Hi folks,
2010 Kia picanto 50k miles.
Brake line rusted through and burst resulting in no brakes. Line replaced, brakes bled and master cylinder replaced.
When car is off there is pressure when pushing the brake pedal but when car is on the pedal goes all the way down. Tried bleeding the brakes with high pressure system but pedal still goes all the way down only when the car is on.
Mechanic is at a bit of a loss and is sure it can't be the abs unit.
Ay ideas?
Cheers
For those that do now know, the Kia Pincato was a cheap small city car.
They were sold often for under 10,000 pounds, nowadays new ones a bit over 10,000 pounds.
The later 2nd generation car was excellent, for what it is.
But the 3rd gen comes with an automated manual and it just doesn't drive that well -
But with the new AyGo being such a wonderful car - Kia will probably have to improve.
The brake booster is faulty.
I have watched Scotty's video on how to fix sinking brake pedal. I think maybe it is a bad replacement master cylinder. Unless there is another leak the mechanic has missed that seems to be the only cause. They are going to try the screw-driver bleeding technique but if the replacement master cylinder is bad that won't help.
Am I along the right lines (pun intended) here?
Yes.
But note that during this parts shortage there are a lot of bad parts going around, for some reason especially on Kia.
when car is on the pedal goes all the way down .. Mechanic is at a bit of a loss
it's a textbook case of malfunctioning booster. This is rookie stuff. You need a new mechanic.
Thanks for replies. I thought the booster wasn't actually in the brake system such that it could cause a leak and that it only physically pushed on the master cylinder to increase the pressure so that it couldn't cause the spongy effect? If I'm wrong about that then it will be the next place to look before replacing the master cylinder again.
Maybe check the brake reservoir... according to the internet were TSBs to replace the caps on these.
It's one of those things were a skilled mechanic needs to use his eyes and his brains to understand what's going on...
Is there vacuum? is there any leaks?
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There isn't much to a braking system,
Please ignore the pressure transducer and load cell part, it's unrelated.
source: https://www.validyne.com/blog/vehicle-hydraulic-brake-system-testing/
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Here's how the ABS system hooks up
It could be the ABS system