braking problem

[Twitch]

Seems to be a Caddi issue. My 89 eldo had it. Sometimes really bad, then others, you dont notice. We changed pads and rotors,,,same thing. Both my SLSs didnt have it, but my pops 98 STS had it. Highway speeds, but very little.
I thought about the ABS also.

Let us know what you find,,,good luck.

[lunarx]

Do you feel a pulsation in the brake pedal?

If not, it could be shock, ball-joint (or other suspension item) related.
V front lower ball-joints are known to fail.

[CTS-V420]

finally got the car in for the brakes...they replaced front and rear rotors under warrenty! are they usualy covered under warrenty? i have 45k on my V and a 100k warrenty...i thought since they were a wear and tear item they would not be covered BUUT I sure wasn't about to complain about frree brakes!

[nikon]

The big question is did it fix the problem???

[bjohnso0]

Sounds like it could be a sticky piston in the caliper. Have the fluid flushed and replaced. If you have non uniform hot spots, something is hanging up. Multi-piston calipers show odd problems when the pistons stick. With a single piston set up a stuck piston would just cause premature wear on one pad.

[thebigjimsho]

Originally Posted by lunarx

Do you feel a pulsation in the brake pedal?

If not, it could be shock, ball-joint (or other suspension item) related.
V front lower ball-joints are known to fail.

Agreed. Some of the worst shimmies are from a loose suspension part.

[fredcook]

Originally Posted by ZEUSROTTY

get new rotors and pads... easy to do in about 30 minutes. I did my rotors paads and brake lines this weekend in about 4 hours... Its is soooooo easy. After that make sure you bed them in properly, and enjoy... Problem solved.

What did you torque your rotors to? I am replacing my rotors, and am getting conflicting torque specs...

[lunarx]

Originally Posted by fredcook

What did you torque your rotors to? I am replacing my rotors, and am getting conflicting torque specs...

Do you meen the wheel lugs or the rotor to hub retaining bolts?

Those retaining bolts should not be very tight (just snug) or you will never get them off next time around.
Don't put a torque wrench on those or you most likely will overtighten them.

As for wheel lugs I only go 65lb.
It's all that's needed, just retorque after your first drive.
Shops go ape-shit on wheel lug torque because they don't get a second chance to retorque.
I personally hate broken wheel studs, so I don't over do it.

If you want the torque for the caliper to the hub, then someone needs to look that up.
I will say only that the spec for that is also needlessly high.
But no harm there, since those bolts are strong.

[OldRoadDawg]

Originally Posted by lunarx

As for wheel lugs I only go 65lb.
It's all that's needed, just retorque after your first drive.

FWIW: Owners manual says for 100 ft lb

[50 4Ever]

Originally Posted by lunarx

Do you meen the wheel lugs or the rotor to hub retaining bolts?

Those retaining bolts should not be very tight (just snug) or you will never get them off next time around.
Don't put a torque wrench on those or you most likely will overtighten them.

As for wheel lugs I only go 65lb.
It's all that's needed, just retorque after your first drive.
Shops go ape-shit on wheel lug torque because they don't get a second chance to retorque.
I personally hate broken wheel studs, so I don't over do it.

If you want the torque for the caliper to the hub, then someone needs to look that up.
I will say only that the spec for that is also needlessly high.
But no harm there, since those bolts are strong.

If you are running stock wheels you need to torque to 100 lbs. If you have a good torque wrench and set it at 100 lbs you will never break a stud. After torquing set the wrench to less than 20 lbs to keep it accurate.

The problem with the shaking sounds to me like a warped rotor. I never have my rotors turned when they get too thin, or warped, because shaving a warped rotor causes thin spots which can lead to hot spots which causes warping again.

Hope you find out what it is...

[lunarx]

Ok Guys,

I don't really expect anyone to use 65lb as their wheel lug torque, if they feel safer with 100lb.

My experience has been that at 65lb, I never had a lug loosen after a retorque.

My only point is really to put anyones mind at rest, should you think you might want to torque above 100lb (to be even safer).
100lb is already much higher than needed.

I swap wheels alot, so I apreciate the reduced stress on the studs.

[fredcook]

Originally Posted by lunarx

Do you meen the wheel lugs or the rotor to hub retaining bolts?

Rotor to hub... the FAQ says...

"The torque specs for the caliper to knucle bolts are: 96 ft lbs.(front) 88 ft lbs (rear)- Rotor mounting screw is 124 LB in (you must convert this to ft lbs if using a standard torque wrench)"

[rdjiv]

Ok here's the deal:

Installed UUC stainless steel brake lines and then got new brake pads about 2 months ago. Brake pedal was spongy and began to notice some fluid weeping near the caliper rubber bleeder valve cover intermittently on all four calipers. Went back to dealer who re-flushed the brake system and conducted a proper bleed, eliminating the pedal issue. Conducted a 1000 mile trip and about halfway in, got shaking in the steering wheel and brake pedal when braking. Vibration is worse when braking hard, shaking most of the car. Looked at the left rear rotor and there are some black marks, almost looks like scoring of some kind. Now vibration is noticable at very low speed braking and still have a fluid leak on the calipers.

Concern: Its sounds to me that the cause is a warped rotor...but how many? What would cause the fluid to leak out of the caliper? I'm not 100% confident in the install of my brake lines and if that is questionable, would a poor pad installation be the overall culprit?

[50 4Ever]

Shaking through the steering wheel is indicitive of something from the front two tires. Just a thought, you might check for tread seperation (bump in the tread). I had this happen in my pickup and under heavy braking it would almost yank the wheel out of my hands.

Don't know about the leaks.