Door hinge spring compressor

[ew1usnr]

I noticed on Sunday that the hinge on my left door is missing a spring that is in place on the right door. That explains why the left door always wants to swing closed and will not stay open.

A replacement spring is available for only $1.25 (plus $8 postage).
See: http://www.macsautoparts.com/ford_falcon_mercury_comet/door-hinge-spring-used-on-lower-hinge-falcon.html

I saw a "door hinge spring compressor" for sale on e-bay for $24.99 + $5 postage.

Door hing spring compressor.jpg

Have any of you replaced these springs? How difficult is it, and is the spring compressor an absolute necessity?

Thanks.