Why do I have to pump my brakes?

[Sal Collaziano]

Hey all. I brought my car into Pep Boys and asked them to check out my brakes because I had to pump them once or twice to get the peddle up (and to stop safely). I told them the car had new pads as of about 2 weeks ago. Anyways, they called me up and told me the brakes were fine - no problems at all.

What would cause me to need a pump or two? Master Cylinder?

 

[The Car Whisperer]

Sal, do you have any leaks? When new pads are installed the pistons in the calipers have to be pushed all the way back into the caliper, on occasion this can cause a leak in the piston seals since they are now riding on an area of the caliper bore that they haven't been on for years, if there was any moisture in your system this area may have developed some surface roughness from corrosion. This surface roughness can cause the seals to let brake fluid seap by and air get into the system.
Your master cylinder may also be going bad, internal leakage. I'd check for any external leaks at the calipers and hoses first. If there aren't any leaks then you might try a complete flush of the system, it could be as simple as some air in the system, just bleeding the brake system thoroughly may remedy the problem. I went around to each caliper and flushed about a half pint of fluid through each caliper, then I went around and did it again. Takes about a quart of fresh fluid to do this.
I just did a complete brake job on my 86'. I didn't have to pump the pedal after the job was completed, so you definitely have something else going on there. Hows the brake fluid level? Is it clean and clear or is it black?
When everything is working properly the pedal should be firm!

 

[Sal Collaziano]

Thanks!

Thank you very much! I will go and check the fluid tomorrow morning when it's light - to see if it's clear or dark. Otherwise, I will take this knowledge with me to the local Corvette repair shop and see what they say. Your reply was very informative.