Austinma62

Hey guys, I recently installed a moser fab 9" w/ 4.11 35 spline w/ wavetrac and adj rod end lca, adj rod end phb, adj rod end torque arm. My problem is at about 60-65 mph and above I start to get a vibration. I dont feel the shifter shake, and the my pinion angle measurements are 4 down from trans outshaft, 1 down for the driveshaft, and 2 up for the rear pinion angle. So therefore my pinion is setup up to rise 2 more degrees to be parallel with the 4 down from my trans output shaft. I also seem to have a pulsing brake when braking from higher speeds, which would be a warped rotor? Cause when we first got all of this together the rear passenger side brake/ rotor was crooked and had to do some grinding on the brake caliper for it to track straighter since it was pointed to far into the car. So is it possible this rotor could be so warped causing it to vibrate at these speeds? Any help ruling out some of this crap is much appreciated!

Pseudonym

iTrader: (3)

A warped rotor would make the car shake when braking from any speed. Is it possible that the driveshaft is out of balance? What about the tie rod ends?

Austinma62

It didnt shake before the rear end swap, so no the tie rods can't be. And the vibration is constant at above 60+mph. The car doesnt shake while braking, but you can only feel the brakes pulsate some when you brake from a faster speed.

Austinma62

The driveshaft is brand new from pst. I would assume they balance that before it leaves there shop?

Pseudonym

iTrader: (3)

Yes, PST balances their driveshafts before they leave. Do the tires need to be balanced? How is the alignment? Also, were the lugnuts tightened and torqued? I think they reccomend 100 ft lbs, but check that before you do anything.

Austinma62

The tires drove fine before the swap. We used lazers and shot them on the floor and we didnt see any problems with the alignment being off. But could the alignment possibly be causing this? Eventually I will take it to a shop and have it checked over professionally.

25thhawk

iTrader: (3)

I would first check for runout on the rear axle flanges. Especially the side you needed to grind. Maybe you have a bad axle. Even new parts can be bad

Austinma62

How do you check for runout? Is there a link or something?

25thhawk

iTrader: (3)

you need to get a magnetic dial indicator. Take the brake caliper and rotor off. Then setup the dial indicator on the brake backing plate so that it touches the face of the axle flange. Then rotate the axle and watch the guage. Looking for only a couple thousandths, if its over .005 then it could be a problem.

Austinma62

Ok. Thanks alot for your help man. Ill give that a shot!

lt1 sport

iTrader: (13)

What slip yoke are you running?

guppymech

iTrader: (7)

Are you sure it was the rotor that was crooked? Maybe Moser welded the axle tube end on crooked causing the brake caliper mounting plate and caliper to actually be the crooked components.