I'm having an issue where when I attempt to do hard braking, the pedal gets extremely firm. I've recently bleed the brakes (it was doing this before and after); and ran nearly 2 L through the system.

I think the issue is with the Brake Booster, or possibly the vacuum assist pump (if there is one). Another test I've done is to pump the pedal when I'm stopped. When doing this I'm able to firm up the pedal after one or two presses right near the top of the stroke. Then slowly the "boost" will build back up and 'power assist' will be restored. Lastly, when doing this I can't hear any type of pump running which I've always been able to hear in other cars.

Any suggestions?

Can anyone point me in the direction of the vacuum pump? If I know where it is I can give it a check.

Thanks

'04 CTT

 

Auxilary vacuum pump is on the passenger side fender area, just in front of the coolant reservoir, under the trim. Also, check all the hard lines coming off of it, I have seen these get hairline cracks, but typically throw a brake booster warning on the cluster.

 

Thanks for the help. I did have a "Brake Booster" warning about a month ago. It came on for about 5 mins and hasn't returned since. I'll check into the vacuum pump. Most cars I've had you can turn the key to the 'ON' (without starting the engine) position and pump the brake pedal and here the pump run. Not sure if the CTT is different, but no pump runs when I do that, and the pedal stays firm.