lowering bolts
Thread Starter
Racer
Joined: Jan 2004
Posts: 254
Likes: 41
From: Lake Charles LA
lowering bolts
Hey guys, I need to tap your expertise about lowering bolts on a '97. I know where the bolts are located, but what size wrench is needed, and which way are the bolts turned to lower the rear suspension? I have a service manual that is no help. It has pix, talks about measurements, but doesn't say which way to turn the bolts to raise or lower.
Thanks in advance!
Thanks in advance!
Safety Car
Joined: Oct 2003
Posts: 3,699
Likes: 16
From: Sun City- Menifee Calif.
Hey guys, I need to tap your expertise about lowering bolts on a '97. I know where the bolts are located, but what size wrench is needed, and which way are the bolts turned to lower the rear suspension? I have a service manual that is no help. It has pix, talks about measurements, but doesn't say which way to turn the bolts to raise or lower.
Thanks in advance!
Thanks in advance!
Team Owner
Joined: May 2001
Posts: 87,294
Likes: 1,579
From: Western NY
If you're also going to lower the front, I'd be VERY careful about doing it on a 1997 (12 year old) car. The bolts in the front are screwed into a steel insert in the spring. If the bolt hangs up in the insert, due to dirt or rust, you run the risk of breaking out the threaded insert, ruining the spring. Or, if you get one side to turn, and the other either won't or hangs up, you could be stuck with an uneven car. Proceed with caution....
Melting Slicks
Joined: May 1999
Posts: 2,365
Likes: 0
From: Vancouver BC
The rears you have to screw out until only a few threads remain showing at the top....the fronts you have to screw in so that all the threads show at the top....use some WD40 to make life easier and relieve the pressure of the front and rear springs on the bolts by carefully jacking the springs up (put something rubbery between the spring and the jack to prevent the spring from being damaged) ...that way you can almost turn the bolts by hand. Indy
Pro
Joined: Jul 2008
Posts: 564
Likes: 1
From: Moyock NC
This might help I got it off the web somewhere
Lowering the C5 Corvette
using the "ride height adjustment bolts"
--------------------------------------------------------------------------------
Based on various postings on various forums the prevailint opinion is that you can lower the rear of your C5 up to about 1" and the front to 3/4" safely with the stock bolts if you have the Z-51 suspension. If you have the base suspension (FE1) or the Continuously Variable Real Time Damping (F45) suspension, opinions on the net (not backed up with any facts) suggest that damage to the suspension may occur if FE1 or F45 suspensions are lowered this far. Some kind of undefined, serious damage can occur if an F45 car is lowered. No one has said what kind of damage or how serious or where it occurs, etc. Could be an urban legend, I suppose.
I checked with automotive author and C5 guru Hib Halverson who said: "Both Delphi and the Corvette Team people told me that F45 has a problem with lowered cars and increased damping, i.e.: the car rides more stiffly." and "I think you can use the spring jack screws to lower the car as much as that will allow. Then road test the car, if you don't like the ride, simply crank up the adjustment again." Followed by: "There won't be damage to the shocks. What I was told is that the F45 system "sees" the decrease in ride height and sometimes increases damping during normal driving where ordinarily there would be no increase." Keep in mind that F45 cars have base springs. Softly sprung cars may have more of a problem with lowering than will Z51s.
So, based on my research, it appears that you can lower the FE1 and F45 about 1/2" in the front and rear safely. Adjusting both front and rear bolts to their maximum will give you approximately 3/4" in the front and 1" in the rear (this will vary from car to car). While this does not sound like much, it makes the car look and feel a lot lower. My air dam was 2" off the road after the procedure. I am considering either cutting off the lower one inch of the air dam or raising the car about 1/2" so it won't scrape so much.
Before starting, measure the height of the front and rear wheel wells from the ground through the center of the wheel. It should be somewhere around 27-3/8" in front and 28-5/8" in the rear. Remember these numbers. Some suggest that the rear lowering can be done without raising the car - well, I'm too big to get under my car unless it is raised - so, the procedure is outlined below.
--------------------------------------------------------------------------------
Lowering the Rear:
1. With the car on a level surface and the front wheels blocked, jack the rear of the car and support with two jack stands. It is actually easier to do the lowering if the wheels are removed, especially when it is time to measure the bolt height to ensure that the car will be level (you might want to remove the wheels now also).
2. At each end of the transverse leaf spring, locate a long bolt, with the threaded up pointed upward. You should see about 1 inch to 1-1/2 inches of exposed thread on the bolt (this is on the top of the leaf spring). Using an 18 mm socket and ratchet on the bottom of the bolt, tighten (clockwise) until there are only two or three threads exposed on the top part of the bolt. Use an 18 mm wrench to hold the top nut in place as you turn the bolt.
3. Leave two or three threads exposed before it contacts the nut. The nut has a small "C" clip on it so it won't back out. It takes about 5 minutes per side to lower the rear about 1". It is a good idea to measure the exposed threads on each side to ensure they are the same.
--------------------------------------------------------------------------------
Lowering the Front: The front, the car definitely has to be raised.
1. With the car safely raised and on jack stands and the front wheels removed, find the end of the transverse leaf spring next to the shock. Locate the 10 mm end of the ride height adjustment bolt. It has a retainer clip
2. With some suspensions (like the F45) it is easier to get at the top of the bolt if the lower shock absorber bolts (13 mm) are removed so the shock can be moved out of the way.
3. Using a 10 mm socket on the top of the stud, turn counter-clockwise (like unscrewing - even though you are not, you are just on the opposite end of the bolt so it looks that way) until tight.
4. Back off the bolt about a 1/8 to ¼ turn to ensure it does not freeze in place in case you want to raise the car at some future date.
5. Re attach the lower shock mounts, put the wheels back on and remove the jack stands.
--------------------------------------------------------------------------------
At this point, the car may not appear to have been lowered very much. Take it for a drive around the block and allow things to settle (and it *will* settle quite a bit). Then, with the car parked in the same spot, re-measure the height of the wheel wells as above. The difference between the two measurements is the amount the car was lowered. Make sure that both sides of the front and rear measure the same. Adjust as necessary.
Drive the car for a week or so then have the alignment checked by a good shop. Align as necessary. If the car feels like the suspension is riding on the rebound bumpers, you may be too low - The best fix is to raise the car by about ¼" and test driving again.
Lowering the C5 Corvette
using the "ride height adjustment bolts"
--------------------------------------------------------------------------------
Based on various postings on various forums the prevailint opinion is that you can lower the rear of your C5 up to about 1" and the front to 3/4" safely with the stock bolts if you have the Z-51 suspension. If you have the base suspension (FE1) or the Continuously Variable Real Time Damping (F45) suspension, opinions on the net (not backed up with any facts) suggest that damage to the suspension may occur if FE1 or F45 suspensions are lowered this far. Some kind of undefined, serious damage can occur if an F45 car is lowered. No one has said what kind of damage or how serious or where it occurs, etc. Could be an urban legend, I suppose.
I checked with automotive author and C5 guru Hib Halverson who said: "Both Delphi and the Corvette Team people told me that F45 has a problem with lowered cars and increased damping, i.e.: the car rides more stiffly." and "I think you can use the spring jack screws to lower the car as much as that will allow. Then road test the car, if you don't like the ride, simply crank up the adjustment again." Followed by: "There won't be damage to the shocks. What I was told is that the F45 system "sees" the decrease in ride height and sometimes increases damping during normal driving where ordinarily there would be no increase." Keep in mind that F45 cars have base springs. Softly sprung cars may have more of a problem with lowering than will Z51s.
So, based on my research, it appears that you can lower the FE1 and F45 about 1/2" in the front and rear safely. Adjusting both front and rear bolts to their maximum will give you approximately 3/4" in the front and 1" in the rear (this will vary from car to car). While this does not sound like much, it makes the car look and feel a lot lower. My air dam was 2" off the road after the procedure. I am considering either cutting off the lower one inch of the air dam or raising the car about 1/2" so it won't scrape so much.
Before starting, measure the height of the front and rear wheel wells from the ground through the center of the wheel. It should be somewhere around 27-3/8" in front and 28-5/8" in the rear. Remember these numbers. Some suggest that the rear lowering can be done without raising the car - well, I'm too big to get under my car unless it is raised - so, the procedure is outlined below.
--------------------------------------------------------------------------------
Lowering the Rear:
1. With the car on a level surface and the front wheels blocked, jack the rear of the car and support with two jack stands. It is actually easier to do the lowering if the wheels are removed, especially when it is time to measure the bolt height to ensure that the car will be level (you might want to remove the wheels now also).
2. At each end of the transverse leaf spring, locate a long bolt, with the threaded up pointed upward. You should see about 1 inch to 1-1/2 inches of exposed thread on the bolt (this is on the top of the leaf spring). Using an 18 mm socket and ratchet on the bottom of the bolt, tighten (clockwise) until there are only two or three threads exposed on the top part of the bolt. Use an 18 mm wrench to hold the top nut in place as you turn the bolt.
3. Leave two or three threads exposed before it contacts the nut. The nut has a small "C" clip on it so it won't back out. It takes about 5 minutes per side to lower the rear about 1". It is a good idea to measure the exposed threads on each side to ensure they are the same.
--------------------------------------------------------------------------------
Lowering the Front: The front, the car definitely has to be raised.
1. With the car safely raised and on jack stands and the front wheels removed, find the end of the transverse leaf spring next to the shock. Locate the 10 mm end of the ride height adjustment bolt. It has a retainer clip
2. With some suspensions (like the F45) it is easier to get at the top of the bolt if the lower shock absorber bolts (13 mm) are removed so the shock can be moved out of the way.
3. Using a 10 mm socket on the top of the stud, turn counter-clockwise (like unscrewing - even though you are not, you are just on the opposite end of the bolt so it looks that way) until tight.
4. Back off the bolt about a 1/8 to ¼ turn to ensure it does not freeze in place in case you want to raise the car at some future date.
5. Re attach the lower shock mounts, put the wheels back on and remove the jack stands.
--------------------------------------------------------------------------------
At this point, the car may not appear to have been lowered very much. Take it for a drive around the block and allow things to settle (and it *will* settle quite a bit). Then, with the car parked in the same spot, re-measure the height of the wheel wells as above. The difference between the two measurements is the amount the car was lowered. Make sure that both sides of the front and rear measure the same. Adjust as necessary.
Drive the car for a week or so then have the alignment checked by a good shop. Align as necessary. If the car feels like the suspension is riding on the rebound bumpers, you may be too low - The best fix is to raise the car by about ¼" and test driving again.
Team Owner
Joined: May 2001
Posts: 87,294
Likes: 1,579
From: Western NY
FWIW, my car is an F45 equipped version (why I ever ordered that option I'll never know......hindsight is 20/20!), and I lowered it as far as it will go, on the stock bolts.
I did the front first, to see where it would wind up, then brought the rear down enough to leave a little "rake", that is needed for aerodynamic stability. My only concern was potential damage to the shocks, but in 17,000 miles of driving, I haven't seen anything. With respect to ride harshness, it's a sports car, not a Cadillac......
I did the front first, to see where it would wind up, then brought the rear down enough to leave a little "rake", that is needed for aerodynamic stability. My only concern was potential damage to the shocks, but in 17,000 miles of driving, I haven't seen anything. With respect to ride harshness, it's a sports car, not a Cadillac......
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
FWIW, my car is an F45 equipped version (why I ever ordered that option I'll never know......hindsight is 20/20!), and I lowered it as far as it will go, on the stock bolts.
I did the front first, to see where it would wind up, then brought the rear down enough to leave a little "rake", that is needed for aerodynamic stability. My only concern was potential damage to the shocks, but in 17,000 miles of driving, I haven't seen anything. With respect to ride harshness, it's a sports car, not a Cadillac......
I did the front first, to see where it would wind up, then brought the rear down enough to leave a little "rake", that is needed for aerodynamic stability. My only concern was potential damage to the shocks, but in 17,000 miles of driving, I haven't seen anything. With respect to ride harshness, it's a sports car, not a Cadillac......
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Team Owner
Joined: May 2001
Posts: 87,294
Likes: 1,579
From: Western NY
Burning Brakes
Joined: May 2006
Posts: 1,049
Likes: 2
From: Houston TEXAS
This might help I got it off the web somewhere
Lowering the C5 Corvette
using the "ride height adjustment bolts"
--------------------------------------------------------------------------------
Based on various postings on various forums the prevailint opinion is that you can lower the rear of your C5 up to about 1" and the front to 3/4" safely with the stock bolts if you have the Z-51 suspension. If you have the base suspension (FE1) or the Continuously Variable Real Time Damping (F45) suspension, opinions on the net (not backed up with any facts) suggest that damage to the suspension may occur if FE1 or F45 suspensions are lowered this far. Some kind of undefined, serious damage can occur if an F45 car is lowered. No one has said what kind of damage or how serious or where it occurs, etc. Could be an urban legend, I suppose.
I checked with automotive author and C5 guru Hib Halverson who said: "Both Delphi and the Corvette Team people told me that F45 has a problem with lowered cars and increased damping, i.e.: the car rides more stiffly." and "I think you can use the spring jack screws to lower the car as much as that will allow. Then road test the car, if you don't like the ride, simply crank up the adjustment again." Followed by: "There won't be damage to the shocks. What I was told is that the F45 system "sees" the decrease in ride height and sometimes increases damping during normal driving where ordinarily there would be no increase." Keep in mind that F45 cars have base springs. Softly sprung cars may have more of a problem with lowering than will Z51s.
So, based on my research, it appears that you can lower the FE1 and F45 about 1/2" in the front and rear safely. Adjusting both front and rear bolts to their maximum will give you approximately 3/4" in the front and 1" in the rear (this will vary from car to car). While this does not sound like much, it makes the car look and feel a lot lower. My air dam was 2" off the road after the procedure. I am considering either cutting off the lower one inch of the air dam or raising the car about 1/2" so it won't scrape so much.
Before starting, measure the height of the front and rear wheel wells from the ground through the center of the wheel. It should be somewhere around 27-3/8" in front and 28-5/8" in the rear. Remember these numbers. Some suggest that the rear lowering can be done without raising the car - well, I'm too big to get under my car unless it is raised - so, the procedure is outlined below.
--------------------------------------------------------------------------------
Lowering the Rear:
1. With the car on a level surface and the front wheels blocked, jack the rear of the car and support with two jack stands. It is actually easier to do the lowering if the wheels are removed, especially when it is time to measure the bolt height to ensure that the car will be level (you might want to remove the wheels now also).
2. At each end of the transverse leaf spring, locate a long bolt, with the threaded up pointed upward. You should see about 1 inch to 1-1/2 inches of exposed thread on the bolt (this is on the top of the leaf spring). Using an 18 mm socket and ratchet on the bottom of the bolt, tighten (clockwise) until there are only two or three threads exposed on the top part of the bolt. Use an 18 mm wrench to hold the top nut in place as you turn the bolt.
3. Leave two or three threads exposed before it contacts the nut. The nut has a small "C" clip on it so it won't back out. It takes about 5 minutes per side to lower the rear about 1". It is a good idea to measure the exposed threads on each side to ensure they are the same.
--------------------------------------------------------------------------------
Lowering the Front: The front, the car definitely has to be raised.
1. With the car safely raised and on jack stands and the front wheels removed, find the end of the transverse leaf spring next to the shock. Locate the 10 mm end of the ride height adjustment bolt. It has a retainer clip
2. With some suspensions (like the F45) it is easier to get at the top of the bolt if the lower shock absorber bolts (13 mm) are removed so the shock can be moved out of the way.
3. Using a 10 mm socket on the top of the stud, turn counter-clockwise (like unscrewing - even though you are not, you are just on the opposite end of the bolt so it looks that way) until tight.
4. Back off the bolt about a 1/8 to ¼ turn to ensure it does not freeze in place in case you want to raise the car at some future date.
5. Re attach the lower shock mounts, put the wheels back on and remove the jack stands.
--------------------------------------------------------------------------------
At this point, the car may not appear to have been lowered very much. Take it for a drive around the block and allow things to settle (and it *will* settle quite a bit). Then, with the car parked in the same spot, re-measure the height of the wheel wells as above. The difference between the two measurements is the amount the car was lowered. Make sure that both sides of the front and rear measure the same. Adjust as necessary.
Drive the car for a week or so then have the alignment checked by a good shop. Align as necessary. If the car feels like the suspension is riding on the rebound bumpers, you may be too low - The best fix is to raise the car by about ¼" and test driving again.
Lowering the C5 Corvette
using the "ride height adjustment bolts"
--------------------------------------------------------------------------------
Based on various postings on various forums the prevailint opinion is that you can lower the rear of your C5 up to about 1" and the front to 3/4" safely with the stock bolts if you have the Z-51 suspension. If you have the base suspension (FE1) or the Continuously Variable Real Time Damping (F45) suspension, opinions on the net (not backed up with any facts) suggest that damage to the suspension may occur if FE1 or F45 suspensions are lowered this far. Some kind of undefined, serious damage can occur if an F45 car is lowered. No one has said what kind of damage or how serious or where it occurs, etc. Could be an urban legend, I suppose.
I checked with automotive author and C5 guru Hib Halverson who said: "Both Delphi and the Corvette Team people told me that F45 has a problem with lowered cars and increased damping, i.e.: the car rides more stiffly." and "I think you can use the spring jack screws to lower the car as much as that will allow. Then road test the car, if you don't like the ride, simply crank up the adjustment again." Followed by: "There won't be damage to the shocks. What I was told is that the F45 system "sees" the decrease in ride height and sometimes increases damping during normal driving where ordinarily there would be no increase." Keep in mind that F45 cars have base springs. Softly sprung cars may have more of a problem with lowering than will Z51s.
So, based on my research, it appears that you can lower the FE1 and F45 about 1/2" in the front and rear safely. Adjusting both front and rear bolts to their maximum will give you approximately 3/4" in the front and 1" in the rear (this will vary from car to car). While this does not sound like much, it makes the car look and feel a lot lower. My air dam was 2" off the road after the procedure. I am considering either cutting off the lower one inch of the air dam or raising the car about 1/2" so it won't scrape so much.
Before starting, measure the height of the front and rear wheel wells from the ground through the center of the wheel. It should be somewhere around 27-3/8" in front and 28-5/8" in the rear. Remember these numbers. Some suggest that the rear lowering can be done without raising the car - well, I'm too big to get under my car unless it is raised - so, the procedure is outlined below.
--------------------------------------------------------------------------------
Lowering the Rear:
1. With the car on a level surface and the front wheels blocked, jack the rear of the car and support with two jack stands. It is actually easier to do the lowering if the wheels are removed, especially when it is time to measure the bolt height to ensure that the car will be level (you might want to remove the wheels now also).
2. At each end of the transverse leaf spring, locate a long bolt, with the threaded up pointed upward. You should see about 1 inch to 1-1/2 inches of exposed thread on the bolt (this is on the top of the leaf spring). Using an 18 mm socket and ratchet on the bottom of the bolt, tighten (clockwise) until there are only two or three threads exposed on the top part of the bolt. Use an 18 mm wrench to hold the top nut in place as you turn the bolt.
3. Leave two or three threads exposed before it contacts the nut. The nut has a small "C" clip on it so it won't back out. It takes about 5 minutes per side to lower the rear about 1". It is a good idea to measure the exposed threads on each side to ensure they are the same.
--------------------------------------------------------------------------------
Lowering the Front: The front, the car definitely has to be raised.
1. With the car safely raised and on jack stands and the front wheels removed, find the end of the transverse leaf spring next to the shock. Locate the 10 mm end of the ride height adjustment bolt. It has a retainer clip
2. With some suspensions (like the F45) it is easier to get at the top of the bolt if the lower shock absorber bolts (13 mm) are removed so the shock can be moved out of the way.
3. Using a 10 mm socket on the top of the stud, turn counter-clockwise (like unscrewing - even though you are not, you are just on the opposite end of the bolt so it looks that way) until tight.
4. Back off the bolt about a 1/8 to ¼ turn to ensure it does not freeze in place in case you want to raise the car at some future date.
5. Re attach the lower shock mounts, put the wheels back on and remove the jack stands.
--------------------------------------------------------------------------------
At this point, the car may not appear to have been lowered very much. Take it for a drive around the block and allow things to settle (and it *will* settle quite a bit). Then, with the car parked in the same spot, re-measure the height of the wheel wells as above. The difference between the two measurements is the amount the car was lowered. Make sure that both sides of the front and rear measure the same. Adjust as necessary.
Drive the car for a week or so then have the alignment checked by a good shop. Align as necessary. If the car feels like the suspension is riding on the rebound bumpers, you may be too low - The best fix is to raise the car by about ¼" and test driving again.
Doing this mod soon.
Racer
Joined: Apr 2007
Posts: 310
Likes: 3
From: Alhambra CA
Today I tried to lower my friend's 97. I started with the front (stock bolts). NOTHING happened!! I drove the car a few miles to make sure it settles, the car has not lower at all. what am I doing wrong?
for the rear I used the longer lower bolts, that was easy. my problem now is that the front is pretty hight and the rear is low. please help. thank you.
for the rear I used the longer lower bolts, that was easy. my problem now is that the front is pretty hight and the rear is low. please help. thank you.
Last edited by Arttysvette; Dec 29, 2009 at 11:50 PM.
Team Owner
Joined: Dec 2008
Posts: 35,874
Likes: 1,600
From: Honolulu HI
Today I tried to lower my friend's 97. I started with the front (stock bolts). NOTHING happened!! I drove the car a few miles to make sure it settles, the car has not lower at all. what am I doing wrong?
for the rear I used the longer lower bolts, that was easy. my problem now is that the front is pretty hight and the rear is low. please help. thank you.
for the rear I used the longer lower bolts, that was easy. my problem now is that the front is pretty hight and the rear is low. please help. thank you.
Racer
Joined: Apr 2007
Posts: 310
Likes: 3
From: Alhambra CA
I was able to turn the bolts all the way til there was no more...
do you suggest I should lift the back until the front gets lower? or should I just leave the car alone til it lowers by itself? what if the front doesnt lower? what can I do next?
Thanks
do you suggest I should lift the back until the front gets lower? or should I just leave the car alone til it lowers by itself? what if the front doesnt lower? what can I do next?
Thanks
Team Owner
Joined: Dec 2008
Posts: 35,874
Likes: 1,600
From: Honolulu HI
Let it settle in for about a week, and then measure from the jacking points underneath the car to find out how the front sits in respect to the rear. If the front is still higher than the rear, you'll need to cut the front bushings or get C6 replacement bolts that allow the front to go lower...or just raise the back up to level the car out.
Racer
Joined: Apr 2007
Posts: 310
Likes: 3
From: Alhambra CA
MTPZ06 Thank you for all the help/advice. I will let the front suspension settle for a week (hopping it will lower). In case that doesn't work, can you tell me how to cut the bushings? it seems pretty tight in there, and I don't think I can use any tool to cut the bushings. Thank you again.
This project turned out to be longer than expected
This project turned out to be longer than expected
