To 'put the brakes on' something or someone means to inhibit their progress or to stall or stop something in some way. When you put the brakes on a car or bicycle it stops. This phrase is similar to 'hit the brakes' or 'stall it', meaning to stop.

1. An archaeological find has put the breaks on building our new facility.
2. Tell the department to put the breaks on that order, the clients' account is in arrears.

1. The recent downturn in sales has put the brakes on our expansion plans.
2. Gary has been getting ahead of himself in the negotiations and offering concessions that have not been signed off on. We need to put the brakes on him.
3. We're putting the brakes on further spending until additional funding has been secured.