Rear brake bleeder valve broken

[tahirawan11]

Hi,

 

i was trying to bleed brake flyid on my toyota aygo 2009. But when trying to open the bleeder screw it broke down (see picture) as it was jammed. My question is do i need to replace the entire brake caliper? 

[flash22]

it is caused by dissimilar metals, you will have to drill it out, remove the rest and then clean it out, for the cost/hassle factor alone, put a new caliper on it

[flash22]

1 hour ago, tsikis007 said:

You can buy from hardware store broken bolt extractor.

You can but due to the dissimilar metals it will have swelled putting in an extractor can make it even tighter - hence the need to drill it to release the pressure

price of an extractor plus a new bleeder and the time, you're at half the cost of a caliper if not more

[tahirawan11]

Ok thanks but i drove the car for a couple of blocks to check brakes. The brakes are working fine and the brake fluid did not leak. Does it mean that the bleed valve is still closed ?  So i can use the car until it id repaired? I also check the brake reservoir at master cylinder and it is full. 

[Derek.w]

8 hours ago, tahirawan11 said:

Hi,

 

i was trying to bleed brake flyid on my toyota aygo 2009. But when trying to open the bleeder screw it broke down (see picture) as it was jammed. My question is do i need to replace the entire brake caliper? 

Heat then cold water can also help then repeat it before trying a screw extractor but a easer method is just to change the brake caliper and return your old unit for a discount off the price.

Note if you overheat it you will destroy it!.

 

[tahirawan11]

Actually i forgot to mention that it is for rear wheel. It has drum brakes, so i think it does not have a caliper so what part do i need to replace instead of caliper for rear wheels?

[Vandals01]

If it doesn't leak, you can leave it as it is.

If you were a perfectionist, you can try left hand drill bit along with extractor.  Be prepared to use a thread chaser to repair the thread and a new bleeder screw.

If that doesn't work, just replace the Wheel cylinder.  I've replaced both of mine last year because of leak on one side and partial seizure on the other.

https://www.gsfcarparts.com/cif101-939 (£18.72 from GSF)

[APS]

12 hours ago, tahirawan11 said:

Actually i forgot to mention that it is for rear wheel. It has drum brakes, so i think it does not have a caliper so what part do i need to replace instead of caliper for rear wheels?

 

It's got drum brakes in the rear. A new hydraulic wheel cylinder is really cheap, so there is no point spending time trying to get the remainder of the bleed nipple out. Since the valve snapped off before you could loosen it, it will not leak and you can drive it. But brake fluid ages and needs to be replaced at some point so you should get a new brake cylinder. 

They look something like this

[Chas G]

Stud extractor from Halfords. Save you risking snapping off the hydraulic pipe connectors as well. 😁

[tahirawan11]

thanks all for your feedback 🙂 I plan to drive the car for a few days and then will change to a new cylinder as there is no point in wasting time and efforts to remove the current remaining bleeder.

Just out of curiosity, if the valve did leak and the brake fluid starts to leak. Does it mean i will loose hydraulic pressure on all four wheels or the brake system is designed in such a way that, a leak in one bleed valve will NOT cause a brake failure in remaining three wheels?

 

thanks

[APS]

1 hour ago, tahirawan11 said:

Just out of curiosity, if the valve did leak and the brake fluid starts to leak. Does it mean i will loose hydraulic pressure on all four wheels or the brake system is designed in such a way that, a leak in one bleed valve will NOT cause a brake failure in remaining three wheels?

"Modern" cars have dual circuits, often split front and rear or diagonally. If you loose pressure (i.e. a puncture) in one circuit you will still have some ability to stop using the other two wheels. You will also have the mechanical handbrake to aid in an emergency.  

That bleed nipple is stuck and won't fall out off its own accord. Still, it is not something you want to try and, as I mentioned, you will need a functioning bleed nipple to replace the brake fluid sooner or later so it must be done by then anyway. Might as well spay rust penetrant on the brake line union now in preparation for replacing the wheel cylinder. 

[Vandals01]

I don't think Aygo will fall down into that "modern" category.  You will probably lose hydraulic pressure on all four wheels.

But it might not be the end of the world.  After all, my cousin did manage to drive to a garage with a brake line ruptured.  How?

Drive slowly, down shifting to slow down the car and use the handbrake to make the car stop.

Drum brakes is both hydraulic and cable operated.  If you press the brake peddle, hydraulic flows into the wheel cylinder, extends its piston, which then pushes the brake shoes against the drum, slowing the wheel down.  If you pull the hand brake, a lever will be extended (hydraulic does not get involved), forcing the shoes to push the drum, again slowing the wheel down.

However, it is kind of risky because:

1. Brakes at the rear is nowhere as powerful as the front.  In normal braking, front account for 70-80% of the braking force, the rear is the remaining 20-30%

2. Drum does not dissipate heat as well as disk.  So it is much more easier to over heat the drum. If the drum overheat and you have no front? Good luck!

3. Rear brake lights will not come on when you use the hand brakes only. So the idiots on your back might not know you are stopping.  Most importantly, police might stop you. And if they find out you are driving without brake hydraulic, you will rest assured to get 6 points for dangerous driving.

[Mjolinor]

I think everything since the 1980s has dual brake systems.

[Crickleymal]

Pretty sure the Aygo has dual brakes

[APS]

16 hours ago, Vandals01 said:

I don't think Aygo will fall down into that "modern" category.  You will probably lose hydraulic pressure on all four wheels.

Modern is a relative term. Dual circuits were introduced in the 60's. Mandated in the late 60's and 70's.

The Aygo has ABS for goodness sake 🙂 

[Derek.w]

As a last resort your can still use your handbrake to stop!.