rayaapp2 Posted September 15, 2013 Share Posted September 15, 2013 I have an odd issue. I installed a set of cardone '80 Toyota Calipers(4 piston solid rotor) on my 240Z with 280Z hubs. The rear brakes are 1982 Maxima calipers and 280zx rotors. Im fairly certain the vibration is from the front as I get hints of it in the steering at low speed. I double checked it wasnt tire related. I do not see anything that would cause this issue. Ive had the front calipers on a shelf for 6 months that were intended for another car I never used them on. I suspect I have a caliper issue. The wheels spin freely so its not likely to be a sticky caliper. Has anyone else had a sticky piston issue with these? I can only suspect that the smaller diameter pistons are sticky or something to that nature that cause an imbalance across the pad... but that seems far fetched. The rotors are true(just turned) and the pads are brand new. Quote Link to comment Share on other sites More sharing options...
dexter72 Posted September 15, 2013 Share Posted September 15, 2013 Did you personally turn the rotors or did you have someplace turn them for you??.. If the rotors weren't set up correctly on the machine, they can be cut incorrectly . Even if an on-car brake lathe was used, the rotors can still be cut incorrectly. You mentioned a low speed steering vibration, When does this occur, Low speed braking, on turns or maybe over bumps????.. Have you made sure there is no free play in the front wheels??? Did you torque the front wheels with a known good torque wrench????.. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted September 16, 2013 Author Share Posted September 16, 2013 I did not personally turn the rotors, but I checked runout before and after confirming they were out .010" and .005" before and now my runout is negligible. Which is why I havent been able to source the issue. The vibration occurs in the pedal and the car at low speed(under 10mph). Its under braking only which tells me its in the braking system somewhere. I do not have any free play in the front suspension. I just replaced the front bearings(and packed them), and I also replaced the ball joints(which were in dire need of replacement). The wheels are definitely torqued correctly. Snap On Torque wrench calibrated within the past year! Its not my tools. Its me or the parts.... lol I had the rotors turned off the car(on hub). Like I said I can only suspect that there is a fault with the brake calipers. I pulled the rear calipers apart and cleaned them out today. I have 2 other sets of front calipers laying around that have low mileage on them for the fronts. Im probably going to rebuild them and slap them on to see if the problem goes away. I just dont see how that could be it. I wish I had a way to drive the front tires on the lift to see where the problem is. Quote Link to comment Share on other sites More sharing options...
Domzs Posted September 16, 2013 Share Posted September 16, 2013 Any pedal pulsation at high speed ( 55 to 65 with light pedal apply ) ? Does the steering wheel feel shimmy ? Check the rotor surface , look for any sign of chatter during machining . Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted September 16, 2013 Author Share Posted September 16, 2013 Domz, You may be on to something I overlooked. Ive never had a problem with chatter on an s30, but many other cars because of improper cut... Yes chatter at high speed! Slight shimmy... I might try and turn the rotors and scuff some emery clothe over them and see what happens. Quote Link to comment Share on other sites More sharing options...
Domzs Posted September 16, 2013 Share Posted September 16, 2013 You really don't have to do anything to the rotor after machining other then wash it REALLY good ( prevents squeaking ) . Just make sure the surface doesn't feel like a record . Quote Link to comment Share on other sites More sharing options...
dexter72 Posted September 16, 2013 Share Posted September 16, 2013 (edited) If you pull the rotors back off, you can use a gasket removing disc on a drill and go over each side of the rotors, use a slow full circular motion covering the entire rotor. Do that for about 30 seconds to a minute on each side of the rotors, should take out any minor imperfections from them being turned. Turning imperfections on the rotors surface can cause your issue, also causes brake noises. The brake pads can actually catch on the rough rotors imperfections and snap back and forth in the caliper mounting bracket. Causes brake pedal pulsations. I work in a dealership and we do this to brake rotors all the time. Edited September 16, 2013 by dexter72 Quote Link to comment Share on other sites More sharing options...
rejracer Posted September 16, 2013 Share Posted September 16, 2013 Ray, In my experience brake vibrations have always been caused by "warped" rotors. I've never had a caliper cause this type of issue. Rotor run out is the difference between inner diameter thickness and the outer diameter thickness, I've never had rotors out of spec with run out cause pulsing, but varying thickness in a radial cross section always does. Even my old 280zx with 250k of "preowned by total stoner" neglected use had silky smooth brakes after machining the rotors and getting PROPER brake pad hardware on it. When I get my rotors resurfaced I make sure everything is assembled correctly before sending it to the shop. I clean the rotor/caliper mating surfaces to bare metal, ensure there is no rust, debris or burrs that would cause inconsistent mating surfaces during re- assembly. Any surface imperfections are addressed via a draw file and know how. I just do the basics, and it's always turned out right for me. I have never used the on car rotor turning option, so I can't speak to that. If you have a 0-1 mic, you can check yourself for warpage. I usually check calipers by hand or with the assistance of a C clamp. If they are free, they have always worked for me. My experience with calipers going out (on 2 different cars) is it will pull to one side either on braking (one stuck open) or when not braking (one not releasing). Either way I've seen both, and neither was a vibrating/pulsing situation, just wanting to steer the vehicle one way or the other. On a side note I have 82/83 280zx calipers & rotors on the rear of mine, what made you choose the maxima caliper vs the ZX? Was it availability or sizing issue? Have fun! Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted September 16, 2013 Author Share Posted September 16, 2013 Ray, In my experience brake vibrations have always been caused by "warped" rotors. I've never had a caliper cause this type of issue. Rotor run out is the difference between inner diameter thickness and the outer diameter thickness, I've never had rotors out of spec with run out cause pulsing, but varying thickness in a radial cross section always does. Even my old 280zx with 250k of "preowned by total stoner" neglected use had silky smooth brakes after machining the rotors and getting PROPER brake pad hardware on it. When I get my rotors resurfaced I make sure everything is assembled correctly before sending it to the shop. I clean the rotor/caliper mating surfaces to bare metal, ensure there is no rust, debris or burrs that would cause inconsistent mating surfaces during re- assembly. Any surface imperfections are addressed via a draw file and know how. I just do the basics, and it's always turned out right for me. I have never used the on car rotor turning option, so I can't speak to that. If you have a 0-1 mic, you can check yourself for warpage. I usually check calipers by hand or with the assistance of a C clamp. If they are free, they have always worked for me. My experience with calipers going out (on 2 different cars) is it will pull to one side either on braking (one stuck open) or when not braking (one not releasing). Either way I've seen both, and neither was a vibrating/pulsing situation, just wanting to steer the vehicle one way or the other. On a side note I have 82/83 280zx calipers & rotors on the rear of mine, what made you choose the maxima caliper vs the ZX? Was it availability or sizing issue? Have fun! As Ive always called it runout is checking for warpage. http://youtu.be/Jfiw-iZcqwA Nominal thickness can be checked with a mic. At least when your checking specs in a book that is how you get them for a RO. I went with the maxima calipers because I had them... a couple pairs of them and the adapter plates from a first gen maxima. If I had zx calipers I would have probably used them, but Im not sure there is much difference. Im not really getting any pull though. Just the shimmy. Today Im going to check and make sure the front rotors arent causing the 'chatter' up front. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 16, 2013 Share Posted September 16, 2013 When I swapped from drums to maxima kit, I found one of my rear stub axles was bent. That would cause wobble of the rotor. Check that. Also, at low speed my CLSD makes the rear of the car shimmy like a wheel is gonna fall off. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted September 16, 2013 Author Share Posted September 16, 2013 (edited) The car had one 240Z stub axle and one 280Z stub axle. I replaced both of them and the bearings. Running the car on the lift and I see and hear nothing from the rear even on braking. I do have a pinion bearing on its way out in the R200 I have in there. I have a whole rear end ready to go with S130 CV axles as soon as I get the funds to purchase the checkered flag adapters. Right now all I have to that problem is an obnoxious noise from the rear that's been there for years. Im surprised it hasnt gone yet, but no vibrations associated with it that I can tell. Both rear ends I have are open diffs. My R200 LSD in my 260Z doesn't have any vibrations even at low speeds... Dexter, I do the same thing... usually while the rotor is on the lathe at work. Since the lathe I was using couldnt make fine cuts well Id hit it with the gasket remover or emery clothe. Im working on doing that now. Edited September 16, 2013 by rayaapp2 Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted September 16, 2013 Author Share Posted September 16, 2013 That made a difference. Im calling this one chatter! Thanks guys. I still have some light chatter in the brakes, but nothing like before. Even experience techs forget the basics sometimes. This is something I should have thought of from the start, but it eluded me for some reason. Ray Quote Link to comment Share on other sites More sharing options...
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