After stopping on the runway in response to a braking anomaly; the flight crew of a B737NG were concerned when their request for CFR response was not responded to. The Tower advised they had not received the request.

Narrative

During roll-out; the First Officer (pilot flying) began to apply manual braking and as the auto-brakes disengaged; we experienced a shudder and wobbling of the rudder pedals. I took control and chose to stop on the runway and asked my First Officer to call the Tower and roll the equipment so that we could be inspected; since at this point we were not sure of what had occurred. Upon setting the brakes and shutting the engines down; I asked Tower to notify me when the 'men and equipment' were approaching so that I could ensure the area was clear and the engines had been shut down.After stopping the aircraft; we also notified Maintenance and Operations; since we would need a tug to take us from the runway to the gate. Since they were the only ones to arrive; we worked with them to ensure all was safe; we raised the flaps; Maintenance installed the gear pins and we were pulled off the runway and into the gate.After I completed my duties and entered the discrepancy into the maintenance log; I phoned Dispatch to discuss the fact that airport Fire and Rescue never responded to our request. The cause of this event has to be a miscommunication between us and the Tower Controller. As I took control of the aircraft and asked my First Officer to inform the Tower to 'roll the equipment;' I turned my attention to stopping the aircraft safely on [the] runway; making a PA to 'remain seated;' calling the flight attendants to ask them about any smell in the cabin and to see how the passengers were reacting. I am certain that both pilots believed the request for AFR had been made. I also thought my questions/statements about the aircraft being safe for the 'men and equipment' to approach were done in a manner that indicated I believed AFR was on the way.Dispatch; who phoned the Tower to ask why they didn't respond; advised their comment was that we never made the request. Fortunately; we didn't need their assistance; but I have learned from the event that next time I want the AFR to respond; I will ensure that we state so clearly and without question.