Oldsmobile/Buick Repair: Brake shudder and rough idle, vacuum leaks, pontiac bonneville

Question
Hi Van,,
I own a Pontiac Bonneville SE 1992. I purchased the car without an enine and installed a used one myself so I'm not sure about how many miles she's done.
The car is running great except for three things. 1. There is a brake shudder especially during hard braking. I replaced the front rotors but I'm still experiencing the shudder. Could it be warped calipers?
2. Sometimes the idle is rough. I've checked for vacuum leaks, cleaned the throttle body, cleaned the IAC and plugs but still no improvement.
3. I recently sent the car in to check the A/C. All it needed apparently was some refrigerant. The air is cold but the air is blown out somewhat weakly. The technician said that that's the best I should expect out of the bonneville. I known you can't judge from where you're at but is there a way I can check if the system is working to it's full potential?

I'd appreciate any help you can offer.
Cheers,
T

Answer
1. No. The rotors warp, not the calipers.
I think you have looseness in the tierod ends or ball joints.

2. "Sometimes"...see if it is affected by the heater/air conditioner control position. That could cause a vacuum leak in one position, and it it is a leaking door control servo, could also be the problem with question 3.

3. One of the doors could be operating improperly, allowing air thru the heater core. Or the evaporator core could be coated with years of dust and leaves. That would restrict the air flow, since every bit of the air flows thru the evaporator.

You may be able to remove the blower motor, and see the dirty side of the evaporator, even if it requires using a mirror.

Van