3/4 ton 4x4 won't drive straight when on the throttle

[67chevy2wd]

I have a 71 gmc 3/4 4x4 with a 3" lift with blocks. It used to wander all over the road. I found out the front wheel bearings were loose. I got them tight and now it seems better but it doesn't feel right. Also when I get on the throttle I have to steer to the right to keep it on the road and when I let off I have to steer left. But when going down the road with no load on the engine I can keep the steering wheel straight. This is in 2wd with the front hubs unlocked. Could this be the 3" blocks causing axle wrap?

[MTCK]

Are the blocks on the front? I hope not.

[Stocker]

Originally Posted by MTCK

Are the blocks on the front? I hope not.

Agree with this 100%, but even if so, front blocks should not cause the situation described.

Rear blocks might, I can't say for sure. Dumb question, are the back tires identical to each other, including air pressure? No broken rear springs -- bushings good and all hardware tight?

[Mr-Jack]

not sure if this is an alignment issue...i would go out and measure the distance between the front tires at the forward most points and aft most points to compare. you can also jack it and use the board tire alignment check to see if you get wheel wobble or if yer passenger side is toed out a little...good place to start also is like Stocker said...start checking all yer hardware and bushings...make sure they're snug. Even after installing new hardware...you should be checking it every so often. I learned this the hard way luckily i didn't loose my front leave spring!

[chas350]

sounds like an alignment issue. was it this way before the lift blocks were installed? has it been in an accident? take it to a shop that does alignments on trucks and have it checked

[67chevy2wd]

I bought the truck with the blocks installed. There are front and rear blocks. I can't imagine it drove this way before I bought it since it drove from Nevada to North Dakota about 8 years ago with the same lift installed. I did ride in it back in 04 but don't remember it being all over the road. It then sat from 04 till Jan of 2010 when I bought it from a friend. I did notice that the link that runs from the steering arm to the tie rod link does not sit level. Could that have anything to do with it? It is pretty bad though. I took it for a drive and ran the rpms up in 2nd gear and when I let off the throttle I shot straight for the ditch. Nothing feels or looks loose in the front end. I did find the front wheel bearings were loose so I tightened them. I gave the rear end a quick look over but maybe I should look it over better.

[67chevy2wd]

Originally Posted by Stocker

Agree with this 100%, but even if so, front blocks should not cause the situation described.

Rear blocks might, I can't say for sure. Dumb question, are the back tires identical to each other, including air pressure? No broken rear springs -- bushings good and all hardware tight?

Good thought on the tire size. That never even crossed my mind. They are all the same though, all four corners.

[LB-LB]

Does it still have the original push-pull type steering configuration? If it doesn't then disregard the response below.

I know my lifted 86 Toyota would pull left when I hit the brakes because of the push-pull steering configuration and the pinon change from braking. I would assume it would go to the right during acceleration if the pinion rotated the opposite way. The push-pull steering and the lift together is the main reason it is driving funny in my opinon.

Change the steering to crossover and it will probably drive fine, assuming nothing else is wrong.

[wildwilly4x4]

DITCH THE BLOCKS AND GET A REAL LIFT!!!. Whether you build your own lift by using rears up front, or buy an engineered one, DITCH THE FRONT BLOCKS. I have never driven a rig that was lifted with a stock steering arrangment that drove "good". I lifted my really nice rig with a 4" kit and a "lift arm" to match, and it never drove right. Crossover steering IS THE WAY TO GO IF YOU ARE GONNA LIFT IT AND DRIVE IT......PERIOD! I know many have gotten buy with not doing it right, but it makes a HUGE difference in drivability......AS DOES A PANHARD BAR. Do what you want, but there really is only one way to do it right.....GM had it wrong from the factory, IMHO. Good Luck wiht your rig!

[Mr-Jack]

While i agree with wildwilly4x4 that crossover steering improves steering drastically on a lifted truck (or even stock) but i wouldn't say that improving on the push pull is wrong as implied above! I've seen trucks with push pull systems that work just fine with 6 or more inches of lift as long as drag links and arms and tie rods are placed properly.i bet if you took the blocks out and put it back to stock height with that push pull it wouldn't go all crazy.

First i would check alignment at home...take you 15 minutes (IF THAT) to take measurements to get an idea. check the wheel bearings again since that was a problem before. If that's all good to go, the angle of the tie rod could be an issue like above stated due to accel or brake or letting off due to pinion with these blocks. Possible quick fixes are raised steering arms or offset drag links, or crossover (hi-) steering.

If you don't know the board nail method, it's pretty easy. drive a nail thru a 2x4 at about a 45* angle and lift the truck up and put it on stands. Straighten the wheels out so they are facing straight forward. slide the board with the nail pointing at toward tire in the middle of the tread pattern. start spinning your tire and push the board close to the nail to wear it barely makes contact with the tire...make sure the board doesn't move or you won't see an accurate response. even on the cleanest of tires, you should be able to see the nail mark go the full circumfrence of the tire if it wobbles around, you got a problem. minor adjustments can be made to get it into an alighnment shop, but if your tie rod is bent that could be a problem as well. grab it with your hand and if it's sloppy, you might have some bad ball joints...it should be pretty tight.

let us know how it works for ya

[67chevy2wd]

I don't plan on leaving the blocks in there. That is how it came and someday I will buy a real lift. I have heard of crossover steering but never researched it. What is all involved with converting to it?

[b454rat]

Is there equal air pressure in the rear tires?? It sounds like a Detroit locker, locking under acceleration then unlocking on coast. My old car had one in it, scared the crap out of me. Let off up and hill around on a corner, headed for the guard rail.

[Mr-Jack]

Originally Posted by 67chevy2wd

I don't plan on leaving the blocks in there. That is how it came and someday I will buy a real lift. I have heard of crossover steering but never researched it. What is all involved with converting to it?

http://coloradok5.com/forums/showthread.php?t=249038

[MTCK]

Crossover steering is nice, but that's not your problem. It may help your problem, but before you do anything else, get a set of front springs and a proper steering arm for the lift you are running. If you have worn front springs with blocks on them you can have all sorts of freaky things happen with that long lever bolted to your axle. Front to rear movement of the axle assembly will cause side to side turning of your tires if the steering wheel is held straight.

http://www.4wheeloffroad.com/techart...cks/index.html

Here are some springs for under 300 bucks.

http://www.offroaddesign.com/catalog/TuffCountry.htm

[gcsupraman]

Originally Posted by 67chevy2wd

I have a 71 gmc 3/4 4x4 with a 3" lift with blocks. It used to wander all over the road. I found out the front wheel bearings were loose. I got them tight and now it seems better but it doesn't feel right. Also when I get on the throttle I have to steer to the right to keep it on the road and when I let off I have to steer left. But when going down the road with no load on the engine I can keep the steering wheel straight. This is in 2wd with the front hubs unlocked. Could this be the 3" blocks causing axle wrap?

I had the EXACT same problem. My issue was a loose U-bolt which caused the bolt (pin) in the center of the spring pack to snap. The leaf springs were shifting under acceleration/deceleration. Not sure if this is your problem....but it's a simple check

-Greg

[BIG V]

does it have a detroit locker in the rear?

[special-K]

Originally Posted by gcsupraman

I had the EXACT same problem. My issue was a loose U-bolt which caused the bolt (pin) in the center of the spring pack to snap. The leaf springs were shifting under acceleration/deceleration. Not sure if this is your problem....but it's a simple check

-Greg

BINGO!! No front end problem will cause this on/off throttle result.It sounds like the left rear if it`s pulling you left when you`re on it.The lose side will try to outrun the truck,which puts that tire forward and in the rear it`s the opposite direction,like a hook`n`ladder.Even the "gettemthehelloughtathere" front blocks won`t cause this problem in rwd.If they are loose everything will feel loose all the time.Your whole front axle will rack separate from the frame.Every move you make will be delayed and like a running a boat.The road will steer you,too.

Every Detroit Locker I`ve had pulls straight when running straight.Both sides are pulling the same.That`s why they`re perfect for drag racing.

[67chevy2wd]

I think what I will do is have someone put the truck in gear and maybe stall it a little to load up the suspension and I will watch in the rear to see if anything is moving. I don't think there is anything wrong in the front. The only thing I was questioning about the front was the steering link angle.

[Blazer1970]

Does it have good shocks?

[msgross]

Originally Posted by gcsupraman

I had the EXACT same problem. My issue was a loose U-bolt which caused the bolt (pin) in the center of the spring pack to snap. The leaf springs were shifting under acceleration/deceleration. Not sure if this is your problem....but it's a simple check

-Greg

this was my guess... measure the wheelbase on both sides

[wildwilly4x4]

Originally Posted by 67chevy2wd

I think what I will do is have someone put the truck in gear and maybe stall it a little to load up the suspension and I will watch in the rear to see if anything is moving. I don't think there is anything wrong in the front. The only thing I was questioning about the front was the steering link angle.

If you continue to run your stock steering setup, with or without blocks, you need to make sure that the draglink is perfectly flat. It can angle some, but the closer to flat that you can get it, the better it will drive. If it has much angle at all to it, when you steer, your steering box will kinda raise the truck vs. moving the steering knuckles since the weight of the truck is less than the force required to move the tires. The closer to flat that the drag link is, the more force you are able to apply to moving the tires in the desired direction, vs. it fighting with lifting the chassis up/down.

[Blazer1970]

Originally Posted by wildwilly4x4

If you continue to run your stock steering setup, with or without blocks, you need to make sure that the draglink is perfectly flat. It can angle some, but the closer to flat that you can get it, the better it will drive. If it has much angle at all to it, when you steer, your steering box will kinda raise the truck vs. moving the steering knuckles since the weight of the truck is less than the force required to move the tires. The closer to flat that the drag link is, the more force you are able to apply to moving the tires in the desired direction, vs. it fighting with lifting the chassis up/down.

And you will also get less bump steer.

[motomaster99]

my 71 had blocks in the front and it throttle steered like this quite badly. I removed them and it completely eliminated the problem.

Make sure your U-bolts are tight, I've had that problem too. Whoever was stupid enough to install the blocks was apparently stupid enough to tighten my U-bolts finger tight.

[cheepin]

Lose the front blocks and get some new leaves.That is scary as hell!I believe front blocks are illegal in most if not all states also.

[LONGHAIR]

Originally Posted by Blazer1970

And you will also get less bump steer.

There is no such thing as "bump steer" on a straight axle vehicle with a solid tie-rod between the wheels.
"Bump steer" is a "toe" change that comes from the suspension travel.