i have a rear end question!

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bamamopar

bamamopar

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Ok my question is when running down the road and I give my dart gas it pulls to the left. It feels like it's in the rear end. Could my center section be going bad? At the track it hooks then pulls left and I break the tires loose. It's a 69 dart 8 3/4 w/741 case I think 3.91 gears. I have Ss springs and everything is tight on the car. It didn't do this until last year. It's no tire because I have changed tires. Please help. I do plan on a center section upgrade as soon as I can. Thanks Mark. I will post a video for the car running later.
 
A lot of a-bodies are not straight in the rear . Check your housing for squareness. If the rear pulls to the left shim the right side back . Opposite for a pull to right.

The front spring perches were usually off on open rear cars. The 340 cars were close. The bodies in white were perfect. My Duster was off a 1/2 inch it was a /6 back half. My 340 Duster on the rotisserie is off 3/16. I have shown this to several members who came here and they found theirs were off as well.

Did you ever watch cars in the burnout box and they can't keep them straight. This is why. I would say this is more than likely your problem. See it on many cars that come here for this same problem your having. They were built this way.

I use a aluminum shim in front of the the perch with with extended bolts if needed.

How even do your tires sit in your wheel house? Some times it is noticeable there. But a measurement from the rear K-member bolts X'd from side to side will tell the story.
 
I haven't really looked to see how close they are. I'll check it today. I'll x it on Tuesday when it's up on the rack. Thanks I can't get it to hook like it is because of it.
 
Mine was a nightmare to get to hook before I fixed it. When it did and got light on the front wheels it would go to the right. If It would be like that now it would turn right with the wheels in the air and I wouldn't make it past 60 ft. You can actually just keep the wheel straight now. No more turning left to go straight.
 
Lots of other factors, though as well..................tires and pressure, fuel in the tank, weight "or not" in the trunk and on which side (battery?) and the springs themselves.

Remember that all conventional front engine rear drive, IE normal engine rotation will try and pull the right wheel "up" because of torque reaction with the driveshaft. That's why if you look at any car from the rear as it launches, the right corner wants to fall.

This is going to try and steer the car some, depending on how stiff everything is

Also, if the springs are weak enough, the are going to try and "wrap" as the axle tries to twist from torque. This will change the effective center of the axle as it sits in the car. If you are running "really weak" /6 springs, etc, this might be pretty severe.
 
The posi could be wearing out more on 1 side,could need some cal tac's. I would inspect the rear 1st to see if anything is mechanically wrong.
 
That looks like it's in the front to me. Double check everything with the left lower control arm. The lower bushing, the strut rod and bushing, everything. If the left lower control arm is somehow loose, the caster will decrease on acceleration and cause your problem. I would suspect strut rod bushings above all, but look at everything.
 
We use to move the front wheel back on one side to fool the lights. never caused a pull on acceleration.

Did any of you ever drive a car with the center pin broke on the spring. Open or suregrip it always pulls after this happens. The first think you do with unitized car is square the housing. 75% are way out. If some of you think otherwise you are in for a rude awakening.

This will also cause uneven rear tire wear. Just went through this on my truck also. I installed 5500 springs on a 3500 because they are shorter and it lets you offset them with only drilling and adding new front perch gussets allowing you to square the housing. You could felt the truck move to one side when pulling heavy weight.

This truck pulls a trailer with total GVW at 32000. class 10 CDL. skid loader and excavator at one time.
 

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Oldmanmopar said:
We use to move the front wheel back on one side to fool the lights. never caused a pull on acceleration.
Click to expand...

If you didn't move the lower control arm back and decrease caster, that's why it didn't cause a pull. Not trying to argue, just making sure he doesn't miss anything.
 
RustyRatRod said:
That looks like it's in the front to me. Double check everything with the left lower control arm. The lower bushing, the strut rod and bushing, everything. If the left lower control arm is somehow loose, the caster will decrease on acceleration and cause your problem. I would suspect strut rod bushings above all, but look at everything.
Click to expand...
The front end is all new PST. But I am having a front end problem with the car. It is going back to the front end Wednesday. I think your on the right track. Thanks
 
RustyRatRod said:
That looks like it's in the front to me. Double check everything with the left lower control arm. The lower bushing, the strut rod and bushing, everything. If the left lower control arm is somehow loose, the caster will decrease on acceleration and cause your problem. I would suspect strut rod bushings above all, but look at everything.
Click to expand...
The front end is all new PST. But I am having a front end problem with the car. It is going back to the front end Wednesday. I think your on the right track. Thanks
 
Be sure to chk the locating dowel on the rear springs, just in case.
Look to see if the rear end looks like it has been moving forward or back on the springs.
That's what it looks like to me. (the rear end is coming forward on one side when you launch)
 
Here is another video of the car leaving. If I leave out about 2k the car is straight but if I leave at 3200 it justs left. I'm now thinking it maybe the front end. I just checked the rear end and everyt looks tight. It don't appear to have any movement in it. I do check it often.[ame="https://www.youtube.com/watch?v=TeBDtHrL0bM&feature=youtube_gdata_player"]VIDEO0010.mp4 - YouTube[/ame]
 
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