I've searched but can't find answer - IRS Rear Torsion Bars

jjjtttggg · Post by **jjjtttggg** » Sun Mar 29, 2009 8:58 am

I'm looking to raise the rear of a 69 beetle - IRS suspension. My thought is to go 1 outer spline which I understand will be a 9 degree change in spring arm angle.

I know that the preload in the torsion bar makes this a dangerous job if not done correctly and I've never done it before so I will be taking every precaution. On top of that, I want to understand as much as I can about the job so I have a good mental picture of what to expect.

I've read every thread I can find on the subject, so I know the basic process. Two things, though, I haven't been able to find that I kind of want to understand before I start . . .

1 - How far will the spring arm typically rotate once it clears the stop before it is completely unloaded? I know this will vary depending on how the suspension is set up, but assuming it's a typical stock beetle with a little bit a age related sag (like mine), what might I expect?

2 - When I pry the spring arm out to get it over the stop. What is moving actually? Is the torsion bar sliding part way out of its fitting in the tube, is the spring arm sliding part way towards the end of the torsion bar, or is the spring arm itself just bending/flexing? Maybe a combination of the three? My concern is whether there's any chance of the torsion bar coming free at either end before the spring arm clears the stop. I'm hoping there's plenty of engagement on both ends to prevent this from happening, but want to understand before I try it.

Thanks for any info. . .

J

Post by **david58** » Sun Mar 29, 2009 9:06 am

Look at this sticky in th newbie forum.

How to Kick Start your Vee-Dub
http://www.shoptalkforums.com/viewtopic.php?t=117123

How to Set preload on rear torsion springs
http://shoptalkforums.com/viewtopic.php ... sc&start=0
How to Lower Your Bug
http://www.shoptalkforums.com/viewtopic ... highlight=

jjjtttggg · Post by **jjjtttggg** » Sun Mar 29, 2009 10:50 am

Thanks David58,

Yes I have seen/read those threads. The one about setting preload almost answers one of my question. He shows a picture with the arm off the stop and rotated way down. It seems from the wording that this is will the preload now off, but with the safety tool in place, I don't know that it isn't just part way relieved.

Thanks again for the links.

J

Post by **FJCamper** » Sun Mar 29, 2009 4:00 pm

Hi jjjtttggg

When you pry the spring arm off the support -- and have a safety tool to control it -- when you fully unwind the tool the spring plate will rotate down and touch or almost touch the ground if you're on a set of jackstands that place you at just above normal ride height.

And, when you do start prying to get the spring plate off its stop, and then to get the spring plate off the torsion bar, you are probably going to pull the torsion bar out of its inner spline socket.

That's why everybody stresses marking, marking, marking, before you disassemble.

FJC

jjjtttggg · Post by **jjjtttggg** » Sun Mar 29, 2009 9:42 pm

Thanks FJ,

That's what i wanted know on the spring plate rotation. Thanks! On the question of coming out of the inner spline. Can it come out before I've cleared the stop and relieved the pressure of the preload? That's what I'm worried about. I'm sort of assumming that both ends have enough engagement that you can pry the thing apart enough to clear the stop and relieve the pressure before the splines on either end clear their sockets. If I'm wrong I want to know about it beforehand as it would seem that it would be a rather violent event if the torsion bar came free on either end while still under load. I'll be taking every precaution so that the car won't hurt me, but if something gives way suddenly, when I'm not expecting it, I'm afraid I'll hurt myself!!!

Best,

J

turbobaja · Post by **turbobaja** » Mon Mar 30, 2009 7:05 am

Your torsion bars have enough splines on either end to stay engauged once they are completely off the bump stops and hanging down at a relaxed angle. This is when you want to measure the angle your plates are at before completely removing the spring plate(s). Scribe a line along the top of the spring plate with a flat-blade onto the torsion housing for a reference line during reassembly if necessary. If you don't make some kind of notes on where you're starting you'll never know where to put them back on to raise/lower it like you want.

Be safe with that spring plate loading/unloading. They make a tool for the job that's cheap and works well. I use the one that hooks over the body mount bolt head just above the spring plate and has a large wing nut to load/unload the spring plate tension by hand (with gloves). Works good.

jjjtttggg · Post by **jjjtttggg** » Mon Mar 30, 2009 9:49 am

Thanks Turbo,

That's what I wanted to know. I will definitely be careful.

Thanks again,

J

jjjtttggg · Post by **jjjtttggg** » Mon Mar 30, 2009 12:07 pm

Another question. . .

Does anybody know the maximum working angle for standard type 1 CV joints?

J

kangaboy · Post by **kangaboy** » Tue Apr 28, 2009 7:53 pm

jjjtttggg wrote:Another question. . .

Does anybody know the maximum working angle for standard type 1 CV joints?

J

ditto...ive seen the conversion chart of what spines put you at what degree or angle...but not the max angle aloud with stock cv's (irs rear).

Post by **Marc** » Wed Apr 29, 2009 3:34 am

From blindchickenracing.com:
Type 1 is 12 degrees
Type 2 is 17 degrees
Type 4 is 22 degrees
930 is 25 degrees