Brakes still pulsating after replacing rotors, pads, drums and shoes!!

[BCKGUY]

Ok, brakes were pulsating so I did what most people would do, I replaced the front brake rotors and pads. Well, that didn't help and the mechanic who did the work said it was coming from the rear. So I had him replace the rear drums and brake shoes today. Well, pulsation is better, but still very noticable. I'm not sure what else could be causing this?? He seems to think it's the tires. What do you guys think? Could it be the calipers? Thanks for your help!

BCKGUY

 

[97-4xFunner]

Pulsation

Haven't encountered this problem personally, but if it were me I would bleed the anti skid. Usually has a bleeder screw on top. THen start inspecting, look for bad tires, bent parts, etc.

 

[piperoo]

When was the last time you had it aligned? Wheels balanced? I was having the same problems...replaced rotors, replaced brakes...still vibrating. Got it aligned and got better tires and 95% of it went away. My tires were slightly cupped on the inside of the tire...and it shook like crazy.

So I would try an alignment and balance and see if that helps.

 

[BTO]

First thing to do is take off the rotors and drums and have them turned. Also make sure the mating surfaces (where the rotors and drums attach) are clean and flat.

I had this same thing happen on my old Grand Prix. New rotors still pulsated. Had them turned fixed it.

 

[BCKGUY]

Thanks guys, I'll try your recommendations. I'm not sure when the last time was it had an alignment done and the tires are going to need replaced soon. I just purchased the T4R about a month ago.

 

[Big Bore]

I did new brakes all around using best parts you could get and it was doing same as you described. Took rotors to shop and couldn't believe how much run out they had. Had them turned and it was a lot better, not perfect but not anywhere near as bad. So yes, new rotors can in fact be warped right out of the box.

 

[BCKGUY]

Ok, call me stupid, but what does "run out" mean??

 

[theizzardking]

Ok, call me stupid, but what does "run out" mean??

you get a dial indicator and clamp it on to the truck and put the indicator part on the rotor, the run out is the variation of measurements taken from the rotor as the indicator turns across the entire surface. when you put the dial indicator on you "zero" it out as you turn the rotor you will see variations across the surface by watching the needle the highest number the needle hits is your "run-out"

you don't really need to know how to do this unless your doing the work yourself,
just ask what the run out was and if the number is big then get the rotors turned, also like i just said in the other thread "GET YOUR ROTORS TURNED ON THE HUB" and make sure you ask the shop if they have that capability not every shop can do that, my local lez schwab does.

if you get it turned on the hub you know there will be no run out or tolerance stack up issues going on , then the only problems left could be pads and bedding in the braking system anyways if your still having problems check other suspension parts

future reference there are a few types of run out, but this is the most commonly used in the auto world

 

[theizzardking]

pics for reference only

and a good general read on the subject

Brake Rotor Service - TechConnect Online News Blog

 

[BTO]

Ok, call me stupid, but what does "run out" mean??

It's the amount of deviation from a true, perfect unit. In this case the rotor should be a flat disk. Since nothing is perfect a "run out" spec is given like up to so many thousands off.

Read this article for a good understanding
Understanding Brake Rotor Service

 

[BCKGUY]

Great info, thanks again!

 

[Big Bore]

Ok, call me stupid, but what does "run out" mean??

Sorry man I should have said couldn't believe how warped they were lol. Machinist term from my youth is all, sometimes I forget to use laymans terms to make it easy for those without the same background. In any event looks like some folks stepped up with some good information to give you a good handle on it.

 

[BCKGUY]

*update*

Well, took 4Runner back to mechanic today to have him check out the brakes again. He put the dial on the front rotors and determined that one of them was warped pretty bad right out of the box. He also thought maybe the rear drums were bad, so we took them back to Advance Auto Parts and replaced the one rotor and both rear drums for new ones. Put them on, drove away and still have severe pulsation when braking. I'm about to take these brake parts and shove em up someones rear. I know Advance doesn't sell the highest quality of parts, but come on!! As much as I hate to, I'm thinking of taking it to the Toyota dealership and letting them deal with it. Any other suggestions??? Thanks.

 

[eric.laprad]

I don't know if the dealer will be able to help either. I have "lived with" this problem for about 80,000 miles (6 years or so) with my 1999 4-Runner. I tried turning the rotors, replacing rotors and pads, new tires (Set of Dunlops and a set of Yokohamas), but nothing seems to help. Even took it to the dealer and they couldn't figure out why the brakes pulsate. Ball joints and tie rods feel tight. I have not replaced the struts... yet. My problem is definitely in the front as the steering wheel pulsates too. Curious if you have resolved it yet.

 

[Mr. Leary]

The stock 4Runner brakes suck. Brake fade and warped rotors will always be an issue until you upgrade the brakes. Stop wasting money now and swap in 199mm or 231mm Tundra brakes. It will not be an issue any more. The 199mm swap is extremely easy, and the 231mm swap is quite easy as well, but may require grinding or changing wheels.

 

[theizzardking]

GET THEM TURNED ON THE HUB

i had the same problem as you had them turned 3 times before i finally got them turned on the hub and haven't had a problem since.

the issue your having is you have stack up,run out on your hub as opposed to on the rotor, so when you turn the rotor till it's 100% flat and put it on a hub that's not you get a surface that's out of line and the problems you're having now.

they way turning it on the hib fixes this problem is, they leave the rotor on the hub and cut the rotor to 100% flat on the hub, that takes out and variation of flatness that may be in the hub......


i this makes sense, you could do the tundra break upgrade and still have this problem.


A "Stack up" of variances in the Spindle + Hub + Wheel Bearing + Rotor tolerances which results in an out of tolerance final reading. Note, all 4 of the components may be within tolerance but the additive effect of their variances may result in excessive run out.

i hope that makes sense to you.

 

[theizzardking]

p.s. you have to ask them if they can do and tell them to turn it on the hub, not all shops are capable of this.

 

[DocMT]

If turning (machining) rotors on the hub cures the problem, then you have bent hubs. That's because a machine that turns rotors on the hub will compensate for the bent hubs because it is using the hub as the base instead of a brake lathe.

 

[theizzardking]

If turning (machining) rotors on the hub cures the problem, then you have bent hubs. That's because a machine that turns rotors on the hub will compensate for the bent hubs because it is using the hub as the base instead of a brake lathe.

it could be any number of things, tolerance stack up occurs from anything from rust and grit to the natural wearing of parts,could be a bent cv or anything behind the rotor, the simplest cheapest fix is to just turn them on the hubs then start worrying about replacing parts if it's still out of tolerance and riding like crap.

you know what i'm saying, he's been through a couple of sets of rotors as it is, had them turned to no avail, you could either suggest he starts taking the hub and whole axle assy apart and measure everything to find whats out of tolerance and replace it or he could just have it turned on the hub and drive on like nothing ever happened.

depends on how much money this guy wants to spend just trying to get his brakes to quit pulsating.

i resolved my brake problem like this about 10K ago and have had zero problems since, so if my hub is bent it's not having any noticeable effects.

but good job pointing that out, seriously, i should have mentioned that as well so the OP could have a full view of what may be going on, i just think turning on the hub is still the best solution for this, but the op needs to decide for himself as it's his truck and his money. :surfer:

 

[DocMT]

I agree that turning the rotors on the hub is a good idea. All I'm saying is that if the hubs are true, then installing rotors that are also true will result in a hub/rotor combination that is true and won't cause any issues. If the hub itself isn't true, then there area couple of options. One option is obviously cutting the rotors on the vehicle. Another easier option that people often overlook is removing the rotor and spinning in 180 degrees and putting it back on. And if that doesn't help, you also have the option of shimming it. That's easy to do with you have a simple dial indicator and a few minutes to see where the excessive runout is so that you can shim it. All of these are good options.