Brake question

[tkneese]

I've bled the brakes but after a short time they get softer and softer and require more pumps to engage the brake. There is no loss of fluid in the reservoir but i do notice bubbles coming to the top in the reservoir after i release the brake. also the fluid level drops temporarily. is this the master cylinder? I cant find any obvious leaks and have bled all 4 wheels multiple times. Thanks!

[LaneRover]

I've bled the brakes but after a short time they get softer and softer and require more pumps to engage the brake. There is no loss of fluid in the reservoir but i do notice bubbles coming to the top in the reservoir after i release the brake. also the fluid level drops temporarily. is this the master cylinder? I cant find any obvious leaks and have bled all 4 wheels multiple times. Thanks!

I had an issue with a new Master where the pedal would slowly sink to the floor. If you stomped on the brakes it worked great but once you tried to keep your foot on the brake (like on a hill or at a light) the brakes would slowly sink to the floor.

I would definitely try a new Master cylinder. Did you bench bleed the master? Is it a 109 or an 88?