1997 Ford Taurus. I recently put new pads on front brakes. Now a few weeks later it requires me to pump the brakes a couple of times to get a firm brake pedal. The first time you push the pedal, it goes to the floor and only the left front brake is engaging. A quick pump or two and I have a firm pedal and good braking. Have checked fluid levels and re-bled all four brakes with no improvement. Is the problem most likely in the master cylinder or is there something else I should check? Thanks

Ask those questions at a repair shop
Your son doesn't have the knowlegdge
to resolve
Replacing a master cylinder & bleeding brakes
more than once, tells me he is lost

Might just be a loose connection on the power steering hoses. You'll need to get under (BE CAREFUL) your car or get it up on a car hoist. You or a mechanic, should be able to trace where the leak is and either tighten the connections or replace the hose. Cold weather brings on leaks ! !
I don't think the brake vibration has anything to do with it. Brake vibration usually means the brake rotors are warping. Common problem. Have you have your brakes checked lately? Might be time for new pads and rotors.
Good Luck

common problem! replace the brake booster! and vacuum pump!

If you put the lifetime pads they are much harder and although you will get extended life the pads have a tendency to squeak try getting in a empty parking lot and put a little pressure on the brake pedal while backing up a few times it sometimes helps but is only temp, I prefer the non lifetime pads for this reason

Hello, to replace the front pads first open the hood and remove the brake fluid cover (will make retracting the piston easier). Next losen the lug nuts till you can turn them by hand than jack up the vehicle and use a jack support stand. Once the vehicle is supported remove the lug nuts and wheel, remove the lower caliper screw and rotate the caliper upward. Remove the old pads, use one of the old pads and place it so it centers the caliper, using a large C-clamp position it with the solid end on the back side of the caliper and rotating handle contact the pad in the center or close as possible. Slowly rotate until the piston is fully retracted into the caliper, your brake fluid may run over but its ok. Install the new pads return the caliper to the normal position over the pads reinstall the lower caliper screw. Put the wheel back on tighten the lug nuts till the wheel is evely and firmly in its normal position. Remove the jack stand lower the vehicle, put the brake fluid cover back on and pump the brakes until they are firm and check the fluid, add some if needed. Tighten the lug nuts, check for leakes. After starting the vehicle pump the brakes a few times, now the fun part the test drive :) allow you self more than normal distance to stop. Tips, I always set the parking brake when working on the front brakes, some people use a 2x4 instead of a brake pad to retract the piston into the caliper, double check your work, i always do and take your time.

Get a new battery - I did and it works OK.
Make sure it is the high output type as used in Jeeps etc. Check spec book for it in shop.

New brakes take a while to bed in so you will see more brake dust than usual. If it carries on after a few hundred km/miles then the new pads are probably cheap and will wear a lot quicker than good quality types.

for the brake pads?its a shim.every brake pads sould have them on each pad.

Linda to be honest with you I was so tired of this situation that in August 08, 2008 I trade the car and now I had brand new Dodge Ram, Im spending a lot of money in gas, but I like to be safe in the road.

Have you put the correct caliper on each side?
Are bleed screws facing upward?
If so you will probably need to have brakes pressure bled to push through air in ABS system.