Introduction/question
Thread Starter
Instructor
Joined: Mar 2017
Posts: 101
Likes: 13
Introduction/question
Hey all! I just made an account as I have bought my first classic car a few months ago, a 1969 Corvette 350 4 speed. The car is pretty solid just some minor stuff, however; the one big question I have is the rear end is sitting too high. I've heard that the end link bolts could possibly be too long but I'm not 100%. Ive measured from the bottom of the bumpers and I'm sitting about 24" off the ground. I'm not sure where the cars supposed to be riding at so whatever suggestions you guys have is greatly appreciate. I'm really happy to be part of the forum and look forward to any suggestions y'all may have.
Instructor
Joined: Feb 2016
Posts: 215
Likes: 26
From: Bismarck North Dakota
longer to lower it and shorter to raise it, the longer it is the less spring load there is on the rear, the shorter the bolt the more the spring is loaded so it raises the rear.
if you look at my recent post on this you can see the effects of it
https://www.corvetteforum.com/forums...ar-stance.html
if you look at my recent post on this you can see the effects of it
https://www.corvetteforum.com/forums...ar-stance.html
Team Owner
Joined: Sep 2006
Posts: 31,271
Likes: 4,362
From: Westminster Maryland
Hi pd,
Welcome!
First Posts!!!
A new 69 for you! Terrific!!!
Often when a 68-72 car seems to be "sitting too high" in the rear it's because of work that's been done on the suspension and/or because of the new parts that were used.
Generally when a longer trailing arm to spring bolt is used as a remedy it's simply that…. a 'band-aid' that doesn't treat the cause.
The original bolts were drilled and had slotted nuts on them through which a cotter pin was set. Because of this there was no torque value for the nut. It was tightened until the hole for the pin lined up with the slot in the nut.
You might want to take a measurement from the ground to the center of the wheel arch. It was typically about 28". The size of the wheels and tires on the car will affect this dimension.
Perhaps if you were to post a photo of the rear suspension on your car now someone might be able to give you some advice.
Regards,
Alan
Welcome!
First Posts!!!
A new 69 for you! Terrific!!!
Often when a 68-72 car seems to be "sitting too high" in the rear it's because of work that's been done on the suspension and/or because of the new parts that were used.
Generally when a longer trailing arm to spring bolt is used as a remedy it's simply that…. a 'band-aid' that doesn't treat the cause.
The original bolts were drilled and had slotted nuts on them through which a cotter pin was set. Because of this there was no torque value for the nut. It was tightened until the hole for the pin lined up with the slot in the nut.
You might want to take a measurement from the ground to the center of the wheel arch. It was typically about 28". The size of the wheels and tires on the car will affect this dimension.
Perhaps if you were to post a photo of the rear suspension on your car now someone might be able to give you some advice.
Regards,
Alan
Last edited by Alan 71; Mar 2, 2017 at 08:03 AM.
Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX
If you measure from the ground to the top of the rear wheel arch, you should be right around 28".
To lower the rear end, you actually "loosen" the nut on the spring bolt.
There should be a cotter key on that bolt, back the nuts off as far as possible and still be able to install the cotter key. Take it for a ride to let the suspension settle, then re-measure.
Measurement "R"
To lower the rear end, you actually "loosen" the nut on the spring bolt.
There should be a cotter key on that bolt, back the nuts off as far as possible and still be able to install the cotter key. Take it for a ride to let the suspension settle, then re-measure.
Measurement "R"
Last edited by Revi; Mar 2, 2017 at 08:10 AM.
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Thread Starter
Instructor
Joined: Mar 2017
Posts: 101
Likes: 13
So I just measures and my passenger side sits at 31" and my drives sits at 29.5". Any suggestions on how to proceed?
Both castle nuts are bottomed out to the point where the bolt turns as the nut turns.
Passenger side
Drivers side
Last edited by philadave19030; Mar 2, 2017 at 01:01 PM.
Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX
It looks like you have the wrong spring bolts installed. Are there holes for cotter keys?
It looks like you have more than enough adjustment room on the bolts that you have, just back the nut off until you get down to 28" ride height.
You can either order the correct bolts with cotter key holes, drill holes in what you have, or just add a lock washer and another nut to lock the nuts in place after adjusting them to the proper ride height.
It looks like you have more than enough adjustment room on the bolts that you have, just back the nut off until you get down to 28" ride height.
You can either order the correct bolts with cotter key holes, drill holes in what you have, or just add a lock washer and another nut to lock the nuts in place after adjusting them to the proper ride height.
Last edited by Revi; Mar 2, 2017 at 02:23 PM.
Team Owner
Joined: Sep 2006
Posts: 31,271
Likes: 4,362
From: Westminster Maryland
Hi pd,
From what I can see in the photos it appears the suspension components are original in configuration except for the bolt from the spring to the trailing arm. It appears to be about 8" long. The original bolts were 6-1/4" long.
Loosening the nuts on those bolts will allow the car to sit lower, but begs the question "why is that length bolt necessary?".
It remains to be seen if there's enough length on the bolt to bring the car to it's typical ride height.
Good Luck!
Regards,
Alan
What is the front ride height (P) dimension?
Sometimes if the car is down in front it raises the rear dimension a bit.
From what I can see in the photos it appears the suspension components are original in configuration except for the bolt from the spring to the trailing arm. It appears to be about 8" long. The original bolts were 6-1/4" long.
Loosening the nuts on those bolts will allow the car to sit lower, but begs the question "why is that length bolt necessary?".
It remains to be seen if there's enough length on the bolt to bring the car to it's typical ride height.
Good Luck!
Regards,
Alan
What is the front ride height (P) dimension?
Sometimes if the car is down in front it raises the rear dimension a bit.
Last edited by Alan 71; Mar 2, 2017 at 02:38 PM.
Melting Slicks
Joined: Feb 2017
Posts: 3,232
Likes: 1,232
From: PHX AZ
addtionally.....
this sets the car higher because A. Much higher spring rate (lbs per inch of travel) B. they didn't match the bolts (longer to lower).
As a check as well, see if the lower strut rods have been bent to compensate for deflections in the rear assy. They should be STRAIGHT.
Good luck...I also have a 350/350 69 4 spd.
unkahal
http://www.eatonsprings.com/corvettespringends.html
Last edited by L-46man; Mar 2, 2017 at 02:49 PM.
Thread Starter
Instructor
Joined: Mar 2017
Posts: 101
Likes: 13
Thanks for all the help guys I truly appreciate it. I'll have to play around with it and see what works out. So after lowering the nuts to almost at the bottom of the bolts the rear only dropped about 1/2-3/4" respectively. So do I need even longer bolts or is there a problem in the suspension somewhere causing the rear to sit this high?
Last edited by philadave19030; Mar 2, 2017 at 03:20 PM.
Team Owner
Joined: Jun 2001
Posts: 23,375
Likes: 1,067
From: Virginia USA
Those are definatly not the correct bolts. As stated long bolts lower and short bolts raise the rear. Also, if you jacked up the rear with the tires off the ground you'll need to drive it or push it back and forth after putting it back on the ground to get the suspension to settle.
A good rule of thumb also is when it is setup correctly the half-shafts and links will be parallel to the ground. It appears in your pictures your half-shafts are lower at the wheel then at the differential.
Be careful if you go with longer bolts to lower it. They may clear the tire but in cornering situations with a large sidewall the tire can flex enough to come in contact with the end of the spring and ruin a perfectly good day.
A good rule of thumb also is when it is setup correctly the half-shafts and links will be parallel to the ground. It appears in your pictures your half-shafts are lower at the wheel then at the differential.
Be careful if you go with longer bolts to lower it. They may clear the tire but in cornering situations with a large sidewall the tire can flex enough to come in contact with the end of the spring and ruin a perfectly good day.
Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX