If my zapco amps break down will the company repair them for free

are you sure you didnt wire the amplifier the front and rear to
left/ right?

check your deck settings to see that the rear speaker rca are connected.
check all wires are connected.
push the mono or bridge buttons are off.

provide more info.

Go to this link and see page 47

http://www.zapco.com/files/Download/DCRef.pdf

4-channel, 4 ohms: 4 x 50 Watts
4-channel, 2 ohms: 4 x 90Watts
Stereo, 4 ohms: 2 x 180 Watts
T.H.D. : Frequency Response: 10 - 25KHz
S/N Ratio: >90dB
Channel Separation: >50dB
Dimensions: 13"L x 9.9"W x 2.25"H

Zapco I450 Zapco I 450 iForce Series 4 Ch. 360 Watt Amplifier

i got a wiring paper that comes with the peq plug,its not a manual but it shows how to wire up a zapco peq

check your settings on your stereo and the amp make sure you have changed to 1 ohm on the amlifier for a briged connection to a subwoofer and change from lpf to hpf on the amp there should be a switch.

Storing as in Distortion? If that's the case lower the output gain from your amp until it is suitable to you ears. It might be all the way open, besides this should be adjusted system to system.

If the amp uses TIP35Cs and TIP36Cs, those will be the output transistors. Measure the resistance between legs 2 and 3 for each of the output transistors. Do any read near 0 ohms?

If you're new to repairing amps. The following page should help.
http://www.bcae1.com/repairbasicsforbcae1/repairbasics.htm

Is it blowing the three 30 amp on-board fuses?

To have 3 speakers bridged, each speaker must have at least a 12 ohm impedance (assuming that all speakers are connected in parallel). If you're running a load lower than 4 ohms (mono), the amp will likely fail.

The fuses don't blow right away because they are cold at first. As they heat up, they can blow more easily (even though the current draw hasn't increased).

Check your ground and make sure it is properly grounded ....it needs to be a very clean paint/gum free area tightly bolted.  Next Check and make sure you are recieving your 12 volts (not running)  13 (running)    by placing your test leads from positive to ground...... then make sure your power remote from your head unit is putting out voltage. 

Go here first http://www.zapco.com/ Good Luck