alaska66

On my 66 the Yoke or u-JOINT is rubbing on the tunnel. I have replaced quite a few of parts -trying to get the car back to original specs. I replaced the rear spring (9 Leaf) with an Eaton spring (believe they were the original suppliers to GM) ---it came with new leap liners. I had the drive shaft balanced and new U-joint's installed in the drive shaft. Replaced the strut rods and all new hardware as well. Replaced the both the upper & lower bushings in the differential carrier bracket. All were torqued to factory spec's. I never noticed a problem before i did this work until i had a looked at the rear compartments where the universal joint did hit before and take out some of the rear tunnel. I have read some of the past post's on a somewhat similar rear end noise. The solution seemed to raise the floorboard. There was a solution to use a hockey puck-cut it in half length wise and install the 2 halves. This would raise sagging rear. Not sure if i agree with this solution. Any advice or suggestions would be welcomed.

Nowhere Man

the luggage stop rivets either fell out of the rear floor tub or it rusted off. either way you need to remove the carpet on the luggage stop and look

Bluestripe67

The techniques listed above are good, but one is missing. Behind the seats is a luggage stop panel. Under the carpet is the metal panel and it is attached all along the to the fiberglass divider that is part of the floor pan assembly. The rivets are often broken and or missing. Reattaching the panel should help. Dennis

alaska66

So, for clarification, the luggage area (Luggage stop panel? would be the area just after the 2 stowage compartments or is the small vertical (8 inches or so) Pulling the carpet would i see these rivets etc?

MrTrim

No, it’s the vertical panel right behind the seats. It’s thin metal.

alaska66

Okay---so what is the correct repair action.? I will i pull up the carpet on that vertical and look.!

TCracingCA

Check body mounts also.

Sometimes the fiberglass tub with passengers inside will just cause a droop, does it happen with people in the car?

alaska66

it was rubbing with no one in the car--it was worse with just the driver---the noise could be heard from my wife outside the car.

DansYellow66

If the rivets have pulled through the body it’s not the easiest job to fix it with the body on the frame still. I think some have managed but probably deviated from the original riveted construction. You may want to just go with the puck spacers for now and save repairing the luggage stop for a later restoration project. The body can be gently pushed up with wood blocks and jacks under the floor pan in order to insert the puck spacers.

fogaley

Every midyear that I work on has sagging floor boards. To correct I have a stock of 1/2" 1/4" & 3/8" hard rubber is 3" wide rolls. If you look at the back of the
crossmember and put your fingers between the crossmember and the floor at the outside frame rail you usually can get most of your fingers in the space.
Moving your hand toward the exhaust circles that space goes away. So I put a 1' 2x4 under the seat reinforcement just back from the crossmember and jack it up till I can get sufficient rubber in the space to equal the outer space. Usually a piece about 6" long is enough.
This will gain space for the hardware that its supposed to have.

Scott

alaska66

Thanks for the reply and info--I will check that tomorrow. Will advise. I don't want to remove the body at this time.

Pop Chevy

Also check the trans mount. If it breaks then the rear of the trans can move around. I had this happen on my 60, makes a horrible sound.

alaska66

Thanks for the reply. The transmission was also rebuilt, and new mounts were installed at that time. A lot of was accomplished to get the car back to original NCR specs.. Damage was done to the tunnel before i did all this work--never noticed it before. When you replace the rear spring and the differential bushings ---your almost at the halfway point of pulling the tranny ---which needed work. Is there a picture or diagram in the AIM which shows these rivets?

silver837

Pretty sure its in the AIM in the body section .

Tampa Jerry

Check the differential mounts. Have they been replaced in poly? Does the problem get worse if there is a passenger in the car? Have you checked the body mounts? If the lower mount has degraded, it could lower the body on the frame. Jerry

Six7390gt

I purchased and installed two of these from Silver Sport Transmissions. It stopped the driveshaft/floor rubbing while going over bumps with a passenger in the car.
https://www.jegs.com/i/Silver-Sport-...01700/10002/-1

alaska66

Did you install these on the crossmember? From the previous replies the floorboard is sagging-possibly the rivets have broken. I have the rubbing all the time now. It is definitely from the yoke/universal hitting the tunnel.

dcamick

I'm sorry, but first things first.

I would, first check floor panel height at the Exhaust crossmember. The floor panel should be no closer to the crossmember than 3/4". Once that is checked and corrected, then I would tighten (rivet) up the cargo panel.

alaska66

hello,
Just checked that. It is definitely sagging right there. About 1/4 of an inch right there. The passenger side is a less than that. Any recommendations on how to tighten up the cargo panel. From a previous reply-it was suggested that i lift the floor panel and insert a 1/2 X 3 piece of rubber on both driver and passenger side. I would think that would lift the tunnel area thus the rubbing would be gone. Save the rivets project for later.

Six7390gt

Yes, the floor supports from Silver Sport go in between the floor and the crossmember. IIRC I used a wood block in between my floor jack and the floor to carefully lift one side of the floor at a time just high enough to slip them in place. I did not drill holes in the cross member to bolt them in place as they are tightly held in place by the floor - and I didn't want to drill the crossmember. They haven't moved since the install last year - or maybe 2 years ago.

Here are a few forum pages I bookmarked while researching the floor sag - driveshaft rubbing problem on my 65.

https://www.corvetteforum.com/forums/c1-and-c2-corvettes/4312789-floor-sag-rivet-tutorial.html

https://www.corvetteforum.com/forums...t-hitting.html

https://www.corvetteforum.com/forums...tion-help.html