03 Avensis Break Failure Crash

August 7, 2015

Hi,

I have a 2003 1.4l petrol avensis (the newer model that year). And I had a crash eariler this week where the breaks failed and I crashed in to the back of the other car in front. I am just wondering is this a known fault with this model (I have googled it and it doesnt appear to be), and any ideas on what could have casued it, or what questions I should asked the garage/insurance assessor.

I was doing roughly 100KPH in the last lane with a good distance to the next car in front, the traffic ahead slowed down so I breaked as normal. But as I approached the other car I felt I wasnt slowing down as quickly as I should and I knew I was going to hit....bang! Id say I ended up hitting at about 15-20KPH, no airbags went off and no major damaged or injuries so feeling pretty lucky sitting here!!

Anyway, after I got out to check my son and the other driver we decided to pull over into the hard shoulder. As I started to move and needed to break I felt the breaks were very soft, so I pumped them a few times but they got worse, I had no choice at that point but to keep going over to the hard shoulder where with my foot to the floor on the break it took a good distance to stop.

There was a trail of fluid across the road behind me, and there was a large leak from around the rear passenger wheel.

The car is in with the approved garage, and they have requested that an insurance assessor call out to view the breaks.

Any ideas on what happened, or what questions should I ask?.....apart from WTF!

Cheers

August 7, 2015

Burst brake pipe from corrosion? It is hard to say but I have seen brake pipes that are badly corroded burst under heavy braking, not just on Toyota models. It sounds like that might have happened, especially as you saw fluid on the road. It happened to me on an old classic motorbike I had, the pipe had become detached from a bracket and had rubbed on the swinging arm, I braked and lost all rear brakes :eek:

August 7, 2015

I thought that was the whole purpose of having a split circuit braking system with tandem master cylinder et al so that if one side went open circuit (as in burst pipe) you would still be left with the other circuit intact?

August 7, 2015

It is, but you would also have a change in the pedal feel, pumping the pedal would draw air and braking would be impaired. The OP said he pumped the pedal and it got worse, it would if the pipe burst, he also said a loss of fluid, It would be an educated guess of course as it could be any number of things, but the most likely

August 7, 2015

Parts King, I wasn't doubting your diagnosis of a burst pipe, in fact it's almost a certainty. But if the other circuit remains truly independent then on the recuperation stroke the master cylinder would not require replenishment from the reservoir. Square section seals in the calliper simply distort when the brake is applied and then pull the piston back when the pedal is released so any fluid used in applying the brakes is returned to the same circuit. As you well know, the only time replenishment is normally required from the reservoir is to compensate for piston travel having to increase because of worn pads, discs etc.

So, all things being equal, when one circuit fails the pedal travel might increase but the integrity of the remaining circuit should not be affected.

August 13, 2015

Hi,

Got the car back yesterday.

The break pipe had corroded and ruptured under the breaking pressure. So they replaced the whole line back up to the engine compartment. They also found the drivers side break pipe was corroding and weeping, so they replaced that section too.