Bent Trailing arms or bent frame help please

[lwb66step]

I have a 66 lwb stepside, I noticed that the rear of the truck drifts going down the road, that is to say that when the truck is driving straight, the rear of the truck looks like it is angled severly to the right. I measured both passenger and driver's side from center of the hub to center of the hub and the pass side measure approx 128 inches, the drivers side measures under 127 inches giving it a full inch variance from side to side. I just need to know if anyone has advice or experience with this rear axle angle problem and how it can be fixed on a budget. Thanks in advance, any input is welcomed.

[Stubnosebrock]

Could be the control arm bushings are shot as well. Make sure the track arm isnt bent too.

[lwb66step]

Originally Posted by Stubnosebrock

Could be the control arm bushings are shot as well. Make sure the track arm isnt bent too.

Thank you for replying, I will check these items prior to freaking out about the possible $600 frame repair.

[Stubnosebrock]

Yep, its always best to check the small, easy stuff first.

[Stubnosebrock]

The track arm bushings could be bad too

[lwb66step]

Originally Posted by Stubnosebrock

The track arm bushings could be bad too

Do you know of a link detailing the different components on the rear suspension and their location? At the risk of sounding stupid, what is the diff betw the track arm and the trailing arms?

[SCOTI]

Originally Posted by lwb66step

Do you know of a link detailing the different components on the rear suspension and their location? At the risk of sounding stupid, what is the diff betw the track arm and the trailing arms?

The trailing arms (on these trucks they're called truck arms) locate the rear housing under the rear of the truck (front to rear locating). The track arm (Panhard bar) helps locate (center) the rear housing between the frame/body (left to right).

[Stubnosebrock]

Well the LMC catalog for our trucks shows the suspension for the truck pretty good. You can look it up online also. The trailing arms are the long arms that bolt under the rear and go up to the frame. The track arm is the rod the runs from the rear(upper right hand corner if looking at the differential cover) to the frame on a bracket. This runs the same direction as the cross members in the frame. This is what keeps the rear straight with the frame, so its very important.

[lwb66step]

got it thanks! I knew how to ID the trailing arms, and now I know how to ID the track arm or panhard bar, I guess I had always called the track arm a "panhard bar" now it makes sense, I was just calling it a diff name

here is a good link to frame specs if anyone was wondering, I pulled them off the FAQ page....

http://67-72chevytrucks.com/vboard/s...d.php?t=422163

[blackedoutharley]

Track arm and panhard bar are the same.. as mentioned, this part centers the rear end side to side.

Don't forget that if you're saying the wheelbase is different from one side to another that it could be caused by the front suspension as well.

Take a snap shot of the rear suspension and post it, maybe one of us will notice something out of synch.

[lwb66step]

Originally Posted by blackedoutharley

Track arm and panhard bar are the same.. as mentioned, this part centers the rear end side to side.

Don't forget that if you're saying the wheelbase is different from one side to another that it could be caused by the front suspension as well.

Take a snap shot of the rear suspension and post it, maybe one of us will notice something out of synch.

but would the front alignment be causing the rear of the truck to "drift" or "dogleg" to the right when moving in a straight line?

here are some pics i ran out to take real quick- see how the drivers side rear is pushed forward toward the fender well?

[blackedoutharley]

Originally Posted by lwb66step

but would the front alignment be causing the rear of the truck to "drift" or "dogleg" to the right when moving in a straight line?

here are some pics i ran out to take real quick- see how the drivers side rear is pushed forward toward the fender well?

It can... there is an alignment angle called "Thrust Angle" and it is not uncommon to see older cars that dog track down the road (meaning the front and rear tires are not running in the same track). This happens primarily when the alignment is done measuring only the front wheels and not squaring the chassis up measuring all 4 wheels.

The way to correct this, assuming the suspension is okay, is to have the vehicle aligned on a rack using all 4 wheel sensors. Even though the rear is not adjustable, you basically align the front end referencing down the imaginary centerline of the vehicle (thrust angle).

Find a reputable alignment shop (stay away from the chain stores) and you probably will find that your problems are easily solved.

Also know that tire wear is only one result of misalignment. Just because it doesn't wear tires doesn't mean it is aligned properly.

As far as the left rear tire being more forward in the wheel well compared to the right side; also know that it is not uncommon for body panels to not be aligned properly on the chassis. In other words: is the bed bolted on straight? This not to say that the rear end couldn't be cocked one way... if it is the alignment will tell you that.

For more info check this out:
http://www.familycar.com/Alignment.htm#Thrust%20Angle

[lwb66step]

Originally Posted by blackedoutharley

As far as the left rear tire being more forward in the wheel well compared to the right side; also know that it is not uncommon for body panels to not be aligned properly on the chassis. In other words: is the bed bolted on straight? This not to say that the rear end couldn't be cocked one way... if it is the alignment will tell you that.

For more info check this out:
http://www.familycar.com/Alignment.htm#Thrust%20Angle

Gap between cab and bed is even on both sides. that tells me the cab and bed are aligned. I keep hoping this is a bent trailing arm issue and not a bent frame. In any case I am taking it to a local alignment shop next week after the holiday to get it checked, they also have a frame rack in house so I will get a firm answer as to what the cause is. thanks for the input.

[Rich 5150 69]

Take a tape measure of the centerline from front to rear wheel on each side, just from the last pic it appears, ( and I mean just appears) that the left front wheel seams to be sitting a little back to far in the fender, but that can be from the angle of the pic...

[lwb66step]

Originally Posted by Rich 5150 69

Take a tape measure of the centerline from front to rear wheel on each side, just from the last pic it appears, ( and I mean just appears) that the left front wheel seams to be sitting a little back to far in the fender, but that can be from the angle of the pic...

I did pull a measurement a few days ago passenger side was 128" from center of the rear hub to the center of the front hub....same measurement on the drivers side is 127" so there is 1" diff in the wheel base from one side to the other.

[Str8axle]

Sounds like the issue is in the right side trailing arm. A wasted bushing is the likely suspect. Do you hear any "unnatural" noises from underneath while driving? I would think with a 1 inch difference in wheelbase from one side to the other, that something should be pretty loose.

[blackedoutharley]

Staggered wheel base helps with times at the drag strip. LOL

[lwb66step]

Originally Posted by Str8axle

Sounds like the issue is in the right side trailing arm. A wasted bushing is the likely suspect. Do you hear any "unnatural" noises from underneath while driving? I would think with a 1 inch difference in wheelbase from one side to the other, that something should be pretty loose.

well with the belt squeal i have i can barely hear the exhaust. I am taking it to the alignment shop this week. will post results here.

[lwb66step]

Ok so I am back from the alignment shop and the issue was the cross member that connects the trailing arms to the frame. Apparently all but 2 of the rivets had been rusted through and the cross member was sitting crooked between the frame rails throwing off the rear axle alignment. $175 later the truck tracks straight and true and drives much better as well. The $175n included a 4 wheel alignment and repair to the cross member. It was more than i wanted to pay but at least the frame wasn't bent.

[SCOTI]

Originally Posted by lwb66step

Ok so I am back from the alignment shop and the issue was the cross member that connects the trailing arms to the frame. Apparently all but 2 of the rivets had been rusted through and the cross member was sitting crooked between the frame rails throwing off the rear axle alignment. $175 later the truck tracks straight and true and drives much better as well. The $175n included a 4 wheel alignment and repair to the cross member. It was more than i wanted to pay but at least the frame wasn't bent.

$175 is one-third of a monthly payment on a new, throw-away car. You'll offset the cost quickly. Glad you found the issue.

[lwb66step]

No doubt I am glad it wasn't a more serious issue, just wish i had caught the problem myself, i could have invested that $$ into slamming my truck, next up, disk brake upgrade cnotch and slam kit. Thanks to everyone on here who posted trying to help me figure this out.