Crotch buckle not working properly?

Crotch buckles sometimes start to not work properly after some use. Usually this is caused by dirt, dust, food and drink entering the buckle and as a result causing the buckle to not click in properly or causing them to get stuck.
Before getting the buckle replaced, it is worthwhile washing it to remove the particulates that may be hindering it's operation. This almost always sorts out any issues with the buckle. There are basic washing instructions on the back of every buckle.
Some buckles are removable by unhooking the plates under the shell, this will allow you to run the buckle under warm running water. If you can't remove the buckle then get a shallow dish of warm water and swish the buckle around in it whilst it's still attached to the restraint. Another thing to try is a can of compressed air, this will also blow out debris and should do the trick.
*At no time should you ever use any chemicals or lubricants, nothing but water or air.
If these do not work then you should contact your manufacturer about a replacement buckle.
Correct and tight is always right.