They were called to the fire at about 6.30pm, where a digger on the back of a trailer was in flames.
Both crews used hose reels to extinguish the fire, with the driver escaping unharmed.
The road was also closed westbound for half an hour, re-opening at about 7pm, and caused major tailbacks during the incident.
However, firefighters were keen to point out that it is dangerous for drivers to leave their cars when stuck in a traffic jam.
Bracknell watch manager Michael Fulwell said: "People thought it was ok to get out of their cars and walk up and down the motorway.
"I know cars on a warm summer's evening with the engine switched off are not nice but the hard shoulder is a dangerous place to be walking about in an incident like this."
Crews left the scene at about 8pm, but it is unclear how the fire started.