Motorcycle Repair: interstate 1987 no rear break after changing, brake master cylinder, bleeder valves

Question
After changing the rear calipers. the rear break won't work.
When you push on it, By hand too, there is no resistance.
It was taken to the shop and for 800$ it was fixed for a few months then no break again.
The fluids are full. The front breaks are ok.
thanks

Answer
Hi Joyce,

Q:  "...After changing the rear calipers. the rear break won't work. When you push on it, By hand too, there is no resistance. It was taken to the shop and for 800$ it was fixed for a few months then no break again.
The fluids are full. The front breaks are ok.

A:  It's difficult for me to accurately diagnose the probelms with the information provided.

The reason the brakes are not working are likely because the hydraulic system has taken on air. Find the source of the air leak and repair or replace parts accordingly.

The usual place of leaks are brake master cylinder plunger, loose Banjo bolts and bleeder valves, and caliper seals. Other sources are not as common.

After the shop returned the GL, did the brakes work well? What was the original reasons the GL went into the shop? Why $800? What was done and what parts were replaced? Jeez!

I return tech information files by email. There was no email address with your question as requested and explained in my instructions.

Respectfully,
Mark Shively