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  #1  
Old 08-25-2003, 02:20 AM
James Scott James Scott is offline
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Question Shaking front (?) BRAKES

I just got back from a weekend trip to the local mountains and foothills, including Yosemite and surrounding small foothill goldrush towns. When going downhill, I experienced a frequent pulsating braking, shaking the steering wheel a little, without pulsing the brake pedal much(?)! It felt like one of the front wheels was going to shake right off the car! This occurred even on light braking - It seemed to smooth out at heavier braking! Thought this might be the ABS kicking in too soon, but why would it smooth out at HEAVIER braking?

Once it pulsated so bad I thought one of the front brake calipers came loose or some equivalent disastrous part failure! It shook really bad on light braking at about 70 mph going downhill at a fairly steep angle!! I pulled over, expecting to find some major failure. . . . . I seriously thought I would have to be towed!!!

Couldn't see anything, continued on, pulsated less (but still substantial!), when road flattened out the brakes smoothed out alot.

HELP! Is this an ABS problem? Weird brake fade? YIKES!!

Thanks for any help!

BTW: Can I have these rotors (fronts cross-drilled) turned by a regular shop lathe or do I need to have them ground as someone suggested to me here?
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1995 Laguna Blue SVX AWD L - 240K (daily driver) - "ReBuILT" used engine at 236K miles (6/13)
2013 Veloster Red - Driver Now??Dropsprings [1/2" rear, 1" front] with Koni Strut Inserts> Magnaflow Exhaust System> ECUTune Stage 1av1 Upgrade (from 1v4)> ECUTune TCU MOD> Aluminum Crankshaft Pulley> Stainless Brake Lines> Phenolic Spacers> Perforated Brake Rotors (dint like, OEM now)> SmallCar Shift Kit (resting since TCU MOD)> 7-Position Ground System> High-Pressure Fuel Pressure Regulator (resting)> ATF Cooler & Campaign Filter> Yellow Polish Polyurethane Bushings> Pioneer Double-DIN Stereo with JL AUDIO Speakers> Driveshaft Rebuilt with C-Clip U-Joints> 15 Min MOD> 20 Min MOD .. . (2011)
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Last edited by James Scott; 08-25-2003 at 02:27 AM.
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  #2  
Old 08-25-2003, 09:57 AM
JLittell
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Are your rotors warped?
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  #3  
Old 08-25-2003, 11:06 AM
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mbtoloczko mbtoloczko is offline
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I know its going to sound weird, but improper lugnut torque can cause exactly what you experienced. I've experienced it with my car, but not quite as bad as you experienced. It may not be the cause in your case, but its easy enought to eliminate it. Jack the wheels off the ground, loosen all the lugnuts, and while the car is still off the ground, retorque the lugnuts to 80 ft/lbs following the standard torque pattern.
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  #4  
Old 08-25-2003, 07:53 PM
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svx_commuter svx_commuter is offline
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Oh this is an old problem. There is a lot of history on this problem. Happy searching You have crappy brake pads and or worn down brake rotors near the minimum and or worn down brake pads and your brake fluid is old and water logged and needs to be flushed. Well that's what fixed mine.
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  #5  
Old 08-27-2003, 01:05 AM
James Scott James Scott is offline
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Question shakey BRAKES!

Well, I put 4 new (fronts cross-drilled) rotors ~ 1 1/2 years ago with OEM Subaru dealer pads. About one month ago, I bled the entire brake fluid and flushed/replaced with new Type DOT 3/4 brake fluid.

HOWEVER, I did get a nail in my right rear wheel ("slow" leak down to 14.5 psi on Sunday morning). I put a plug in at the Mariposa NAPA Auto Parts parking lot at ~ 3 pm. When remounting the tire, I forgot to tighten the lug nuts until the full weight of the car was on the tire! WOULD THAT HAVE CAUSED THIS PROBLEM?

Please let me know any of your further thoughts! THANKS!
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1995 Laguna Blue SVX AWD L - 240K (daily driver) - "ReBuILT" used engine at 236K miles (6/13)
2013 Veloster Red - Driver Now??Dropsprings [1/2" rear, 1" front] with Koni Strut Inserts> Magnaflow Exhaust System> ECUTune Stage 1av1 Upgrade (from 1v4)> ECUTune TCU MOD> Aluminum Crankshaft Pulley> Stainless Brake Lines> Phenolic Spacers> Perforated Brake Rotors (dint like, OEM now)> SmallCar Shift Kit (resting since TCU MOD)> 7-Position Ground System> High-Pressure Fuel Pressure Regulator (resting)> ATF Cooler & Campaign Filter> Yellow Polish Polyurethane Bushings> Pioneer Double-DIN Stereo with JL AUDIO Speakers> Driveshaft Rebuilt with C-Clip U-Joints> 15 Min MOD> 20 Min MOD .. . (2011)
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  #6  
Old 08-27-2003, 02:49 AM
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Andy Andy is offline
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As above, the 1st thing to check is your lug nut torque as this is a frequent cause of the shake, normally caused by overtightening.

As you have cross drilled rotors, check them for cracks.
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  #7  
Old 08-27-2003, 05:25 AM
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If it's not the lug nuts, it's time to check the brakes again. 1-1/2 years is plenty of time to wear them down.
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  #8  
Old 08-28-2003, 01:51 AM
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1.5 years to wear down pads and/or rotors? I hope not, especially with organic pads. With that said, there's certainly no harm in checking the brakes, but I'd just like to point out that there have been numerous people who have posted on this forum to say that retorquing the lugnuts on all wheels to the proper specs as stopped wheel shimmy when braking.
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:: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ ::
1995 Laguna Blue SVX L AWD 5MT (sold)

Visit my locker

SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads.
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  #9  
Old 09-03-2003, 07:34 PM
James Scott James Scott is offline
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Question shaking brakes

I re-torqued all my nuts (so to speak) and still experience the shimmy somewhat while braking. [I'm not doing the repetitive downhill braking that I was recently, tho!]. I'm wondering still if it could be an ABS problem (premature), causing the shaking. Also, could it be related to a need for front bearings? I hear a bearing noise at about 35 mph [I hope it's fronts since I did the rears a few months ago!]. The other thing is that I just realized that it's been 12,000 miles since my last balancing of my wheels - I usually balance every 4 to 6,000 miles! [Doesn't shake the steering wheel tho hardly at all unless braking (and only then just sometimes)]. I'm also trying to find some shop that can GRIND my rotors [since the fronts are cross-drilled] while I wait.

Let me know what YOU THINK!? THANKS!
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1995 Laguna Blue SVX AWD L - 240K (daily driver) - "ReBuILT" used engine at 236K miles (6/13)
2013 Veloster Red - Driver Now??Dropsprings [1/2" rear, 1" front] with Koni Strut Inserts> Magnaflow Exhaust System> ECUTune Stage 1av1 Upgrade (from 1v4)> ECUTune TCU MOD> Aluminum Crankshaft Pulley> Stainless Brake Lines> Phenolic Spacers> Perforated Brake Rotors (dint like, OEM now)> SmallCar Shift Kit (resting since TCU MOD)> 7-Position Ground System> High-Pressure Fuel Pressure Regulator (resting)> ATF Cooler & Campaign Filter> Yellow Polish Polyurethane Bushings> Pioneer Double-DIN Stereo with JL AUDIO Speakers> Driveshaft Rebuilt with C-Clip U-Joints> 15 Min MOD> 20 Min MOD .. . (2011)
Valentine One Radar Detector with Remote Display - ucan'tseeme!
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