Car "pulsing" when braking lightly?

[theoutbackdream]

Hello all,
I have a weird problem with my t4r only at city speeds. When I come to a stop light, I will press the brakes pretty lightly from a reasonable amount of distance, maybe 50yrds before the light, so I'm on the brakes very lightly. The brake pedal itself doesn't pulse, but the car brakes like it has warped rotors...

Now.. I don't think it's warped rotors because when I get on the brakes hard, it brakes 100% fine/straight without any pulsing/vibrations. At highway speeds, it's completely fine.

So could it really be warped rotors? Or is this just normal? Or is something wrong?

 

[RedSled]

Probably just some pad material build up on the calipers, find a safe road, run it up to about 50-55 mph and brake pretty hard, but do not stop, repete. If you come to a full stop you add more material to the calipers, drive and let the brakes cool down good and you should be good to go.

 

[theoutbackdream]

Probably just some pad material build up on the calipers, find a safe road, run it up to about 50-55 mph and brake pretty hard, but do not stop, repete. If you come to a full stop you add more material to the calipers, drive and let the brakes cool down good and you should be good to go.

That makes sense since this doesn't happen every time/day, and doesn't happen after getting off the highway, when i'm braking the heaviest...

Are there anyways to prevent this without having to go slotted rotors? Or just brake hard? Lol

 

[kcdehart]

Mine does this. It's so annoying. On the highway there's zero vibration, but when I brake at like 10mph for stoplights and such, the entire car sloooowly pulses. It feels horrible and I'm always embarrassed when I have passengers...

I'll try the heat em up method, but might just get the rotors turned or replaced if that doesn't help.

 

[RedSled]

That makes sense since this doesn't happen every time/day, and doesn't happen after getting off the highway, when i'm braking the heaviest...

Are there anyways to prevent this without having to go slotted rotors? Or just brake hard? Lol

You could try a different pad, some people like ceramic, or semi metalic. That also effects the stopping power.

 

[kcdehart]

You could try a different pad, some people like ceramic, or semi metalic. That also effects the stopping power.

Yeah, different compound pads will make a big difference. I've noticed that unless you get the top-tier ones, auto parts store brand pads will leave deposits. I ended up going with EBC redstuff/yellowstuff on my 3000GT to get decent pads.

If you're willing to spend the money/if you do a lot of towing or have a heavy rig, you might wanna check out EBC Yellowstuff pads. They're great for trucks. Not particularly cheap, though.

 

[MidwestT4R]

I just went through the same thing, but it turns out I had a sticky rear brake pad. The rear calipers float and the pads should easily come out of the bracket they are in. I had two issues. First, one of the caliper bolts had become sticky. The rubber boot had split so it got a bit grimy in there. I pulled the caliper bolt, bought a boot kit at AutoZone for 6 bucks and redid it. The caliper bolt was not rusty so I just cleaned it and reinstalled it. The second issue was that on one side of the rear brake one pad was stuck in there very hard. I mean I had to use a screwdriver to pry it out. I pulled the pad bracket off the hub, popped off the stainless shims and filed the rust out from underneath the shims. It seems like the rust caused the shims to compress around the tabs on the end of the brake pad. So it was literally stuck in there. Once I cleaned it up and reinstalled everything the pad went in easy and moved better.

I talked with a mechanic friend of mine and he thought that my stuck pad was just riding on the rotor surface and heating it up on one side faster than the other. So the rotor would warp a bit and you would get pulsing. It didn't do this all the time so I don't believe the rotor was permanently warped. It would happen after I had been doing a fair amount of stop and go driving around town. And it never pulsed right when I started driving. And it never pulsed on the highway. Only after it heated up.

It turns out the pads were low so I just did a brake job when it was apart. Put new rotors on with new pads and no more pulsing.

Just pull your rear tires and the caliper. Check the caliper bolts to make sure they are lubed and that they float. Then see if the pads are really stuck in there hard or whether they can be taken out reasonably easy. If you have one stuck on one side then clean it up like I did and see what happens. You could probably check and lube both sides in about an hour or two depending on your experience on the 4runner set up.

 

[kcdehart]

I just went through the same thing, but it turns out I had a sticky rear brake pad. The rear calipers float and the pads should easily come out of the bracket they are in. I had two issues. First, one of the caliper bolts had become sticky. The rubber boot had split so it got a bit grimy in there. I pulled the caliper bolt, bought a boot kit at AutoZone for 6 bucks and redid it. The caliper bolt was not rusty so I just cleaned it and reinstalled it. The second issue was that on one side of the rear brake one pad was stuck in there very hard. I mean I had to use a screwdriver to pry it out. I pulled the pad bracket off the hub, popped off the stainless shims and filed the rust out from underneath the shims. It seems like the rust caused the shims to compress around the tabs on the end of the brake pad. So it was literally stuck in there. Once I cleaned it up and reinstalled everything the pad went in easy and moved better.

I talked with a mechanic friend of mine and he thought that my stuck pad was just riding on the rotor surface and heating it up on one side faster than the other. So the rotor would warp a bit and you would get pulsing. It didn't do this all the time so I don't believe the rotor was permanently warped. It would happen after I had been doing a fair amount of stop and go driving around town. And it never pulsed right when I started driving. And it never pulsed on the highway. Only after it heated up.

It turns out the pads were low so I just did a brake job when it was apart. Put new rotors on with new pads and no more pulsing.

Just pull your rear tires and the caliper. Check the caliper bolts to make sure they are lubed and that they float. Then see if the pads are really stuck in there hard or whether they can be taken out reasonably easy. If you have one stuck on one side then clean it up like I did and see what happens. You could probably check and lube both sides in about an hour or two depending on your experience on the 4runner set up.

My rear pads were in the same shape when I replaced em a month or so ago. I had to pry 3/4 of them out with a screwdriver. I wonder if mine could've permanently warped the rear rotors or something like that.

Then, the new anti-rattle clips also wouldn't fit with the new pads. So they're rattling like mad over bumps till I figure out how to solve that part...Might end up shaving off the end of a pad so they fit in em.

 

[MidwestT4R]

My rear pads were in the same shape when I replaced em a month or so ago. I had to pry 3/4 of them out with a screwdriver. I wonder if mine could've permanently warped the rear rotors or something like that.

Then, the new anti-rattle clips also wouldn't fit with the new pads. So they're rattling like mad over bumps till I figure out how to solve that part...Might end up shaving off the end of a pad so they fit in em.

I think you are referring to the stainless shims that you install in the bracket that holds the pads. Maybe they are just for anti rattle. I thought they were there to help prevent the metal tabs from rusting onto the brake pad frame. Either way, I literally took that pad bracket off of the hub and took a metal file to the part where the stainless shims fit. I didn't file it bigger. I just filed off the rust that accumulated under the shims. And that is on all the surfaces the stainless shims touch. Before I did this I could barely fit the pad in one side because of how tight it was. After doing this on all the surfaces where those shims go, top and bottom, both sides of the brake pad bracket, the shims fit flush and the pads installed just fine. The before and after was pretty clear. Before I filed it you could see gaps behind the stainless shims when I put them in the bracket. Small gaps but enough to see how it could cause compression on the pad tabs. After filing the shim fit flush on all surfaces and the pads went in fine.

 

[kcdehart]

I think you are referring to the stainless shims that you install in the bracket that holds the pads. Maybe they are just for anti rattle. I thought they were there to help prevent the metal tabs from rusting onto the brake pad frame. Either way, I literally took that pad bracket off of the hub and took a metal file to the part where the stainless shims fit. I didn't file it bigger. I just filed off the rust that accumulated under the shims. And that is on all the surfaces the stainless shims touch. Before I did this I could barely fit the pad in one side because of how tight it was. After doing this on all the surfaces where those shims go, top and bottom, both sides of the brake pad bracket, the shims fit flush and the pads installed just fine. The before and after was pretty clear. Before I filed it you could see gaps behind the stainless shims when I put them in the bracket. Small gaps but enough to see how it could cause compression on the pad tabs. After filing the shim fit flush on all surfaces and the pads went in fine.

Yeah, they're called "anti-rattle springs" sometimes. And believe me, the pads rattle over any damn bump without em. It sounds awful. As soon as I hit the brakes and go over the same bump, no rattle.

I might give filing em a try. Or just hit the surfaces with some sandpaper.

 

[jfry008]

Hello all,
I have a weird problem with my t4r only at city speeds. When I come to a stop light, I will press the brakes pretty lightly from a reasonable amount of distance, maybe 50yrds before the light, so I'm on the brakes very lightly. The brake pedal itself doesn't pulse, but the car brakes like it has warped rotors...

Now.. I don't think it's warped rotors because when I get on the brakes hard, it brakes 100% fine/straight without any pulsing/vibrations. At highway speeds, it's completely fine.

So could it really be warped rotors? Or is this just normal? Or is something wrong?

I had the same problem, when stopping at low speed my car made a 'whop whop whop' sound and had a shake to it. After replacing the tires, front calipers, front rotors, and front wheel bearings. I came across this thread: https://www.tacomaworld.com/threads...differential-bearing-vibration-thread.152173/

The front differential needle bearing was my problem. Which only affects the V6 4wd 4Runners. I replaced the needle bearing with the clamshell bushing from ECGS and all is well.

Its worth looking into.

 

[kcdehart]

I had the same problem, when stopping at low speed my car made a 'whop whop whop' sound and had a shake to it. After replacing the tires, front calipers, front rotors, and front wheel bearings. I came across this thread: https://www.tacomaworld.com/threads...differential-bearing-vibration-thread.152173/

The front differential needle bearing was my problem. Which only affects the V6 4wd 4Runners. I replaced the needle bearing with the clamshell bushing from ECGS and all is well.

Its worth looking into.

Was this all the time when slowing down? Or just when braking?

 

[nevada]

Probably just some pad material build up on the calipers, find a safe road, run it up to about 50-55 mph and brake pretty hard, but do not stop, repete. If you come to a full stop you add more material to the calipers, drive and let the brakes cool down good and you should be good to go.

this. all day this.

excellent advice!


as said, the rotors aren't warped, its most likely friction material build-up, as mentioned. if the above doesn't work, unfortunately the solution is the same as if they were warped. to resurface or replace the rotors and pads.

you might even be able to pull the rotors off, and carefully buff the braking surface with a 3M pad, or course sand paper.

 

[jfry008]

Was this all the time when slowing down? Or just when braking?

It happened when slowing down at low speeds, even after letting off the brakes if I remember right.

 

[kcdehart]

It happened when slowing down at low speeds, even after letting off the brakes if I remember right.

That makes sense. I just wanted to check to be sure. Not sure about OP, but mine stops pulsing when I let off the brakes

 

[theoutbackdream]

You could try a different pad, some people like ceramic, or semi metalic. That also effects the stopping power.

Hmm.. maybe i'll give this a shot..

 

[theoutbackdream]

I had the same problem, when stopping at low speed my car made a 'whop whop whop' sound and had a shake to it. After replacing the tires, front calipers, front rotors, and front wheel bearings. I came across this thread: https://www.tacomaworld.com/threads...differential-bearing-vibration-thread.152173/

The front differential needle bearing was my problem. Which only affects the V6 4wd 4Runners. I replaced the needle bearing with the clamshell bushing from ECGS and all is well.

Its worth looking into.

I'll keep this in mind, but after a quick scan of that thread, it seems like nothing related to what i'm having issues with. I don't get any sounds at all. Just the car "pulses" with the nose diving as if I had warped rotors.

 

[theoutbackdream]

this. all day this.

excellent advice!


as said, the rotors aren't warped, its most likely friction material build-up, as mentioned. if the above doesn't work, unfortunately the solution is the same as if they were warped. to resurface or replace the rotors and pads.

you might even be able to pull the rotors off, and carefully buff the braking surface with a 3M pad, or course sand paper.

braking surface, as in the pard it self? Wouldn't this only be a temporary fix?

 

[nevada]

braking surface, as in the pard it self? Wouldn't this only be a temporary fix?

not the pad, the rotor. everywhere the pad touches.
and not necessarily. If you can get that material off, it will brake smoothly again. if you can adjust your driving style, you should be able to keep it off.

though, to be honest, there is no repair that is 100% permanent, or guaranteed. its the nature of disc brakes anymore...

 

[theoutbackdream]

not the pad, the rotor. everywhere the pad touches.
and not necessarily. If you can get that material off, it will brake smoothly again. if you can adjust your driving style, you should be able to keep it off.

though, to be honest, there is no repair that is 100% permanent, or guaranteed. its the nature of disc brakes anymore...

Interesting...

I'll give this a shot.. If it doesnt work, i'll probably just leave it until I need new rotors/pads or it annoys the hell out of me..