Question on brakes for Toyota

[Yeobh]

Brake bleeding for ABS system for some high end continental and some Asian cars are not so straight forward  as  commonly done by just vacuuming at the bleed screw or just pressuring the system with 10 to 15psi  forces ( for those who still use leg power to bleed the system, it is time for them to retire for good)

To get the best result it is best for the mech to check the procedure for the respective make and model of car service manuals ( service manuals are not easily available and prices are that cheap )

From time to time you get comments from mech that such and such make and model are difficult to bleed and they general will assume that is the way the cat brake system is designed. Some will try to recommend to change the system components to improve the braking force.

Whenever you need to bleed yr car brake system, go to shops that are knowledgeable and have the right skills and tools to undertake the task. DO NOT endanger yr life by going for the cheapest and fastest service.

[Techgod]

I made a plunge and changed my brake hose, front brakes and rotors, unfortunately it is not them who has caused the inconsistent brake pedal travel. 

Even when I bang table at Toyota, the mechanic tested it and certified it is normal.

Yes I did heard from mechanic that nowadays brakes are not straight forward to bleed but going to Toyota to perform brake bleed should solve the issue but it did not. 

They mentioned they took out the brake calipers and washed them. 

Next up to change is the master brake cylinder, thank you all for the reply, will keep ya guys updated if I have solved the issue. 

[Yeobh]

16 hours ago, Techgod said:

I made a plunge and changed my brake hose, front brakes and rotors, unfortunately it is not them who has caused the inconsistent brake pedal travel. 

Even when I bang table at Toyota, the mechanic tested it and certified it is normal.

Yes I did heard from mechanic that nowadays brakes are not straight forward to bleed but going to Toyota to perform brake bleed should solve the issue but it did not. 

They mentioned they took out the brake calipers and washed them. 

Next up to change is the master brake cylinder, thank you all for the reply, will keep ya guys updated if I have solved the issue. 

Bleeding via vacuum unit has its limitation as air bubbles in the brake fluid are always trying to float upwards towards the master cylinder. The highest possible  vacuum created by ventri in the bleeding unit is  not more than 25 inches of mercury.

The best way is to use a reverse bleeding method develop by a American company - the system actually pump brake fluid into the bleeding screw and cause the air bubbles to naturally float upwards and burst at the fluid surface of the master cylinder.

The next best alternative , widely use on European cars,   is the pressure brake bleeder. Here the fluid is pump and force into the brake system causing the air bubbles to bleed via the brake bleeding screw.

Hope this helps

[Justacar]

Hi Techgod,

I saw your post and I am having the same experience, so I created an account to share.

I have a Harrier Turbo ( late 2018). Whenever I send the car in for servicing, the brakes feel sharper when I pick up the car. Not sure if it’s because they clean the brake pads. Then, over time - typically a month or so, the initial biting point for the brakes get lower and lower. There’s a limit for how much it deteriorates - it doesn’t get to a point where the brakes don’t work, but essentially there is a bit of play at the top of the pedal (feels like an air gap) where the brakes don’t bite. 

I have flagged this once and gotten the same response - technician has checked and everything is “normal”. I will probably try asking again the next time I go for a maintenance. 

I don’t know if it’s the master brake cylinder - I have had that fail on me once on an old car (intermittent failure), and that was scary (near total loss of brake power). This is much milder in comparison.

Would be interested to know if you happen to find the magic bullet for this. 

[Yeobh]

16 hours ago, Justacar said:

Hi Techgod,

I saw your post and I am having the same experience, so I created an account to share.

I have a Harrier Turbo ( late 2018). Whenever I send the car in for servicing, the brakes feel sharper when I pick up the car. Not sure if it’s because they clean the brake pads. Then, over time - typically a month or so, the initial biting point for the brakes get lower and lower. There’s a limit for how much it deteriorates - it doesn’t get to a point where the brakes don’t work, but essentially there is a bit of play at the top of the pedal (feels like an air gap) where the brakes don’t bite. 

I have flagged this once and gotten the same response - technician has checked and everything is “normal”. I will probably try asking again the next time I go for a maintenance. 

I don’t know if it’s the master brake cylinder - I have had that fail on me once on an old car (intermittent failure), and that was scary (near total loss of brake power). This is much milder in comparison.

Would be interested to know if you happen to find the magic bullet for this. 

The only way to determine whether there is a leak in the brake system is to subject it under presuress of about 15 to psi. This can only be carry out with a pressure brake bleeder. The best s to have the test over 24 hours.

[Techgod]

@Justacar We are on the same boat, i am still trying to find out the reason. Trying out basic complete brake flushing and bleeding at other outlets. 
 

I am guessing if the car brakes sufficiently, AD will not deem it as an issue. Yes esp after servicing the brakes are naturally high and the AD will not find any fault with it. If there are more owners facing this issue we could raise it up to BM
 

@Yeo thanks for the technical explanation. Guess this will be a diy kind of check. Currently no workshop i have seen will perform this test. The brake system is complicated.

[Yeobh]

17 minutes ago, Techgod said:

@Justacar We are on the same boat, i am still trying to find out the reason. Trying out basic complete brake flushing and bleeding at other outlets. 
 

I am guessing if the car brakes sufficiently, AD will not deem it as an issue. Yes esp after servicing the brakes are naturally high and the AD will not find any fault with it. If there are more owners facing this issue we could raise it up to BM
 

@Yeo thanks for the technical explanation. Guess this will be a diy kind of check. Currently no workshop i have seen will perform this test. The brake system is complicated.

This pressure testing for leak is NOT for DIYers unless you have the pressure brake bleeder set and be able to hoist up the vehicle for leak observations. Simple tapping with a small inspection hammer on pipe joints may help to quicken the leak. 

Edited March 6, 2021 by Yeobh