[DrRadar]

My guess is there is a leak on high pressure side that opens only when pressure is high and in certain positions. For example, flexing in the line might squeeze as cracked hose shut in some positions (no leak) and open in other (leak). Temperature may also influence leak vs. no leak. Likely suspect is high pressure line but could be pump or possibly low pressure hose.

Try wiggling hoses with engine running and warm and wheels in various positions. Take care not to get burn... Wear gloves and consider uses a tool to do reaching and moving.