Deuce front lift blocks

[bill2444]

Hi, I was looking for some opinions of our more learned members. I want to do the 395's on my Deuce but think the front needs a little lift. I like the ride that it has now ( springs maybe slightly sagged)
Now to the meat of the question: Lots of our heavy highway equipment uses lift blocks between the front axle and leaf springs. Our suspensions were factory built that way. But I thought in the 4x4 world that was a major NO-NO. Our suspensions were built by International and GMC. Some blocks are 2" and others are 3". Same configuration as the deuce. U-bolts even appear to be the same dia. But our trucks are 48,000# gvw rated. And range in build dates from 72' to 05' that have the blocks. But then again when you talk about lift blocks, usually bad things are said.

So now what do you guys think of using a set of 2" blocks from one of our parts trucks (International with a 14,000# front axle) on a Deuce to gain clearance and looks. ( new u-bolts are a given).

 

[wehring]

I'll bite

This is a touchy subject but I will bite. I am not a fan of lift blocks but I don't consider welded blocks of reasonable height (2"-4") to be lift blocks. I would feel comfortable with 2" blocks that were welded to the tube and new (longer) u-bolts.

I don't like lift blocks in the rear because of the spring wrap you get from the mechanical advantage. Of course this is mostly a concern when you are running in 2wd and the rear axle gets all of the power. This effect is lessened when you split power to the front axle.

So (except with Tres Chic rock crawlers) the front blocks will only see the divided power and never the full brunt of the driveline's input. The only forces you need to worry about are lateral when you turn. The theory is that the truck wants to spit the blocks out when you turn. The axle goes one way and the truck keeps going straight. This is mitigated by welding the block to the axle.

Again this is simply me rambling. Just my .02

Justin Wehring
979 997 3112

 

[m16ty]

I'd rather cut the springs loose from the frame and add the blocks there. Welded in good and braced where needed of course.

 

[Elwenil]

Adding or increasing the size of lift blocks are a bad idea no matter what. If the suspension system was designed for a particular size block, fine. Adding them to suspension not designed for them or adding additional lift by increasing the block is a bad idea, especially on the front. In may ways adding lift blocks to the front axle is much, much worse than adding it to the rear since the front axle is the steering axle. With a lift block you are spacing the axle's centerline away from the spring and adding leverage against the spring, causing axle wrap at each bump. In the front where caster angle is critical for stability and control, the caster angle can fluctuate wildly with each bump as the axle swings back and forth, pivoting where it mounts to the spring. If you want lift, have a spring pack built or lower the spring mounts in a a safe and structurally sound manner. Either way I would make sure the steering and suspension geometry does not change during the modification.

 

[tm america]

If you want to do a lift between the spring and axle get some different spring perches that weld onto the axle. in the lift height you want... They make them for rockwells.. But even that adds alot of leverage on the spring when braking but it is doable.

 

[PropDr]

Adding or increasing the size of lift blocks are a bad idea no matter what. If the suspension system was designed for a particular size block, fine. Adding them to suspension not designed for them or adding additional lift by increasing the block is a bad idea, especially on the front. In may ways adding lift blocks to the front axle is much, much worse than adding it to the rear since the front axle is the steering axle. With a lift block you are spacing the axle's centerline away from the spring and adding leverage against the spring, causing axle wrap at each bump. In the front where caster angle is critical for stability and control, the caster angle can fluctuate wildly with each bump as the axle swings back and forth, pivoting where it mounts to the spring. If you want lift, have a spring pack built or lower the spring mounts in a a safe and structurally sound manner. Either way I would make sure the steering and suspension geometry does not change during the modification.

Don't forget bump steer due to the drag link not being parallel to the ground because of the added height of the block. The more extreme the angle of the drag link the more the truck will want to rip the steering wheel out of your hands when you hit a bump or dart one direction.

 

[jesusgatos]

Lift blocks should NEVER NEVER NEVER be used on front axles. Ever.

 

[PropDr]

Lift blocks should NEVER NEVER NEVER be used on front axles. Ever.

I think the engineers @ Paccar would argue with you on that one. I'm not a fan of blocks either but their is a time and a place for everything. It all depends on the design.

 

[Clint Patterson]

lift it between the spring and frame

 

[Elwenil]

I think the engineers @ Paccar would argue with you on that one. I'm not a fan of blocks either but their is a time and a place for everything. It all depends on the design.

I think if you look that most of all the axles that have blocks on them on road tractors use a drop axle so if the axle were to pivot where the spring mounts to the axle, it's still pivoting close to the spindle centerline. So it's not exactly the same thing as adding blocks to a suspension system not designed for them.

 

[bill2444]

You might be on to something, None of our equipment that has blocks is a front drive axle.

 

[heftybuilt]

I would have to say that lift blocks in the front would not be a good idea. I have been lifting trucks for 10 years and would never recommend this and in some states it is illegal.
As far as in the rear I would not go more than 3 in blocks and if you do I would install some traction bars to pervent axle rap.

 

[PropDr]

Even if you rearch the springs, or put spacers between the frame and shackle brackets etc. your still going to have geometry issues. It's not like you can order up a offset steering arm to correct the angles. A spacer between the top of the knuckle and the arm would work but I don't know if the studs will take the extra stress. The other option is to lower the steering box, but that is easier said than done.

 

[jesusgatos]

Depending on how the vehicle is lifted, raising/lowering the steering arms might make the bump-steer even worse. The drag-link doesn't need to be horizontal, as much as it needs to be parallel to the front half of the leafsprings, sort of like how track-bars and drag-link (on vehicles with cross-over steering) work best when they're the same length and set at the same angles.

 

[PropDr]

Depending on how the vehicle is lifted, raising/lowering the steering arms might make the bump-steer even worse. The drag-link doesn't need to be horizontal, as much as it needs to be parallel to the front half of the leafsprings, sort of like how track-bars and drag-link (on vehicles with cross-over steering) work best when they're the same length and set at the same angles.

That's true. The only reason I said that is because the last time i looked at my truck the front part of the spring is fairly close to level. Then again I didn't put the inclinometer on it and its sitting on uneven ground. Next time I won't over simplify things so much.