Hi all, first post here!

I have been getting some tire rub on the rear inner fenders, so I looked at the suspension and the leaf springs seem to be sagging. I attached a picture. These are definitely bad, right? The only reason I ask is I pulled one out and it looks pretty new. Also, I'm talking to the guys at ESPO and they are saying some cars' springs just look like that...

Thanks!

They actually look like they're sagging enough there's a reverse arch. I'm not an expert but IMO they need to be re-arched or replaced.

Not sure mine looks much different. What size tires are you running?

Welcome to the 1st Gen site.

Have you compared your vehicle height measurements to the specs? Here, in Fig 0-14, are the specs and measurement points:
http://www.thefirstgensite.com/library/68sm/gi/gi.html


And I'm curious. What is that bar I've circled?

Yes, welcome.
Do you have rub on both sides or just one?
Is your spring-shock mount plate cracked? Looks like a crack line just above where the shock mount stud is attached.
You have the axle bump stop mounted onto the frame, one would think that would stop the body from dropping low enough to contact the tires, unless you have really tall tires.
The springs don't look that old but yes, your springs look like they're sagging more than should, but more concerning would be the condition of all the bushings. If they are worn enough, that and worn out spring leaves, you may be getting excessive side to side movement of your axle assembly which may be causing the tire to contact the inner fender skirt. Sometimes the center bolt breaks which would cause the axle to shift in the perch, but if you had the spring out you'd catch that.
Have you lifted the car and checked the axle bearing play? I had a retainer and bearing slide loose on a GTO axle, would cause more outward movement that in, but who knows?
If the springs and axle and tires are all what they should be, perhaps the alignment of the axle assembly, frame, and body are all a bit out of spec.

Bob S. - is that a modified lower spring-shock mount plate on your car? Looks like it has an extra plate of steel welded to it, The one I have sitting on my desk looks just like the one in fbird68's pic. I know the 67s are a bit different due to the shock positioning, but yours looks completely different.

Bluebird, I have a hybrid rear end. 67 bird with a 69 multi leaf rear. I used 67 lower plates because of the non staggered shocks. If you’re talking about the partial spring leaf, I have no clue. I noticed that too after I snapped the pic. The car came with that rear and springs but had slapper bars for the lower plate. The 67 lower plates ended up working well.

Hey Bob,
I looked at Pozzi racing, he has a pic of what you have and calls it a 68 Mono leaf spring lower plate. I looked at some vendors and sure enough, what you have they sell as 1967 lower plate for mono leaf springs. I wonder why it's so different from the multi? I kinda like the Idea of having the shock bolted on with the bracket on both sides of the eye. As for the bottom leaf not extending out fore and aft, that's normal.

Wonder if Camaros came with monoleafs on some models in 68 but had staggered shocks. The you'd use two of the same side of the 67 lower plates with one rotated around. On 67's there's right and left side lower plates.

Bob S, I'm running rear 255/60s on 15x8 wheels.

Jim, thanks, I hadn't seen those specs. I should've looked at those... I was using the AMA specs which have rear rocker to ground at 6.2". Not sure why there is a discrepancy... Mine is 8.5" which is pretty close to the stock 8.1" so that makes a lot more sense now. The bar you circled is a mount for the parking brake line. I'm pretty sure it is stock because the service manual mentions it.

Bluebird thanks for all the info. I'm getting rub on both sides. I hadn't thought about the axle bearing play, I will check that. No plate crack or broken center bolt. The bushings look pretty good as well, but I'm by no means an expert.

I think I'm going to replace the springs and see what happens. The only thing is there are no part #s on these springs so I will have to guess at how much lift to get to clear the tires. The free arch on mine is 5 3/8" and new stock springs with no lift is 6 3/8". Been searching around on the forums and it seems like for most people it ends up being trial and error.

That bar/bracket is interesting. I have not seen it before. I suspect there was a design change. There was discussion a few years ago about an parking brake cable routed under the spring. Perhaps that '68 had the design too. I see that bracket in a Service manual view but not in the parts book. I know my cable is well above the spring and has never had mounting like that.

I only have run the stock 14" wheels and tires so I might suspect your wheel/tires.

Not sure about a ‘69, but that tire size just won’t fit inside the wheel well on a ‘67 or ‘68 on rims with a standard setback. I have the same size on ‘68 on Crager SS’s. I think they have a 4.25 or 4.5” Setback, and they rub without help from air shocks. I have fresh +2” multi leaf springs and air shocks.

I’m currently considering a set of American Racing Torque Thrust rims. They are available with a “deeper “ back spacing so those tires will tuck into the well.

Well just for reference I know for a fact that my 69 springs are bad and I have more arch than you. Quite a bit actually, and my rear sags. So confirm that. I don't get any rub but I've got a little less tire than you.

My concern is that when I replace them the ride height will be all "jacked up". And I kind of like the lowered look. I really don't want to get into lowered springs etc. but we will see I guess. Not on my list right now so...

Yes, there were mono leaf springs with staggered shocks. The non-staggered were only an early design, they changed over to staggered (mono and multi) to try to eliminate wheel hop. My rear axle assembly is a 1969 and was mono leaf. I put new multi leaf springs on a couple years back, I had to drill out the perches to accept the centering bolt head and weld blocks to the perches to fit the multi leaf spring pack. It was worth all that to get rid of those dreaded air shocks that were on the car to keep the back end from dragging on the pavement due to worn out springs.

The multi leaf staggered shock lower plates are different left to right.

I also run 255/60R15 (BFG radial TA) tires on the rear, they are on 15" rally II wheels with zero offset. The Camaro Chevrolet rear axle assembly is an inch narrower than the Firebird BOP axle assembly, so my wheels and tires fit 1/2" inboard of where they would if I had a stock Firebird axle. I still have plenty of clearance inboard of the tires.

Bronze Bird may have hit on your problem, if it isn't the springs, it could be your wheel offset. If your wheel is offset, positive or negative, your tire will move outboard or inboard the amount of the offset. Sometimes folks get a bit confused when dealing with backspace, I know I did. Wheel is measured inside the rim and backspace is measured from the wheel mounting surface to the outside of the rim. So an 8" wheel with zero offset will have 4" of distance from the mounting surface C/L to each inside rim. The same wheel will have a 4-1/2" backspace. My tire sits in the wheel well the same place as would be if I had a stock Firebird axle and an 8" wheel with a 5" backspace. Do you know what the offset of your wheels are?

Which leads me to the question I should have asked first, where is the tire rubbing? On the inside of the fender well outside the trunk, or against the quarter panel? If you look at the beautiful drawing I had commissioned at great expense and sacrifice, is it rubbing at A or B? If A a smaller offset wheel may help, if B a larger offset wheel will move the tire inboard.

Thanks bluebird, great picture! I think if the new springs don't fix the problem, I will look into the offset. I have the BG Rod Works 15x8's with 0" offset. The picture shows where tires are rubbing, so I could see how a larger offset would help.

Springs arrive in a couple weeks, I'll update when I get them installed!

Man, that rub is a fair ways in from the outer edge of the tire. Are you sure the wheels have zero offset? The tire seems to be out a bit more than most I've seen. Is the rear axle assembly stock? Looks like the wheel is negative offset or the axle assembly is wider than stock. But could just be the pic.

You will also have to consider that even with a stiffer or higher arched spring, when you hit a real good bump in the road, such as a severly out of aligned bridge abutment, your car is going to sink down on the springs and with the tire sticking out of the wheel well you'll still get tire rub. Maybe not as often as with the softer spring but in a severe case the spring may drop enough to have the axle tube contact the bump stop. With the tires out like that they will still contacted the fender.

I noticed a tiny line of blue on my tires when I was in Calgary last summer. Right on the outside corner of the tire. I was also getting a vibration when decelerating from about 110 MPH. Couldn't figure out why the tire was contacting the fender while driving around tight curves at high speed. Wasn't due to any large drops or bumps in the road. When I got home I checked everything I could think of and discovered the differential carrier spacers had come loose in the axle housing. Of course the axle shafts had rubbed against the spacers and filled the differential with grindings so I had to take the thing apart to clean it up and reinstall with new spacers and bearings. The differential was moving in the housing and so were the axles which caused the tire rub. That's why I asked if the bearings were tight on your axles. When the retainer and bearing on my GTO axle came adrift the fender cut my tire so badly I had to buy new tires.

Your springs arent flat. They're only flat-ish... THESE are flat springs!!!

note hideous exhaust install, too...