I'm seriously thinking about putting two of the stock rear blocks from my F250 on the front to raise it up 1.75". They aren't that tall and they are factory Ford blocks so I don't see what the problem would be?

 

Also, while we're on the topic, If I decide to just put new springs on the front do you have to remove the front bumper?

 

I don't know all the technical stuff but I don't even like having lift blocks in the back. All the side force your truck takes when you turn seems like a lot for some lift blocks..

 

Most DOT agencies will tell you that they are illegal, and not DOT approved, because the y are probably one of the unsafest things a person can do when modifying a truck. The side loads incurred during a turn will eventually cause a front block to wiggle out, and, well the rest is going to be a mess. At that point your decision to modify a truck is no longer limited to the owner of the truck. This will have an effect on anyone else on the road around you. With little controll over a vehicle which has fallen off of the spring perch, because the axle is no longer connected to the spring will cause a loss of control, and if you are very lucky will limit damage to just yourself. Not always the case, if this occurs while you are in traffic, someone is going to get hurt.
Given the costs involved, I do not see why anyone would want to install blocks up front. Asside from the saftey problems, the cost of new longer u-bolts and the blocks, are about the same money as installing new hangers, or a mini spring pack. Heak all new springs are not that much more, and the labor involved is about the same.
Sometimes short cuts are not really short cuts, and money saving ideas don't really save any money.
In this case, because of the saftey involved, no amount of money saved could justify the use of front blocks.

 

How can the block "wiggle" out if I'm using factory Ford blocks that have the large stud sticking up in the middle?

 

That alignment pin is there to "locate" the spring relative to the axle pad, not designed to hold the block in place. When the loads of the truck are placed laterally (during a turn usually) the block will lean. As it leans, less of the pin is actually in the hole. The spring is flexable, and when you combine the flex of the spring with the roll, or lean of the block, it will at that point take very little to pursuade the block out of its little home. The taller the block, the greater the leverage, and the more likely this is to happen. It is literally a house of cards. Looks good when it is standing, but eventually will come down.
Many guys dont even like them for the rear, but the rear does not see the same side loads as the front, so it is considered acceptable in the back, but never the front.

 

thanks for the info

 

I wouldnt run a lift block on the front on a truck that doesnt even see the road.

 

Ditto, about the worst modification to a truck you could make.

 

If you never drive your truck again... then I say it's A-OK to run blocks in the front!

 

If 1" of lift is enough, you could use ORU's 1" zero rate add-a-leaf. It's essentially a small block that bolts to the springpack.

 

The biggest factor for not putting blocks on the front axle is braking force. The front brakes do most of the work when stopping and most of the vehicle weight is on the front axle so all it would take is one hard stop to cause the blocks to spit out or break the u-bolts!!!

 

In addition to some of the points already made, I would be concerned about bump-steer. Look at a stock leaf spring, sans block, and imagine a backwards force being applied to one or both front wheels (e.g. hitting a pothole). You could see how it would be pretty resistant to spring wrap. The spring might wrap a little, but not much.

Now stick a lever (in the form of a lift block) between the axle and the spring. Because of this, the backward force applied from the bump now has a higher mechanical advantage over the spring, making it easier to wrap it, and amplifying the distance that the axle moves when the spring does wrap. And with a solid front axle, virtually everything that happens to one wheel affects the other.

The worst-case situation might be that with a particular length of lever (block) and a particular set of springs, hitting the right bump at the right speed might even induce an oscillation.

Take a look at the spring pack lifts, and they are really more like blocks that they are springs. But the big difference is that they have leafs that extend forward and backward from the axle. I suspect that it is done this way to reduce or eliminate the conditions I just described.

BTW, all of this stuff can be tolerated on a rear axle, because it won't have a profound effect on steering.

I am not a suspension guy, this is mainly speculation on my part.

 

There is wayy too much flexing going on in the front suspension of a truck to EVER put blocks in the front. If it's money that is the issue, do an add a leaf, that's about the cheapest safe mod you can do to raise the front, probably the next cheapest is spring hangers, this will retain the factory ride and no other mods are required unless you go over 3 inches, then you'll need an adjustable track bar, and possibly a drop pitman arm. But blocks in the front is EXTREMELY UNSAFE.....don't do it please!!! Just save your money for a bit.

 

What if the axle came stock with a 2.5" rise on it where the leaf rests, not an addition, just raised up structural steel so it doesn't move and the leaf makes the same amount of contact with the axle?