sneaky7980

iTrader: (15)

Trying to track down a vibration from the rear that started after a brake change.
Aside from less stopping power, can i remove my rear rotors and pads, install a spacer to make up for the missing rotor, then drive it to see if i found my problem? I figured that the caliper will just close and nothing else would happen.
I can live with no rear brakes for a test drive, just didn't want to screw something up.

proelky

iTrader: (13)

Before you get flamed from everyone, I would say NO!

sixvi6-camaro

iTrader: (9)

I'd have to say NO.. with no rotors and pads the calipers won't just close.. the pistons will probably completely press all the way out of the calipers and loose all the brake fluid and have no brakes at all.

Turnin20s

iTrader: (12)

^^ Yup, your pistons will go past where they are suppost to, fall out, and cause all of the brake fluid to be lost. Why don't you just go down to your local parts store and pick up some new rotors for $30 and see if it goes away.

SS SLP2

iTrader: (8)

.....install a spacer to make up for the missing rotor, then drive it to see if i found my problem? I figured that the caliper will just close and nothing else would happen......
MY .02' I would try it , the key being...install a spacer..,I would duck tape the "spacer" a 2x4, 1x4 whatever fits into the space
good luck, Johnny

99ssleeper

iTrader: (98)

yes you can. apparently half the people who replied didnt bother reading the whole post....but yes, as long as the piston has something to push against, it would work.

why would you think the brake rotors are causing the vibration? its unlikely they are the problem unless youre getting a shake when stopping only. if the veh vibrates and the steering wheel stays straight when stopping, then yes, it might be the rear rotors.

sneaky7980

iTrader: (15)

Just to clarify, i was going to install a spacer that goes onto the axle itself, with holes for the lugs to go through, so my wheel will still be in it's proper location. I can make that at work on my lunch break.
That should keep the calipers from hitting the wheel, and put something (yet to be determined) in the caliper to keep the pistons from compressing to far.

This thread piggybacks another i started about a vibration that i've been trying to track down. Without making the other thread too cluttered, i decided to creat this one specifically about an idea i had to further isolate my problem.

Without reposting the other thread completely, here's some cliff notes;

NOTE: Vibe doesn't happen when the car is stationary, only when above 70mph, regardless of RPM's.

1. Installed new rotors and pads, vibration immediatly upon first drive (70-85mph)
2. Reinstalled old rotors and pads, no change
3. balanced wheels, no change
4. rotated wheels, no change, vibe still in rear
5. put on a lift, ran it up to 60, left rear shakes bad, right rear a little. Shop and myself looked at all suspension components, u-joints and trans mount. All looked good.
6. re installed the new rotors and pads, checked park brake for rubbing, check mating surfaces of rotor to axle, no change.
7. Checked pinion angle, all good
8. wheels re balanced at a different shop, no change
9. i even checked the rear bumper skin and the air dam to see if they were flapping in the wind! Checked exhaust mounts/hangers also, all good.
10. followed the car while going down the road to see if i would notice a bad shock, looked good

I know this is an odd question to ask but now you guys know what i'm dealing with! I've worked on a lot of cars, f-bodies included, and this one has me stumped.

I appreciate any input.

sneaky7980

iTrader: (15)

I know what you mean, i'm just trying to isolate as many components individually, to completely without a doubt, eliminate them from the equation.

I work on jets for a living and i've seen some crazy **** be the root of the problem!

Common sense tells me that my plan will work in regards to the rotor's, but it never hurts to double check!

Thanks for the help guys, any additional thoughts are appreciated!!!

Powered By V8

iTrader: (2)

bent axles maybe?? has the car been in an accident or driven on horrible roads? just a wild guess...

sneaky7980

iTrader: (15)

That's usually the first thing people ask me, but it was fine until that damn brake change. If i hit a hole or something on my initial test drive, bent rims or an axle would have been my first thought. I've never heard of anyone bending an axle while jacking a car up. My luck i'm the first!

Powered By V8

iTrader: (2)

hmm...are the springs/shocks still sturdy and in place? maybe some rusty bolts or dry rotted bushings broke/came loose when the rear was hangin down?

edit: did you do the good ol' pull on everything you could get your hands on that may be loose underneath the car when it was on the lift?

sneaky7980

iTrader: (15)

We looked everything over and i put my hands on everything. I know what your saying in the first part of your reply and that was my first thought as well. Even though everything seemed ok i STILL am thinking the same as you.
I've already told the wife that i have to order new rims and tires to fix the car (ha ha), but i don't know if she'll buy off on some new strano springs and koni's also!

I'm taking it to a shop this weekend where i can put it up on a lift for a day or two, maybe actually start dissassembling some of the susp components for a better look.

THanks "powered by v8" for the advice! Stay tuned...

VIP1

Since you balanced everything else, what about the drive shaft?

Also, I would not do as you suggest with removing the rear rotors. Too much can go wrong too quickly.

Turnin20s

iTrader: (12)

I'd bet on a bad u joint or something along the lines of that. I had a bad vibration like that on my car, all I did was swap in a 6 speed and everything went to hell. I replaced the driveshaft and the tranny mount and everythings good now. Just because they look good doesn't mean they are, if you know what I mean. All my stuff was new, new poly tranny mount, new u joints, new gears, new pretty much everything. Well they had about 1000 miles on them, but still.

I'd try u joints and a tranny mount, u joints will be about $25-$30 unless you want something expensive and the tranny mount is about $10 and if the tranny mount deosn't fix the problem you could always take it back

Good luck man, I hope you find it

Jeep_junkie

Make sure you've got a piece of wood or something similar secured between the brake pads if you do test drive without the rear rotors. Failing to do so will allow the piston to pop out of the caliper. Then you'll have a nasty brake fluid douche to clean up as well as bleed the rear brakes.

BIG BAD BLACKSS

iTrader: (4)

Did you jack the rearend up by the axle? Could the axle tube have moved some?

sneaky7980

iTrader: (15)

Initially no, but after about the 4th time i was trouble shooting, yes.
I'm leaning toward swapping out the u joint right now.

BTW i've decided not to try my "rotor delete" idea at this time, going with the u joint first.

I'll keep you posted...

sneaky7980

iTrader: (15)

I went ahead and put on a different set of wheels and tires that i borrowed just for the hell of it. Vibe improved a little but still there.
One thing i have noticed is that the vibe is more pronounced when decelerating from about 80-60mph. I tried decelerating going down hill and up, a lot more noticable when going downhill.

In the mean time i'm going to swap the orig wheels back on, pull the rear rotors off for one more final insp and replace the u-joint.
I'm wondering if i should go ahead and have the driveshaft balanced while it's out?

Thoughts?

Viper

iTrader: (6)

Yes, get it balanced.

ChevyThunder17

iTrader: (48)

I would say that you should always get the driveshaft rebalanced when replacing a u-joint, but that's just me.

Have you checked out the front of the car? Things aren't always what they feel like they are.