Project Report: Front Torsion Springs Remove and Replace

[Another JR]

Hi All,

 

I’ve mentioned in a few threads that I was planning to swap out the optional 5600 lbs FGAWR heavy duty camper springs and install the base 5200 lbs rated springs on my GMC 3500hd cclb srw gas truck. I just did the job this morning and wanted to report on it because it was actually quite easy. 
 

The parts (left and right torsion bars) totaled $570 with shipping and 10% WA sales tax from my local Chevy dealer. It was the same price as the on line dealers and the shipping pickup is more convenient. Plus I like them and want to give them business. My GMC dealer next door charges msrp for parts.  
 

The job took me 2.5 hours, but the first 20 minutes of that was figuring out how to properly jack and support it because it was the first time for me on that truck.  The torsion springs were not stuck at all to either the lower arm or the torsion key, and once they were unloaded everything came apart easily. My truck is 12 months old and I store it indoors so no rust. 
 

First thing is to set up for the job on a flat, level surface with gas tank near empty, and measure the height of the front suspension. I measured from the bottom of the wheel to the fender edge to eliminate tire deflection as a variable. 
 

Next jack up the front of the truck. I jacked each side separately on the main frame member just forward of the transmission mount crossmember, and supported the frame on the actual front jack point just forward of that. You don’t need to jack the wheels off the ground - just raise the front end about 3 inches to mostly unload the suspension. The rest of the spring unloading can be handled at the torsion key. However, you do want to jack it up at least this high or the forces on the tool would be higher than I would be comfortable having. For safety, always keep your head, hands, and fingers where they won’t get hit if the tool suddenly fractures. There’s a lot of force and a lot of energy stored, and you never really know how good foreign steel is. 
 

I borrowed the torsion spring unloading tool from Autozone’s tool loan program. They have both the smaller and larger tools for GM trucks, but they don’t have them identified properly in their computer system. The tool you want is the larger one - the CTA 4045 pictured below. The smaller gray one won’t fit. I did not have any clearance problem with the exhaust system putting the tool in on the right side. I had at least 1/4” clearance.
 

i counted the turns when i removed the torsion key adjustment bolt on each side and used that as my starting point for the new springs. It ended up being within one turn to achieve the previous height with the new bars.
 

Once the adjustment bolts are unloaded by the tool, you back them all the way out, and remove the piece the bolts thread into (can’t remember the name). Then loosen the tool to completely unload the torsion spring. Repeat for the other bar. Now wiggle the torsion spring and shift it forward, being ready to catch the torsion key when it falls off the end of the spring. Repeat for the other spring. 
 

Removing the frame member that contains the torsion keys at the rear end of the springs was two bolts, not excessively tight. The cross member is not heavy but you need to support it when you remove the two bolts because it doesn’t have clearance to angle much to one side or the other. It needs to come relatively straight down.  
 

Once the cross member is out of the way, the torsion springs slide rearward and come out. The springs typically are not perfectly straight, and mine were installed with the bow upwards. I checked my new bars and put a mark on them and installed them the same way. It probably doesn’t matter, but that’s what I did. 
 

Reverse all of that to reinstall everything, and reload the torsion springs the same number of bolt turns as before as a starting point.  After you take the truck off the supports, you need to roll it forward a few feet and back to relax the tires and get an accurate initial height adjustment. 
 

My plan is to drive the truck a bit and check the adjustment. Since I’m putting it back at exactly the same height, I should not need an alignment, but I’ll post in a few days if that isn’t the case. 
 

The general ride feel after the change is a bit softer. It’s definitely noticeable but not a large change.  It is very noticeably softer when I hit a larger bump or dip in the road. 
 

Here are some photos from the job:  

 

 

Edited April 27, 2022 by Another JR

[Another JR]

More photos:

[sheath]

Nice work.

Looking forward to reading a 6 month drive report to see your satisfaction after some time on the truck.

[Another JR]

I took my Four Wheel Campers pop-up off the truck to do this job and to add an external gray water tank.  I’ll post on the ride/handling difference after I have it back on for a bit. 

[Another JR]

I’ve had the camper back on for a month now and just got back from a long highway trip.  (My loaded pop-up slide in camper puts 100 lbs on the front axle and 1700 lbs on the rear axle.).
 

The difference going back to the base torsion springs when driving at highway speeds is very noticeable when going over bumps and dips. The suspensions response is well matched front to rear now, and the truck does not pitch nose up when hitting dips and bumps.  
 

After this trip I’m definitely glad I made the change. The suspension feels “right” now.  I highly recommend that, if someone bought the snowplow suspension but isn’t going to install a plow and isn’t putting a very heavy load on the front suspension, they should consider installing the base front springs in their truck.  It took me 2 hours and $570 to change them. 

[Ray@Paula]

On 5/30/2022 at 11:11 PM, Another JR said:

I’ve had the camper back on for a month now and just got back from a long highway trip.  (My loaded pop-up slide in camper puts 100 lbs on the front axle and 1700 lbs on the rear axle.).
 

The difference going back to the base torsion springs when driving at highway speeds is very noticeable when going over bumps and dips. The suspensions response is well matched front to rear now, and the truck does not pitch nose up when hitting dips and bumps.  
 

After this trip I’m definitely glad I made the change. The suspension feels “right” now.  I highly recommend that, if someone bought the snowplow suspension but isn’t going to install a plow and isn’t putting a very heavy load on the front suspension, they should consider installing the base front springs in their truck.  It took me 2 hours and $570 to change them. 

Thank You Jon, Awesome job & write up!! I can definitely see that it was well worth the work along with price. It's nice to know that having an unwanted snowplow package can be dealed with if needed. Glad it all worked out with your camper... Nothing worse than a harsh ride traveling cross country. This thread is a keeper!! Tganks again. Ray