Brake failure!!

[Ultra-VoX Junior Member Find all posts View Profile Close Ultra-VoX]

Very unnerving experience when the brakes on my 2006 VX decided to pack it in. Was out and about yesterday and went home to drop some gear off before heading off again. Got to the first corner after leaving my place, eased on the brakes as normal but felt very little resistance in the pedal. The car hadn't slowed and cornered a little quickly. I let the car roll on and tried to brake again and got nothing.

I managed to turn around and get back home, driving quite gently. Once parked I realised I could quite easily push the pedal right to the floor. No difference whether the engine was running or not. Brake fluid reservoir was full so that wasn't the issue. Couldn't see anything obviously wrong around their either. It happened quite suddenly as there was no sign of something happening before that.

Got an ex-mechanic mate to come round today and check it. Started to do some elimination so checked the lines to each wheel, Checked the pedal set up, gave it a quick bleed etc. Nothing seemed amiss there and couldn't find the source of the problem.

Clearly I cannot drive it anywhere so will need it towed to get it fixed. Not sure whether to take it to a Toyota dealer or to a brake specialist. Was going to make calls to each and get feedback before deciding who is most likely to fix the problem.

Does anybody have an idea what the issue could be?

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

Again very hard without seeing it.
So there no leak?
Does it have a vacuum booster?
Likely a master cylinder problem.

[mackayvx Advanced Member Find all posts View Profile Close mackayvx]

Geez mate thats definately scary...
First thing i would do is flush the whole brake system with new brake fluid.
There is alot of debate over the best bleeding method...
My vacuum bleeder works a treat...

Your fluid could be way past its used by date.

[Ultra-VoX Junior Member Find all posts View Profile Close Ultra-VoX]

Brake fluid is relatively new. Had a major service last August.

Master cylinder? Is that the thing that looks like a small compressed air tank next to the brake system?

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

The master cyliner is connected to the brake pedal by a lever mechanism. By ppushing on the lever you are pusing a piston in the cylinder which creates pressure in the brake fluid and thus pushing the pistons in the calipers to force the pads onto the discs. There are additional bits such as the ABS module which influence the brakes and how they operate.

It is nigh on impossible to diagnose so given the fluid level is ok and no leaks the three main possibilities are:

the mastercylinder is kaput, it is not translating your pedal pressure into fluid pressure, that is pushing on the pedal is not creating pressure in the brake system

you have air in the system somewhere. It is entirely possible to have a leak that sucks air without leaking fluid or much fluid

your pads are all contaminated and are not providing any friction

Given you have little pedal pressure it is likely one of the first two. If you have recently had the fluid changed and the system bled then it could be as simple as rebleeding the system. I know of another vehicle where the owner fitted larger brakes for track days. The fit and bleed went off without a hitch but a couple of days later same story, no pedal and no brakes. In the end he had to get a pressure bleed done at a dealer because there was a set sequence and if you didn't follow that air was left in the ABS unit.

Brake specialist is the only thing I can suggest. These systems are complicated.

[Ultra-VoX Junior Member Find all posts View Profile Close Ultra-VoX]

Thanks mj. The issue happened quite suddenly and there has been no gradual deterioration or other warning. Pretty much rules out option 3. Not sure about the re-bleeding either as it was 6 month ago I had the service done. WOuld have expected something to become apparent sooner if that was the issue.

From your description it could well be the master cylinder as I get the impression something 'went'. Anyway I've booked it in at a Toyota service centre. Just need to get the tow arranged.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Hopefully not an expensive fix.

[Bazza Senior Member Find all posts View Profile Close Bazza]

I had a very similar incident a few year ago in my 120. Lost all brakes while towing my 5mtr boat down the last hill into Wiseman's Ferry ( NSW ) That was a sphincter clenching moment. The dealer had it for a week and said that they had replaced everything under warrenty but could not find the cause. It never happened again.
Bazza

[Ultra-VoX Junior Member Find all posts View Profile Close Ultra-VoX]

Fair to say Bazza's experience was slightly more hair raising than mine.

They shouldn't have too much trouble replicating my problem though as its still there. Its off at the service centre now. Will let you know the outcome.

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

From what u said its not air, if there is air in the system, you would have a spongy pedal but it would pump up.
That is a few short pumps driving and each on gets better.
Air can't get their on its own. If it was worked on then u had the problem, it could have been bad bleeding procedure.
If u had a leak it can get air in.
You have no leak. This has not started since brake service.
Still think master cylinder.

[SWR Banned Find all posts View Profile Close SWR]

Hi Guys
Found these old links so thought it would be a good idea to put them all together here!
Brake RECALL 2006 = 14-08-2006
http://www.pradopoint.com/showthread...ke-RECALL-2006
DOES YOUR PRADO BRAKE PEDAL DO THIS? = 31-05-2007
http://www.pradopoint.com/showthread...-PEDAL-DO-THIS
Pedal hits the floor = 26-04-2008
http://www.pradopoint.com/showthread...hits-the-floor
Brake failure = 14-05-2011
http://www.pradopoint.com/showthread...-Brake-failure
Cheers

[Ultra-VoX Junior Member Find all posts View Profile Close Ultra-VoX]

Got the car back yesterday. Firstly they identified it had the wrong brake fluid in it. Dot 4 was used instead of Dot 3. Not sure the difference but they said Dot 4 in Toyotas can affect the rings/seals over time.

They flushed the system and replaced the fluid with Dot 3. Fully tested and could find no other problem. I've been driving a day and a half all seems fine now.

The explanation appears valid and I'll take this as a learning experience. Had a few other issues with my last service and from now on I'm going back to Toyota for them. Cost is no different and they at least know the vehicles requirements.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

I was always under the impression that you coud use DOT 4 when DOT 3 was specified as they are essentially the same fluid just that the DOT4 fluid has a higher boiler point. So I googled this. It seems Toyota almost alone will not accept DOT 4 in lieu of DOT 3 and cites your experience that seals can be affected. Very interesting. There is conjecture on the web that Toyota tried a particular brand of DOT 4 fluid and had big problems so has since drawn the line and said no DOT 4 to be used ever.

Hopefully your brakes are back to normal and stay that way.

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

I know thats what toyota says, but, many brake specialists use dot 4 no probs.
I think it's coinsedance.
How much for the flush / bleed?

Hope it works!

[mackayvx Advanced Member Find all posts View Profile Close mackayvx]

I bought this dot3 / dot4 thing up a while ago...
I got shot down in flames suggesting dot4 wasnt the right fluid to be using...

Glad you got it sorted...