Hi Guys,
i am about to change the front rotors and pads on my 2014 RX450h. I have watched a few YouTube vids using other models (300 and 400) but wondered if there are any significant differences. Any advice (particularly re torque specs) would be much appreciated.
Many thanks!!

 

How many miles are on it? It is rare for brake pads to last less than 100,000 miles. Mine on my HS250h look almost new at 93,000.

Look in the RX350 forum or youtube as it is the same. The front pad & rotor replacement process is the same. Try searching here in the RX350 forum and the sticky as others have replaced brakes.

Be sure to clean and regrease the caliper slide pins!

In fact, these same brakes are on the 2008+ Highlander & 2011+ Sienna and I think the ES350, Avalon and Camry. You were looking at older vehicles that may not be relevant.

 

Thank you for the input. My car has just been for its 80K service and they say the rotors are below Lexus spec at 31mm. The pads still have 4-6mm on them but I’m going to replace these at the same time as the rotors. Good to know that there won’t be any unexpected surprises when I start the job. I did see the importance of greasing the sliders and took note. I’m assuming that the torque settings will be the same as for the models in the YouTube videos I have seen. Thanks again for your time and advice. Much appreciated!!!

 

Just bed in pads and rotors IMMEDIATELY after install. Thank me later.

 

Thank you for your advice. By “bed in” do you mean pumping the brake pedal? And do I do this before attaching the negative battery terminal?

 

Grahama - have you ever replaced brake pads before? Have you bled brakes before? Do you have someone experienced to assist and teach you?
I ask because of your question above which would only be asked by someone lacking certain car repair knowledge and experience.

New brake pads should be bedded in and you may need to bleed the brake fluid when replacing your pads.

Read this excellent explanation on how and why to bed in your new brake pads:

https://www.tirerack.com/tires/tiret...419110414!b!!g!!


However, I suggest you take your vehicle to a shop after replacing the pads and have them do the brake fluid bleeding properly as the brakes are an essential safety system and not something you want to risk your life on by using them to get car repair experience. A brake system malfunction can get you or others injured or killed.
Brake fluid absorbs water and should be bled or flushed every 3 years or so.

 

How do I break-in new pads and rotors?

Brake Bedding Instructions

The break-in process for new brakes is called “bedding.” It consists of heating up and cooling down the brakes in a controlled way.

The bedding process transfers an even layer of Brake Pad material to the new Brake Rotors. This improves the braking performance. It can also release any gas in the pad material to prevent future Brake Fade.

How is it done?

Many brake manufacturers have a specific bedding procedure. If so, follow those instructions. If not, follow the instructions below.

First, find a safe place. This could be a track or an open stretch of flat road. Be sure that you are able to speed up and slow down multiple times, away from other vehicles.

1. Speed up to 35 mph.
2. Use moderate brake pressure to slow down to 5 mph.
   1. Do not come to a complete stop.
3. Repeat 2-3 times.
4. Speed up to 55 mph.
5. Use strong brake pressure to slow down to 5 mph.
   1. Do not brake so hard that the ABS activates or the wheels lock up.
   2. Do not come to a complete stop.
6. Repeat 4-5 times.
7. Drive for 5-10 minutes to allow the brakes to slowly cool down.
   1. Use light brake pressure when needed.
   2. Try not to come to a complete stop.
8. Park the vehicle and let the brakes cool for an hour.

Notes

• During the bedding process, try not to come to a complete stop.
  • Squeezing the pads against the hot rotors can cause uneven material transfer.
  • This can result in squeaking, pulsating and reduced performance.
• Performance brakes have a higher temperature tolerance.
  • This means you may need to perform more rounds of speeding up and slowing down.

 

Thank you for that! I needed clarification of your term “IMMEDIATELY” Much appreciated!

 

Thank you for your concern Clutchless!
i have been working cars since becoming my Dad’s “apprentice” in the early sixties, but this is my first Hybrid so I am being super cautious.

 

Good practices:
Let the evidence lead you to the needed repair(s)
shimmy/shake during braking --> Rotor [most-likely]
Pad -> examine the thickness and even wear. [stuck caliper]
Rotors can go bad when pads are not replaced at the right time or mechanical issues.

If proper maintence is done there should be no need to replace the rotors. I have done million + miles collectively on various vehicles and never had a need to turn/replace rotors.

Since the basics are already understood, just learn the differences.
a) Electrical pump in 450H. Constant pressure on the brake pedal will pump out the fluid. The pedal and pump work with the vehicle switched off with battery power.
b) With ABS a brake service tool can make the bleeding process lot simpler.
c) If your brake pads need replacement before 50K miles, something needs to be investigated. [driving terrain, driving habit etc].


Salim

 

Hi Salim
thank you for your comments.
Point a - I intend to have the keys well isolated from the car but will also disconnect the - terminal from the battery.
Point b - I really don’t plan on bleeding the system, hopefully this replacement will be possible without needing to do that.
Point c- my car has just been for its 80k service and the technician said the rotors were just under Lexus’ minimum spec at 31mm hence the change. The pads are between 4 and 6 mm so not too bad but I’ve decided to renew them anyway at this time.
Once again thank you for your input!

Graham.

 

Weird, are you sure the minimum is 31mm? Mine are as follows and they are barely worn at 100k. The minimums are stamped on the rotor. So no need to guess, look for the info on the rotor. Here's a quick google search so you have a picture of where to look. It's on the "hat" part, sometimes hard to find, this example is not. Example Rotor Thickness Stamping

If the rotor is good but you are gunho on the pads then just do the pads. The brake bleed is a bit nuts even with Techstream. Be sure to have a lot of fluid OR recognize that when you get to the rears it SHOOTS out easily ounces worth when the pump bit engages. You gotta be quick on the open and close. Maybe 1 - 1.5 seconds.

Also make sure to measure the thickness using a caliper with something like this so you get the right thickness of not just the outside. HF Caliper If you just have a regular caliper then use some coins and do the math. If you use the coins method stick them on with blue painters tape, you'll thank me for that tip. If you don't stick em on you'll understand why soon enough, and yes I've had to take a whole caliper apart when a coin slide between pads too much.

Front
Pads: 8.4mm est Stock Max 12mm? (i can't find that info anywhere)
Rotors: Min: 25mm Measured: 27.9mml
Stock Max 28mm
Rear
Pads: 7.5mm est Stock max 12mm?
Rotors: Min: 8.5mm Measured: 10mm
Stock Max 10mm

 

I follow very simple ... rule of thumb .. guidelines.

1. Rotors never wear down.
2. Rotors can get warped [heat-cool, over-torqued] or pitted/grooved [worn pads]. For these two reasons, you need to replace or turn the rotors.
3. OEM pads have a slot in the middle and scalloped ends. As the pads wear out, one should replace the pads as soon as the slot is gone or the scalloped end is gone.

Investigate when ever there is uneven wear. Shaking of steering wheel based on wheel rotation. Hybrid model pads needing replacement before 60k [80K + typical]. Rear pads 100k+
I have found shops try to include rotor turning as part of brake job.


Salim

 

Rotors do not warp.

Look up this article:

TECHNICAL WHITEPAPER:
The ‘Warped’ Brake Disc & Other Myths of the Braking System

And this:

https://www.onallcylinders.com/2016/...-theyre-false/

Myth #1: Brake Judder and Vibration Comes from Warped Rotors

StopTech says the term “warped brake disc” has been used in motorsports for years, but we’ve heard the same reference made on everyday passenger cars, too. In fact, brake vibration (and the warped rotor excuse) has led many cars to be returned to their manufacturer under lemon law rules.

But according to StopTech engineer Carroll Smith, brake vibration doesn’t come from warped brake discs.
“Presuming that the hub and wheel flange are flat and in good condition and that the wheel bolts or hat mounting hardware is in good condition, installed correctly, and tightened uniformly and in the correct order to the recommended torque specification, in more than 40 years of professional racing…I have never seen a warped brake disc,” said Smith, who authored StopTech’s white paper on the topic. “I have seen lots of cracked discs, discs that had turned into shallow cones at operating temperature because they were mounted rigidly to their attachment bells or top hats, a few where the friction surface had collapsed in the area between straight radial interior vanes, and an untold number of discs with pad material unevenly deposited on the friction surfaces — sometimes visible and more often not.”

Smith says every vibration issue he’s seen attributed to a warped brake disc has actually turned out to be friction pad material that was transferred unevenly to the surface of the rotor. This uneven build-up results in thickness variation (TV) or run-out due to hot spotting that occurred at elevated temperatures.

Smith explains how the problem occurs by taking a more in-depth look at the nature of braking friction in his white paper. The bottom line, though, is you must properly break in your brake pads and rotors to prevent materials from transferring between surfaces in a random fashion. This allows the bonding resins to be burned off slowly to prevent uneven deposits and fade. The right break-in procedure will also relieve any thermal stresses on new brake rotors and will transfer a smooth layer of pad material onto the disc.

 

Well, I am now officially on my 3rd set of front pads and rotors, at 247,000km (153,000mi). Decided to change them myself this past Saturday rather than loading the trunk full of gold bars for the work to be done by a service place. I was pleasantly surprised how easy the front rotors came off. The very few brakes I've done before usually end up with me slamming the rotors with a sledge to get them to release or wrenching in a bolt with all my might to push them off, but even though these rotors have been on for a long, long time, one side only required a slight tap and the other side basically came right off as soon as the caliper bracket was removed. Backs still on 2nd set, but I think I will do them when I put the summer tires on in a few weeks. I had to do the fronts immediately, just starting to grind the pad's metal backing plate into the rotor. They were 102% worn out.