GM 1/2 ton truck owners; experiencing broken leaf springs?

[Jstpssng]

Many of the 4WD GMs have blocks now. That only makes the twisting forces on springs worse. Blocks are never good.



Isn't going from 3 leaves to 5 leaves just adding leaves? Overloading is an obvious cause of broken springs, but another factor is spring twisting caused by aggressive braking and acceleration. When some of these guys put the peddle to the metal with ~400hp/400ft.lbs., those springs get quite an S bend in them. The blocks only make the problem worse. Adding a leaf will usually improve the situation along with better shocks for the pothole problem. Be a little careful in adding springs, as there's a lot involved with building a spring pack. Your results will vary. The idea is to cut down spring flexing and twisting. Thin leaves usually do a better job at not breaking as long as they don't get overloaded. Oh, and don't forget about those driveline angles.



That's normal with many springs. It has to do with design and ride height.

Yeah, i was being rather redundant. It seems like the 3 thicker springthey are putting in now don't flex as well and break instead. If it was my truck I would consider replacing them with an older style with 5 thinner leaves.

 

[RayCo]

Just curious about this as far as a general driving habit thing, but are you one who slows down for speedbumps?

 

[crazyal]

My Tundra has a couple of broken leafs. Of course when building my house I would routinely load it with 24 to 30 sheets of 8' and 12' sheets of 1/2" sheetrock. Riding for 25 miles on the bump stops really isn't the best idea.

 

[RickB]

More truck springs break running empty on rough roads than loaded or overloaded in any conditions. Late winter/springtime driving conditions are great for the suspension business. Ask anyone involved in the trucking business when spring suspensions were typical on OTR and heavy trucks.

 

[bdeboer]

I had a '99 1/2 ton for six years without breaking springs. Currently have a 2005 stays loaded with tools etc. year round. No trouble with springs.

 

[zzvyb6]

Adding leafs to a spring pack does two things to the vehicle. It adds damping via friction because of the sliding between the leafs during compression. That's good for durability and overstress reasons because it keeps the dynamic loads down relative to the static load. The bad aspect of this is the ride quality degrades because the friction lessens travel at light load variations (like driving down a smooth road).

The other reason to add leaves is to produce a nonlinear ride rate and to taylor it so that the ride is smooth and pleasant when the truck is empty and to increase the rate when the load increases. This keeps the vehicle off the bump stops at max static load.

You'd be surprized at how many owners (and even dealers) remove leaves from the HD packages because of compaints by owners about the ride quality.

All of these changes require a shock tuning change because the ride and dynamic loads are affected. Aftermarket shocks add a lot of extra load because they want you to know that you got something for your money by the large change in ride. The OEM shocks were designed for ride AND durability considerations. Your Grand BullDoggie xTra Basher shocks will probably wind up breaking the shock mounts which could eventually lead to spring breakage.

Then there is the aftermarket tire effect. An aftermarket tire which is OK from a static balance but is way off in dynamic balance will eventually weaken the material in the steel spring. This affects mounts as well as shocks and springs.

Show me a failed spring and I can probably find the reason for it in the aftermarket or an owner modification.

Been there in the design and specification of chassis parts for GM. We even have to account for 'foreseeable misuse' by owners and operators. That means the 6 sigma owner will put in the truck as much as they can, regardless of tire, axle, spring or seat load limits or recommendations.

You would be surprized at the number of 'expurts' who modify the spring packs by either adding or removing spring leaves to the existing pack or adding lift kits to add the 'Hazzard County' effect. Others do something called 'bulldozing', where they deliberately overload the truck (at both ends even), in order to 'improve' the look of the truck. There is another technigue used which involves using a torch to soften or weaken the springs (both coil and leaf type), in order to add that 'We Be Bad' look.

None of these techniques is recommended. All have some serious safety and durability consequences.

What's funny is how often you see a used truck for sale and can see where the owner tried to remove or hide their 'improvements'. Now why would they do that? These are the ones we see in the courtroom where the manufacturer was blamed via a 'design defect'. These claims and disproving them bought me a nice house, property and some nice farm machinery.

 

[Jstpssng]

Just curious about this as far as a general driving habit thing, but are you one who slows down for speedbumps?

Yeah, that's one thing that frustrated me after the last time my springs were replaced; how come all the people blasting past me when I slow down never have any problems?

Adding leafs to a spring pack does two things to the vehicle. It adds damping via friction because of the sliding between the leafs during compression. That's good for durability and overstress reasons because it keeps the dynamic loads down relative to the static load. The bad aspect of this is the ride quality degrades because the friction lessens travel at light load variations (like driving down a smooth road).

The other reason to add leaves is to produce a nonlinear ride rate and to taylor it so that the ride is smooth and pleasant when the truck is empty and to increase the rate when the load increases. This keeps the vehicle off the bump stops at max static load.

You'd be surprized at how many owners (and even dealers) remove leaves from the HD packages because of compaints by owners about the ride quality.

All of these changes require a shock tuning change because the ride and dynamic loads are affected. Aftermarket shocks add a lot of extra load because they want you to know that you got something for your money by the large change in ride. The OEM shocks were designed for ride AND durability considerations. Your Grand BullDoggie xTra Basher shocks will probably wind up breaking the shock mounts which could eventually lead to spring breakage.

Then there is the aftermarket tire effect. An aftermarket tire which is OK from a static balance but is way off in dynamic balance will eventually weaken the material in the steel spring. This affects mounts as well as shocks and springs.

Show me a failed spring and I can probably find the reason for it in the aftermarket or an owner modification.

Been there in the design and specification of chassis parts for GM. We even have to account for 'foreseeable misuse' by owners and operators. That means the 6 sigma owner will put in the truck as much as they can, regardless of tire, axle, spring or seat load limits or recommendations.

You would be surprized at the number of 'expurts' who modify the spring packs by either adding or removing spring leaves to the existing pack or adding lift kits to add the 'Hazzard County' effect. Others do something called 'bulldozing', where they deliberately overload the truck (at both ends even), in order to 'improve' the look of the truck. There is another technigue used which involves using a torch to soften or weaken the springs (both coil and leaf type), in order to add that 'We Be Bad' look.

None of these techniques is recommended. All have some serious safety and durability consequences.

What's funny is how often you see a used truck for sale and can see where the owner tried to remove or hide their 'improvements'. Now why would they do that? These are the ones we see in the courtroom where the manufacturer was blamed via a 'design defect'. These claims and disproving them bought me a nice house, property and some nice farm machinery.

I've never been much on modifications, realising that you need to know what you're doing. Been running pickups for 35 years, between 35 & 50K miles a year; the only time I ever broke a leaf spring was when I overloaded my '84 F150 hauling bark mulch.

Until 2 years ago that is when I broke the springs in my '07 Silverado.
Now the above mentioned on my '09 Silverado.

More truck springs break running empty on rough roads than loaded or overloaded in any conditions. Late winter/springtime driving conditions are great for the suspension business. Ask anyone involved in the trucking business when spring suspensions were typical on OTR and heavy trucks.

We're all foresters, the heaviest load we carry is a snowsled or an ATV. As they say, it isn't the weight that breaks them; it's the release.

 

[wny770]

Kinda funny reading this. The main rear spring broke on my '08 Silverado. I really don't haul anything heavy in the bed at all..... I thought it was a fluke, but the more people you talk to, I guess it is not that uncommon.