BUICK11 Posted December 2, 2006 Report Share Posted December 2, 2006 First let me say Thank you to all who set me straight on the Cooling system question. Now for a Slight problem on my 1999 STS front brakes. 49000 miles Was told by Cadillac mechanic best not to turn rotors? I purchased a set of Wagner Front rotors and Raybestos Cermaic front pads. We do not drive the card hard. Now After about 8000 miles starting to notice a slight vibration when you make a fairly hard stop from 50 mph. Since I kept the original rotors. I was thinking about having them cleaned up...since they were not tore up.. I was also going to buy a set of OEM pads (Not AC Delco Durastop) I tried doing a search but would once again really appreciate some comments from the experts. Please keep in mind we do not drive the card hard BUT we do not like the vibration. Anyone have the correct part number for Front Pads I should order? Thanks to all! Frank Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 2, 2006 Report Share Posted December 2, 2006 The manual states that it is not necessary to turn the rotors when the brakes are done if there is no shudder, vibration or surface imperfections. Many here subscribe to that and I am sure it works for them and am I disagreeing with them. The argument is that the more material you take off the rotors the more susceptible they are to overheating and brake material transfer, which starts the shudder cycle over again... That said, I am from the old school and believe that when the brakes are done, that I want to provide a square, flat, clean, non directional surface for the new pads to mate to. When I do my brakes I take them to a GOOD machine shop and tell them all I want is a non-directional 'clean up' of the surface and to take as LITTLE material off as possible. I have two sets of rotors and get the old ones done and keep them in my garage for the next time I do my brakes. I have NEVER gotten to the point where my rotors are too thin to cause them to overheat, but I am very diligent in changing pads before the rotors are damaged (gouged, scored, etc) Do a search under shudder and vibration for lots of information on it and the theories behind it. There is major disagreement as to whether or not the rotors are 1) warped or 2) whether brake material transfer is the culprit when it comes to shudder or 3) whether BOTH warping or material transfer can cause shudder at times which I suppose is possible. I will say this, look closely at your rotors, when you have shudder, you will notice an outline of your pads on the rotor at times, indicating brake material transfer. Black glazed rotors indicate overheating possibly from a caliper that is extended too far or from sticking sliders. In all my days I rarely replace calipers unless there is a leak. Sticking caliper pistons happen in my opinion because the piston is out too far and the piston cocks, once its pushed back with new pads and the sliders are cleaned up the sticking is usually gone.. Repair shops LOVE replacing calipers IMHO... I am a firm believer that if the rear brakes are NOT picking up their share of the braking (as little as that is, probably only 25% of the total) the front brakes become overheated and cause brake material transfer. Inspect the rear when you do the front for black overheated rotors and pad thickness. It is also a good practice to either bleed or have the front and rear systems bled to 1) get the air out and 2) to flush out the old fluid as it is hydroscopic (absorbs water) causing it to boil earlier and compress lessening the caliper clamping forces. Getting the absorbed moisture out is also good as it can corrode caliper pistons, etc... Just as important is to clean the sliders and to use a HIGH quality, HIGH temp silicone grease (some have used SILGLIDE successfully). The new GM pads comes with silicone grease. Cadillac sells replacement caliper bushing kits, I replace them each time I do my brakes so that the calipers are tight to the sliders. Replacing the caliper bushings is often overlooked. It is advisable to torque your wheel lug nuts to 100 ft lbs to provide uniform clamping force on your rotor to avoid deforming the rotor either by over tightening or uneven tightening One more thing, while I never officially do the 'bedding procedure' when I do new pads, it is worth a read do a search under bedding... When I do my new pad test drive, I am sure that I naturally bed the brakes Those are my thoughts. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
JimD Posted December 2, 2006 Report Share Posted December 2, 2006 When you have the 'old' rotors cleaned up, or cut, call around to local repair houses or machine shops and find one that can do a non-directional finish cut. Use a torque wrench when installing wheels. The last time I ordered OEM front pads, the part number was 18045379 and that included new pad wear sensors. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
BigCat83 Posted December 2, 2006 Report Share Posted December 2, 2006 The anti-rattle clips may not be properly cleaned and lubed for the pads to slide freely (track where the tabs on the pads are installed). Try cleaning and lubricating this area (use proper caliper lube) re-assemle and try. I have found that if this area isn't cleaned and lubed the pads/caliper assembly will not slide smoothly thus vibrating as the caliper actuates. Link to comment Share on other sites More sharing options...
BUICK11 Posted December 2, 2006 Author Report Share Posted December 2, 2006 Thanks. Made a few calls and found a machine shop that can perform "non directional finish cut" on the Rotors. The correct part number for OEM pads appears to be #18048652. For my 1999 STS. The posts on this makes your head spin! Appreciate comments Frank Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 2, 2006 Report Share Posted December 2, 2006 The posts on this makes your head spin! If you think that is bad, search synthetic vs dyno oil, what is the best tire or K&N when you get a chance Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
BUICK11 Posted December 2, 2006 Author Report Share Posted December 2, 2006 Think I will pass on those searches. One more question Do you know if the OEM pads #18048652 will be Rivited or Bonded? Frank Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 2, 2006 Report Share Posted December 2, 2006 My memory tells me that they are bonded, because my last set were way way low and the idea of rivets ripping into my rotor did not come to mind, I was more concerned with the backing plate. I think the rear might be riveted. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
adallak Posted December 2, 2006 Report Share Posted December 2, 2006 The anti-rattle clips may not be properly cleaned and lubed for the pads to slide freely (track where the tabs on the pads are installed). Try cleaning and lubricating this area (use proper caliper lube) re-assemle and try. I have found that if this area isn't cleaned and lubed the pads/caliper assembly will not slide smoothly thus vibrating as the caliper actuates. What is exactly the caliper lube? Thanks. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Ranger Posted December 3, 2006 Report Share Posted December 3, 2006 It's silcone lube that is used on the slide pins. Link to comment Share on other sites More sharing options...
adallak Posted December 3, 2006 Report Share Posted December 3, 2006 It's silcone lube that is used on the slide pins. Thanks Ranger. I thought it was something different. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 3, 2006 Report Share Posted December 3, 2006 Interesting article on the subject of brake shudder: http://www.zeckhausen.com/avoiding_brake_judder.htm Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
BUICK11 Posted December 7, 2006 Author Report Share Posted December 7, 2006 Just a update. Followed advise of the experts. 1 Cleaned up Rotors with Non Directional Finish cut on my old original rotors $24.00 2 Purchased OEM pads #18048652 $67.90 They were bonded and included new sensors and retainer clips. Slicone Lube pack included as well. 3. Purchased can of silicone lube at Pep Boys $15.00 Thanks to one and all! Frank Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 8, 2006 Report Share Posted December 8, 2006 You didn't say how its riding! I assume your braking is smooth.... Glad you get er fixed, Mike Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
BUICK11 Posted December 8, 2006 Author Report Share Posted December 8, 2006 Smooth as glass. Also go out torque wrench 100lbs Really appreciate advice !! Thanks again Frank Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 8, 2006 Report Share Posted December 8, 2006 A torque wrench is a great tool, I have three 1 -100 ft lbs, 25 - 250 ft lbs and 10 to 300 in lbs. Glad you got it fixed. Now to avoid the stutter when your brakes are hot from hard braking don't hold them down hard at a stop, i usually put the car in neutral so I don't need hold the car with the brakes. A tip, to determine if the rear is shuttering, when you are at highway speed, hold your parking brake down and if you have shutter you will feel/hear it. The vacuum release will not allow the brake to engage it will come back up again.. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
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