 33 degrees.

2) Divide the single wheel weight (840lbs) by the spring rate for the current 24mm torsion bar (120 lb/in ) which gives a droop of 7.05".

3) Divide the single wheel weight by the new spring rate for a 27mm torsion bar which gives a droop of 4.43 inches.

4) Subtract the two gives 2.62 inches. Reduce the angle by an amount to make up this difference.

5) Using 1 degree = .25 inches, I would need to reduce the 33 degree angle by about 10.5 degrees, to about 23 degrees.

This should put the rear ride height back in the range of 24.5 inches which is where it currently sets.

Now if I can just get this damn arm off so I can test the calc.
Old 03-27-2003, 08:25 PM
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Pry bar works well. Just make sure to back it with some cardboard so that you don't gouge a hole in the undercoating.

Not sure if you took this into account, but don't forget to include the angle of the car when you measure the radius arm, otherwise your final measurement won't be what you expected.
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Old 03-27-2003, 08:54 PM
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Quote:
Originally posted by Neilk
Pry bar works well. Just make sure to back it with some cardboard so that you don't gouge a hole in the undercoating.

Not sure if you took this into account, but don't forget to include the angle of the car when you measure the radius arm, otherwise your final measurement won't be what you expected.
My car is up on stands in the rear. I'm thinking that I removed the issue of the angle of the car from the equation by using the level (see pic). Unless my logic is wrong, if I use the level as my reference point for both the current set up angle and new set up angle, the calculated reduction should be the same. I used a jack to adjust one end of the level. What do you think? Ignore the fact that at the point the picture was taken, the radius arm was still connected to the trailing arm. I was just testing the setup at that point. I took the actual angle measurement with the radius arm hanging free.


Old 03-27-2003, 09:11 PM
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Autobonrun:
You can double-check your calculations using Tom fitzpatrick's software where you simply plug 'n jug some numbers. Check Archives under any of our names or "vintage bus"...
See http://www.vintagebus.com/

----Wil Ferch
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Old 03-28-2003, 05:40 AM
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I'm going to take the liberty of piggy-backing on this thread since my question relates to Autobonrun's activities.

Where would I get a an "Angle Finder" as pictured in Bentley's manual to measure the angle of the torsion plate? I hope to adjust my height in the next few weeks and think the tool will make it easier.

TIA,
Bill W.
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Old 03-28-2003, 05:47 AM
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Harbor Freight has one for $5.
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Old 03-28-2003, 06:27 AM
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Bill: The angle finder can be had from any tool supply house, esp. those that serve machinists.

Autobhan: Yes, as long as the base level you are establishing is used identically for both the before and after angle you should be fine for determining the difference you want to achieve.

John
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Old 03-28-2003, 06:28 AM
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BTDT. To remove the spring plate with bushings, I bought two different styles of crowbars from Home Depot. I needed both types, as the leverage angle and access on the passenger side (with oil thermostat) was different from the driver side. As others have suggested, I used a wrench between the body and crowbar to minimize any damage. There was no way screwdrivers were going to give the leverage needed. I struggled for more than an hour, and after returning with crowbars from HD, both sides were off in five minutes.

Home Depot has those angle finders also. Sears might as well.
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Old 03-28-2003, 06:55 AM
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Here's another way to skin the cat.

I knew my free hanging angle needed to be 22 deg. (thanks to Wil and Thom's number crunching telling me what the angle should be for a 29mm rear bar). I made a rigid cardboard right triangle with a 22 deg angle in it (drawn with AutoCad) and held a torpedo level on the back of the triangle. While holding the triangle level, I check to see if the spring plate is parallel with the hypotenuse/diagonal of the triangle. Once I get the spring plate parallel with the the triangle, I push the spring plate and torsion bar into the torsion tube to engage the splines.

If the splines don't engage, you can reindex the splines or adjust the spring plate angle with the adjusting eccentric.

Obviously the cardboard triangle method only works for one application. The angle finder tool works for whatever angle you need to set. I just don't like how the angle finder wanders all over the place.
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Old 03-28-2003, 07:33 AM
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Kevin,

I did the same thing using MS Paint to make find the correct angle for my brake pistons. I drew a line then shifted it 22 degrees (can't remember the exact angle) and then drew another line intersecting the first line. I printed it out and then traced that pattern onto cardboard.
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Old 03-28-2003, 08:59 AM
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Auto,

Your level setup will certainly work. I just added an extra step by making the cardboard template and thus eliminating the need to measure the "leg" of the triangle each time. The "leg" being the calculated amount that you would measure down each time (to a fixed point on the spring plate).

Neil,

Yep. I too did that for the brake piston angle as well.

I have these two cardboard triangles in my tool box and i'm sure people would pick them up and say what the heck are these for??????
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Old 03-28-2003, 09:21 AM
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can somebody post a drawing of these cardborad things I need to make?
Old 03-28-2003, 11:00 AM
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Here's how I made mine



I used a small torpedo level. Not all that accurate, but doesn't need to be with adjustable spring plates. You could make a larger triangle and use a slightly larger level if desired.
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Old 03-28-2003, 11:58 AM
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Kevin,

Did you take into account the angle of a car on jackstands? If you didn't, your 22 degree angle might be off by 3-5 degrees.
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Old 03-28-2003, 12:13 PM
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My floor is relatively level (only about an inch of grade between the front and rear jackstands) and the same four stands are put under the car at the same height setting.

Still, you make a very good point Neil. Something my simpleton brain did not consider. I do recall the final angle at which I set my spring plates was not exactly at 22 deg. But, at least the triangle method gave me a good place to start.

Thanks!
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Old 03-28-2003, 12:17 PM
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Thanks much for posting the diagram. Let me see if I have this right -- I want to change to different size torsion bars (F&R). So I....
1. Measure the angle of the R spring plate with car on flat level ground suing a bubble level to find the horizontal.
2. Plug that into Will's calulator with wt. info etc. and get an angle out.
3. Then when reassembling, I set the R spring plate with the new, different R torsion bars to that angle as above.
4. I make any small adjustments with the sliding nuts on the spring plates.

Correct?
Old 03-28-2003, 12:28 PM
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