Perhaps Typical But New to Me Noises

[jontam]

Recently bought a 2002 GL V6 from an acquaintance. He had the rotors turned and was complaining that they were still noisy. I took it in for service and had new rotors and pads installed along with new front struts. (65k miles). Still making a slightly rubbery grinding pulsating noise in the front at low speed with or without brake pedal pressure. Probably makes a noise at higher speeds - just cant hear it. Took it back. They replaced (at no charge) the drivers side wheel bearing. Took the car home in the rain, it seemed better. Next day same issue. Took it back. They replaced all 4 boots and cv. No charge, but same noise. The repair shop doesnt know what to try next, suggests a transmission problem. Ideas or would you please direct me to the thread that probably exists already for this issue. Thanks!

[Yellow Eyes]

I get a little bit of a squeal on my front passenger side brake when I step on the brake. It's not exactly the same as yours, but the way I see it, I still stop, and as long as I keep stopping that little noise isn't going to bother me.

But also, when I did buy the car, the dealer had to install 4 new rotors and brake pads. It was a very pulsating car then, and it fixed it quite nicely, it just has that little sqeak. Not bugging me too much.

[jontam]

This is more like a continuos rub fading in and out in intensity. Perhaps not a safety issue. However, it would seem that something is prematurely going to wear out. Thanks for your reply.

[xeroinfinity]

If you are getting a scratting whether you are braking or not I'd say you calipers arent returning after applying the brakes and its always dragging them on the rotors.

Didnt do it wet because it was lubing it up so it didnt srcatch.

Just my hypothisis,
I've had the same problems with my N-bodies before and it was the caliper pins not slidding properly.

Also If the rotors were warped and they turned them, they are still warped.
Replaceing them may also help like Yellow Eyes said he had done to his.

Hope that helps!

[jontam]

I would tend to agree. Wonder why the shop didnt check this. But, I will have some time this weekend to take the wheels off. What do you suggest? Just lubing the slides with? Much appreciate your response. Oh, it does have new rotors on it now. In fact the shop tried different new rotors just to be sure.

[ec437]

First off, rotors don't warp. That is a rumor. They do do other things, but they don't warp.

Second, I had a problem that sounds similar to this on my lexus. I fixed it by taking the wheels off and hand-torquing the lug bolts to spec with a torque wrench. Many shops simply use impact wrenches set to maximum force, and that can cause problems on a lot of cars.

[xeroinfinity]

jontam, You need brake grease for the slide pins.
Also might want to replace the metal clips on the calipers.
They sell a kit with those and new rubber boots for the pins, and it also usually has new pins.

Since the rotors were already changed, the above should fix the constant grinding. Also make sure the PADS are on Right. That being the wear indicator goes on the inside of the rotor.
Some people dont pay attention how the y came off and this will cause all sorts of problems, such as you have described.

Here is a link to one of those kits.
Caliper Hardware KitThis specific kit doesnt show new slid pins, though I know they sell them in one of thier hardware kits.

ec437,
if you read his posts you would know that he is experiancing grinding not pulsing or other assosiated troubles indicative to over torqing the lug nuts.
Though I would make sure they are torqued to 100 FT LBS and no more!

Also ec437,
ROTORS DO WARP!
I have 4 stacks 5ft tall of warped rotors, they may not look warped but if you messure them with a dial gauge/calipers.
They are inconsistant in thickness and you can see low spots in between the vent sections of the rotors.

[ec437]

Originally Posted by xeroinfinity

ec437,
if you read his posts you would know that he is experiancing grinding not pulsing or other assosiated troubles indicative to over torqing the lug nuts.
Though I would make sure they are torqued to 100 FT LBS and no more!

Also ec437,
ROTORS DO WARP!
I have 4 stacks 5ft tall of warped rotors, they may not look warped but if you messure them with a dial gauge/calipers.
They are inconsistant in thickness and you can see low spots in between the vent sections of the rotors.

I did read his posts. I suggested what I did because it is free and easy, and it fixed my problem which was similar to what he described. There is no harm in trying it.

Your rotors may have deposits on them. I don't really want to get into an arguement about it, but I will try to dig up the links for you. Perhaps we have different definitions of warping.

*EDIT*

here is the link: http://www.stoptech.com/tech_info/wp...rakedisk.shtml

[xeroinfinity]

Well warping is a variance of thickness and this is commen with N-body automobiles. Which I am very familar with.

In material science warping is the bending of materials under the action of force or heating or cooling.
(You may think I meant Warp means to bend or twist)

I'm not saying uneven torq on the lug nuts isnt his problem,
but I would not think brand new rotors would still be causing them to Drag/grin continuesly.

No need to post links for me, I have all sorts of write ups on brake service and the problems encountered during routine brake service.

More on service....
It is extremely important to open the bleeder screw when compressing caliper pistons or wheel cylinders during routine brake maintenance. When a caliper piston is pushed in, brake fluid gets forced backward, up into the system. Since the caliper is the lowest point in the system, dirt and corrosion naturally accumulate there.

When this grime and dirt finds its way into the HCU portion of the ABS system, it can cause valves to stick. This can lead to: a vehicle pulling one way or another; accumelators sticking open, which leads to low pedal; compensator ports pluging, which leads to dragging brakes; and of course, it can make the ABS light come on due to all of the above.

If technicians get in the habit of opening the bleeder when they compress the caliper piston, as well as selling customers a brake fluid flush, these problems will more than likely be prevented.

Brakes Not Releasing -- causing grinding.
When there's an uneven thickness problem on the discs at relatively low mileage (under 50,000), accompanied by short lining life, it's possible the brakes aren't releasing fully, allowing the shoes to stay in contact with the discs.

A defective caliper piston (sticking when you try to push it back), a bad piston seal (not retracting the piston) and a sticking caliper are all possibilities.
When the caliper doesn't slide smoothly back and forth, that's trouble, and short lining life from failure to retract the shoes completely is just one consequence. The brake shoes may also slap unevenly against the disc, another cause of pulsation.

Most calipers slide along guide bolts, through bushings with plastic or metal sleeves. When you remove the caliper, inspect everything. If the guide bolts are corroded, replace them with brand-new ones, lubed with silicone grease (don't try cleaning them). Ditto (including silicone lube) for the sleeves if they're corroded or cracked, and the bushings if they are deteriorated.

Invest in a good torque wrench, keep it in the trunk and use it to tighten the lug nuts instead of the lug wrench when you have a flat. You should enjoy smooth moderate stops for the life of the car.

Hope that helps !

[jontam]

Put the new brake caliper kit on today. And cleaned/greased the slides. No difference. I did not open the bleeder on the caliper when I pushed back the piston. I did open the master filler cap. I noticed that the reservoir level did not increase as I slowly pushed in the piston using a c clamp. Also the wear indicators on the inside pads are on top (drivers side wheel) where the manual says they should be on the bottom. I believe I will bleed that caliper next and if that doesnt solve the binding I will get try a new caliper. Comments?

[xeroinfinity]

Originally Posted by jontam

I did not open the bleeder on the caliper when I pushed back the piston. I did open the master filler cap.

that screws up your system by pushing moisture and crap that settles to the lower line back up into your abs modulator

Appearently you didnt read what I said above.....

Originally Posted by xeroinfinity

More on service....
It is extremely important to open the bleeder screw when compressing caliper pistons or wheel cylinders during routine brake maintenance. When a caliper piston is pushed in, brake fluid gets forced backward, up into the system. Since the caliper is the lowest point in the system, dirt and corrosion naturally accumulate there.

You'll need to bleed your system realy realy good

[alero99]

I never knew that about the bleeder valve when compressing the caliper and recently my car has been pulling to the left. There are new tires with a fresh alignment job so it cant be those. So im assuming that i screwed it up when i did my pads and rotors. If it is the valves sticking how is this fixed? and where is the bleeder valve?

[jatzarik]

of course if you have a lot of corosion, the bleeder screws will break and you'll have to replace the caliper or cross your fingers that you won't ever need to replace your brake hoses or lines.

[xeroinfinity]

Welcome to AF jatzarik.

Please look at the dates befor posting !
We dont need to bring up threads older then 3 months..


this is closed!