[marosell]

The bike has been difficult to push from a stand still and I've noticed friction and noise from the front of the bike, so today I looked at the front brakes. Replaced brake fluid by bleeding them, and then set out to remove brake pads to take a look at them.

I could not hand depress the pistons and couldn't get the brake pads off without removing the calipers. 1. Safe assumption that this being frozen caused the calipers to constantly press the brake pads against the rotor slightly, making the bike difficult to push?

Started cleaning the calipers with brake cleaner, and to see how well the work, I used the brake lever to move them. See picture. I noticed that only the one on the left moved up and down. 2. Does this mean there is something wrong with the one on the right?

In my distraction to attempt to get the one on the left to move, I continued to press the handle until the one on the left blew out. DOH. I put it back in with the help of a c-clamp. 3. I take it there is air in here now and the fluid needs to be bled?

I pushed them both flush with the caliper to more easily clean everything. Now I still can't get the one on the right to move up any.

Already ordered factory pads to put in.

4. Do I need to rebuild the caliper? The caliper currently does not leak. I found seals, do I need new pistons? Not sure how much they are corroded and can't easily clean them without taking them off. Is this a difficult procedure?

 

[7xclm]

Both the caliper and master cylinder needs to be rebuilt. With one piston being frozen the pad will not engage the rotor correctly. You also introduced air in the system when the piston blew out of the caliper.

 

[marosell]

Why does the master cylinder need to be rebuilt? Can I not bleed the air out of the hose?

 

[7xclm]

With the way the cylinder looks I would bet the master cylinder looks the same way inside.

 

[RONW]

In my distraction to attempt to get the one on the left to move, I continued to press the handle until the one on the left blew out. DOH. I put it back in with the help of a c-clamp.

It's been done before with the same results, but very few have told it funnier. Still rolling on the floor. Personally I'd leave the master cylinder for a winter project though. Or 2 years from now.

 

[7xclm]

Marosell your signature tells me you care about your bike. Why just do half a brake job. Rebuild everything then you will know it is perfect.

 

[John Hopkins]

You already answered most of your own questions, buy a new master cylinder repair kit, they don't cost much. The pistons on the caliper will be corroded but this is not the end of the world you can clean them up like new with a plastic scouring pad maybe scotchbrite or el cheapo..take photo's of the way the springs and everything else fits so that you don't have to ask silly questions when it is time for reassembly fit new pads and then strip, clean and repair the master cylinder using the new repair kit and more photo's, replace the fluid and bleed the brakes and you will be good to go for a few years...The whole thing will only take a day.

 

[marosell]

Replace the brake fluid line or keep existing?

 

[7xclm]

Brake line needs to be flushed for sure. Look for any cracks and replace if you find any. Have you ever rebuilt a caliper or master cylinder?

 

[marosell]

I haven't done either but I have a manual. Just ordered seals and pistons. Will order MC kit.

 

[John Hopkins]

Take photographs before you undo anything..clean everything before you reassemble and if you want to replace the hydrolic hoses do so, they only cost about $30..black residue in the fluid is a sign of rotting hoses..

John.

 

[marosell]

Is there a hose you recommend? Factory? I've read some people use braided stainless?

 

[John Hopkins]

I'm in a different country but all hoses are braided, most factory hoses are well made, you measure from the centre of each banjo nut, but an inch or two longer will not hurt, just don't get it shorter..The braiding is a cover over the top of the hose and Stainless is simply what the bits on the end are made of..the choice is stainless or chrome..I have used both and for an old bike like yours I would go for the cheapest 'usually chrome'.

John.

 

[marosell]

Hose looks to be in good shape.

Just wanted to post an update. I got a set of caliper seals, new pistons, and a MC rebuild kit. Want to thank the help from everyone here, but also wanted to post a link to a video tutorial on how to do the caliper rebuild, the caliper on my bike is very similar to this one:

Dual Piston Caliper Disassembly and Rebuild Procedure

This video was very, very helpful. Did everything the way Tom did it.