Brake caliper pistons

Is there a right or wrong direction to install the brake caliper pistons?

When I removed the pistons from the calipers, they had the solid face side facing the brake pad. Every YouTube video I've watched of a Honda brake caliper being rebuilt shows the open end of the barrel facing outwards towards the brake pad; which is completely opposite of how I removed them. These calipers have never been touched since new. I would think the way I found them installed would require a lot more fluid in the caliper to fill the entire piston with brake fluid.

Calipers, pistons and seals were all in good shape and came apart easily. I've still got some cleaning to do today to the lands for the piston's seals. But they look really good. Even though the pistons looked good and could clean up great, I went with complete rebuild kits from BrakeCrafter's. I'm about to dig into the caliper bodies now and do a real deep clean inside and out. Then back together they go.

 

Nice photos and your brake parts look great!

Pretty straight forward job, once you get the first one done and realize how everything goes together.

I used Joe Nelson's tutorials (see below) as well as the FSM and other service manuals for reference.

https://v4dreams.com/maintenance.html

23. Brake Caliper Disassembly

2. Rear Caliper Sleeve Replacement ('86-87)

Make sure you lay all kinds of protection cloths and rags over your bike areas to protect them from any spilled brake fluid. That stuff is very nasty!

 

I use brake fluid only - as a lubricant for reassembly of the new seals and pistons.

 

If everything is going to be used soon, no issues. But if your are rebuilding to be used in the future, the brake fluid with absorb moisture and crystallize, making a mess. That was the last time I ever used brake fluid for assembly. Plus I fucking hate brake fluid, so any time not having an open bottle around or having to smell it or be around it... bonus.

Personal choice: Millers Oils Red Rubber Grease, "for piston seals in brake circuit applications". West Yorkshire, England

 

Yes - this has always been my scenario.......but appreciate the head's up on the other scenario.

 

I still use O-ring lube for the seals. Has worked just fine in the past. The first piston I put back together I put them in backwards. Just kept taking brake fluid..hahaha

 

As far as I know, these calipers have never been touched before. I've owned the bike for almost 30 years and bought it from the original owner with 5k on it. Still had the original Dunlop's on it. I believe these are the original pistons. Either way, the new pistons are going in correctly. The original pistons cleaned up nicely but I still went with new pistons from BrakeCrafters. I figured, I'm already in there, so.... I replaced everything. Even the pads.

 

Thanks Baz. Everything looked really good and came apart nicely. I also use FSM, YouTube, and rely heavily on Joe's tutorials.

The project has been an enjoyable one so far. Carbs are completed and ready to go back on. Tank is cleaned. Front brake system will be finished today. Clutch system will be next on the agenda, followed by rear brakes. Then moving on to front fork rebuild and new tire install. She's getting there slowly but surely. Taking my time and enjoying the moments. I'll post more pics as the project continues.

 

On the 86, the cavity is indeed inward due to the anti-squeal pads facing the brake pads. Only difference is more fluid to prime the system.

On a couple bikes I have eliminated the pads and spun them around.

 

Thanks Cap. I used the red grease that the BC kits supply. Suff works really well. I did wipe a bit of DOT 4 in the barrels

 

I spun them around and used EBC pads. I've never seen a caliper that had pistons that way. Thanks for the insight. Now I know why they were like that.

 

Front brake master disassembly and reassembly. The outer piston seal was leaking but the internal seals still looked good. Snap ring journal had some crud but cleaned up nicely. Piston was fairly clean. It cleaned up like new and was re used. Very little crud in the sleeve, cleaned up nice with fine steel wool. New BC kit installed as well as new OEM diaphragm. Good as new!

Before







AFTER

 

Did you remove the caps?

 

I used new pistons from Brake Crafters. I didn't see any caps on them. The old pistons still have the caps. I didn't think they came off the old pistons.

 

Ahh.

They do, and they have a nonmetallic pad in there, that's why I asked.

Sounds like you're set!

 

Did you ever get any brake squeal on the bikes you eliminated the caps/pads from?

 

just when this brake topic began, the vtr250 ive been riding for years gradually locked up the front brake as i rode---LOCKED !!!!--never had that before in 30+ years riding---cracking the bleeder open for a second freed it enough to ride back home for examination---found nothing wrong--then yesterday about 15 miles later the brake locked up solid again-=--ready to crack the bleeder again and carry on----WTF ?