I've used a set of water pump pliers. Put a chunk of rubber on the jaws to protect the metal and then squeezed the two sides of the door checks together.

"Y mae dafad ddu ym mhob praidd"
1972 4/4, 1981 MGBGT, 1984 FLHT1340, 1980 XLH1000, 1990 ZX10