Oxy/Acetylene for bent Leaf spring?

[OverkillYJ]

I have two front leaf springs that have a little bend to them. Nothing horrible. These are custom packed for a 95 Wrangler. I hit a stump a while ago while bushwacking, and bent the main leaf about 10" before the main eye on the frame. I tried to bend them strait with no heat and an 8k lb winch on the trail. It helped and got me home that day, but they still aren't strait.

My plan was to take a rosebud tip and heat up the bend real good, then gently press it strait again. I wanted to make sure that using heat on this was not a horribly stupid call though. Is is going to make it super brittle and prone to break? Will the leaf lose its flexible characteristics in the part of it I heat?

If needed there is also a full length leaf in these spring packs I could clamp the main leaf to when I reassemble to give it some extra durability and strength. It would also prevent the main leaf the has the eyes from flexing independantly of the full length leaf under it, I assume making it more durable.

If this is a bad idea, would it be able to be done right with a digital laser thermometer to avoid heating it more than I need to and destroying the spring steel properties? I am not sure and cannot find any reliable info on this. I found people doing this, but no one with enough metal experience to tell me if it is good enough for a road vehicle.

I do know spring shops can straiten them. I do not know what method they use though. Costs about $200 where I live if you take the springs to them yourself. All they do are springs. Thing is this is a regular problem for us offroader's I would like to take care of these myself in the future as needed for people in my groups.

Sorry the pic *****. Before I sold my axles I did not take a pic of these springs in particular, so I just cropped a photo to show how slightly bent these are. They are not horrible, but I plan on selling these and want to make sure the buyer still gets a good usable part.

Thanks for any help you guys can offer!

 

[that-guy]

I'm no expert on such a problem, but I would think that it would create a weak point, but again, I'm no expert. it seems to me like it should be like heating a regular spring to lower a car like they did back in the day. did it work, sure, but the fatigue resulted in decreasing the life and functionality of the spring, and/or causing it to crack and break

 

[jeepinerdeep]

I'm not sure you'll ever get back to original.....springs are like a tie rod, once it's bent, it'll keep bending in that spot sometimes much easier than before.

I see you don't have any U shaped keepers.These hurt your flex on extension for sure, but they do help keep things together.

Hopefully someone else has a better idea, I think you're best off having the spring shop arch you a new main leaf and bolt it in.

Time for coilovers?

 

[MoonRise]

Ixnay of the heating of the springs.

Doing so will change the material properties of the steel.

Heating mild steel to red hot and bending it is one thing. The mild steel does not really have enough carbon in there to 'respond' to heating and cooling (for good or bad).

Heating a steel that has more carbon or alloying elements in it than mild steel though is a whole 'nuther can of worms though.

Once the leaf took a bend, it -is- 'weaker' there (because the material has exceed the yield point and taken a plastic deformation, aka it is now bent ).

Press or bend back into mostly the desired shape is about all you can do.

Unless you get into completely annealing the part, reshaping it, then hardening it, and then tempering it. Which is waaaaay more work than just heating it to red-hot with a rosebud.

Nope to heating it and bending it. Once you do that, you no longer have uniform or known material properties in the spring.

IMNSHO.

 

[red92s]

Even a small amount of weld spatter from welding near a leaf spring can be pretty disastrous to it's life. I would think that heating it with a torch would result in similarly bad outcomes.

http://www.trucksuspensionparts.com/2012/07/leaf-springs-and-common-causes-of-failure.html

 

[kf4zht]

Heating a section of spring material and letting it cool will probably destroy the temper. Chances are it would make it softer, but depending on the metal used it could have other effects.

Do you know what type of steel they are? Can you contact the original maker? I would try and find a new main leaf and assemble the rest of the pack with that.

 

[Kevin54]

If you heat it, you will ruin it. Look at all the kids that torched their coils to drop their car a little. After a while, the car kept dropping until it was riding on the bumpstops. Either hit the junkyard, or go to a place that makes springs. Believe it or not, leaf springs aren't really all that expensive. I don't know if you have any place around you, but in Ohio, Springfield exactly, there is a place called Ajax Springs, and they can make up a set of leaf springs the same day. IIRC, a lot of the guys with S10's were going there and getting sets of 2-3" drop springs for something like $250 a pair, but that has been a couple of years back. I know my nephew has used them quite often.

 

[OverkillYJ]

My brother works at a steel treatment place. They do government contracts for battleships, as well as regular hardening and media blasting. I will ask one of the seasoned foremen as well.

@JeepinerDeep. Like I said these are custom springs. They are designed for SOA and are 6 leaf packs with two full length leafs. The 2 clamps are more towards the center for better flex. And it works. The driver side tire in the two flex pics has about 1" of room over it with custom 1/8" thick steel flares that gave about 3-4" of extra clearance. These are only 33's, and they stuff all the way into the wheel well with 7" of lift on my YJ. That is far beyond the normal flex.

@ Everyone else. I figured if I only hit the part that is bent and keep the heat as minimal as possible, then use a new leaf spring clam to clamp the two full length ones together right where they bolt into the frame if it would make a difference. Leaf springs are way different than coils in the way they absorbe the weight and flex of the vehicle. I woulod NEVER heat a coil. With leafs I figured I could gain the strength from the second leaf that is not normally there on the stock pack so these two move together at the point where I straiten it. The eye they are near is a fixed point, so the stress in regards to flex in that particular point is minimal. most of the flex is towards the center of the spring and the shackle side.

Before going to a spring shop I can go pickup leaf packs with the same main leaf that I have bent for $15 each at the yard 15 minutes from my house. I just was not sure if heat was any type of option at all. I have a solid reputation on the work I do for people. Even if I replace it though I will still bend at least one strait and then stress test it.

After thinking about it though, I will probably get new main leafs for these more expensive packs I have from the yard, then sell all the pieces I have left after swapping them out to someone as is and let them do what they want with them. Or just play with them and heat to see what they can take and how much heat is too much. I have lots of leaf spring stuff so the knowledge for the future would help.

I am going to coils up front in case anyone was wondering. I am doing a 6" rear stretch with Cherokee leaf springs, and bringing my front axle forward about 5" and using 9" lift TJ/XJ coils with a custom 4 link. I already have 4 packs of the Cherokee Springs to make two custom packs similar to what I have now for the rear. I have a bunch of spring pads, graphite spray, clamp kits, and center pins. Since I was doing this work already I figured I would see if I could tackle these bent ones while I was at it so I could finally post them for sale. In good shape they are worth quite a bit.

I just tore it apart about a month ago and sold the motor and both axles for about double what I paid for the Jeep (excluding what I put into it since it was a stock 4cyl). I still made out great with enough profit to buy everything I need. I have a 302 to drop in, an 04' F350 Superduty posi 10.5 rear to narrow, and am shopping for a HP 60 Kingpin Front to narrow. Hoping to finish it by May. I have everything except the front. I already have my NP435/205 combo as well.

Thanks for all the info and help guys. Every bit of extra knowledge I get in regards to this type of stuff is worth quite a bit to me. Some things are so specialized it makes it very difficult to get strait answers.

 

[rsanter]

Bad idea
Hearing will anneal them and that portion will no longer be a spring.
It would be better to take the springs apart and use a press to straighten that area the best you can

Bob

 

[ddawg16]

Been there....

Replace the bent spring.

 

[OverkillYJ]

I wish I had a press... I have tried rigging things to bend these strait with an 8k lb winch, but it only got me so far. They spring back to the bent position, just a little less bent. The force it takes to straiten one without heat is crazy, and dangerous if I am not setup for it.

I bent it very far with the winch so that it inverted, and it still didnt take it out.

 

[Kevin54]

The bad part about heating them up is that you will take the temper out without having the proper stuff to retemper the springs. At best, it will be a hit and miss deal. What you may want to do is call the spring place around your area, and ask them what you asked the Members on here. You would most likely have to heat them to a dull red, straighten them, then cool them. But if you cool them too rapidly, then you will make them brittle. If you let them slow cool, then the temper may be out of them completely leaving you with two soft springs. The spring place could tell you haw to do a proper fix, and if they aren't pricks about it, they will tell you over the phone.

Or call this place here in Ohio, tell them you are out of State, but a fellow friend or 4 wheeler in Ohio told you about them. If they know you are out of State, but they came recommended, they may be a little easier to get some info out of. https://local.yahoo.com/info-15840554-ajax-spring-alignment-company-springfield

But remember, a lot of places don't like to give info out because they want your business. Being out of state may work a little better to gain info. And then again, when it comes to something like a spring, they may not want to give info because if something happens, they won't want to be responsible in any way.

Also try doing a Google search for bending and tempering a leaf spring. You may get a few hits from some backyard fabbers.

Good luck and let us know what you come up with.

 

[OverkillYJ]

The bad part about heating them up is that you will take the temper out without having the proper stuff to retemper the springs. At best, it will be a hit and miss deal. What you may want to do is call the spring place around your area, and ask them what you asked the Members on here. You would most likely have to heat them to a dull red, straighten them, then cool them. But if you cool them too rapidly, then you will make them brittle. If you let them slow cool, then the temper may be out of them completely leaving you with two soft springs. The spring place could tell you haw to do a proper fix, and if they aren't pricks about it, they will tell you over the phone.

Or call this place here in Ohio, tell them you are out of State, but a fellow friend or 4 wheeler in Ohio told you about them. If they know you are out of State, but they came recommended, they may be a little easier to get some info out of. https://local.yahoo.com/info-15840554-ajax-spring-alignment-company-springfield

But remember, a lot of places don't like to give info out because they want your business. Being out of state may work a little better to gain info. And then again, when it comes to something like a spring, they may not want to give info because if something happens, they won't want to be responsible in any way.

Also try doing a Google search for bending and tempering a leaf spring. You may get a few hits from some backyard fabbers.

Good luck and let us know what you come up with.

Thank you. That helps a lot. I live in Philly. The best spring guy in the city is a South Philly ****, but he knows what he is doing. Last time I saw him and tried to ask him anything at all he said I do this, you do that, let me worry about it. And that was when I was already giving him money.

 

[ddawg16]

Thank you. That helps a lot. I live in Philly. The best spring guy in the city is a South Philly ****, but he knows what he is doing. Last time I saw him and tried to ask him anything at all he said I do this, you do that, let me worry about it. And that was when I was already giving him money.

In his defense......us rock crawlers tend to be very much a DIY crowd....he gets tired of people wanting to know how he does it so they can do it themselves.

After about the 100'th guy asking you how you do it, you'd be a **** too....

A good spring guy is worth the money.

 

[Mike007]

OP, you say these are custom springs. I'm curious who made them? I recently bought custom spring over springs from Alcan. They weren't supposed to allow axle wrap. In 3 trips they are already bent and I've experienced axle wrap. Alcan has basically told me to go scratch, so I may be in the market for new springs.

 

[betweencenters]

hmmmm...Plans to weld a casting himself to be sure it`s done right......But wants to apply heat to spring. O.K. I`ll watch.

 

[OverkillYJ]

I have these 4 used springs I am going to wire wheel and paint each leaf after I take both pairs apart. Install pads, new clamps, and use graphite on them. I will end up with a military wrap pair in the end that has two main leaves and then three smaller ones instead of the 4 pack they are now. I have to make a new traction bar too.

I think they will come out nicer then what I got from him last time. The big thing he did was re-arch my leafs. I learned though that it is better to just build them from used leaves that are already broken in. It will not settle as much and still stay pretty much the height I assemble it at. I will also get better flex with thicker packs right from the start.

My goal with the rear springs is to keep flex on the trail, but also be heavy duty enough to tow. Otherwise I would put coils in the back too.

As for the bent ones, I am going to replace them. I am going to the yard Saturday anyway and know they have a few to choose from. $30, and with all the spare leafs I will be good for a long time.

 

[rancherbill]

Heating is a very bad idea for all the reasons that have been listed above.

.....I can go pickup leaf packs with the same main leaf that I have bent for $15 each at the yard 15 minutes from my house....

Do it. Save time and energy and move on to a real problem where you can have a good effort/reward ratio. On this problem you will expend a lot of effort and save $15 and it won't work anyway.

 

[kerrynzl]

I wish I had a press... I have tried rigging things to bend these strait with an 8k lb winch, but it only got me so far. They spring back to the bent position, just a little less bent. The force it takes to straiten one without heat is crazy, and dangerous if I am not setup for it.

I bent it very far with the winch so that it inverted, and it still didnt take it out.

Make one! so you can use a bottle jack

Hot Rodders have been doing this for years to "reverse eye" leaf springs
[ photo blatantly plagiarised from the H.A.M.B ]

 

[jm3]

Here is how to fix it:

Only use heat to open the clamps (if needed)

Separate the spring pack to get the bent leaf out.

Use a small sledge hammer* and anvil to recontour the spring, 100% cold-working.

Reassemble in order of disassembly, and enjoy.


* We always called them a "minijack" but I have no idea where that name came from.

 

[OverkillYJ]

Make one! so you can use a bottle jack

Hot Rodders have been doing this for years to "reverse eye" leaf springs
[ photo blatantly plagiarised from the H.A.M.B ]

If I make that I might as well make one with parts I can swap so I can use it to bend tubing. Been needed a bender for a while.

 

[rob0781]

Ever see someone build a main ply from scratch? The ply is heated in a forge till its red hot to make the eye. Same press that you arch a spring could easily straighten that ply out and match the arch to the other without any issues as long as it is not rotten.

 

[theoldwizard1]

I do know spring shops can straiten them. I do not know what method they use though. Costs about $200 where I live if you take the springs to them yourself.

For that kind of money I would want a whole new leaf !

 

[OverkillYJ]

For that kind of money I would want a whole new leaf !

That price is per pair on rebuilds/repairs.

 

[OverkillYJ]

Ever see someone build a main ply from scratch? The ply is heated in a forge till its red hot to make the eye. Same press that you arch a spring could easily straighten that ply out and match the arch to the other without any issues as long as it is not rotten.

You lost me, but what you are saying sounds important. All these leafs are in great condition. Not even light rust or scaling.

I did just buy a porta power 10 ton hydraulic puller. I need to make a frame I can put different attachments and dies in in to use as a press/tube bender/ anything else I can think of.

I was with you and know what you mean with the heat to make the eye, but you lost me on the other part.

 

[MScott]

Old time hotrodders used to reverse the arch on mainleaf springs (to lower the front of the car) by beating the spring with a small sledge hammer over two wood blocks. They just held the spring on the blocks and beat the spring until it arched in the opposite direction so that the eye was on the top instead of the bottom. Took a long time and was murder on the ears unless you used ear protection but it could be used in your situation.

 

[pop pop]

jm3 gave you good advice. Springs are made and repaired by cold working, not hot work.
Visit a spring shop and notice the size of their arms.

 

[kerrynzl]

Old time hotrodders used to reverse the arch on mainleaf springs (to lower the front of the car) by beating the spring with a small sledge hammer over two wood blocks. They just held the spring on the blocks and beat the spring until it arched in the opposite direction so that the eye was on the top instead of the bottom. Took a long time and was murder on the ears unless you used ear protection but it could be used in your situation.

It's known as "Cold Bulldozing"
One of the best activities on a Sunday if you have a pesky neighbour that insists on practicing bagpipes