Will not drive straight

[big bad orange]

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[big bad orange]

So I have just finished rebuilding the front end on the 72 and the steering has to much power under say 35 mph it's fine but if I go highway speed I have to keep correcting the steering and the steering wheel does not come back to center.
Parts replace inner/outer tie rods, upper/lower ball joints, upper/ lower control arm shafts,shocks, pitman, idler arm, steering box,rag joint, adjustment sleeves, and the pump is an original 67-72 power steering pump.

After that I had it alined (driver side is left colum)
Camber .1 .7
Caster. 1.5. 1.2
Toe .20. .21
Front
Cross camber -0.6
Cross caster .3
The tires I have on are 205/65?/15 (I needed tires and they where free)the tires where balanced right before front end work.
All I want is to have less power assit (less twitchy on the highway)
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[Lee H]

What is the date code on the tires? How much tread (in 32s) do the tires have, on each end and in the middle?

[big bad orange]

The date code is 2110 so the 21st week in 2010. And as far as depth I was getting 6/32-7/32 on the outside and 8-9/32 on the inside the backs are at 8-9/32 too. The story on the tires my firends dad bought them for his ford tarus and about a year ago it blew a freeze plug, I got the tires back in June and ran on them with the bad front end until now
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[JointTech]

did you have it aligned? Theres a lot of talk of shadetree alignments on this site and for some that may work but the $140 I spent at the tire shop was well worth it to me.

[67 cst swb]

sounds like your caster and/or camber are way out of adjustment

[big bad orange]

Yes I had it aligned ,the place I went charged me 70bucks ,I posted the after ailment results
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[TBONE1964]

A tire with good tread and balanced does not necessarily make it a good tire. What are the rear tires like, the same as the front? I would rotate them and see if your condition changes. You should expect a little (very little) pull from road crown but not like you describe.

I would say have them recheck the alignment but not until you are sure you have good tires. Did the alignment tech test drive the truck when he finished or just park it?

[big bad orange]

I should have stated this better my steering is so powerful it only needs a finger to turn the wheel
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[poorboy]

If the camber is .1 on the driver and .7 on the passenger and caster is 1.5 on the drivers and 1.2 on the passenger this could contribute to the problem. Camber will always pull to the more positive number and caster will always go to the smaller number. When I align a vehicle I try and get camber even and have a .5 split to the driver side to compensate for the road crown.

If your power steering is too touchy you might try a different pressure valve in the back of the pump.

[big bad orange]

The more I look into it I think it might be the pressure valve in the pump and I need a weaker spring. Any idea where I would buy one
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[Lee H]

Originally Posted by big bad orange

it only needs a finger to turn the wheel
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That's typical for 70s-80s Chevy power steering. These old trucks are not like today's trucks, you have to actively steer the old iron.
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[Keith Seymore]

What is the actual specification for caster?

1.5 degrees doesn't sound like much caster to me.

K

[big bad orange]

So I have been looking more into caster and from what people on here say 2-3 is where a power steering truck should be. I will go back to the shop and see if they will reset the caster so the steering wheel will come back to center. I also found shims for the pressure valve on the pump so I hope that makes the steering more heavy. Thanks for all the hel
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[BrianG]

What was the pump from. You did mention it was the correct era, but was it correct for a truck. Used to work at the plant where those things are (well, were) made. They were different between a truck and a car.

[big bad orange]

Yes got it at Carlisle truck show and the guy said he pulled it from a c10
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[cdowns]

do you have a sway bar? that will help a bunch as far as tracking

[Keith Seymore]

Originally Posted by cdowns

do you have a sway bar? that will help a bunch as far as tracking

It shouldn't unless there is a torsional input; the sway bar is just along for the ride during straight ahead driving and jounce inputs.

K

[Lee H]

Just for reference, here my alignment specs. I have a few thousand miles on it, tracks great, wheel returns to center, no twitching, even tread wear.


Camber -0.1 0.1
Caster 2.6 2.6
Toe .20 .19
Front
Cross camber -0.2
Cross caster 0.1

[cdowns]

Originally Posted by Keith Seymore

It shouldn't unless there is a torsional input; the sway bar is just along for the ride during straight ahead driving and jounce inputs.

K

not true without a sway bar the trucks sway back and forth goin down the road//that is how they get thier name SWAY BAR

[Keith Seymore]

Originally Posted by cdowns

not true without a sway bar the trucks sway back and forth goin down the road//that is how they get thier name SWAY BAR

If a person is experiencing body roll going straight down the road then there is something else going on; either poor motion control due to worn/damaged shocks or a response to an undulating road surface.

K

[motorcritter]

My thoughts- needs more caster- not too much, though. Then it won't steer well at all!
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[cdowns]

Originally Posted by Keith Seymore

If a person is experiencing body roll going straight down the road then there is something else going on; either poor motion control due to worn/damaged shocks or a response to an undulating road surface.

K

i guess all roads in michegan are like a pool table most places they are nowhere near flat and true


go drive a vehicle without a sway bar and see fer yourself

[big bad orange]

Yup no sway bar . The more I think about it its caster, since the low caster I am over correcting which is the problem. I am still getting used to powersteering in a truck that for a year I drove with a 1/4 turn of slop. the schocks are brand new
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[Keith Seymore]

Originally Posted by cdowns

go drive a vehicle without a sway bar and see fer yourself

Please read my profile and introduction thread.

K