Brake issue

[Rathead]

Hard to describe as it has only happened a couple of times, but here it goes:

There is a lot of vibration in the pedal and it feels like pressure is released then the pedal has a lot of resistance and will not go down as far as it should (I think). Braking performance seems to be affected as well and there is some noise heard by myself and my passengers.

It only happens if I am coming to a stop and braking hard while driving on a rougher than usual road. It also happened when I was in 4wd in the snow over ice while coming down a slight slope.

I've tried braking hard on a smooth road and everything seems fine.

I'm replacing my calipers, pads, and rotors this week and hopefully that will fix it, but if anyone has some insight into what the problem might be please let me know. Thanks.

It's '99 4runner.

[Seanz0rz]

that is likely the ABS kicking in. feels kinda like a very tiny jackhammer is hitting the back side of the pedal.

not uncommon.

[QSVeilside]

Yep. Also happens when you hit a pothole while braking.

[corax]

It only happens if I am coming to a stop and braking hard while driving on a rougher than usual road.

If it was only on a rough road, I'd say it's weight transfer to the front while braking which would make you feel the rough road more. It's likely just ABS, does the brake "pulsate" while it's going down?

[Rathead]

I'd say, yes it pulsates.

I thought it might be the ABS, but you guys think it's common huh?

Doesn't feel normal to me.

[corax]

Make sure your seat belt is on. In an empty parking lot, take it up to ~ 20 - 30 mph in a straight line and try to push the brake pedal through the floor like someone just pushed a stroller 5 feet in front of your bumper. Does the brake pedal have the same vibration that you're talking about? If so, that's likely the ABS.

If you have any doubts, ask you local Toyota dealership if you can take a test drive with one of their technicians to illustrate the problem and ask their opinion. If the dealership doesn't charge you, tip the technician - they get paid for the amount of work they do and if you don't pay, they don't get paid. It's a good idea to have a friend in a dealership.

[MTL_4runner]

I agree that if it is not warped rotors (you'd be feeling the pedal vibrating at different intensities while braking no matter what your speed) then I'd have to say you were experiencing ABS as well. I would hate to see you replace all those parts only to find out it was your ABS kicking in.

[SD4runner]

What you've said perfectly describes the ABS kicking in. It doesn't feel normal at all, its a weird feeling and has a buzzing noise. Unless its happening a lot, I wouldn't worry about it, but, since you said it rarely happens...thats normal. I'll get it when braking over a rough decline, or anywhere where my wheels may lock up. In 4wd it seems not to be much of an issue though. And, it turns off with the e-locker engaged.

[Rathead]

This is my first vehicle with four wheel ABS so I may just not be used to it.

I needed to replace the pads soon anyway and wanted to upgrade the rotors too. I may hold off on the calipers however.

Corax, dealership sounds like a good idea and thanks for the tip about tipping.

Thanks to everyone else for the help too, I really appreciate it.

[MTL_4runner]

I needed to replace the pads soon anyway and wanted to upgrade the rotors too. I may hold off on the calipers however.

If you are going to do everything, then without hesitation get the Tundra pads/calipers/rotors.
You'll be greatly impressed by the difference in stopping capability.