I have a 2001 Hyundai Accent GS with around 145,000 miles on it. Transmission is brand new 2019. Engine is stock engine. My brake pedal is very spongy and does not allow for emergency braking in hard stop scenarios and is not safe for the road at the moment. We have replaced the following parts with OEM and proper standard parts. 1.6 Liter 4 Cylinder engine.
Master cylinder & booster(OEM Part) dealership part $600
Calipers (calipers have flex to them) (Non OEM Part)
Pads (brake pads still have no bite during hard stops according to shop I had it tested at) (Non OEM Part)
We have had the rotors milled and they are still close to brand new on the thickness scales. (Non OEM Part)
Lines have been bleaded more than 12 times in total so far. Took it to a shop and they said the lines are more than perfectly clean. The guy said he has never seen cleaner lines. When he talked to me.
New drums were put on the back wheels a couple months ago. One is warped a little. (Non OEM Part)
Shop had adjusted rear brake shoes and bleed system with only minimal improvement. May have contamination in brake line, but the shop couldn't tell because we had already bleed them 3 times before.
That's it for that.
What happens before I start the car is I will get in and before I even put my key in the ignition i can pump the brakes and they become harder but remain sort of bouncy with a bouncy feeling. Then when the engine is turned on, the pedal loses all pressure. I can push it all the way to the floor and it has very minimal braking power. It'll stop the car slowly at 15 or 20 mph. But will never lock up like it was doing before and is supposed to. The dealership doesn't seem to know what's wrong with the car and my dad doesn't either. We are kinda at a loss for what could be wrong with the car. I can't seem to find the problem or solution on the internet as it seem to be a problem that not many have had. If ever...
After going to the dealership to get the Master Cylinder and Booster put on my car now does have a check engine light on but that hasn't effected anything that I know of yet.
Any ideas on what could possibly be wrong with the car is very appreciated. Both my dad and the dealership are at a loss for words. And the mechanics I have gone to seem to not know what's going on either.
Does this car have ABS? Did you replace the brake lines too, or are they still the original 20yr old brake lines? Are your losing brake fluid?
Yes it has ABS. Brake lines have not been replaced as far as I know for the life of the car. I am not losing any brake fluid. Or at least there are no signs of any leaks along the whole car.
If it has abs could easily be a problem in the ABS system. But if not it would have here in the system the guys aren't bleeding it out right or they just told you the fact of parts which is typical on a 21-year-old Korean car lot of times the old parts aren't any good because they've been sitting on the shelves for 20 years
We put in a code reader and we came up with the following codes.
300 2 or more cylinders are misfiring
304 cylinder number 4 is experiencing misfires
303 number 3 cylinder
722 output speed sensor
Does the 722 code have anything to do with the braking system?
302 cylinder number 2
Damn, I’d start by doing a compression test. If that engine is worn out, stop right there & drive the car as is, or junk it. It’s worth nothing & don't throw your hard earned money at a car which is ready for the junkyard. The P0722 code shouldn’t affect your braking - https://www.autocodes.com/p0722_hyundai.html
Oh ok thanks 🙂
In that case, it sounds like your ABS module is the issue.
Did the first shop bleed your brakes using a fancy scan tool? Any ABS codes?
Right now we are not sure about the ABS. The original shop just bled the brakes as normal procedure recomended by huyndai
ABS brakes usually need to be bled using a scan tool.