scottshoe Posted September 19, 2004 Report Share Posted September 19, 2004 Any help would be appreciated..... Just replaced my rotors and pads (slotted and cross-drilled with ceramic pads) because I had a "pulsation" at higher speeds when on the brakes, figured it was a rotor. Well on the test ride I now have the pulsation at all speeds when braking. Could it be a bad caliper? I'll be taking it back apart tomorrrow to look for loose or warn parts, but will take all suggestions. Wife's not happy about $300 out the window and problem still there! Link to comment Share on other sites More sharing options...
Scotty Posted September 19, 2004 Report Share Posted September 19, 2004 That IS odd, my only guess is that you have a bad hub, tie rod. Jack up each front tire and grab the tire at 3 and 9 o'clock and shake, you should have minimal play. Are the tires in balance? Do you feel the pulsing through the steering wheel? WHen you look it over make sure the flanges are clean and wire brush them if you can, both were the wheel sits and where the rotor sits on the hub, good luck. Look your tires over good Link to comment Share on other sites More sharing options...
Barry94 Posted September 19, 2004 Report Share Posted September 19, 2004 Perhaps the rear brakes are at fault ?? 2008 STS V82016 Colorado Z711970 Corvette LT-1 Coupe Link to comment Share on other sites More sharing options...
sprucegoose Posted September 19, 2004 Report Share Posted September 19, 2004 Wow, that is kind of surprising after installing new rotors and pads that you would experience this... Like Scotty said, make sure that all the flanges (faces) of the rotors and hubs are clean. Do you have a way of indicating the run-out on the rotors? I scraped my hubs clean with a sharp putty knife and then wire-brushed the entire surface clean. Also, make sure the lug nuts are torked down evenly... There is a chance that it could be the hub or the tires I guess. Did you service the pins and bushings of the calipers when you did this? I just recently did my front brakes, and my pins were corroded beyond belief... The grease was totally solidified. Make sure they are operating freely and lubricated with silicone grease. Especially here in winter climates with road salt this is a problem. You can easily check this without disassembly by clamping the piston back aways to produce some clearance between the rotor and pads, and then grabbing the caliper and see if you can easily slide it back and forth on the pins over that clearance. '09 Cadillac CTS-4 3.6 direct injection, 128 K mi. '15 Chevy Tahoe LTZ, 5.3i V8, 125 K mi '70 Firebird Formula 400, Bored+.04, RAIII heads, M21 4spd., in-process restoration! Link to comment Share on other sites More sharing options...
Regis Posted September 19, 2004 Report Share Posted September 19, 2004 Perhaps the slides need cleaning and regreasing. Something that's neglected often. "Burns" rubber " I've never considered myself to be all that conservative, but it seems the more liberal some people get the more conservative I become. " Link to comment Share on other sites More sharing options...
scottshoe Posted September 19, 2004 Author Report Share Posted September 19, 2004 I did all 4 rotors and pads. I took it back apart this am and the one of the pins was extremely hard to get out. It appears that the rubber that the pin rides in came out a bit when removing the pin the first time. I pushed the rubber back in and lubed the pin again plus some wd-40 for extra slickness. Seems to have helped alot. Looks like the pads that were on it show more wear on the front 1/2, so this was probably my problem from day one. I'm sure that it was a "cheapie" brake job, and real recent, I didn't even have to push the pistons in for the new pads to fit over the new rotors! Thanks for all your input! Link to comment Share on other sites More sharing options...
johnnydone Posted September 19, 2004 Report Share Posted September 19, 2004 there is a tip in the manual make sure your wheels are torqued to 100lbs otherwisec pulsing may occur Link to comment Share on other sites More sharing options...
scottshoe Posted September 20, 2004 Author Report Share Posted September 20, 2004 I will get the correct lube this weekend, but for now I torqued the lugs to 80 lb. ft. (as high as my motorcycle torque wrench goes) and that fixed 98% of the problem. So I'm hoping with correct lube (pins looked like new, Florida car) and correct lug torque my problems will be gone... then on to the exhaust! Link to comment Share on other sites More sharing options...
sprucegoose Posted September 21, 2004 Report Share Posted September 21, 2004 I did all 4 rotors and pads. I took it back apart this am and the one of the pins was extremely hard to get out. It appears that the rubber that the pin rides in came out a bit when removing the pin the first time. I pushed the rubber back in and lubed the pin again plus some wd-40 for extra slickness. Seems to have helped alot. Looks like the pads that were on it show more wear on the front 1/2, so this was probably my problem from day one. I'm sure that it was a "cheapie" brake job, and real recent, I didn't even have to push the pistons in for the new pads to fit over the new rotors! Thanks for all your input! Yup, that's exactly what I saw on mine... The pads were wearing uneven, thickness varied almost 1/8" from the front edge to the back! I had a hell of a time trying to get those pins and bushings out. I literally had to punch them out with a drive pin! The bushings were not to be saved, as they were just falling apart. The bushings for mine were just $4.50 per side, and make a unbelievable difference. They slide so nice one you replace those bushings and clean up or replace those pins. Like Guru says, do not use WD40, that will be jammin' up in no time! Need to get some high temp lube in there, just don't get it all over!! So... What's up your sleeve for the exhaust system? I love a great sounding Northstar roar!! '09 Cadillac CTS-4 3.6 direct injection, 128 K mi. '15 Chevy Tahoe LTZ, 5.3i V8, 125 K mi '70 Firebird Formula 400, Bored+.04, RAIII heads, M21 4spd., in-process restoration! Link to comment Share on other sites More sharing options...
scottshoe Posted September 21, 2004 Author Report Share Posted September 21, 2004 Nothing crazy for the exhaust, 2 1/4 upgrade from the "Y" back with Dynomax Super Turbo's and Z-28 style stainless tips. I've had loud cars (400+HP Mustang with two chamber Flowmasters, 500+HP small block Chevy with same, etc.) but I just want this one to sound strong, not STRONG! Link to comment Share on other sites More sharing options...
sprucegoose Posted September 22, 2004 Report Share Posted September 22, 2004 That's cool, I hear you... (no pun intended!) That is exactly what I did on my Eldo and I am very happy with the sound. Here is a post from this summer when I completed that. http://caddyinfo.ipbhost.com/index.php?sho...t=0entry15038 I agree, I don't want this car to sound like my 70 Formula with flowmasters right off the headers. That is a whole different animal! '09 Cadillac CTS-4 3.6 direct injection, 128 K mi. '15 Chevy Tahoe LTZ, 5.3i V8, 125 K mi '70 Firebird Formula 400, Bored+.04, RAIII heads, M21 4spd., in-process restoration! Link to comment Share on other sites More sharing options...
scottshoe Posted September 22, 2004 Author Report Share Posted September 22, 2004 Took my car over to the local cruise night (not IN it) and the brakes are just as bad as when I started. Looks like I'll be getting the new "bushings" that go in the calipers for the pins to slide in... I may buy the new pins too. It has to be the caliper moving on the pins... everything else is new!!!!!!!!!!!!! I sure am glad this thing is a Florida car, everything is so clean and easily taken apart!... not like my last project - An Astro van with 180,000 miles of hard Michigan life! Link to comment Share on other sites More sharing options...
sprucegoose Posted September 23, 2004 Report Share Posted September 23, 2004 Don't you just love going to those "Cruise Nights"?! That is my biggest source of motivation to get my Firebird done. Yes, MI and WI crust is really a joy to work on sometimes isn't it? I remeber when I first bought my Eldorado (MI car), I went to replace the fuel filter and the bolt that was holding the bracket in place just snapped right off! The brake lines are another concern of mine as they are slowly being eaten away by that cancer... Well, I hope it is just your pins and bushings, but if you are developing too much heat from driving with them dragging, even a little, you may have warped rotors again... I hope I am wrong with that, but it is possible. With proper lubrication and new pins and bushings it may be able to overcome more runout, as the calipers will ossilate back and forth vs. sending the bulk of the vibes back through the car. It would be best of you could check for runout, seeing as you'll be removing the calipers anyway. If you don't have access to a dial indicator, you can always just do a quick visual with the front end up on jackstands. I have done this to check for noise in front driveline before. You would have to have a few of the lug nuts in place with some washers to hold down the rotors against the spindle face. Then start the car up and put it in low and let the rotors free-wheel at idle while you stand next to them and watch them to see if there is significant run-out. Being a toolmaker, I know this is easy for me to judge the runout just by eye if it is .005, .010, or .030", but it may not be for just everyone of course! At least you would be able to pick up something obvious that way. Just make sure that everything is clear of those drive wheels, hang the calipers off to the side with a piece of wire coat hanger, and make sure the Ebrake is on. Good luck! '09 Cadillac CTS-4 3.6 direct injection, 128 K mi. '15 Chevy Tahoe LTZ, 5.3i V8, 125 K mi '70 Firebird Formula 400, Bored+.04, RAIII heads, M21 4spd., in-process restoration! Link to comment Share on other sites More sharing options...
scottshoe Posted September 23, 2004 Author Report Share Posted September 23, 2004 I do have a dial gauge... hoping to not have to try to find it! I used to tune my brothers 250 roadrace bike when he ran in the AMA and still have most of the specialty tools we needed to keep the bike in tune. I took it apart again tonight and sprayed out the holes and made sure the bushings were all the way in. Greased the pins with high-temp grease and put it together... didn't test drive it yet as I am trying to get my stuff together for a dirtbike ride theis weekend. Michigan is hell on cars... luckily this one will only be driven occasionally in the bad weather. If the thing still pulses I will have to really dig into it. I still think it is something to do with the caliper because the problem was exactly the same from the second I put the new rotors on! Link to comment Share on other sites More sharing options...
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