Brake question

So my wife's 2019 4 runners brake pedal goes almost to the floor and the steering wheel shakes pretty badly when pushing the pedal hard. She has no idea how long it's been doing this. I ordered new rotors and pads I haven't looked into it yet, we are on vacation and drove her vehicle 800 miles to south Carolina. I know this problem is typically tracked back to the master cylinder but are there any other problems it could be?

 

Sounds like warped rotors, which will cause pulsation during braking. Low pads can cause a soft pedal and excessive heat which can also contribute to warping. If it were me I would bite the bullet and get them checked/changed before a 800 mile return trip.

 

I'd be hesitant to trust it that long. IMO, you should consider getting it into a shop asap.

 

Probably wouldn't take a trip in a vehicle having brake problems, but here we are...

First check fluid level. Brake booster, air in lines, leaks, could all be the reasons you are having issues. Inconsistent braking force will cause uneven wear on pads and rotors.

 

need 4 new calipers! and rotors. has nothing to do with "master cylinder" - whatever it means. but first with dial gauge check run-out of hub

 

You have two problems. 1) warped rotors causing shaking when brakes are applied. 2) air in the lines probably from water moisture boiling in brake lines. A brake fluid flush is very easy to perform and you don’t need any fancy tools. If I was on vacation I would probably take it to a shop and have the brake fluid changed. It is so easy I would be surprised if they charge more than $100.

 

Pulsing/shaking when pushed hard is definitely warped rotor. Change the rotors and pads yourself first, you'll save tons.

 

Just keep driving. You’ll be fine. It’ll work itself out.

 

Check torque on the wheels!!! Loose wheel means loose rotor which wobbles/shifts and pushes the pistons on the caliper in, then you get soft pedal. I never thought a loose wheel could do that until a friend on the TW forms said they had that happen to him!

 

Welcome. The shaking is warped rotors. The soft pedal feel is due to the pads being worn, which in turn causes low fluid levels. Change out the pads, rotors, and do a brake flush. Don’t forget to bed the pads and rotors properly.

 

Is the rig still under warranty? If so, take it in.

Otherwise, do a brake line flush...then I would check the pistons if any are seized. If seized, buy a rebuild kit from the dealer...its relatively cheap. Its a DIY project. Lastly, I would check and replace the pads and rotors if warped.

 

Thanks for all the responses, I ordered rotors and pads when I got to south Carolina. They were here when I got home. When I started changing them I noticed the inside pads were seized to the pins so only the outside of the caliper was pushing on both driver and passenger side. So I sent my wife to autozone to get new pins, cut the old ones out, new rotors and pads and problem solved.

 

Not to be picky. I’d use only Toyota pins in there my friend.

 

use a thin coat of high temp anti seize on the pins

 

Toyota pad retention pins are just as bad as aftermarket - they all need a coat of grease to keep rust from seizing.