Launch question/Going left

Wade Mahaffey · 03-29-2010, 08:02 AM

Check the ladder bar brackets on the rear housing. Sometimes the holes will enlongate (oval) from a loose bolt condition. This will allow the preload to change at the "hit". If this is the case, simply make some sleves about 3/8" long that fit the bolt fairly tight with about a .250 wall thickness. Weld (TIG) them to the ladder bar brackets (one for each hole, 8 total). Take the time to determine the correct location of the sleves to be welded in place. You can use the undamaged bracket to comfirm the proper hole location. Use a pair of dividers (dividers: as in a device/tool used to draw a circle, only using the points to determine location instead of a tape measure). After the fix, reset the preload and confirm at the track (compare tire temps after the burnout).
There could be a shock issue, or a tire issue but these things usually will cause a slight drift in one direction and not a consistant hard move. However, you will need to make shock adjustments a few times each season. This will compensate for normal wear of the shock, most of which happens in the trailer during transport.

Wade Mahaffey

Mike Pearson · 03-29-2010, 04:07 PM

I agree with Wade. I had the same problem with my car. It was the front hole on the ladder bar mount that was worn out. I fixed it by adding a plate with the correct size holes welded to the front ladder bar mount. Just a slight bit of slop in the holes will cause some crazy results. My car would cross lanes.

04BlackSilverado · 03-29-2010, 05:34 PM

Could a bad tire on the left side, cause the better right tire with traction, to push the car left?

Can you swap the tires and see if it pulls to the right to verify?

Newbie with a guess for what it's worth... Good luck.

Ed Carpenter · 03-29-2010, 06:33 PM

Ok I took it all apart today. First i will admit I'm not an expert on suspensions. I'm still learning so bear with me.

Shocks are ok. Not broke or bound up

No broken welds or cracks

Axle tubes are not bent or twisted

Axles are ok

However on the passenger side the ladder bar bracket that mounts to the axle tube both holes upper and lower are eggshaped. You could grab the ladder bar and move it a little bit when it was mounted in the car. The drivers side you could not move at all. That side the holes are still true with no eggshape at all.

Also this may be where the prelaod comes in im not sure but on the drivers side where the ladder bar mounts to the bracket(rear) the upper heim joint has 5 threads showing with the bottom showing 9 threads. Now on the passenger side the upper has 2 threads and the bottom has 6. I'm no expert but doesn't the top one set the pinion angle only? Why would they be different? Isn't the bottom one used to set the housing straight in the car. Again I'm no expert I want to learn all this for future use. Thanks for all the input. Should i string the car from the front crossmember to the front mounts for the ladder bars? Ed

Also this is how I bought the car. If it's all jacked up I want to fix it right.

Mike Pearson · 03-29-2010, 06:59 PM

Thats your problem Ed. Repair the bolt holes by either the method that Wade suggested or the plate method like I used. Put your ladder bars side by side and make sure that you can slide a bolt through both heims on all 3 heims. I usually set my car up using some solid joints and some strut rods set to the same length as the ride height of the shocks. all of the bolts should slide in and out of the front and rear end brackets. The bars should have 2 degree down angle in the front in relation to the rocker panel. about the same on pinion angle. If everything is square and level you should not need any preload.

Good Luck!!

Tod Lane · 03-29-2010, 07:14 PM

Quote:

Originally Posted by deuces wild

Ok I took it all apart today. First i will admit I'm not an expert on suspensions. I'm still learning so bear with me.

Shocks are ok. Not broke or bound up

No broken welds or cracks

Axle tubes are not bent or twisted

Axles are ok

However on the passenger side the ladder bar bracket that mounts to the axle tube both holes upper and lower are eggshaped. You could grab the ladder bar and move it a little bit when it was mounted in the car. The drivers side you could not move at all. That side the holes are still true with no eggshape at all.

Also this may be where the prelaod comes in im not sure but on the drivers side where the ladder bar mounts to the bracket(rear) the upper heim joint has 5 threads showing with the bottom showing 9 threads. Now on the passenger side the upper has 2 threads and the bottom has 6. I'm no expert but doesn't the top one set the pinion angle only? Why would they be different? Isn't the bottom one used to set the housing straight in the car. Again I'm no expert I want to learn all this for future use. Thanks for all the input. Should i string the car from the front crossmember to the front mounts for the ladder bars? Ed

Also this is how I bought the car. If it's all jacked up I want to fix it right.

The last pass we made with our Nova before we parked it for a couple decades it pulled the Heim joints out of the top of the ladder bars in the back when I hit 2nd gear.

Rear diff rotated up, pinion angle went to about 60 degrees, car turned hard left.

NewHemi · 03-30-2010, 01:33 PM

Glad you found it... that is one of those problems that can make you crazy, when you can't figure it out at the track, short of pulling the whole rear suspension, links etc out..

But now that you got it all out, and with the great help here, it sounds like your going to be back square pretty quick.

That is what makes this site so good. Ask and you will get answers... and at least one of them usually points it out...And you often get tips on lot of place to look too.

David
The New Hemi Guy

GOAT69 · 03-30-2010, 03:27 PM

Ed, when you reassemle your rear end square it as if you were starting from scratch make sure it's settled before making any adjustments, use scales if you can get a hold of some. Any preload should be done on the scales & log corner weights, your best indicator of true suspension is how the car comes out of the water, it should be dead straight.

Carlo

03-29-2010, 08:02 AM	#1
Wade Mahaffey Senior Member Join Date: Apr 2007 Posts: 581 Likes: 0 Liked 18 Times in 8 Posts	Re: Launch question/Going left Check the ladder bar brackets on the rear housing. Sometimes the holes will enlongate (oval) from a loose bolt condition. This will allow the preload to change at the "hit". If this is the case, simply make some sleves about 3/8" long that fit the bolt fairly tight with about a .250 wall thickness. Weld (TIG) them to the ladder bar brackets (one for each hole, 8 total). Take the time to determine the correct location of the sleves to be welded in place. You can use the undamaged bracket to comfirm the proper hole location. Use a pair of dividers (dividers: as in a device/tool used to draw a circle, only using the points to determine location instead of a tape measure). After the fix, reset the preload and confirm at the track (compare tire temps after the burnout). There could be a shock issue, or a tire issue but these things usually will cause a slight drift in one direction and not a consistant hard move. However, you will need to make shock adjustments a few times each season. This will compensate for normal wear of the shock, most of which happens in the trailer during transport. Wade Mahaffey

03-29-2010, 04:07 PM	#2
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,454 Likes: 617 Liked 1,943 Times in 584 Posts	Re: Launch question/Going left I agree with Wade. I had the same problem with my car. It was the front hole on the ladder bar mount that was worn out. I fixed it by adding a plate with the correct size holes welded to the front ladder bar mount. Just a slight bit of slop in the holes will cause some crazy results. My car would cross lanes. __________________ Mike Pearson 2485 SS

03-29-2010, 05:34 PM	#3
04BlackSilverado Junior Member Join Date: Mar 2010 Posts: 11 Likes: 0 Liked 0 Times in 0 Posts	Re: Launch question/Going left Could a bad tire on the left side, cause the better right tire with traction, to push the car left? Can you swap the tires and see if it pulls to the right to verify? Newbie with a guess for what it's worth... Good luck. __________________ 2004 RCSB Silverado 6.0L 2WD

03-29-2010, 06:33 PM	#4
Ed Carpenter Live Reporter Join Date: May 2006 Location: Dripping Springs, Tx Posts: 2,709 Likes: 186 Liked 520 Times in 132 Posts	Re: Launch question/Going left Ok I took it all apart today. First i will admit I'm not an expert on suspensions. I'm still learning so bear with me. Shocks are ok. Not broke or bound up No broken welds or cracks Axle tubes are not bent or twisted Axles are ok However on the passenger side the ladder bar bracket that mounts to the axle tube both holes upper and lower are eggshaped. You could grab the ladder bar and move it a little bit when it was mounted in the car. The drivers side you could not move at all. That side the holes are still true with no eggshape at all. Also this may be where the prelaod comes in im not sure but on the drivers side where the ladder bar mounts to the bracket(rear) the upper heim joint has 5 threads showing with the bottom showing 9 threads. Now on the passenger side the upper has 2 threads and the bottom has 6. I'm no expert but doesn't the top one set the pinion angle only? Why would they be different? Isn't the bottom one used to set the housing straight in the car. Again I'm no expert I want to learn all this for future use. Thanks for all the input. Should i string the car from the front crossmember to the front mounts for the ladder bars? Ed Also this is how I bought the car. If it's all jacked up I want to fix it right. __________________ Ed Carpenter 2005 Chevy Cobalt A/SM Race Engine Development

03-29-2010, 06:59 PM	#5
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,454 Likes: 617 Liked 1,943 Times in 584 Posts	Re: Launch question/Going left Thats your problem Ed. Repair the bolt holes by either the method that Wade suggested or the plate method like I used. Put your ladder bars side by side and make sure that you can slide a bolt through both heims on all 3 heims. I usually set my car up using some solid joints and some strut rods set to the same length as the ride height of the shocks. all of the bolts should slide in and out of the front and rear end brackets. The bars should have 2 degree down angle in the front in relation to the rocker panel. about the same on pinion angle. If everything is square and level you should not need any preload. Good Luck!! __________________ Mike Pearson 2485 SS

03-30-2010, 01:33 PM	#7
NewHemi Senior Member Join Date: Dec 2009 Location: Ohio Posts: 472 Likes: 0 Liked 1 Time in 1 Post	Re: Launch question/Going left Glad you found it... that is one of those problems that can make you crazy, when you can't figure it out at the track, short of pulling the whole rear suspension, links etc out.. But now that you got it all out, and with the great help here, it sounds like your going to be back square pretty quick. That is what makes this site so good. Ask and you will get answers... and at least one of them usually points it out...And you often get tips on lot of place to look too. David The New Hemi Guy

03-30-2010, 03:27 PM	#8
GOAT69 Junior Member Join Date: Sep 2009 Posts: 3 Likes: 0 Liked 0 Times in 0 Posts	Re: Launch question/Going left Ed, when you reassemle your rear end square it as if you were starting from scratch make sure it's settled before making any adjustments, use scales if you can get a hold of some. Any preload should be done on the scales & log corner weights, your best indicator of true suspension is how the car comes out of the water, it should be dead straight. Carlo