Rear Lowering Bolts

[WVZR-1]

Originally Posted by randy ransome

The top Part No. is the Bolt. The bottom No. is the nut.

I believe that what you bought were 5/8 and NOT 9/16 and based on the fact that the OE bolts are really M14-2 X 225 the 5/8 are maybe a stretch and to be considered a "no fit". I've never tried a 5/8 but I have 9/16 and I'd think (it's been many years) that the 5/8 won't work. 5/8 would explain maybe the lesser cost also.

Maybe someone has a new bushing and they can confirm the diameter of the bore. I don't have one new or used.

[randy ransome]

Originally Posted by WVZR-1

I believe that what you bought were 5/8 and NOT 9/16 and based on the fact that the OE bolts are really M14-2 X 225 the 5/8 are maybe a stretch and to be considered a "no fit". I've never tried a 5/8 but I have 9/16 and I'd think (it's been many years) that the 5/8 won't work. 5/8 would explain maybe the lesser cost also.

Maybe someone has a new bushing and they can confirm the diameter of the bore. I don't have one new or used.

Yes they are 5/8 but I got them to fit without much trouble.
5/8 has got to be stronger than 9/16.
Mine work fine.

[WVZR-1]

Originally Posted by randy ransome

Yes they are 5/8 but I got them to fit without much trouble.
5/8 has got to be stronger than 9/16.
Mine work fine.

"without much trouble" - tells me NO FIT - also I believe the first/only time I've seen a "USS/coarse" substitution - I don't get it

[randy ransome]

Originally Posted by WVZR-1

"without much trouble" - tells me NO FIT - also I believe the first/only time I've seen a "USS/coarse" substitution - I don't get it

I was only trying to give you the information on the bolts I used.

You do what you want with that info.

[IMZZ]

I tried the Fastenal route too and they could not find a bolt that size. They took my number and called me back when they found it and quoted me about $35 a bolt.

I ordered the kit from a Corvette shop and they just notified me that they are out of stock.

Anybody else just lower the rear. I don't want to go too low and drag on everything but the rear fender gap is just too wide.

[Mystic ZR-1]

Wouldn't lowering just the rear screw up the
balance/handling of the car?

[RussMcB]

Good responses. It's good to know the original size is 14mm, and that 5/8" and 9/16" are options.

I went ahead and ordered from a Corvette vendor. I never found a significantly less expensive alternative. Even the Fastenal PN above appeared as $15 apiece on their web site. I'm sure a more reasonable price is out there, just not worth the effort to find it.

Now I'm thinking about the next steps ...

I like Gunny's idea about the cotter pin. Good safety measure. I'm also leaning towards jam nuts. I *think* that will give a little more adjustability. Maybe even help with cross weights? I'm hoping to find that out in a week or two.

Originally Posted by Mystic ZR-1

Wouldn't lowering just the rear screw up the
balance/handling of the car?

I haven't come across any posts saying it screws up geometry or roll centers. Just not to go too far because the bump stops are abrupt.

[RussMcB]

Originally Posted by IMZZ

I tried the Fastenal route too and they could not find a bolt that size. They took my number and called me back when they found it and quoted me about $35 a bolt.

I ordered the kit from a Corvette shop and they just notified me that they are out of stock.

Anybody else just lower the rear. I don't want to go too low and drag on everything but the rear fender gap is just too wide.

Ken, I ordered from these guys (and they say they are in stock):

http://www.vbandp.com/component/virt...d=114&Itemid=1

I'm planning to lower only my rear. Like yours, mine is too high compared to the front. Front seems perfect, rear has big gaps between the Goodyears and fender lips. Might be because I'm not running a spare tire or original heavy exhaust (but it was too high even before I made those changes).

[IMZZ]

Originally Posted by RussMcB

Ken, I ordered from these guys (and they say they are in stock)

Thanks for the info. I had already ordered them from the other place so I guess I'll just wait for them.

[Hib Halverson]

With respect to rear trim height, the first thing to do is get under the car and inspect the rear spring mount.

There may be metal "shims" either above or below the rear spring. To have the lowest ride height with the most suspension travel, the first thing to do is make sure all the shims which are there are below the rear spring. You don't want any above the spring and you don't want a mix of shims above and below. You want them all below the spring. Do not remove the shims. Just make sure they're all on the bottom.

As for rear spring bolts, keep in mind that long, grade-8 bolts from generic bolt suppliers (Fastenal, Granger and etc) may lack one important feature that some of the C4-specific lowering kits sold by Zip Products and other Vette parts vendors have and that is the bolt being threaded for a uncommonly long distance. Having 3 or 4 inches of threading on the bolt gives you trim height adjustabillity which you can't get with a bolt having an inch or an inch-and-a-half of thread.

With C4, suspension travel is limited to begin with on those cars. For street use, a little lowering can be desireable but a lot of lowering is going to make for two problems 1) lack of rear ground clearance and 2) lack of adequate suspension travel at the rear.

Finally, I have found with "Barney," my '95, that having proper adjustable rear spring bolts is really nice when the car is loaded up to the max with two people and cargo for a long road trip. For many years my standard procedure before the Wife and I load up for a long trip is to use the spring bolts' adjustability to raise the rear of the car half an inch or so. Once we, all our gear and a fuill tank of fuel are in the car, it will sit level. Not only does that insure adequate suspension travel at the rear (and the ride comfort which comes with that) during the trip but, if the trip involves night driving, it's preserves headlight aim.