New 7-Leaf Spring Installed, Now I get shaking when Accelerating
Thread Starter
Burning Brakes
Joined: Nov 2001
Posts: 787
Likes: 1
From: Toronto Ontario
New 7-Leaf Spring Installed, Now I get shaking when Accelerating
New 7-leaf Rear Spring Installed, Now I get shaking when accelerating
I had the spring shop install a new 7-leaf spring. The ride is a bit stiffer then the old 9-leaf spring. Problem is I am getting a shaking ( seems like it is coming from the drive train) under acceleration, seems like all 4 wheels need balancing but when I cruise at any speed the vette runs fine. With the new spring the rear end sits 1 ½ inches higher. The rear is a total of 301/2 inches from the ground to the bottom of the wheel well with 70 X 225 tires. Could this have screw-up my alignment? Any suggestions
I had the spring shop install a new 7-leaf spring. The ride is a bit stiffer then the old 9-leaf spring. Problem is I am getting a shaking ( seems like it is coming from the drive train) under acceleration, seems like all 4 wheels need balancing but when I cruise at any speed the vette runs fine. With the new spring the rear end sits 1 ½ inches higher. The rear is a total of 301/2 inches from the ground to the bottom of the wheel well with 70 X 225 tires. Could this have screw-up my alignment? Any suggestions
Safety Car
Joined: Oct 1999
Posts: 4,101
Likes: 10
From: NorCal
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (73-454)
Whoa, sounds like a u-joint binding on the half-shaft. I'd bet that the old joints, used to working in a certain range, have worn grooves in the cross-piece from the needle bearings. Now that the angle is slightly different, they're binding up. To check it, jack up both sides very slightly under the spindle end (your trying to duplicate normal ride hieght) of the trailing arms and turn the tire. It'll feel like there is resistance when you get to the tight part, and you might even here a slight pop or "crack" when it goes by. Post what you find.
Hans
Hans
Melting Slicks
Joined: Apr 2000
Posts: 3,286
Likes: 8
From: San Jose California
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (Wrencher)
Yes, your alignment will change a little bit, but I agree with Wrencher that it sounds an awful lot like U joints. Probably from all your harrassing of C5's :D Don't wait for one to break!
Chuck
Chuck
Thread Starter
Burning Brakes
Joined: Nov 2001
Posts: 787
Likes: 1
From: Toronto Ontario
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (Chuck Harmon)
Last week I changed the diff fluid, I did jack-up both sides of the rear, I turned the rear wheels and everthing seemed normal. You can imagine the angle of the half shafts when both sides were jacked-up Like I said the wheels turned fine. I am also wondering if the rear of the vette is to high (301/2 inches from ground to the buttom of wheel wells. If these little minor thinks keep on croping-up I just might throw in the towel and buy a new C5 and leave the C3 to the hard core fixer-uppers
Racer
Joined: Oct 2000
Posts: 283
Likes: 0
From: Cedar Rapids Iowa
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (1bad69)
Is the vibration occurring on when the tires are spinning freely a.k.a. burning rubber? If so you made be experiencing wheel hop. The most common cause of wheel hop is old worn out shocks.
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (73-454)
Your 7 leaf probably has a bit more arch than the old niner. Get some grade 8 10" bolts and lower the rear until the half shafts are parallel to the ground. You and your u joints will like it much better.
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Thread Starter
Burning Brakes
Joined: Nov 2001
Posts: 787
Likes: 1
From: Toronto Ontario
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (flynhi)
Your 7 leaf probably has a bit more arch than the old niner. Get some grade 8 10" bolts and lower the rear until the half shafts are parallel to the ground. You and your u joints will like it much better.
Melting Slicks
Joined: Apr 2000
Posts: 3,286
Likes: 8
From: San Jose California
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (flynhi)
If the car is sitting higher at rest, accelerating will squat the rear end back down and bring the half shafts closer to level and the u joints less angled. Therefore, this can't be the problem since the car is smoother at cruise when the U joints are angled the most.
Be careful about longer bolts. The tire sidewalls flex enough going around corners to rub the ends of the springs. This will cause catastrophic tire failure to THE critical tire on a corner! This would be extremely embarrassing while in the midst of showing up a C5. :cheers:
Chuck
Be careful about longer bolts. The tire sidewalls flex enough going around corners to rub the ends of the springs. This will cause catastrophic tire failure to THE critical tire on a corner! This would be extremely embarrassing while in the midst of showing up a C5. :cheers:
Chuck
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (Chuck Harmon)
Chuck is right about the possibility of sidewall rubs. I never experienced it with steel spring, but I did have it occur with a VB spring. Actually, my rub was on the end of the bolt, not the spring itself. After I trimmed off the unused portion of the bolt, I had plenty of clearance with 255/60/15s.
Is it possible that your rear is higher due to no spare?
Is it possible that your rear is higher due to no spare?
Thread Starter
Burning Brakes
Joined: Nov 2001
Posts: 787
Likes: 1
From: Toronto Ontario
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (Chuck Harmon)
If the car is sitting higher at rest, accelerating will squat the rear end back down and bring the half shafts closer to level and the u joints less angled. Therefore, this can't be the problem since the car is smoother at cruise when the U joints are angled the most.
Be careful about longer bolts. The tire sidewalls flex enough going around corners to rub the ends of the springs. This will cause catastrophic tire failure to THE critical tire on a corner! This would be extremely embarrassing while in the midst of showing up a C5. :cheers:
Chuck
Be careful about longer bolts. The tire sidewalls flex enough going around corners to rub the ends of the springs. This will cause catastrophic tire failure to THE critical tire on a corner! This would be extremely embarrassing while in the midst of showing up a C5. :cheers:
Chuck
Melting Slicks
Joined: Aug 2001
Posts: 2,043
Likes: 1
From: Elkhorn WI
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (73-454)
when they installed the spring, they might have that sucker tightened all the way up the threads :smash: on the spring ends...(near tires)....how many threads are showing at the bottom? length of the bolt? you could buy longer bolts as flyhni suggested and cut off the excess so that there is no rubbing...or just buy the toughest grade bolt at the desired length.
My main/7th leaf on my new VB-7 leaf I replaced with a shorter/stronger leaf to give myself more clearance for the sidewalls....this leaf was a Guldstrand leaf. :yesnod:
BTW- I have a question....I see lots of people replacing rear-springs...was the spring you removed "flat-lined"? If so, why do people remove the dead spring and neglect to replace the rear-shocks? when the spring quit doing its job, wouldn't the wear and tear, and only support now coming from the shocks, kill them quickly? Then when you replace with a new, strong spring the shocks don't/can't live up to their end of the deal anymore?
[Modified by ylose, 7:54 AM 6/13/2002]
My main/7th leaf on my new VB-7 leaf I replaced with a shorter/stronger leaf to give myself more clearance for the sidewalls....this leaf was a Guldstrand leaf. :yesnod:
BTW- I have a question....I see lots of people replacing rear-springs...was the spring you removed "flat-lined"? If so, why do people remove the dead spring and neglect to replace the rear-shocks? when the spring quit doing its job, wouldn't the wear and tear, and only support now coming from the shocks, kill them quickly? Then when you replace with a new, strong spring the shocks don't/can't live up to their end of the deal anymore?
[Modified by ylose, 7:54 AM 6/13/2002]
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (73-454)
I would engineer & upgrade all springs to match & set ride height, but then again I would also use a seasoned block, match the cam to the engine & install a BB in a CORVETTE!
:cool:
:cool:
Race Director
Joined: Oct 2000
Posts: 14,967
Likes: 79
From: central FL, near the beach.
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating
i have the 7 leaf and i get no squat; i also leveled the halfshafts by adjusting the bolt length.
What wheels do you have? not uni-lugs i hope :(
i will make this :cry prediction:
IT MAY HAVE THE SAME PROBLEM IF SWAPPED BACK!
What wheels do you have? not uni-lugs i hope :(
i will make this :cry prediction:
IT MAY HAVE THE SAME PROBLEM IF SWAPPED BACK!
Race Director
Joined: Oct 2000
Posts: 14,967
Likes: 79
From: central FL, near the beach.
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (73-454)
i was all set to buy a MN6 c5, but when i discovered some had incurable wheel-hop,i lost interest. :(
do you get wheel-hop? or a vibration?
do you get wheel-hop? or a vibration?
Le Mans Master
Joined: Dec 2000
Posts: 7,245
Likes: 4
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (1bad69)
67...where you been??? when are you coming out for a few rides in the cars????
I've been thinking about inviting you guys over sometime in July and then we could cruise out to "The Ridges" for a looksee - 20 minutes from my place.
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (drives61)
Wouldn't the easiest thing to do be to take it back to the shop that fitted the spring, explain the problem & let them find the cause?
:cheers:
Hi 67 :)
[Modified by UKPaul, 3:20 PM 6/13/2002]
:cheers:
Hi 67 :)
[Modified by UKPaul, 3:20 PM 6/13/2002]
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (73-454)
someone mentioned the half shafts should be parallel to the ground....that is correct. Also, the spring will be parallel or have a slight arc. My guess the sping shop used short bolts, therefore rising the back end.
Team Owner
Joined: Jun 2001
Posts: 43,136
Likes: 155
From: Thomson Georgia
Re: New 7-Leaf Spring Installed, Now I get shaking when Accelerating (UKPaul)
Wouldn't the easiest thing to do be to take it back to the shop that fitted the spring, explain the problem & let them find the cause?
:cheers:
Hi 67 :)
[Modified by UKPaul, 3:20 PM 6/13/2002]
:cheers:
Hi 67 :)
[Modified by UKPaul, 3:20 PM 6/13/2002]