67 Adjusting Rear Body Ride Height

[Al P.]

I want to increase the rear body height over my rear tires about 1 inch and I have read this:

"Adjust the ride height to your favorite position by tightening or loosening the spring bolts."

To raise it a bit higher can I tighten the Spring Bolts that connect the rear trailing arms to the transverse rear spring? Does this actually raise the body higher?

I have poly spring cushions and adjustable (non stock) spring bolt assemblies that are easily adjusted in or out for setting. My spring is good also. Just need a bit more body height for tires.

How much added height can one get by doing this?

Or is there an easier way to accomplish the same thing?

Thanks

[Joe R.]

Re: 67 Adjusting Rear Body Ride Height

Al,

The adjustable rear spring bolts are usually long enough and threaded enough to raise the rear a couple of inches if needed. The ones I have seen have a ny-lock nut. By tightening the nut (shortening the bolt) the car is raised thus giving you more distance between the wheel well lip and the tire.
Have fun with your 67!

JR

[Al P.]

Re: 67 Adjusting Rear Body Ride Height

Thanks Joe! Seems simple enough.

[Gene M.]

Re: 67 Adjusting Rear Body Ride Height

Al,

The adjustable rear spring bolts are usually long enough and threaded enough to raise the rear a couple of inches if needed. The ones I have seen have a ny-lock nut. By tightening the nut (shortening the bolt) the car is raised thus giving you more distance between the wheel well lip and the tire.
Have fun with your 67!

JR

Joe,
I just don't see where one is going to raise the ride height by the nut position on the two outer spring bolts. The length of that thread is about an inch or less and needs to accept a cotter pin to secure the nut on original equiptment. If Al is looking to put the top of the tire below the fender lip (hot rod style, as in tire to big) the original parts under the corvette are not going to get him there. The top of the tire is designed to sit above to in line with the lip (depending on the suspension age). Also note fooling around with the rear ride height changes alignment.

[John H.]

Re: 67 Adjusting Rear Body Ride Height

Joe,
I just don't see where one is going to raise the ride height by the nut position on the two outer spring bolts. The length of that thread is about an inch or less and needs to accept a cotter pin to secure the nut on original equiptment.

Gene -

I think Joe is referring to the aftermarket 8"-long bolts and Nylok nuts some guys use with aftermarket rear springs to bring the rear ride height down to normal; as you noted, you can't do that with the OEM 6" bolt, nut, and cotter pin.

[Gene M.]

Re: 67 Adjusting Rear Body Ride Height

Gene -

I think Joe is referring to the aftermarket 8"-long bolts and Nylok nuts some guys use with aftermarket rear springs to bring the rear ride height down to normal; as you noted, you can't do that with the OEM 6" bolt, nut, and cotter pin.

Yes, I agree. But changing the ride height will screw up the rear suspension geometry and alignment. The 1/2 shafts are not designed to run at extreme angles.

[Al P.]

Re: 67 Adjusting Rear Body Ride Height

All,
I do not want the tops of the tires under the body - my tires right now - the outside side of them are actually under the body where they should be . I just like one more inch higher on that rear body panel that sits over the upper sidewalls of the tires.- that's all.

[Gene M.]

Re: 67 Adjusting Rear Body Ride Height

Al,
If your spring or cushions has "flattened out" causing the rear to sag, you will need a new cushions or spring or get it re-arched. If you "jack up" with after market bolts on a bad spring you would be looking at other problems. The car should sit fairly level front to rear. Typically new spring and cushions will have the car sit higher till driven some and things settle in.

[Al P.]

Re: 67 Adjusting Rear Body Ride Height

My spring cushions are red Poly - they are not flat - Spring looks good as well. Drive shafts are perfectly straight & parallel to the floor.

I just measured ride height from tire bottom to fender lip on both front and rear and I have 25.5" all round - so the car is level.

I have larger radials on rear. I can put my finger between the rear fender lip and tire on the driver side and there is a bit more clearance than the passenger side.

Perhaps it's the camber adjustment on the rear passenger side tire that I need extend my adjustable strut rod out a tad to bring that tires top more inward? (thus a bit more lip clearance)

The good thing is tires don't hit the fender while driving.

I was concerned as the passenger side rear clearance is a bit "tighter" than the drivers rear side. Is this normal?

[Gene M.]

Re: 67 Adjusting Rear Body Ride Height

My spring cushions are red Poly - they are not flat - Spring looks good as well. Drive shafts are perfectly straight & parallel to the floor.

I just measured ride height from tire bottom to fender lip on both front and rear and I have 25.5" all round - so the car is level.

I have larger radials on rear. .......................

Perhaps it's the camber adjustment on the rear passenger side tire that I need extend my adjustable strut rod out a tad to bring that tires top more inward? ...................

I was concerned as the passenger side rear clearance is a bit "tighter" than the drivers rear side. Is this normal?

Al,
I would not put more camber in the rear to gain tire clearence. A sure way to destroy tires in short order. How big are the rear tires and what rims are you running? '67 ralley's?

A small difference between tire and fender lips from side to side is normal. Was body ever lifted off the frame, if so could be reset more parallel with side frame rails and equal spacing.

You say all equal height to fender lips but you have different diameter tires front to rear, so is this true?

[Robert M.]

Re: 67 Adjusting Rear Body Ride Height

Gene -

I think Joe is referring to the aftermarket 8"-long bolts and Nylok nuts some guys use with aftermarket rear springs to bring the rear ride height down to normal; as you noted, you can't do that with the OEM 6" bolt, nut, and cotter pin.

John
My 67 rear is a bit high. I just want to understand you correctly. I have OEM bolts, nuts, with cotter pins. Are you saying there is only one position for the cotter pin? That than makes adjusting the nut impossible.

[John D.]

Re: 67 Adjusting Rear Body Ride Height

My 67 sat a couple of inches high with a aftermarket rear spring. maybe thats the easiest way to do it.

[Joe L.]

Re: 67 Adjusting Rear Body Ride Height

Yes, I agree. But changing the ride height will screw up the rear suspension geometry and alignment. The 1/2 shafts are not designed to run at extreme angles.

Gene------

Actually, GM used a version of this method to adjust the rear ride height of Corvettes beginning in the 1975 model year and through the 1982 model year. During this period there were up to 5 different length bolts used in order to adjust the rear bumper height. This was done to comply with "5 MPH bumper" crash standards. The special length bolts were never available in SERVICE, though.

[John H.]

Re: 67 Adjusting Rear Body Ride Height

John
My 67 rear is a bit high. I just want to understand you correctly. I have OEM bolts, nuts, with cotter pins. Are you saying there is only one position for the cotter pin? That than makes adjusting the nut impossible.

Robert -

The link bolt design doesn't provide for any adjustment, and none is possible; the cotter pin just keeps the nut from falling off. That's why there is no torque specified on the nut in the Assembly Manual - it tells you to just turn the nut down until the cotter pin hole is exposed, and install the pin. If that doesn't result in proper rear ride height and the rear is too high, the spring isn't to spec and you'll need to buy one of the aftermarket kits with 8" bolts and Nyloc nuts to bring the rear ride height down to design.