In 327, after hearing news that Han Zhao had suffered losses at Later Zhao's hands, Zhang Jun disavowed all titles granted by Han Zhao and returned to Jin titles, and attacked Han Zhao's Qin Province (秦州, modern eastern Gansu). Han Zhao's prince Liu Yin counterattacked, and, after defeating Former Liang general Han Pu (韓璞), captured all Former Liang territory south of the Yellow River and further crossed the river, but did not advance further. However, Zhang Jun did not resubmit to Han Zhao. As Han Zhao disintegrated and fell to Later Zhao in 329 after its emperor Liu Yao was captured by Later Zhao forces, Former Liang took the opportunity to regain lands south of the Yellow River. In 330, Later Zhao's emperor Shi Le sent messengers to persuade Former Liang to submit (by granting him honors, including the nine bestowments), but Zhang Jun refused and detained Shi Le's messengers. Later in the year, however, after Later Zhao's general Shi Sheng (石生) the Prince of Hedong defeated the nearby Xiongnu chieftain Shi Qiang (石羌), Zhang Jun became apprehensive and submitted to Later Zhao.