Hi all,  Well I replaced my wire wheels with stock rally wheels and OEM size 225 R70 15 tires (Sumitomo HTR $42 at tirerack).  The car handles much better now with no wandering around the lane.  Now it tracks through a curve in a predictable manner, just like it did back in 73.   The previous owner had monster tires on the rear, and it looked jacked up.  With the new tires the car is more level, but the rear is still too high.  the front measures about 27.8 inches and the rear is over 30 inches (floor to inside wheel arch).  The car has the stock 9 leaf steel rear spring, and stock 6.5inch bolts at either end of leaf, with only 1 thread showing on bolt end.  I don't see any spacers or any other cause for the rear to be raised.  Is it possible the shocks are lifting the rear?  How can I tell?  I am going to try removing one of the shocks, replacing the wheel and lowering it down and measuring the height.  Any other ideas?

John, unless there are air shocks back there, the shocks ain't goona be the problem.

You may need to get longer spring bolts to lower the rear. Also, measuring the body for ride height isn't always accurate. The best way to determine actual ride height is by measuring from the surface(floor) to the frame. I have the specs posted here...somewhere...

It looks like longer spring bolts will do the trick, and, you can adjust the rear up or down wherever you want.(within the limits of the bolt length)

                                                    Chassis SpecsAdams' Apple2006-10-03 07:19:03

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Joel Adams
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Yes, I know I could lower it with longer bolts, but I don't understand why I would need them.  If the spring is stock, and the bolts are stock, what could be providing the lift?  Maybe I do have air shocks.  I will pull a rear wheel and check it out tonight.  I assume air shocks have some kind of air inlet valve on them, right?  I think using longer bolts would be messing with the geometry of the rear suspension to correct some unknown problem.  The engineer in me says not to do that until I fully understand what is wrong.

John, how absolutely certain are you about the rear spring being "stock"? Is it possible the PO replaced it with an aftermarket spring that is stiffer?
Normally, the rear spring will be almost flat across(veiwed from the rear), with the car sitting level on the ground. If there is a noticable downward arch across the spring, AND the rear is too high, it may have been replaced somewhere down the line...possibly to clear the truck tires they had on it?

Does yer trans make noise, or grind when shifting cold? If not, and it is just "baulky" until warmed up, you may want to go to a lighter weight lube.

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Joel Adams
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Joel,  I guess it is possible the spring is not stock.  I counted 9 leafs on it, so assumed it is probably stock.  I will check how flat it is tonight.  Maybe I can post a picture, if I can figure out how.

Try a non-synthetic 50/75wt gear lube. No special brand...Pennzoil, etc. is fine.
The grind in rev. is "normal"...it is non-synchronised.
Check the clutch adjustment, also. It could have an effect on the shifting, hot or cold.

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Joel Adams
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I checked the clutch freeplay and it is right on (I forget the spec).  However my clutch requires a very high force to depress.  I suspect some PO put a competition type clutch in it.  When I replace the engine I plan on replacing the clutch and maybe having the trans rebuilt.  I will try changing out the gear lube with 50/75.  Why not use synthetic?

Well, you could use a synthetic, but...Muncies/Borg Warners have a tendency to "weep"/leak anyway. The synthetics will only make it worse. If you were having the trans rebuilt, with new seals, and the front of the case where the countershaft goes thru sealed, it would be otay. Plus, it's not a good idea to mix the two types of lube, tho it's not really devastating, either.

If you don't mind a little more seepage, and keep an eye on the fluid level in the trans, you could go to the synth. lube. My opinion is it's better to wait until the trans has been built/sealed to go with the synth. Of course, with a synth. lube, you can go to an even lighter weight lube. There are "0" weight lubes on the market now, believe it or not! Almost all of the pro racers(drag/Nascar, etc.) use "0" weight lubes in the diffs and trans. But then...they also change that lube quite often. I have used Synergyn "0" weight gear lube in several standards and diffs, with no bad results.(so far...knock on wood!)

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Joel Adams
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Hi Joel,  I measured my frame clearance last night.  I got roughly 7.5inches at the front (behind the front tire), and 8 inchs at the rear (in front of rear tire).  My shop manual specs 7.9 inches for both, so It looks like my front springs sagged a bit, but the rear is pretty close to right on.  Also my rear spring looks almost flat across as you described, and my shocks don't appear to be air shocks.  So, since my frame is close to level, I guess the 2 inch rise in my rear wheel arch must be due to spacers between the frame and body at the rear.  I am not exactly sure how the body mounts on the frame, but I will be checking for this tomorrow night.  There is definately 2 inches more clearance between the top of the tire and the top of the fender arch in the rear compared to the front, so something is off.  I think as you stated the most important issue for proper driving/handleing is that the frame is level.  So I don't want to lower the rear more than .5 inches.  Any other ideas?  By the way do you ever attend any car shows in the central Texas area? 

As for da brake install, there are some neat tricks/tools.

These clips fit down between the pad and the pistons, to keep the pistons pushed back, making it a snap to install the pads. I use a socket stuck between the pads to do the same thing.
Ride height...hmmm...all I can suggest is using longer spring bolts to lower the rear. That, or raise the front, and the rear will come down some also.

I doubt that anyone has replaced the body mounts in the car. I really doubt that they were "staggered" to raise the rear up more than the front. That would make the body not sit right, and the doors/hood etc. not line up properly.

Just fer fun, I'll go measure my '74, and see what kind of clearance I have on my fenders/tires. Now ya got me curious!!

Otay...I measured my car...
Front tire to fender clearance: 1 1/2" (measured with straight edge across the top of the tire)

Rear tire/fender clearance: 2 1/2" (measured the same way)

Front chassis measurement: 7"
Rear chassis measurement: 7"
(both measurements taken at the place specified on in the assy. manual["J" & "K"]...see "specs" in above post, which allows for a +/- .50", or 1/2" window)

So...my car sits level, but there is 1" more clearance in the rear than the front. Not noticable to me...or anyone else!

The assy man. for '73 shows heights at "J" @ 7.91"
"K" @ 7.89", also with a +/- .50" window.

Also, when making any chassis/fender measurements, make sure the tires are inflated to proper specs as shown on the door sticker.
I think your car is probably OK...you just got used to seeing the larger tires back there, and you can notice the diference now. I can see a big difference(1") in the clearance between the front and back tires on my car, but, it looks right. But then again...I'm weird... Git in the car(or have someone else git in it), and look at it then...it's not the same!

I have been down yonder to Austin a couple of times in da past...once to the "Heat Wave" show(the PROPER name for THAT one!!! I think Satan hisself was a judge!! ), and, to the Longhorn Corvette Club show one year...got run out by a tornader!!!    Adams' Apple2006-10-04 13:18:52

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Joel Adams
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Thanks for the info Joel.  I have the origional GM shop manual with the same specs as you noted.  In addition to the J-7.91"and K-7.89"  The specs call for approximately (I don't have the manual here at work) 27.9" floor to highest point in fender arch both front and rear.  So if your frame is level (J and K) equal, than I don't understand how the fender arch in rear could be higher than the fender arch in front.  Are you running the same tires front and rear?  If so your 1 inch differential between tire top and fender archs sounds out of spec to me  (not a big deal, but mine is 2 inches out).  I could take out .5" to 1" with longer bolts and get closer to spec keeping the frame close to level, so that is probably what I will do.  Could you measure from floor to fender arch and let me know what numbers you get?  I get 27.75"in front, and 30"in rear.  My tires are 225 70 R15, and I am currently running them at 25PSI.  Book calls for 20psi.  If I deflate them, It would probably lower the frame less than .5"   I will do that and remeasure everything, just for the sake of accuracy.

I get 27 1/2" floor to arch on da front
28 1/2" on da rear. I do have 225-70R15s on it @20psi.

I will agree that it sounds goofy to have the different fender arch measurements, given that the frame is level, but, the body mounts have probably squished(highly technical term!) down over the years, and the front of the car bodywork, which has very little to support it, may have sagged a bit. The only thing holding the front of the body, from the firewall forward, is the radiator core support.
I'll upload a pic from the side, and you can take a look at how mine sits. It does have a little rakish look, but I know the frame is level, so any "rake" comes from design, and old age!

                                                  Click on image


The brake clips will only be available at a Corvette supplier, as far as I know. Adams' Apple2006-10-05 08:27:41

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Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

  Your Rear Spring might indeed be Stock but that dosn't mean that A Spring Shop hasn't Rebuilt it with the additude that a  little more Arch is better. I have seen quite a Few Vettes that are High for no other reason. Longer Bolts are the Quik and Easy.

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My Car...PIC 1     PIC 2