Car shakes when braking over 110km
 

Car sometimes shakes when i brake over 110km/h. or going fast downhill. Does it mean i need to get new brake pads for my car? Also when i wash my car, my rear rims get the most brake dust, and my fronts barely get any. All signs that my front brake pads are done?
And can you guys recommend me a place that has cheap brake pads + installation?
Thanks

shaking in the brakes is more likely to be warped rotors than pads. Pads tend to squeal when they need to be changed. I'd get them checked out.

The rotors are most likely just glazed, you can worry about them being warped at 60kph.

To be honest, even made in china $20 rotors are better than some OEM ones... but you shoudl be careful how you spend your money. If it still stops, let them warp... as long as you're not tracking or going to snow with them.

you can try rebedding the pads to see if it goes away. if it doesn't, then most likely it's warped rotors

can warped rotors cause the the front brakes to be less effective? Because my fronts barely get ANY brake dust whenever i wash my car and my back rims are basicallly black from all the dust. How much are rotors typically? For just a normal A4.
Thanks a lot for all the help!

Depends on the pads, the fronts SHOULD be caked with dust, as they take most of the pressure, but i've seen both ways.

+1. Warped rotors almost always vibrate when braking at high speed. You can try to get them machined if it's not warped too much or if you want replaced.

Like 5P4RK4 said, if the pads are almost gone, it will squeal as this is what they are designed to do.

Brake dust could just be from the type of material that the pads are made of. Ceramic pads generate less brake dust, and most higher end cars will use this material as it has less dust, and greater stopping power. Metallic and organic brake pads produce more of the black dust you're used to seeing. Almost all cars will have more of braking at the front than the rear (hence the larger brakes up from vs the rear).

If you're concerned, take it into a brake shop and get some advice on what to do. If you're selling it, then just leave it as is, or as you already mentioned, get some budget pads if you want to use that as a selling point.

i have the same problem expect mine doesnt shake when going down hill.... only going down hill while braking... problem is i have 1 front drivers side rotor... u can feel the rotor, if its flat its fine and if it feels not flat its warped.. i put new brake pads on the front and they seem a bit better but u can still feel the vibrations sometimes.... get them machined and get new brake pads too

fyi dont rinse your brake rotor when its hot or it will wrap again

Warped rotors is a myth. read the FAQ. lol

dunno why no ones mentioned it, but it could also be a joint. a worn joint will also cause vibration upon braking. usually tie-rod

I am a mechanic and what you are descibing is almost always attributed to warped rotors. It is a good idea to get them fixed as the shaking and vibrations can damage ball joints/tie rod ends/bushings and wheel bearings as well as reduce the stopping power of the car.

Probably a good idea to get it checked out..... then again i havre ridden on warped rotors for years and it doens't really bother me too much. I always am checking to make sure all my ball joints etc are in good shape. Its how bad they are warped i guess. When it starts to bother you enough or its getting really bad then take it in and replace them

The problem with running the car on warped/shaking brakes is , it will cause damage to other parts of your car , bushings and balljoints / tierods etc.
if you ever drove a car with shaking brakes you would see what I mean , I think it's a "pay now or pay later" thing...

i just got a new used car and the brakes pulsate at almost all speeds. Is it a slam dunk that the rotors are warped? Should i replace rather than resurface? Should I invest in a dial indicator and measure runout to be sure? There are some scary cheap replacment rotors online... check these out

http://www.thepartsbin.com/catalog/i...03&No=0&Npp=15

mine was resurfaced and now it feels like new but mind you the car is only 12k km old

if the minimum thickness will allow it, and they're not pitted or rusty, just resurface

Buy a set of brembo blanks from Lordco (cheap) and take the car in for a brake job. If the rotor can be shimmed (within spec), then let them do it and go return the blanks later. If not, slap on the new blanks and you're good to go.

I dont understand the whole rotor shimming thing. Geometrically speaking, what purpose does shimming do?

So I had a bad brake pulsation and after reading some reviews I decided to give the $30 lordco el cheapo rotors a try. When I installed them the lordco pads that I also got were the thick versions and with the piston fully retracted in the caliper the pads were still too thick to install. Since the old pads were about 60% and I had to get to work in the morning, I put the old pads back on.

The bad brake pulsation I had is gone, however there is still some minor pulsation at low speeds noticable when coming to a stop. This was noticable immediatley on the first test drive. So...

IS the new rotors with used pads causing this?
Or are the el cheapo rotors not 100% true?
Or is it another geometric issue at fault that can cause this?

maybe the new rotors you put on are warped? when i used to use lordco rotors, i'd machine them before i put them on my car and many times they were never perfect. did you clean the hubs before putting the rotors on? maybe the rear rotors or drums are warped? maybe theres excessive run out in the hubs or something. it's hard to say man

ive ruled out the rear drums by pulling e brake from 50 km to zero with no pulsating.
Maybe I'll get the lordco jobbers resurfaced and that will help.
But do u think the used pads would contribute to this? I dont see how they would.
After that the next thing to check would be hub runout i suppose.

Is this on the fronts or rear? If the new pads do not fit in the calipers, check to see if they are the right pads or that you have the caliper piston fully compressed. There is no reason why the new pads wouldn't fit.

When Chun said shimming, he meant having the rotor resurfaced on a lathe. There, the machine will take a bit of the metal off of the rotor and will give you a flat surface.

its most likely a small warp in the rotor that is only noticeable over 100k because it is so small..
its not the pads the pads wont cause pulsating since they only apply constant pressure according to your foot.

The first problematic clue I see is the fact that you note your rear rims are collecting the most brake dust. A great majority of your braking should be done by the front brakes, not the rear. This is an obvious sign of a sticky calipar. Because it's sticking, you are generating extreme amounts of heat to the rear brakes, doing damage to both, your pads and rotors. The heat will definately glaze the rotors and also warp them. In addition, the heat will also change the consistancy of the brake pad material, making braking less effective. All in all, a sticky calipar on one corner of the vehicle will affect all corners of the vehicle as the other three have to work harder to accomplish the same task; bringing the vehicle to a stop. You need you have your brakes taken apart, have the sliders lubricated, and see if you can't free up that sticky calipar. If the piston is siezed (which it probably is based on the assumption that it's been sticking long enough for you to recognise a pattern of more collecting on the rear) you will need to replace that calipar. Also, it's an ideal time to change the pads and replace and necessary brake shims or clips

I am aware this thread is getting old, but I see some new posts here.

+1 for Warped's comment about worn suspension bushings or ball joints being a potential for shaking during high speed or downhill braking...I have experienced this myself but I drive an old Datsun and it is a known issue on these cars (and any other car that uses T/C rods in the front suspension).

Flattire, I have seen many of the cheap Lordco rotors (made by Fenco if I remember correctly) that have been warped right out of the box and I no longer use these for that reason. I recommend you have them resurfaced and go back to get the correct pads for your car seeing as they have obviously given you the wrong ones. Your old pads will not cause any shaking/pulsing, it's the rotors. It could also be worn suspension bushings or ball joints in your case too, and I would check for this if the problem persists after machining your rotors. Hub runout is extremely unlikely, but not unheard of.

rotors will warp on one side as well. i have machined rotors that do that.