Rear brake caliper

Hello, I have a 2009 Royal Star tour deluxe. It was my dad's and my first bike so I have been learning and doing everything myself. I'm not an engine guy to begin with but I know the basics.

My back brake is spongy and has harldy any pressure. I have bled the brake line. I noticed the pistons are still sticking out slighly and the pads still touch the rotar when I release the brake.

Is it spongy because the pistons are not fully sliding back in giving it the normal pressure?

The bike sat for almost three years and I have already fixed the front fork seals and clutch release cylinder from sitting. I'm thinking the pistons need to be cleaned same as the slabe cylinder. I bought a whole new slave cylinder but my local shop prices a new rear brake caliper at $469.

Am I on the right track with my diagnosis?

Can I rebuild the caliper?

Am I stuck buying a whole new caliper?

Parts to rebuild the caliper can be purchased from places like partzilla.com at a discount. Or a complete caliper can be purchased.

https://www.partzilla.com/catalog/yamaha/motorcycle/2009/royal-star-tour-deluxe-s-xvz13ctsy/rear-brake-caliper

If the RSTD is like the Venture, the rear brake is too powerful.

You still have air in the line....

You still have air in the line....

Go to Harbor Freight and buy a Mighty Vac vacuum pump with the brake bleed kit, about $30.00 IIRC. It takes about 3 minutes to bleed the rear system and get all the air out.

Go to Harbor Freight and buy a Mighty Vac vacuum pump with the brake bleed kit, about $30.00 IIRC. It takes about 3 minutes to bleed the rear system and get all the air out.

24 inches of clear tubing. 1/4 inch thin wall works easiest but 1/4 inch thick wall can be used by boiling the end and opening up with a suitably sized Phillips screwdriver.

Loosen the bleeder valve on the caliper, put on the hose and open the bleeder valve. Make sure the hose goes up to form a loop before it goes down to the container.

Press the pedal until all air is out and the fluid is clear. Don't let the fluid in the MC get too low or air will be getting back into the system and you will have to start over.

Close the bleeder valve and remove the hose.

The whole job will take less than 10 minutes.

You might just as well do the left front brake line because, after all, they are integrated. Now that you have found out how easy it is to bleed brakes you might just as well do the right front brake. All three brakes can be bled in a half hour or less. The right front brakes and the clutch are the easiest ones to bleed.

Are the RSTD brakes linked?

If so, you've probably got the rear line bleed thoroughly and the air is in the high point on the front link. Start with the front and make sure to bleed at the steering neck bleeder first.

The two posts above would not apply to this bike. The RSV and RSTD do not have linked brakes.