Hyundai Genesis Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
All right I have a tough one for you guys. My brakes work normal most of the time but for some reason, when driving on the highway for over 15 minutes or sometimes the first drive in the morning or even after holding the pedal for a long period of time, something happens to my brakes where my pedal becomes very firm and doesn't do anything even if I stomp on them as hard as possible. I need to pump the pedal six or seven times until the car finally starts to slow down. I've done the usual vacuum check valve test and for some reason the results were reversed of what they were supposed to be. I took the hose off of the filter side of the intake and was able to blow air through but not suck. I'm currently at a loss and any help would be appreciated. I'd bring it to the dealer but I just spent 1500$ replacing the TB with a few other things along with 1200$ for winter tires and rims, so I'm on a tight budget atm.
Thanks.
 

·
Premium Member
Joined
·
14,904 Posts
Probably something the ABS pump.
Disconnect the battery for like and hour and connect it back up, to reset all the computers.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
Probably something the ABS pump.
Disconnect the battery for like and hour and connect it back up, to reset all the computers.
The computer has been reset a few times in the process of changing the throttle body last month, not sure if this started before or after but it was near that time... you think something could've glitched out in the process? And another reset could fix it?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #4
74989


So just to make sure that it's not an issue with the brake booster check valve, which is what I circled I hope, I was able to blow into the vacuum line in the direction of the arrow but not suck. From what I've read online, this is the reverse of what it should be. But I could also be wrong. Anyone know if it's working as it should?
 

·
I'd rather do it myself
Joined
·
18,361 Posts
From the vacuum source side....

The booster line valve should be open under vacuum and closed under pressure.

The turbo side it should be open under pressure and closed under vacuum..
 

·
Registered
Joined
·
6 Posts
Discussion Starter #7
From the 2010 manual. Is the pedal high and hard with no brakes?

First 4 would be low pedal, 5 does not apply


View attachment 74990
Yeah the pedal is at it's highest point and firm as hell when it happens. Need to pump the pedal a few times at that point to get the brakes to engage.(kinda scary having zero brakes on the highway) I was taking a look at the service manual yesterday and the only 2 possible options I saw in the same list you put up was either air in the brake system or a vacuum leak as this issue is intermittent. But I just can't seem to figure out how there would be a vacuum leak since the brakes work fine 90% of the time.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #10
Alright so I believe I've figured out the issue if anyone is experiencing the same thing... turns out that it only did it when the brakes were wet. So I did some research and turns out that big brakes like the brembos could potentially slip when there's water in between the brake discs and pads, especially if the pads are used or of lower quality. The fix for this is better pads and the temporary fix is to press the brakes periodically when wet in order to warm them up and dry them off.
 
1 - 10 of 10 Posts
Top