C5 Lowering bolt sizes?
Le Mans Master
Joined: Aug 2004
Posts: 9,420
Likes: 8
From: Southern New Jersey, The wet part at the bottom
St. Jude Donor '08-'09-'10
I've posted on this subject before and will again here. The stock rear ride height adjuster bolts are 14mm in diameter. Most kits and Vette owners buy Grade 8, 7" X 1/2" bolts to lower the rear of a C5. Here's where I don't agree. I originally bought 1/2" grade 8 bolts washers and nyloc nuts from www.boltdepot.com in Mass. but after reading of two bolt failures in here I reordered and installed {Grade 8 7"X9/16" bolts washers and nyloc nuts} with success. Here's why. 14mm is in between 1/2" and 9/16". So if you are going to replace the stock bolts (for more length) why use something smaller? Bolt Depot is a good source for this parts buy to lower the car, and will cost you about the same as a kit you may buy that you know nothing about as far as tensile strength goes. You will be able to install the 9/16" bolts in the stock rubber bushings with the help of a little white lithium grease with no problem at all.
Last edited by Ol'55; Aug 25, 2007 at 09:48 PM.
Thread Starter
Safety Car
Joined: Jun 2005
Posts: 4,977
Likes: 256
From: St. Louis Missouri
I've posted on this subject before and will again here. The stock rear ride height adjuster bolts are 14mm in diameter. Most kits and Vette owners buy Grade 8, 7" X 1/2" bolts to lower the rear of a C5. Here's where I don't agree. I originally bought 1/2" grade 8 bolts washers and nyloc nuts from www.boltdepot.com in Mass. but after reading of two bolt failures in here I reordered and installed {Grade 8 7"X9/16" bolts washers and nyloc nuts} with success. Here's why. 14mm is in between 1/2" and 9/16". So if you are going to replace the stock bolts (for more length) why use something smaller? Bolt Depot is a good source for this parts buy to lower the car, and will cost you about the same as a kit you may buy that you know nothing about as far as tensile strength goes. You will be able to install the 9/16" bolts in the stock rubber bushings with the help of a little white lithium grease with no problem at all.
Instructor
Joined: Apr 2007
Posts: 104
Likes: 0
From: Saratoga Springs New York
I've posted on this subject before and will again here. The stock rear ride height adjuster bolts are 14mm in diameter. Most kits and Vette owners buy Grade 8, 7" X 1/2" bolts to lower the rear of a C5. Here's where I don't agree. I originally bought 1/2" grade 8 bolts washers and nyloc nuts from www.boltdepot.com in Mass. but after reading of two bolt failures in here I reordered and installed {Grade 8 7"X9/16" bolts washers and nyloc nuts} with success. Here's why. 14mm is in between 1/2" and 9/16". So if you are going to replace the stock bolts (for more length) why use something smaller? Bolt Depot is a good source for this parts buy to lower the car, and will cost you about the same as a kit you may buy that you know nothing about as far as tensile strength goes. You will be able to install the 9/16" bolts in the stock rubber bushings with the help of a little white lithium grease with no problem at all.
I used the 9/16" bolts ,fine thread,grade 8 ...everything is all fine......
I used the 9/16" bolts ,fine thread,grade 8 ...everything is all fine......
Racer
Joined: Aug 2007
Posts: 497
Likes: 0
From: Monrovia California
Nuts bolts hardware
Although I dont use them anymore X employee check out this place for all your needs and I mean all. www.mcmaster.com/
Burning Brakes
Joined: Jul 2007
Posts: 881
Likes: 2
From: hill billy hell
You have some choices to lower the front, 1)Back the bolts out all the way. 2) Remove the bolt and remove bushing. 3)Install thinner Bushing.
I would do the front first and then the rear
http://www.zip-products.com/Zip/prod...DC97B2548663C0
Last edited by jirasvet; Aug 27, 2007 at 11:18 AM.
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Racer
Joined: Aug 2007
Posts: 288
Likes: 1
From: RSM CA
You do not have to buy any bolts for the front. You need to do search on the forum to get more info.
You have some choices to lower the front, 1)Back the bolts out all the way. 2) Remove the bolt and remove bushing. 3)Install thinner Bushing.
I would do the front first and then the rear
http://www.zip-products.com/Zip/prod...DC97B2548663C0
You have some choices to lower the front, 1)Back the bolts out all the way. 2) Remove the bolt and remove bushing. 3)Install thinner Bushing.
I would do the front first and then the rear
http://www.zip-products.com/Zip/prod...DC97B2548663C0
I want to know how much the longer bolts will drop the back and will I be able to drop the front the same amount so the car stays flat with out buying any special parts or cutting the bushings.
I just want to drop the car so it sits on the tires better (stock wheels and tires) and reduces the gap.
Im going to start out using the stock bolts, and see how that looks, after looking under the car I would think anything more than 1.75 drop will bottom out the shocks.
Matt
Team Owner
Joined: May 2001
Posts: 87,357
Likes: 1,592
From: Western NY
While I do appreciate your taking the time to post some information you didnt really answer the question.Maybe I didnt ask clearly enough.
I want to know how much the longer bolts will drop the back and will I be able to drop the front the same amount so the car stays flat with out buying any special parts or cutting the bushings.
I just want to drop the car so it sits on the tires better (stock wheels and tires) and reduces the gap.
Im going to start out using the stock bolts, and see how that looks, after looking under the car I would think anything more than 1.75 drop will bottom out the shocks.
Matt
I want to know how much the longer bolts will drop the back and will I be able to drop the front the same amount so the car stays flat with out buying any special parts or cutting the bushings.
I just want to drop the car so it sits on the tires better (stock wheels and tires) and reduces the gap.
Im going to start out using the stock bolts, and see how that looks, after looking under the car I would think anything more than 1.75 drop will bottom out the shocks.
Matt
Going more that this, will require longer bolts in the back, and removal of them completely in the front, at least in my experience...
Racer
Joined: Aug 2007
Posts: 288
Likes: 1
From: RSM CA
Lowering the car in front by backing the OE bolts all the way up, assuming the threads aren't rusted and will go all the way, will net you somewhere between 3/4-1" of drop. At that point you can still use the OE rear bolts, although switching to a "Nylock" nut would be advisable.
Going more that this, will require longer bolts in the back, and removal of them completely in the front, at least in my experience...
Going more that this, will require longer bolts in the back, and removal of them completely in the front, at least in my experience...
Thank you that was very helpfull, I do appreciate the first hand information.
I think when I'm ready I will take pictures and make a simple guide so other Corvette newbs like my self can easily lower their cars saftly and easily.
Matt
Burning Brakes
Joined: Jul 2007
Posts: 881
Likes: 2
From: hill billy hell
