DS vibration after installing MM LCA's...

[elite130]

I just installed a set of Maximum Motorsports LCA's last week. I took the car out this weekend to go to a car show and I noticed I now have a vibration from about 65mph and up. The vibration only occurs when I let off the gas and stops after the car begins to coast; but while under load, the vibration goes away. The vibration is coming from the center of the car, and it definitely isn't an out of balance tire. Because of this, I know the vibration is coming from the driveshaft.

Help me out here...why would installing the MM LCA's put the driveshaft out of balance? Are the MM LCA's and the stock LCA's different lengths (therefore changing the pinion angle)? What can I do to fix this, other than getting an alum. ds. or getting my stock ds re-balanced? I'm going to try to rotate the ds 1/4 turn. What else?

My friend installed the same set on his '04 two weeks ago and is experiencing the same problem. Help us out!

Thanks :SNSign: !

 

[Torinalth]

i dunno boss... sounds kinda odd.. installed mine with no issues... but lets take a stab at this.

yes it is very possible that the stock LCAs are different from the MM LCA length. reason being could have been ford production tolerances made your stockers shorter or longer, you got a freak batch of LCAs from MM, your driveshaft is already worn from the incorrect pinion angle from the poor stock LCAs and now that its corrected its not happy...

there are lots of reasons, but i really do kinda doubt that its because of the LCAs... jack the back of the car up (so the wheels are not touching, and you can get under it). have your friend start the car, and slowly engague the clutch, and get the rear wheels turning... watch the driveshaft for anything bad looking. then slowly accelerate and see if you DO see the vibration in the shaft, or maybe somewhere else.

maybe its just me, but two of you in te same area having the same problem kinda sounds like install error to me considering i have never heard of this before... but stranger things have happend. shrug, find the true cause (not just speculation) and then narow down from there.

Torinalth

 

[hotrodnut]

My guess was the vibe was always there and they were being absorbed by the stock mushy soft rubber bushings.

 

[squares98]

thats what I'd assume too. I didnt realize how shot my rearend was until I put on lca's.

 

[elite130]

What I'll probably do is check the pinion angle, make sure that's not messed up, but that's probably not it because I'm lowered right about 1". So it is probably the driveshaft, but like Torinalth said, I'll do some tests before I go ripping out my diriveshaft. If it does look like it is the ds, I'll be buying a FRPP Aluminum ds.

Thanks all for the help. I was just curious if anyone else had the same problem?

 

[comatose]

Your symptom sounds like a pinion angle problem, or u-joint issues on the driveshaft.

 

[comatose]

I had your exact issue, and an aluminum DS cleared it up. The guy I talked to at the driveshaft shop, who is pretty experienced, said that aluminum is very forgiving for vibes, and he was right! Mine are gone!

 

[hotrodnut]

When I installed my lowers I did get a tad bit of vibrations that I didn't notice before hand.

I thought it may have been the pinion angle since I had lowered it, so I bought the adjustable uppers. After tweeking the angle I found it had helped some but was not eliminated. Next step was to install the FRRP Aluminum Driveshaft and that cured it.

 

[blackfang]

I know the LCA's from MM will increase NVH due to the bushings. I didn't notice anything too bad, but it was a little different.

 

[elite130]

Is there anybody other than FRPP that sell Aluminum Driveshafts at a decent price?

 

[blackfang]

I went with FRPP from Summit.

 

[helty]

I experienced the same thing, and Im willing to bet its the pinion angle. We had to raise and lower the rear axle quite a bit to get the holes in the axle mount to line up with the spherical bushing on the lca's.

 

[RandyStinchcomb]

pinion angle is off

 

[BooWFO]

gee these sounds oddly familiar.

 

[GettinThere]

Elite130, did you remove the quad shocks?

Do y'all think keeping the quad shocks on would help lessen this problem?

 

[Torinalth]

i removed mine... dont have the problem. pinion angle will be fixed for me when i get my Torque arm. angle adjustament for the win.

Torinalth

 

[elite130]

Elite130, did you remove the quad shocks?

Do y'all think keeping the quad shocks on would help lessen this problem?

Nope, I left them on.

 

[Kilgore Trout]

Did you remove the dog bone?

 

[elite130]

Did you remove the dog bone?

Nope, left that on too. All I did was install the LCA's, I didn't take anything off or add anything.