Topic: Steps to replace front brake caliper assembly

[Lou]

My '73 CB 350F is leaking brake fluid and I suspect it's from inside the caliper. I think I'll replace the pads, piston, ring, and caliper. I bought it months ago and have no idea when the previous owner did any brake work so probably best I do it.

Before I start, I thought I'd check with those more experienced. Are these the steps?

1. Remove Bolts
2. Pull off inner part of caliper (closest to spokes)
3. Pull brake lever which will push off pad and piston (in case want to re-build later)
4. Remove brake line from outer caliper
5. Put on new caliper (with new pads, piston) in reverse order
6. Add brake fluid, bleed brakes, and top off brake fluid to proper level

Also, how do I adjust front brake so pads make contact with disk with right amount of brake handle squeeze?

Thanks!

[Scott S]

 That sounds OK, but when you push out the piston by squeezing the brake lever, there will be a lot of fluid behind it. Be prepared for that.

 You can probably rebuild your caliper. Get a new piston (preferably stainless steel or phenolic) and the square section O-ring for the caliper. You will probably find it's leaking because the piston is rusted/pitted and/or the O-ring is old and damaged.
 Clean out the groove for the O-ring really well and make sure it's seated properly. Lube up the new piston with a bit of brake fluid and push it in nice and square. It will be a snug fit.

  After you've bled the brakes, here's how you adjust the caliper:

http://forums.sohc4.net/index.php?topic=70796.0

[Scott S]

 If you don't want all of the fluid leaking out during the swap, pick up a set of these:

https://www.amazon.com/AMPRO-T70547-Hose-Pinch-Pliers/dp/B00A8FNOP0

 Pep Boys, etc, will have them too. But it's probably a good idea to flush out the old fluid anyway, once you're done.

[mattsz]

Clean out the groove for the )-ring really well ...

Solvents/chemicals, or elbow grease, or both?

[Scott S]

Clean out the groove for the O-ring really well ...

Solvents/chemicals, or elbow grease, or both?

 Yes.

 I take a pick tool and scrape out the dried fluid. I soft brass brush or wheel works too. Soft brass....not steel...if you use a brush on a drill.

 And some kits.

https://4into1.com/brake-caliper-rebuild-kit-honda-cb350-360-400f-450-500-550/

https://4into1.com/brake-caliper-rebuild-kit-stainless-piston-honda-cb350-360-400f-450-500-550/

[RAFster122s]

Godffrey Garage has the phenolic pistons.  Replace your rubber hoses with braided stainless steel Teflon brake hoses. Rubber lines should be replaced every 6 years as they deteriorate with time.

https://godfferysgarage.com/product/optional-rotor-centers-painted/

[Scott S]

 Find a hydraulics shop near you and take in the old hoses. They can make new ones in rubber or braided.

[RAFster122s]

I called around to a few in my area and they won't touch/make brake lines... Showing up with your lines you might have better luck. If you need lines that have the DOT imprint, then you would need to buy them from Spiegler, Apex, or other places that advertise they sell them.

My only fear for lines that didn't have the imprint would be insurance company would discover that if the bike were to be crashed and totaled and would deny a claim as they look for anyway to get out of paying.
David

[Scott S]

 The shop near me has a rig to test them. I forget what PSI, but it's some ungodly number that you would never see on a vintage bikes braking system.
 I've been using them for years.