Torsion bars needed source???

[scotmarechaux]

where can I find torsion bars for astro safari vans. 1994 and 2003. I have looked and find none.

[Herbie]

I think only Dorman has them now. I have been working with a custom spring maker her in California to try to get a run of stiffer-than-OEM springs made, but it has been slow going to get an accurate assessment of the range of lengths and end-sizes (and clocking) that will be the most "universal".

[Astrophysics]

Hi Herbie,

I found the fab shop in Chatsworth Ca called Sway Away. Today I called them and spoke with Brian on the phone. I told him that many of us Astro Safari AWD owners want firmer torsion bars so we can add heavy bumper and winch. Brian did say his spine end has 47 slices versus the 6 sided hex of original torsion bar. That will allow height adjustments and preload adjustments. His new bars are typically 15% firmer for the Chevy truck customers.



He said he can also make new thinner front sway bars if we want to get more articulation.

He can also make sway bar disconnect links.

My prototype disconnect link is kinda heavy at 1 lbs 10 oz each since the Uni strut Clevis P1973 is 1/4" steel.

AP

[Herbie]

That's who I was working with, but we kept getting stuck on settling on a length and hex-end size. I had had two different bars (left/right) drop-shipped to him from junkyards and apparently there were year-over-year differences. I will have to reach back out and see if we can't just settle on something and give it a try. Did it sound like he had something ready to ship? If so, that's great - I'll be right in line with you!

[MountainManJoe]

what would be required for creating a universal anchor point? Fabbing whole new lower control arm?

What about adapters?

[Astrophysics]

Hi Guys,

Brian mentioned one of his standard PN’s PN 1763.
I think it was a 52" long bar.

I need to look again on his web site.

He did say that the spring rate is increased by using slightly larger diameter steel.

Tomorrow I will measure the diameter and length of torsion bars on my 2003 Astro AWD and post the info.

AP

[Astrophysics]

Hi All,

Crawled under Astro 2003 AWD to measures OEM front torsion bars. The bars are about 1.09 " in diameter for the body of the bar with the ends expanding to larger material for the last 3 inches or so to accommodate the hex.
The total length are about 35 1/5" long with hex at both ends. The rear hex is about 1.41" across flats for drivers side.
The forward hex is about 1.75" for driver side aka Left side and is stamped 701 and has a CCW arrow with L.
Forward hex about 1.76" across flats for Right side passenger side forward hex and is stamped 702 with a Clockwise arrow and R.

Drivers side still had GM Part number paper tag, 15990701,
The rear hex drivers side Left was stamped AY 282; the rear hex was about 1.4125". Across flats of hex part of key.

Right side passenger side rear hex also stamped AY 282 and about 1.495" across flats of hex at key.

AP

[MountainManJoe]

35 1/5" long

[Herbie]

The length is one of the things that stymied the conversation I was having last year. Some of the bars are as short as 34.750, some are more than 36" long.

Since not everybody lists distinct lengths and part #s, and some list "interchange" parts, it's hard to nail down what lengths correspond with certain years. I've never been able to figure out if one length of bar will work for all AWD vans. I'm hoping so - if one length will work, and with the splined-adjusters, that should give maximum parts compatibility...

[Astrophysics]

Hi,
Good points.
The hex at each end seems to be about 3" long. This could allow some tolerance as the hex enters the key at the rear.
I need to read the shop manual again as it describes removing torsion bars after removing load and removing key.
I think it says to slide the TB (torsion bar) slightly to rear to clear cross bar and then pull it forward.
Aha! That is way the hex is 1.75" at the forward end, and only 1.49" at the rear. The bar can be pulled out from the front.

So, the key and the torsional load is what hold the TB in place.

There is tolerance in the design because the female hex tunnel can accommodate male hex of varying length.
This could explain the 33, 35, 35 1/2, 36" variations in total length.

It would seem prudent to design for the longest common TB length. And cut the hex or splines to be about 4 to 5" long on each end.

Just remember that the OD of rear hex is smaller than OD of forward hex.

This would be a good trip to Pic n Pull to carefully remove some addl TB samples.

At least the 36" length TB show be a little less expensive material wise compared with 52" long Chevy truck TB.


AP

[Astrophysics]

Howdy,

Front spring rare on AWD Astro options to increase spring rate:

1. New torsion bars with larger diameter to increase force needed to twist them.

2. Replace front shock with a coil over spring, but it is a tight space.

3. Re design front sway bar and sway bar end links to allow it to be a spring

4. Add Timbrin rubber spring to replace front bump stops

5. Add steel U channel Clevis from top of front shock mount that allows round steel shaft to extend and drops down to connect to inline coil spring that is secured to lower control arm.

AP

[Astrophysics]

Good news on AWD front spring rate increase!

eTrailer and Summit Racing , etc. sell the Timbren rubber spring kit,
PN TGM Fast4, which is $225.40 for the pair.
They are used on front of AWD Astros that need up to 1300 lb of extra capacity on front axle for vehicles with heavy snow plows mounted to front bumper.

This should also help with heavy brush guard bumper and winch.

These rubber spring replace the OEM jounce bumper with a hollow rubber spring

Yippee.

AP

[Herbie]

Nice!

For that price, it's certainly worth giving it a try until/unless we can nail down a torsion-bar upgrade. Adding that to my To-Do list!

[Astrophysics]

Hi,

I spoke with Summit Racing on phone today.

Timbren also has a PN TBI-GMFAST that is rated 2,400 lbs. it is also $225.40.

On Monday I will call Timbren directly on their East coast number 905 444-9004 to ask them for more details.

The 2400 lbs version looks a bit longer and stronger.

AP

[Astrophysics]

Hi,

Measured gap on the front bump stop on my 2003 AWD Astro which has heavy brush guard 80 lbs plus 80 lbs winch and winch tray.

About 5/8" gap, the rubber bump stop is about 2" tall.

The Timbren rubber spring should be a great way to increase spring rate and raise front end a bit without cranking torsion bar.

AP