brake vibrations

When I apply my brakes on the highway, the whole car shakes and somethng rattles under the passenger side dash. Are my rotors probably warped? Might it be the heater core that's rattling?

Yep, if I had to guess I would check your rotor's.

If it doesn't do it until you apply the brakes, yep, what lou S. said. You have warped rotors. If it is that bad that things are rattling under your dash, you better have them checked as well as your front suspension.

yeah, I guess my brakes are pretty shot, They squaek unless I press the brake pedal. Is this squeaking something that replacing the pads/ rotors might fix, or are there caliper parts that also need fixing?

o yeah- the thing rattles when I go over bumps too. It just sounds like the car is gonna fly apart when I apply the brakes (especially at high speeds).

The squeeking is probably the sensors(metal tabs) on your pads rubbing against the rotors. Sounds to me like ya need new brakes(pads and rotors).

the rattleing is kinda normal for the blazers, seeing that the plastics like to work a bit loose after a while, check the rotors like everyone else is saying it sounds to me that they are warped, and get some new pads!

The squeaking you hear is the wear indicator. It is designed to squeal to let you know that the pads are wearing down and that they need to be changed so that you don't become a machinist and turn your front brakes into a lathe.

As far as plastics on the front brakes, I have never seen plastic on any front disc brakes I have worked on. It doesn't mean that there may not be out there somewhere but owing to the hear produced, I can't see it.

As far as the front brake squeal is concerned, there are several products available that you put on the back of the pad that comes into contact with the caliper and the anvil or when you purchase you pads just ask for anti-squeal pads. These are placed on the back of the pads with a self-adhesive.

Interior plastic is what i am talking about I didnt specify, pardon! I dont know if that is the rattling he is hearing but I do know a lot of the blazers rattle on the inside because of the plastic!

MY 94 has rattles that I am sure are from loose plastic connections in the interior, but for him to say," it feels like the car is gonna fly apart" he needs to change those brakes TODAY-----wouldn't ya say guys.

Agreed!....emphatically

agreed

Yip, thirded.

New rotors and pads. Don't replace the calipers, they won't need changing yet.

Any suggestions on new pads and rotors? I think drilled and slotted is a waste (unless for aesthetic reasons), but I don't like how stock rotors rust. I was leaning towards stock delco rotors. Are ceramic pads any better than the semimetallic?
thanks

Normal rotors will be fine. AC Delco ones are very expensive.

Get a normal set or pads more int eh middle price range and don't go for ceramic unless you want sqealing brakes all the time.

Any suggestions on new pads and rotors? I think drilled and slotted is a waste (unless for aesthetic reasons), but I don't like how stock rotors rust. I was leaning towards stock delco rotors. Are ceramic pads any better than the semimetallic?
thanks

bendix pads, bendix rotors. I recommend nothing else. If you have 4WAL abs dont force the brake fluid backward thru the ABS unit, open the bleed screw as you bottom the piston. If your caliper bolts are even the slightest bit loose or rusted on the threads, replace with the doorman oversize unit - warning: the part listed for the blazer is actually wrong, use the part that is 1/2" longer and cut some of the tip off and redrill the keeper

Thanks,
The caliper bolts are the ones that require the 3/8 allen head, right? Those are in good condition right now. Is the bleeder screw on the master cylinder, or the abs unit? Again, my Haynes manual seems to be a waste

the caliper itself

OK,
I think I've figured out how to replace the pads and rotors. Hints would be nice.

1) apply E-brake, jack up front wheels, and take the wheels off.
2) Undo the 2 caliper bolts, remove the caliper, and take the pads off.
3) At this point open the bleeder valve and push the piston in. (Might air get let in, or fluid out?) Close the bleader valve.
4) Pull the rotor off. Is there a retaining clip or trick to this?
5) Put the new rotor on.
6) Put the new pads in the calipers remembering the "anti rattle clip."
7) Reattach the caliper, the wheel, and off you go.

Will the brakes need additional bleeding after the new pads and calipers are installed on the new rotors?

I'm assuming yes, but help on this matter would be appreciated.
thanks!

when you pull the calipers off, the rotors fall to the floor with a clank. Unless the keeper is not still on any of the stud from the factory, but u kill that with a needle nose pliers.

when it comes time to push in the piston, slightly crack the bleeder and push while a hose it hooked up to the bleeder, as long as you close the bleeder right as the piston bottoms, you are ok

I'm sure it'll make sense when I see it, but how does the caliper bleeder work? I don't want to waste your time with this brake garbage, but is it a screw with a valve?

I understand the physics of how this all works, but I haven't done it yet, so I don't know what to expect. It all sounds like paintball terminology to me!

quaddriver Do you mean I'll have to attach a hose to the bleeder? Or do you mean while the brake line is still attached?

OK,
I think I've figured out how to replace the pads and rotors. Hints would be nice.

1) apply E-brake, jack up front wheels, and take the wheels off.
2) Undo the 2 caliper bolts, remove the caliper, and take the pads off.
3) At this point open the bleeder valve and push the piston in. (Might air get let in, or fluid out?) Close the bleader valve.
4) Pull the rotor off. Is there a retaining clip or trick to this?
5) Put the new rotor on.
6) Put the new pads in the calipers remembering the "anti rattle clip."
7) Reattach the caliper, the wheel, and off you go.

Will the brakes need additional bleeding after the new pads and calipers are installed on the new rotors?

I'm assuming yes, but help on this matter would be appreciated.
thanks!

Hold up there.

Instead of using the bleeder, open up your brake fluid resevoir cap and take a little bit out of it and leave it open. When you push the caliper pistons back for the new pads the excess fluid will do into the brake fluid resevoir.

This way you won' have to bleed the system. :)

Just swap and go!

Also, get a piece of wire to hang the caliper on while you change the rotor. DO NOT HANG IT BY THE BRAKE LINE!!!!

thanks for the advice,
How should I take the fluid out? Just remove the black cap that says "do not open - closed system" and siphon it on out? If there are better suggestions I'm all ears.
thanks

p.s. hahaha BlazerLT, you already think I'm that hopeless? I may be a newbie here, but my wisdom tells me dexcool fixes all!

huh?

sorry, it's getting late.

How would you suggest taking the excess fluid out?
thanks

Old turkey baster?

Never push the fluid back into the system! Your pushing crappy burnt fluid up and into the ABS. If you want to do that and possibly get dirt into the dump and isolation valves, then go to it. Otherwise, listen to what quaddriver told you.

That makes sense, however how would you suggest I bleed the brakes? Do the caliper bleeding again?

brake fluid is hygroscopic, meaning it sucks water and contaminants out of the air.

most blahzers have 4WAL ABS, meaning the fronts are protected by the abs unit, you REALLY dont want to push contaminated fluid backwards thru these valves.

On the brake caliper by the banjo bolt (the bolt that holds the brake line to the caliper) is a bleed screw, typically 3/8" or less in size, typically rusted to crap. before you begin, remove it and replace with a new one. some fluid will dribble out, but thats ok. then as you push the caliper piston back in open this screw with a brake bleeder hose attached ($8 at advance auto with a little catch bottle) this way no air can get back in the system, then you simply close the valve when done and thats it.

THEN if you need brake fluid, you are adding fresh.

and with the captured brake fluid? drink it. report back the results

That makes sense, however how would you suggest I bleed the brakes? Do the caliper bleeding again?

No it doesn't make sense and these guys don't know what they are talking about.

The fluid is not burnt nor is it exposed to anything in the braking system so all you have to do is push back the caliper cylinders and you will be fine.

What the hell are you guys bullshitting about the "fluid in the brake lines is burnt" crap. So in essense everytime I change my brake pads I have to flush and bleed the braking system? Stop it with this misleading garbage. I can't believe you are trying to pull off the "fluid is burnt more the closer to the wheels".

It is a closed system so pushing the small amount of fluid back into the resevoir is perfectly fine and read your repair manuals and they say EXACTLY what they say to do to the letter.

1.) Open the resovoir and if it is full take some out of it.
2.) Remove the caliper
3.) Remove and replace the rotor.
4.) push back the cylinder on the capiper and install the pads.
5.) Intall the caliper on the rotor.
6.) Pump the brakes 3-5 times.
7.) Top up the brake fluid and install the resevoir cap again.

You are done.

You only bleed a braking system if you remove the caliper and remove the lines.

No it doesn't make sense and these guys don't know what they are talking about.

The fluid is not burnt nor is it exposed to anything in the braking system so all you have to do is push back the caliper cylinders and you will be fine.

What the hell are you guys bullshitting about the "fluid in the brake lines is burnt" crap. So in essense everytime I change my brake pads I have to flush and bleed the braking system? Stop it with this crap.

Give me a break and you know better than to spew that bullshit. It is a closed system so pushing the small amount of fluid back into the resevoir is perfectly fine and read your repair manuals and they say EXACTLY what they say to do to the letter.

geeezus. you dont work on many ABS systems do you?

Brake fluid in a container is clear to slightly yellow. brake fluid in a 'closed system' after so many miles is brown or blackish. this is from water, contaminants and BURNING from the heat transfer in the caliper. why do you think dot 3 and 4 brake fluids have such a high boiling point? when subjected to heat, the glycol in brake fluid changes in chemistry and discolors and yes, the manuals DO say to flush the system at each brake change. for normal usage my method dumps the lions share of the front fluid out to be refreshed with new.

*Looks At Service Manual*

Funny, my service manual and both repair manuals don't say that. Look on the net for the disc brake replacement guides, none of them say you have to bleed the braking system every pad change.

Nonsense to replace the fluid every pad change, pure and complete neurotic nonsense. DOT3 and 4 fluids last more than 30-40k and YOU KNOW IT!

What you are doing is making an easy job into a unnecessary pain in the ass.

Everyone else does what I do for a pad change, even the dealer did it my way when the changed the pads the first time when I didn't have the time to do it myself and it was too cold.

I watched them do exactly what I said to do and the funny thing is they NEVER bled the system.

So:

everyone elses simple replacement or your unnecessary flushing and bleeding?

I'll take everyone else.

I watched them do exactly what I said to do and the funny thing is they NEVER bled the system.

Training just aint what it used to be.

Its a real simple rule of thumb:

Is the brake fluid in the resevoir clear with a slight amber color?

Yes: do nothing

No: flush and refill

Anything else is negligence

Sorry bro, every single guide and repair manual says you don't have to do that everytime you swap in a quick set of pads.

Have any of you guys had your rotors resurfaced? Supposedly it's cheaper than buying new rotors, but rotors are so cheap online anyways, I wanted your opinion.

Have any of you guys had your rotors resurfaced? Supposedly it's cheaper than buying new rotors, but rotors are so cheap online anyways, I wanted your opinion.

cheap rotors are cheap....good ones like bendix even with my volume disounts are still typically more expensive than a resurface and if you resurface you get an inferior rotor so its worth the few bucks to replace.

an example - just did a 93 T&C van that has rotors of 1.100" with a minthink of .994" or .106" of wear available. At time of the brake job they were 1.050". Assuming I could clean them up with .010" on each side (typically most shops just gouge .015" per side off) that would leave them with 1.030" or .036" of wear left. We already know that the pads took .050" of rotor off to wear so the recut rotors would not go the distance, IF the wear rate was a constant, which it wont be now because the thinner metal will be affected by heat more and hence wear even faster.

quaddriver, do you have any suggestions on who to buy both pads and rotors from?

Does zinc or cadmium plating detract from the quality of braking? I would like some rotors that don't rust up, but I want to know if this is just stupid. I don't want that drilled and slotted garbage.

quaddriver, do you have any suggestions on who to buy both pads and rotors from?

Does zinc or cadmium plating detract from the quality of braking? I would like some rotors that don't rust up, but I want to know if this is just stupid. I don't want that drilled and slotted garbage.

just get regular brakes. I have accounts at advance, autozone, napa and carquest (simply because that is all that is near me) and I play them off one another to get the best price.

Have any of you guys had your rotors resurfaced? Supposedly it's cheaper than buying new rotors, but rotors are so cheap online anyways, I wanted your opinion.

If you have original rotors from GM, I would keep them and resurface them before I ever replaced them for aftermarket if they are perfectly smooth and not warped.

The metal on GM rotors is much less prone to heat warping and even if it is 10-20 more for the resurfacing of the older rotors, it will be better.

FIRST!

Get your rotors turned (shaved) and hopefully that fixes your problem for cheep, but if your rotors are way too burnt out, the perhaps new rotors wont be a bad idea. :-)

That happen to me on the freeway, and holy **** it scared the crap outa me.

Also check if its all your breaks or just rear or front. Mine happen to be the back breaks, and the best way to test that is when your on the freeway push the Ebrake alittle and if it starts to shake like hell then its your back breaks :-)

Little trick i learned.

Hope it helped.

I agree with Blazer LT. The original rotors should be turned first.
The original rotors do have a tendancy to "flake" on the backside and become chewed up which causes your pads to scrap up pretty bad. The good thing is that the original rotors are quite thick and heavy (solid metal). And although they will look pretty bad on the back side they can usually be turned.
After reading a bit about this, once the rotors are turned, the tendancy to "flake" goes away and there are few problems afterward. The rotor metal it appears becomes somewhat "heat treated" and actually becomes stronger.
This is what I did with mine about 30,000 Km ago (2 yrs) and everything is fine (about 1/2 pad still left).
Got rotors turned for about $15 each and slapped on a set of pads about $40 (Canadian) like BlazerLT described.
Just my opinion.

Let's not forget that these are the factory rotors. They have been driven for 9 years now. I'm pretty sure that since the rotors are warped now, shaving more layers of te rotor will leave me in the same situation in the near future. That is IF the rotors can be turned. Upon inspection of the rotors, they looked pretty irregularly chewed up (the pads have been changed maybe once- blame my father). But there obviously was a little thickness left. The rotors are soo rusty however, that I could not read the markings on the edge to see if they can be turned. I plan on buying new.

O yeah from my first post I said there was rattling under my dash- It turns out my pesky hinge bolts needed those magical spring washers. No more rattle! Hallelujah!

O yeah from my first post I said there was rattling under my dash- It turns out my pesky hinge bolts needed those magical spring washers. No more rattle! Hallelujah!

They worked did they?

Yeah, but you should just go to the hardware store and get some lock washers. The dealer charged me $6 for two, and they are tiny little things. Maybe you know a nicer dealer. I wish they wouldn't overcharge for washers (im happy with the rattle gone), but this is a part they should have included from the beginning.

True, but lock washers wouldn't have done for this problem.

The cone washers were needed to wedge in there.

I had to pay CDN$5.20 a piece for mine.

Freaked me out when they said that but oh well, the truck is mint now.

How hard is it going to be to push the brake caliper pistons in? I've read you should use a c clamp, but I don't want to go and buy one if it's not necessary. There also have been doubts over whether opening the master cylinder reservoir and pushing the calipers in is good for abs. Anyways, what should I expect?

p.s. my car may feel like its flying apart, but at least those spring washers make it sound likes it's still together!

It's not that hard to push your calipers in as long as you remove your master cylinder reservoir cap. I've done several pad replacements and you can (with the old pads still on there) pry them open with a pry bar, that way you won't damage the rotor or a big set of channel locks. If it doesn't go easily don't force it.

Yip, and also take a little bit of fluid out of the brake fluid resevoir to make room for the fluid you will be pushing back.

Also, doing it this way will mean you don't have to bleed the system either.

Wow
All this talk over replacing pads and rotors??
I can see and understand both sides of this issue.
But
Having someone open up a bleeder valve to do brake pads is just over kill.
I have worked on thousands of S-10s and have never had to do that.
Unless the brake fluid was over heated or a open line the fluid should still be good.
Have any of you guys had air in the abs unit and tried to get it out with out a pressure bleeder??? Its tuff as heck to do. And by opening the bleeder by someone who is not trained in that system is taking a very large chance.
And as far as where does the fluid go?? If no fluid was added to the master cylinder there should be plenty of room.
Let not forget what happens if he breaks the bleeder valve no it will cost him more money to fix that.
Just an old GM Techs 2 cents worth.
Fireplug

Yip, and also take a little bit of fluid out of the brake fluid resevoir to make room for the fluid you will be pushing back.

Also, doing it this way will mean you don't have to bleed the system either.

Just a little comment Fireplug. How can one see if the fluid is burnt or discolored just by looking at the caliper?

Everytime I have done front disc's, I open the bleeder and capture the fluid as I compress the caliper which forces the fluid into the container. And everytime, inevitably, I found crap in the container. I close the bleeder before removing the clamp, no air gets in, no bleed. Would you really want to force this back up into the ABS unit?

Just asking for your point of view, sincerely.

Thanks for backing me up.

Some people in this forum has preached that you have to bleed the system everytime you replace the pads which in my mind is just plain ridiculous.

ARE the rotors blue in color?? That is the first clue that there was an over heat problem.
Are you sure this crap was not sitting in the bleeder its self??
All my years working on rwal 4wal abs systems I cant remember 1 case of gunk geting back into the abs pump. I am not saying that it could not happen just that I have never seen it or talked to anyone that it has happened to.
I have see air get into to pump and valves because someone did not bleed the system the correct way and case $$$ problems.
Its nice to have a good chat like this.
Fireplug

Guys please remember there are all kinds of different skill levels in here. Some Techs and a lot of newbies who have never work on any car before.
I for 1 dont want to cause them more problems if I can avoid it.
Look at it as a lesser of two evels.
The new guy screws up the bleeding now has to go get a pressure bleeder and thats if he can rent 1 or tow it to a shop who will charge 3 time the amount because he tried to fix it him self.
Fireplug

I got new rotors and am going to install them tomorrow. I have all the tools and I'm confident I will be able to accomplish the task even though I have never done it before. As long as the piston pushes in easily I can't foresee any problems!

It should as long as the Brake resevoir cap is off.

Remember to take some of the brake fluid out unless it is low.

TIP
Keep the old brake pad on the caliper piston while you push the piston in . That helps to protect the piston from any damage from c-clamp or pry bar or what ever you use.

OK Fireplug, I get your point and agree. However, I was the unfortunate sod who got to redo a system that someone did what you say. It was a Dodge RAM, hmmm, maybe that was the problem...LOL

You are correct in that it is the lessor of two evils. Listen to Fireplug, he's right.

Now THAT is something smart that I haven't thought about.

will i be able to push the piston in with my hands?