Hello FGF!

Been lurking for a while as I shopped for a car. About a month ago I purchased a 68 400 4spd convertible. Its a driver quality but I think its pretty nice and it sure is a hell of a lot of fun. Previous owner did quite a bit of work to it (new interior, borg warner 5 speed, new subframe, plus other stuff). I'll post the pictures as soon as I find a place to host them.

The car has a couple of issues so I'm hoping to get you guys' sage advice as I work my way through everything.

Anyway, first up is a surprise subframe issue - at least I'm pretty sure its a subframe issue. Turns out the right front tire is rubbing against the outside rear render well in a sharp right turn (outside edge of the tread). Its noisy when it happens, and its weird because I didn't notice it until after I'd already bought the car and was loading it on the truck for shipping a few days later. Sigh.

So now I have it in my local shop to work out a few kinks, and my guy is telling me that the replaced subframe is somehow not straight - ie shifted to the right a bit (measured 1/2 inch). Which is resulting in the right front tire sitting further back in the well than the left front tire, thus causing the rubbing. So my question is - instead of a costly new subframe replacement, is it reasonable to think that a frame shop but be able to pull it just a bit to get the right tire to clear wheel well? The car drives otheriwse very well imo.

Also, follow up question: the car came to me with Cragar SS 14x7s (numbers on the boxes are 5 x 4.5,4.75,5) Also the box says +3 std. Tires are BFG TA 225 70 r14. I also got the supposedly original Ralley II's (which I need to verify codes on). We swapped the wheels back to the Rally's on the front to see if it made any difference in the rubbing, and the Rally's wouldn't clear the calipers (orig disc brake car) without the spacers they had in there for the Cragars. Does this make any sense? The calipers look correct, but I'm having the whole brake system redone (new rotors, calipers, drums, shoes, lines, etc) so wondering if I should maybe be looking at a smaller/different caliper?

My whole goal in this exercise is just to get the rubbing to go away as easily as possible so I can spend some quality time driving the car and then decide what i ultimately want to do about the subframe later down the road.

Thanks in advance for any advice you have.

Todd

The front sub frame can actually be installed/bolted up slightly skewed, so it's not out of the question that it may be slightly out of alignment. But, this would mean you have to loosen up all the sub frame & core support mounts and see if it can be ever so slightly realigned with out having to re-adjust the front body panels.

Aftermarket fenders both front & rear have a wider wheel well lip, which could possibly contribute to your issue. Then a spacer as well will also shift the geometry of the wheel as it moves through the turning radius. So it may be a combination of things all adding up. So I think your on the right track in thinking about wheels & tires and possibly rotors/calipers to be able to use them with out spacers. I bet that will take care of it? But you may still want to have the alignment of the Sub frame checked out in the future...

Congrats on the new toy! It's all about the Smiles per mile!

Brett!

Provide the attached measurements from the '68 Service Manual to your local shop and they can verify if the subframe has shifted:

'68 Service Manual - Frame

X2 on what Brett said. The subframe might not be bolted onto the car straight. You can take measurements to verify this. You can take a measurement from the center of the rear wheels to the center of the front wheels, if one is shorter then you know the subframe is not on correctly, also you can take measurements from the pinch welds underneath inward from the rocker panels from around the front of the front doors to the outboard side of the subframe. So take a couple measurements from the pinch weld to the outboard side of the subframe on one side and then do the other side. All the measurements should be the same from the pinch weld to the subframe from side to side, if it isnt then your subframe is canted on the car or sitting further to one side then the other or a combo of both. Dont let them replace a subframe untill you have or they have measured it to make sure it isnt just an alignment problem with the way it is sitting on the car. You can also take all kinds of measurements to figure this out, but in my opinion, the pinch weld measurement will give you a good idea if the subframe in not sitting straight on the car. And if it isnt then you have to do what Brett said and loosen all the stuff, and try and get the subframe straight on the car. This will fix a lot of issues, that maybe you havent seen yet. I cant give you an answer about the brake calipers and wheels, as I am not familiar with the 68 items even though they may be close to what I have on the 69, but I thought the 68 came with different calipers then the 69 have.

Ok lets try this - here's the car

And thanks for the advice so far.

Here are pics of the wheels, calipers, and spacers





Does this caliper look correct?








Here's the only wheel code that was still visible. Does it tell us anything?

With respect to the subframe, its definitely out of whack. The shop guys measured and you can tell by looking at the front wheels, the passenger side sits significantly back in the wheel well.

Any way to tell if its just bolted in crooked, or actually bent? In going through the receipts, looks like the last owners mechanic put in a used one. No way to tell if it was actually straight I guess.

Turns out this car has weld in subframe connectors. Do those need to be removed to do the unbolt/adjust procedure?

Couple more pictures of underneath:

As far as the Rally II's, those would not be original to the car. For 68, they were JC's - 14x6. The pic you posted is an HN - I'm pretty sure they would be from a 74 Ventura / GTO - I know, because I bought some from a friend's salvage yard way back in the 70's directly from a wreck. While they are not exactly the specs of a JC, my recollection was that they were about as close as you can get, as far as offset and backspace. Very miniscule difference. All 68 Firebirds had standard drum brakes, but you could get front discs as an option. The JC's fit both drum and optional disc for 68. It just could be that the very slight difference of the HN is the reason for not clearing the calipers - I suppose it could also be that these are not the original disc brakes? - maybe someone else can shed some light.

Nice looking car - enjoy the summer with the top down.

Thanks. I could not find the HN code anywhere, so as I suspected, not the correct wheels.

This car was front disc from the factory, verified by PHS. So something cleared the calipers, just not sure on the wheel and the caliper combo.

I could not tell if the subframe is correct unless you did the measurment brother! As far as the disk brakes goes who knows brother... I dont know and could be wrong but I didnt think 68's came with Disk brakes! I could be wrong cause I really dont know!

Yes, you could get front discs from the factory. HN rallys are off an early 70's Pontiac, and should clear stock disc brakes without a spacer. Might be aftermarket brakes, but they look stock at first glance. Might be as simple as took wide of tires. 205's is about the stock width from the factory.
welcome to the site.

Weren't 4 piston calipers on 67 birds only?

I believe '68's had two versions of front disc brakes. Neither version were well liked. I dont know about 67.

Thanks for all the responses.

Can you guys tell by the pictures if these are 4 piston calipers?

Well, i guess when you don't know, you don't know, you know!

Also, I forgot to mention, but I beleive that you will have to remove the subfram connector to be able to shift the front subframe to fit correctly.

I just measured mine and I am off 1/2" side to side. I will have the body shop guy fix it prior to installing the fenders. What should I have him shoot for for tolerance?
Gordy

Definitely. They are welded in.

I'm trying to stop the wheel rub without having to jack with the subframe if possible for now. Does anyone have any ideas on why the HN wheels won't clear the calipers? We now believe the calipers are stock. Seems weird.

As mentioned earlier, I think you need JC code wheels. Here is a link to some wheel codes, http://www.pontiacserver.com/wheels.html
Good luck
Gordy

As close as possible!

So the HN rally's cleared the calipers with dropping down to a 5mm spacer. Also, gonna drop down to a 215 70 r14 from a 225 70 r14 which should pick up another 1/4 inch + in diameter, so I think I may have found the temp solution for the rubbing issue.

JA for disc, JC for drums. (even confirmed with your attachment)

I'm not seeing a distinction between disc and drum for a 68. Am I missing something?

In the reference, under 14x6 JA, '67 firebird with disc. ('67-'68 same)

Then down a chart to JC, '68 drum brakes.

Not a well filled out table, but close enough to interpret.

So the rotors need replacing and it looks like you cant get the same 2 piece rotors that match the 4 piston calipers that are on there. So we're gonna go with a whole new system and convert to 69 single piston calipers and rotors.

Good news is the HN Rally's clear these calipers (tested on another car in the shop) with no spacers at all. Looks like the 14x7 Cragar SS's will clear these as well. Good news all around. I know ya'll were nervous :-)

I couldn't sleep knowing of your problems. LOL
Glad you got it figured out.

Mounted the new 215 70 14's BFG in the front and it clears the fender lip just fine.

Also, replaced the jacked up rear shackles with stock shackles and the stance is much better imo. Love to know what you guys think. I'll post some after pics when its all put back together.