rear axle (bouncing)

Author Topic: rear axle (bouncing)  (Read 2631 times)

Swedefish

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rear axle (bouncing)
« on: September 12, 2007 - 01:53:50 PM »
How come that the rear axle keeps bouncing when I step on it.
Some thing is wrong with the rear springs or shocks, but what.
Does the angle of the pinion have anything to do with it?
All help is appreciated, so that I can do a decent burnout.  :burnout:




Swedefish

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Re: rear axle (bouncing)
« Reply #1 on: September 13, 2007 - 10:21:32 AM »
No one got a clue?
Does anyone know of a site or link where I can read about how to set the rear axle up for drag racing?
Any thoughts is appreciated

Offline jeryst

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Re: rear axle (bouncing)
« Reply #2 on: September 13, 2007 - 01:06:19 PM »
It's called wheel-hop. Put some traction bars on it and it'll clear right up. Should cost at most a couple hundred bucks. Easy to install.

Offline cowboy

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Re: rear axle (bouncing)
« Reply #3 on: September 13, 2007 - 01:12:08 PM »
-
Go for "Cal-tracks" -  jævligt godt.. :wow:
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Offline HP2

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Re: rear axle (bouncing)
« Reply #4 on: September 13, 2007 - 01:36:21 PM »
Is it bouncing during burnouts or during launch? Does the whole car porpiose or does just the suspension bounce? Have you changed anything recently?

Could be worn or incorrectly valved shocks, could be worn springs, could be mismatched spring rate, could be incorrectly placed spring clamps.

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Re: rear axle (bouncing)
« Reply #5 on: September 13, 2007 - 02:28:49 PM »
Thanks guys :thumbsup:
Is it bouncing during burnouts or during launch? Does the whole car porpiose or does just the suspension bounce? Have you changed anything recently?

It`s bouncing when I leave from a redlight or trying to do a burnout and it`s only the suspension that bounces, I think.
It`s not a race car though.
It`s a stock -67 Barracuda, six leafs in the leafsprings, stock shocks, nothing fancy.
Did have the springs disassembled to be sandblasted and painted. Shocks are from my local speedshop.

Offline Chryco Psycho

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Re: rear axle (bouncing)
« Reply #6 on: September 14, 2007 - 02:52:06 AM »
do you have coilover shocks on the rear ? the coilovers always cause a bouce

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Offline BIGSHCLUNK

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Re: rear axle (bouncing)
« Reply #7 on: September 14, 2007 - 08:50:28 AM »
As I recall either this month's or last month's issue of Car Craft has an article on this exact problem. I'd say a good pair of traction bars will most likely cure your problem.    :thumbsup:
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Offline basement

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Re: rear axle (bouncing)
« Reply #8 on: September 14, 2007 - 09:48:24 AM »
From the way I understand it is, the rear axle is trying to twist/rotate under extreme acceleration and a pinion snubber would help keep that from happening. :2cents:

Offline Super Blue 72

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Re: rear axle (bouncing)
« Reply #9 on: September 14, 2007 - 10:49:39 AM »
As I recall either this month's or last month's issue of Car Craft has an article on this exact problem. I'd say a good pair of traction bars will most likely cure your problem.    :thumbsup:

 :iagree: I was just thinking that.  It was a real nice article explaining about wheel hop and how the suspension moves during hard launches, etc.....
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Offline mrbill426

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Re: rear axle (bouncing)
« Reply #10 on: September 14, 2007 - 11:09:39 AM »
From the way I understand it is, the rear axle is trying to twist/rotate under extreme acceleration and a pinion snubber would help keep that from happening. :2cents:

That's what I thought, the (hidden) snubber was the Mopar traction device instead of those rather unsightly furd and chebby looking traction bars.

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Re: rear axle (bouncing)
« Reply #11 on: September 14, 2007 - 12:57:09 PM »
Then a adjustable pinion snubber would be a great investment?
I do have a pinion snubber, but it`s the one from the factory.
Would like to avoid the traction bars.

Offline mrbill426

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Re: rear axle (bouncing)
« Reply #12 on: September 14, 2007 - 02:07:28 PM »
Then a adjustable pinion snubber would be a great investment?
I do have a pinion snubber, but it`s the one from the factory.
Would like to avoid the traction bars.

I have used them before, had one on a '69 Road Runner and it worked very well.  I have one set aside for the 'Cuda for when that "project" reaches the rear axle.  :thumbsup:

Does not mean that something else may be going wrong back there with yours, like shocks as mentioned.

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Swedefish

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Re: rear axle (bouncing)
« Reply #13 on: September 14, 2007 - 03:15:29 PM »
Thanks guys

do you have coilover shocks on the rear ? the coilovers always cause a bouce

No CP, it has leafsprings at the rear.
When I had them apart I didn`t pay any attention to wich one was the right or the left, but does that matter?

Offline HP2

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Re: rear axle (bouncing)
« Reply #14 on: September 14, 2007 - 03:59:11 PM »
CP is talking about the kindof over load coils that fit over the stock shock.

The right to left orientation may matter, depending on what springs you have, as some are biased for the right side. A bias design means there may be additional half leafs on the bottom of the pack for extra torque control. With six leafs, it sounds like they are not original, so we can assume they are somewhat new and not worn out. Additionally, since they were apart for blasting and painting, they may have put the band clamps on in positions that have created an imbalanced frequency or they may have put too many back on and the spring can't seperate enough to force the front segment up. The only time I've ever had wheel bounce in a mopar was when I was messing with the rear segment clamp position.

The snubber will help over come the bouncing, especially if your springs are weak and at or below stock height, but if the rear springs are set up to operate properly, the body seperation they create will prevent a snubber from ever contacting the floor, rendering it useless.