Drivetrain How to fix driveshaft rubbing on the floor pan?

[manicmechanic007]

If he takes the shorter snubber out of it, and put the bigger one back in
It will just ride on the snubber like a hard tail
Welcome to lowering
You are gonna need to lower that crossmember or modify the trans mount to sit lower and jack the rear end back up an inch or so

 

[manicmechanic007]

In regards to post 39
That is the opposite of neutralizing the suspension
That is putting the suspension on a bind
Not advisable

 

[General karthief]

In regards to post 39
That is the opposite of neutralizing the suspension
That is putting the suspension on a bind
Not advisable

go back and read the post again, I think you misunderstood.

 

[Mustang5L5]

Yeah, I think you misread my post. I was referring to some type of aftermarket arms which the bushing design eliminates that binding and do not need to be torqued at ride height.

Since my car is apart right now, here’s what I mean.

Stock type arms absolutely should be done at ride height.

 

[AeroCoupe]

This combination of springs and dampers has been put on this chassis a lot and he should have zero issues. I ran this combo and had zero issues.

There are mechanical issues with the current control arm bushings that are most likely 100% of the problem. No shimming to change drive line angle, lowering of crossmembers, raising of the car’s ride height etc. should be done until the bushing issue is addressed. Once that is done the driveline angles should be checked and will most likely be good to go but if not address it. OP should then take the car for a spin and see if the issue with the DS scraping is solved and if the vibration issue is solved. If not them start working the problem methodically one thing at a time.

Until the bushing issues are corrected we are throwing darts blind folded.

Mike knows his stuff and so does the General so pay attention.

 

[manicmechanic007]

Well, I agree, if it has heim joints type suspension pivots, you can tighten them any way you want
It'll be a clanker either way over bumps
The rubber was there for a reason

 

[AeroCoupe]

Jesus man, I have a full MM suspension under my Coupe and its quiet as a church mouse. My T-Bird is a full Griggs car and again quiet. Rubber was there due to the crap angles of the four link and the known binding issues. Does is help with NVH? Sure but most of us are willing to deal with a little NVH to gain some performance.

 

[Mustang5L5]

Those aren’t heim joints on that end. That’s a 3-piece poly bushing on the chassis end which a lot of “street” type arms have. Spherical on the axle side.

They don’t really add a noticeable amount of NVH. No clunking at all. I have a significant chunk of the MM catalog under my car (up front mostly) and it’s impressively quiet.

 

[2000xp8]

The MM stuff does give the illusion that it's a heim joint, probably the best of both worlds design (which is why i wouldn't use anything else).

 

[manicmechanic007]

Similar to having solid motor mounts
Try them, for me, once was enough

 

[limp]

If your around central Florida, you can use the stock 2 3/4" that came out of my 83... I assume it would fit
I had a new 3" steel tube built for my new rear/TKX swap

 

[AnthonyA1234]

If your around central Florida, you can use the stock 2 3/4" that came out of my 83... I assume it would fit
I had a new 3" steel tube built for my new rear/TKX swap

I’ll see how it goes after the control arms if I still have issues I’ll shoot you a dm. Thanks for the offer!

 

[bwest]

@AnthonyA1234 - is that D/S 4"? The SS springs + OEM LCA's will sit the ass end of the car LOW. If you're riding on or contacting the pinion snubber (shorty), you have sheet of paper (or less) clearance going through the top of the tunnel. With a 3.5" D/S, those springs and non-adjustable LCA's (the box alum type - and spring sits higher than OEM LCAs) it would hit the ebrake cable. I changed to the MM adjustable LCA's, lifted the back of the car up 1.25" and didn't have a problem again.

When sitting low, these cars don't have a ton of D/S space at OE driveline angles. Add a larger diam D/S and wore out bushings, you'll end up with more pinion lift and then contact. Changing the trans crossmember for more clearance will only screw up your driveline angles, so you'd be trading 1 problem for another.

It looks like you have a few items you're fighting here, but the drop of those springs + big D/S aren't helping the situation.

 

[AeroCoupe]

Again, I ran these springs with stock control arms and the FMS driveshaft with zero issues. I am lower now with the coil overs and it only rubs the ebrake cables if I am really stressing the suspension.

Fix the bushings and then if needed make moves from there. We know the bushings are back and causing the rest end to move all over the place and in directions it normally would not. One thing at a time.