The importance of brake caliper maintenance

Hoove · Monday at 8:37 PM

Brakes after I bleed them or change the pads haven’t always received the attention from me that they should. Recently I purchased a Suzuki TL1000s and decided to upgrade the front brakes. I purchased a pair of six piston calipers and larger master cylinder off of eBay. The calipers were pretty gummed up so I decided to completely rebuild them with new seals and pistons. The job was pretty straightforward and went well without any issues. While the calipers were apart I decided to have them powder coated Lollipop red. Anyway this got me thinking about the V-Max. I put on a set of Sumitomo 6 piston calipers when I built the bike somewhere around 2015 the seller said the worked fine but could not verify if they had ever been serviced. I put them on the bike with new pads and a 17mm radial master cylinder and they worked great. Last summer I noticed the brakes were less than impressive and didn’t bite like they once did. After I did the Suzuki brakes it made me think I should also do the V-Max as well and also take the opportunity to powder coat them as well. Long story short the pistons in the left caliper were completely stuck and would not budge with regular force on the master cylinder. I removed the pads while still on the bike and pumped the brake lever to push the pistons out as far as I could to make removing them easier but the left ones would not budge. I pulled the calipers off and tried forcing the pistons out with 120lbs of compressed air. I managed to get them to come out far enough to grab them with vice grips and pull them out knowing that they would get trashed and need replacement. I managed to get all the seals and new pistons installed and now it works better that I ever remember. I had the V-Max calipers powder coated Lollipop blue.
Moral of the story brakes need love too.View attachment 96396 View attachment 96397 View attachment 96398

Traumahawk · Monday at 8:55 PM

Hoove said:
Brakes after I bleed them or change the pads haven’t always received the attention from me that they should. Recently I purchased a Suzuki TL1000s and decided to upgrade the front brakes. I purchased a pair of six piston calipers and larger master cylinder off of eBay. The calipers were pretty gummed up so I decided to completely rebuild them with new seals and pistons. The job was pretty straightforward and went well without any issues. While the calipers were apart I decided to have them powder coated Lollipop red. Anyway this got me thinking about the V-Max. I put on a set of Sumitomo 6 piston calipers when I built the bike somewhere around 2015 the seller said the worked fine but could not verify if they had ever been serviced. I put them on the bike with new pads and a 17mm radial master cylinder and they worked great. Last summer I noticed the brakes were less than impressive and didn’t bite like they once did. After I did the Suzuki brakes it made me think I should also do the V-Max as well and also take the opportunity to powder coat them as well. Long story short the pistons in the left caliper were completely stuck and would not budge with regular force on the master cylinder. I removed the pads while still on the bike and pumped the brake lever to push the pistons out as far as I could to make removing them easier but the left ones would not budge. I pulled the calipers off and tried forcing the pistons out with 120lbs of compressed air. I managed to get them to come out far enough to grab them with vice grips and pull them out knowing that they would get trashed and need replacement. I managed to get all the seals and new pistons installed and now it works better that I ever remember. I had the V-Max calipers powder coated Lollipop blue.
Moral of the story brakes need love too.View attachment 96396 View attachment 96397 View attachment 96398

Good point. Before I ever started making the 07 faster, I upgraded the brakes first.

Fire-medic · Monday at 9:11 PM

Use a grease gun in the caliper, brake line disconnected, that female plugged. Use the brake bleeder to fill the caliper w/grease, & any stuck piston(s) will come loose. A manual grease gun generates ~2,000 psi. It's no big deal to clean-out the grease. You won't need to ruin a piston or pistons. Block the pistons which do easily move, so they can't move far. Leave the stuck piston(s) free to move.

This is an elderly SOHC Honda 750 caliper, the idea is the same. The last tag on the bike was about 40 years old. Oh, it was stuck!

Hoove · 2025-01-07T02:20:40-0500

Well that’s brilliant. I wish I would have asked for advice in advance!!!!

it's_tricky · 2025-01-07T11:40:55-0500

Fire-medic said:
Use a grease gun in the caliper, brake line disconnected, that female plugged. Use the brake bleeder to fill the caliper w/grease, & any stuck piston(s) will come loose. A manual grease gun generates ~2,000 psi. It's no big deal to clean-out the grease. You won't need to ruin a piston or pistons. Block the pistons which do easily move, so they can't move far. Leave the stuck piston(s) free to move.

How do you clean the grease out of the caliper afterwards ?

Fire-medic · 2025-01-07T17:51:26-0500

I usually use brake cleaner in a spray can, let the red wand do the work. You can disassemble the caliper halves, if you want to be sure that all the grease is purged.

Of course, complete disassembly allows you to remove any oxidation or corrosion, and it allows you to make an informed decision on what needs replacement.

I like to use a brass bristle brush like the Dremel tool uses, to clean the caliper piston bores, and some crocus cloth or something like 120 or 220 grit wet-or-dry sandpaper on the pistons.

The narrow, wide-diameter brass bristle brush Dremel piece fits the narrow O-ring bores very-well, and it makes an easy job of cleaning them. Be sure to wear your eye protection, as the brass bristles can and do shed bristles like a porcupine sheds his quills! Wearing a shop apron to do this will also keep the front of your shirt from catching all those broken-off, shedded bristles. Don't believe it? You will, after trying to work without one and then finding numerous brass bristles stuck in your shirt, a source of physical irritation.

If they're pitted (the pistons) in the area where the square O-ring is going to be travelling as the pads wear, time for new pistons. If the bore is pitted, safety dictates new calipers or good, unblemished used ones.