Alum Driveshaft Hitting Underbody

[Mystic_Cobra]

Anyone else with a lowered Cobra and an aluminum driveshaft experiencing the driveshaft hitting on the e-brake bracket in the tranny tunnel?

I switched from H&R Sport springs (lowered 1.6/1.5) to H&R Race springs (lowered 1.25/1.0) and it still hits on hard acceleration when the car is empty or on any acceleration with a car full of gear or when I hit big bumps.
I plan to pull the driveshaft back out again tonight and grind down that bracket as much as I can.

What else would cause my rear end to sag? (I'm sure I'll be sorry I asked that)

At least the front tires don't rub in the fender wells anymore!

[Cobra-R]

I am sure others can give more info on this, but have you changed your bump stop after the car was lowered.
Not sure when a bumpstop change is needed and when it is not, but it's the only idea I have.

How much larger in diameter is the aluminum driveshaft than the stock steel shaft? I can take measurements for you to compare since my car is on the lift right now. :thumbsup:

Brian

[Mystic_Cobra]

I think the stock diamter is 3" and the aluminum shaft diameter is 4", but don't quote me on that. When I installed the alum DS, the car was on a drive-on rack. There was about 3/4"-1" clearance with my SFCs installed before I added the 4pt bar and switched to the slightly taller springs.

I still don't know what parts in the suspension counter the rear end squatting when I step on the gas. Anyone, anyone??

[johnbasf]

They are both 3 1/2". Mine does it too Jimmy. Mine is on Kevinstands so I'll try to do something with the bracket also. I'll let you know what I did.

[cobra96]

I don't know if this will help, but when I installed my alm drive shaft on my fox body it kept hitting. I found out later that my upper control arm bushings were shot. I replaced the whole arm with the stiffer svo one and have not had a problem since?

[Mystic_Cobra]

Thanks, guys. One mod leads to another...

I was wondering if the control arms, upper or lower would help. I have stock arms/bushings and 115,000 miles, more than 60 1/4 mi passes and more than 12 track days.
I still don't really understand what they do.
Would it be upper or lower or both?

[smashedheadcat]

It would probably be the upper control arms. I always thought that the older fox stangs had quite a few problems with upper control arm bushings going bad. Who knows.. But, i'd have to say that the sagging would be minimal with bad control arm bushings, but it could be the problem. THe bolts that go through the bushings go directly through the center correct........ (center of the bushing) Now, if that bushing grows too soft, that bolt would want to sink down into the bushing. Now, that's me trying to "understand" I guess I see how this could lower the car.... but i'd only think, at max, and 1/8 and inch. Heck I dont know.:D

[Mystic_Cobra]

It's not just that the car is lowered. I actually measured my fenderwells with the sport springs and compared the heights to my other mystic (sorry) and the numbers are very close to what the mfr suggests for lowering. The problem is when I accelerate. So, if the UCAs job is to resist squatting, then that could be the problem. I don't know if I can check the condition of the bushings without removing them? Does anyone?
I'm going to do a search on cc.com and see what I can find there, as well.

[johnbasf]

I have the MM PHB and TA and LCA's amd mine rubs.

[Mystic_Cobra]

DAMMN1T!

You're not helping!

:D

What else could it be? Adjustable LCAs?:bounce:

[White98SVT]

I don't have any problems. I have almost the entire Steeda G-trac suspension minus the front swaybar and my driveshaft stays put:bounce:

[BAD PNY]

Jimmy

I have the same DS on my 98 and have never had a problem. That was with stock ride height, lowered, stock UCA, adjustable UCA. I never had the problem no matter what configuration the car was in. I am basically stage 4 KB now and no problems.

[Snake98]

youre right you must be sagging too much.....i have a 98 with a FMS alum. driveshaft and eibach pro's and i havent had any problems with bumping or fender rubbing. -Rob

[Aaron94]

Cant you just drill a couple small holes in the floorpan, and then bent the bracket up a little and then wrap a Zip Tie around the line and through the holes in the floor???? LOL. sorry i couldnt resist.... :thumbsup:

:rotf: :rotf: :rotf:

[Mystic_Cobra]

I have thought about beating the floor with a hammer, since it's under the console, but hadn't thought about cutting it up yet.
I did climb under there last night and tried to fix it.
I described the rubbing as being a foot behind the shifter, but it's really about halfway back on the driveshaft. It's where the e-brake cable goes from a single cable to a double cable. The DS is hitting the bracket that holds the rear double cables.
Holy Loc-tite, I couldn't get the bolts out of the DS even with my impact wrench. Luckily I was able to reach up over my muffler and around the DS with my air grinder and grind off about a 1/4" of the bracket. This has helped quite a bit. I drove it today and with a passenger, it only bumped one time and it was on a big bump.
I had a couple of other thoughts.
1.) I could go ahead and replace the UCAs since they're (relatively) cheap.
2.) Go with me here...I thought about "lowering" the driveshaft in relation to the car. I had my motor mounts replaced at about 100,000 miles because the motor had dropped on one side and the exhuast (2.5" H) was hitting the floor pan. What if my tranny mount is breaking down like my motor mounts did? Would a new trans mount give me more space between the tranny/front of the driveshaft and the floor pan? Or am I way off?

I took off about as much of the bracket as I felt safe doing. I didn't want the cable to come loose.

[johnbasf]

Jimmy, I got under the car and looked at the rub tonight. I got to thinking about where it's hitting. Mine is rubbing on the passenger side of that bracket. I got my 2' level out and checked the rear end for center. I need to move the rear over @ 3/8" towards the drivers side. This MAY help the rub. I hope this helps a little. I know you don't have the PHB nut I'll let you know how it goes at CMP.

[Mystic_Cobra]

Hmm. That's interesting that yours rubs the pass side, mine rubbed on the drivers side of the bracket. I guess I can't adjust my rear to the right without the PHB?
I'm thinking UCAs next. They're cheap and fairly easy to install, right? Plus mine have 115,000 miles on them.

[johnbasf]

Dean S. has some for sale in the FOR SALE forum.

[White98SVT]

Originally posted by Mystic_Cobra
They're cheap and fairly easy to install, right? Plus mine have 115,000 miles on them.

Yeah they are cheap and they are easy.

[Mystic_Cobra]

Cheap and easy, my favorite.

Oh, I better stop.

:eek:

[Mystic_Cobra]

OK, I thought I'd update those who were following along with my rear end problem. I changed the upper arms and lower arms this weekend. I went with the Ford HD uppers with new diff bushings(per MM) and new MM standard lowers. I had a tough time getting the bushings out of the differential housing. The bolt that comes with the MM bushing removal tool got stripped when I was removing the second bushing. Not sure if my rear end was excessively rusty or if I didn't lube the threads sufficiently. After locating another 7/16 - 20 bolt, I was able to get things rolling again. One of the bushings was cracked and the other was shot. There was a hole in the bushing from where the rubber had deteriorated.
The car definitely feels better especially coming out of turns. AND the driveshaft is no longer hitting (knock on wood). I won't be able to fully test it until after we get out of the body shop.
Smiles all around. :D :D :D

[johnbasf]

:thumbsup: :thumbsup: