Yaris braking problem Help Please!

[kris11]

Please can I get some advice before I approach my main dealer.

Bought car from new Yaris 2004 T Spirit, 54,000 mileage. When driving over 40mph if I brake the brake pedal has resistance around half way up. It feels as if the pedal is pushing back up.

Went to my local mechanic who changed the rear drums as they were excessively worn, bled the system but the problem persists. He put the car on a diagnostic machine and it shows no fault. He said he the discs and pads are fine too. He suggested my only option is to go to the main dealer.

Has anyone had anything similar? He believes it is a fault with the ABS system. Strangely no issues when driving slower and braking normally.

Thanks in advance of any guidance!

[FROSTYBALLS]

Hello Kris - welcome to Toyota Owners Club. Post moved to the Yaris club.

[kris11]

Thank you Frosty and apologies for not posting it in the correct place.

[TomdeGuerre]

I think you have a problem with your brake servo. A vacuum source from the engine is connected to the diaphragm ‘booster’ chamber with a rubber hose and a check valve. If the rubber hose or the check valve is leaking you can get a hard / soft / sinking action of the pedal. But what you are getting might be early signs of internal failure of the servo, with brake fluid leaking back into the servo inlet. Do you have to top up the fluid regularly or is there any signs of leakage around the master cylinder/ servo area? If you’re lucky you might get away with a hose or check valve. Otherwise you need a new brake servo and probably a master cylinder at the same time – that would make sense.

[kris11]

Thanks for your input Tom.

My mechanic has said there is definitely no leak with the brake servo being fine. He also bled the brakes. He is convinced it is the ABS system in relation to the pedal?

Thanks anyway.

 

[Madasafish]

Did he bleed the clutch?

 

If not, get it done. It shares the same reservoir and air in the clutch lines will affect braking.

[kris11]

Thanks for your input Madasafish. I have left a message with the mechanic asking if he bled the clutch. I'll update once I hear from him tomorrow.

He seems pretty convinced it is the ABS system but it just don't make sense as breaking below 40 mph everything feels perfect. Even when you brake at speed you feel push back on the pedal but it still brakes. He is adamant there are no leaks but what you say makes good sense. 

[TomdeGuerre]

When you apply the brakes normally, as pressure builds up in the master cylinder this generates a counter force against the servo push rod to close off the atmospheric port thereby maintaining a state of equilibrium. ie when you’ve applied enough pressure, want to maintain it and neither increase or decrease the braking effort.  Normally this reaction is well damped and you hardly notice it but if it becomes very noticeable then that is nor normal.

I would have said it’s difficult to see how the ABS can cause your problem, not impossible though. Let us know what the outcome is after investigation. 
 

[Irene8]

I have just signed up for your club but am experiencing the same problem with my automatic 2004 Yaris. Mine happens at lower speeds.

The diagnostic machine does not through up a fault code. The mechanic says  it is the sensors thinking I am going into a skid. He has said he can change the sensors but that is expensive and may not be the cause of the problem.

Any suggestions ?  Please don’t be too technical as I have no knowledge of cars. 

 

Many thanks

Irene

[scannerman]

If you can find a fuse for the ABS, if you pull it and try driving to reproduce the problem, if it still does it, I would suggest it's not the ABS.

[Irene8]

Many thanks

[Taisoll]

Please can someone advice what could be the issue with my 2008 Toyota Yaris. The car speed reduces and stop when you apply brake. Then the brake become hard and refuse to move even with the engine running.

[MRichards]

That sounds like the brake servo. With the engine off, pump the brake pedal a few times to remove the vacuum from the servo, the pedal should get quite hard. Put your foot on the brake and apply some constant pressure (as if you were stopped in traffic). Start the engine, if the servo is working correctly, you should notice the brake pedal gets lighter (i.e. the servo is working, giving you assistance when you press the brake pedal) and perhaps even drop a little. If there's an issue with the servo, the pedal will still feel hard with the engine running.

[Sassy__]

Hi, I have a similar issue with my 2004 1.0 yaris. When I go to use the brakes, occasionally I will get a vibration/juddering in my pedal. It doesn't affect the braking performance very much if at all but it seem to be getting more frequent. It tends to happen when I'm coming to a stop from a slow speed but it's too inconsistent that when I try and explain it to anyone they all give me a different diagnosis. I am planning on bleeding my brake lines to see if it is something simple like air or dirt in there but would love some more input 

[MRichards]

Is the vibration you're getting the same kind of feeling as when the ABS engages? I've heard of issues on Mk1 Yaris' where the ABS kicks at low speed, though I've never had this on mine so never researched this myself. If it is a different feeling, it could be worth taking out the pads and the slider pins to grease them up - brakes need to be able to slide freely without binding to work properly. Bleeding the brakes may also be a worthwhile exercise, though that usually fixes issues with spongy pedals etc.

[wildtapholer]

If I've had any sort of feeling of judder from the brake peddle when braking it's always been the disc's being warped slightly, it feels like the brake peddle is pulsing under your foot.

[bathtub tom]

Does the car have ABS and if so does the ABS light come on when this pulsing occurs?

[Starensis]

I’ve found - when braking over potholes or manhole covers, traction control kicks in causing pedal judder ( ABS activates).

[flash22]

1st off, make sure your wheel nuts are tight, what condition are the pads and disks in ? A bit of rust under the top hat of the disc is enough to give vibrations under braking

lots of short journeys ? Take it for a long run and get some heat in the pads and disks

[m456an]

I have same problem, happens occasionally it is only when car is about to stop. I know the brake servo is working. Did the test. Though the brakes seem good. Did anybody solve the problem. Anyway MOT test very soon. Don't really think it is the abs as the car is about to stop when it happens.

[MikeSh]

This is quite the zombie thread. Four people before m456 have asked for and been given advice and not one has come back with any conclusion of what eventually happened. Seems to be the modern way.

6 hours ago, m456an said:

Don't really think it is the abs as the car is about to stop when it happens.

I wouldn't assume that. Something could be playing up at low speed and telling the system lies. I think somebody above suggested pulling the fuse to test, but as yours is only occasional that's probably not a good idea.

Would it be an MOT fail? (If it did it during the test.) Or just advisory?

[Bper]

Hi Mike,

It may be interesting to read this article on this break peddle issue. Read it through as it describes and gives a fix below. Hope this helps.

https://blogproautomotive.com/brake-pedal-pushes-back-when-stopping/

[MikeSh]

57 minutes ago, Bper said:

It may be interesting to read this article on this break peddle issue.

That's the sort of thing I was imagining really. With rust and dirt the sensing might be OK at speed as any extra or missing pulses could be lost in the frequency, but at low speeds they could be 'seen' as sudden change in wheel speed and acted on. (I don't know how likely it is, but it seems plausible to me.)

[m456an]

Yeah it does all hint at the ABS sensor seems to attract metal dust just like a central heating filter which is a magnet. Though I could not get the relay fuse out, I stopped as I thought that I may damage the housing.

I tried to take out one sensor to try to clean it, but the bolt holding it broke it seems to happen all the time with old cars. So I tried using a SDS+ drill but that did not work, perhaps I needed a smaller drill bit.....

 

I will get the garage to take out the broken bolt and to clean the other sensor too. Just takes a little effort to break the bolt, I did not even know I had broken the bolt untill I looked at the socket and there it was.

 

So a lesson for people with new cars, clean the sensor and add anti sieze to the bolt nuts every 2 or 3 years. I am sure none of these super expensive service plans have this in their things to do list.

[m456an]

UPDATE

MOT TEST

FAIL- Due to a leak in the drum brakes. I mentioned the funny noise, but the guy said as long as ABS light does not go on. And everything works there is no problem-fixing the leak may solve the problem???

THE GARAGE

Replaced cylinders and pads for rear brakes. £240.

Problems still remained.

AFTER THE GARAGE

Relay fuse remover tool arrived from China £5 from China with full tracking. Took out fuse, it did break taking it out. Did disconnect Earth before, this is important when doing anything with fuses. ABS light went on.

THE GOOD AND THE BAD NEWS

The trip to Heathrow Airport, over 100 miles. The problem is gone. No more funny noises when the car is about to stop. The bad news is I lost my debit card, but lucky I had some cash to pay the parking at the airport. Then got out of airport went on hard shoulder put on hazard lights. Opened my bank app and ordered a new card, checked my bank balance and nothing was taken out.

Arrived home, no problems with car.