Rubber Brake Hose for Honda CB350G / CB360 / CB450 / CB500T / CB550
Factory-style rubber brake hose kit for the full front hydraulic disc brake system on the vintage Honda twin and four-cylinder lineup. Sold as a complete pair — upper hose + lower hose + six copper crush washers. Same rubber hose Honda used from the factory, made to original dimensions with correct banjo fittings.
Why You Need This
The front brake does most of the stopping on a motorcycle. Rubber brake hoses from a 50-year-old Honda have seen fifty years of pressure cycles, temperature swings, and ethanol-era fuel contamination. They swell under pressure, they crack at the fittings, and they eventually leak fluid where the handlebars rotate. Brake fluid attacks rubber as it ages and absorbs moisture. Any deterioration in the rubber parts — cracking, swelling, or weeping — means replace immediately. A weeping master cylinder seal can fail under hard braking.
This kit is the direct OEM-style replacement. If your bike is still running factory rubber, this is the correct first move. If you want a firmer lever and a cleaner visual, see our Stainless Steel Brake Line alternative.
Specifications
| Spec | Detail |
|---|
| Replaces OEM Part Numbers | 45125-379-003, 45126-300-003, 45126-333-000, 90545-300-000 |
| Kit Contents | 1 upper hose + 1 lower hose + 6 copper crush washers |
| Upper Hose Length Options | Factory Bars (shorter) or Superbike Bars (longer) — select at checkout |
| Fits Models | CB350G (1973), CB360G/T (1974–1976), CB450 K3–K7 (1970–1974), CB500T (1975–1976), CB500K (1971–1973), CB550K (1974–1978), CB550F (1975–1977) |
| Brake Fluid Spec | DOT 3 |
| Lever Free Play Spec | 2–5 mm (0.08–0.2 in.) at the tip |
| Sold As | Complete hose kit |
Rubber vs. Stainless Steel — Which One Should You Get?
- Rubber (this kit): matches the factory look, feels the same as original, and is the right answer for a restoration-correct build. Rubber flexes slightly under pressure, which gives the brake lever its original feel.
- Stainless Steel (sibling kit): braided stainless over a PTFE core. Doesn't flex, so the lever feels firmer and more immediate. Cleaner visual. Our USA-made SS kit includes CB750 fitment that this rubber kit does not.
Installation
Difficulty: Intermediate. A brake hose swap is a full-system service — you'll drain fluid, disconnect lines at both ends, install new hoses with fresh crush washers, and bleed the entire system.
Tools needed: 10 mm and 12 mm box wrenches for banjo bolts, 8 mm box wrench for the bleeder screw, clear vinyl tubing for bleeding, catch bottle, clean DOT 3 brake fluid, nitrile gloves, rag to protect paint.
- Before starting, protect any painted surfaces near the master cylinder. Brake fluid damages paint on contact.
- Drain the old fluid from the master cylinder using a pipette or by bleeding it out at the caliper.
- Disconnect the upper hose at the master cylinder and at the junction block. Note the orientation.
- Disconnect the lower hose at the junction block and at the caliper hard line fitting.
- Install the new upper hose with a fresh crush washer on each side of each banjo fitting. Crush washers are one-time-use. Tighten snug — the crush washers create the seal, so you don't need excessive torque.
- Don't forget the rubber boot on the upper line before threading the banjo bolt. It's the most commonly missed step.
- Install the new lower hose the same way.
- Fill the master cylinder with fresh DOT 3 brake fluid and bleed the system using the two-stage method (purge lines first, then bleed at the caliper).
- Test the lever. It should feel firm. Free play should be 2–5 mm at the tip. If the lever feels spongy, there's still air in the system and you need to bleed again.
Our Ultimate Guide to Rebuilding the Honda CB Hydraulic Front Brake System covers the complete rebuild including rubber hose replacement. See Part 2 for the two-stage bleed method.
Frequently Asked Questions
Which upper hose length do I need — Factory Bars or Superbike Bars?
Measure your existing upper hose from center of banjo hole to center of banjo hole. Factory-bar bikes use the shorter option; Superbike-bar bikes (taller risers) use the longer option. If you're running aftermarket bars, measure first and pick the closest length.
Does this fit my CB750?
No. CB750 owners should order the Stainless Steel Brake Line — that kit includes a longer lower hose specifically for the CB750's early finned caliper. This rubber kit covers CB350G, CB360, CB450 K3–K7, CB500T, CB500K, and CB550K/F only.
Does this fit my CB450 K3 or K4?
Yes. Honda used the same rubber hose part numbers across the CB450 K3 through K7 model years. The caliper body and bleeder screw orientation are different between K3/K4 (early style) and K5/K6/K7 (late style), but the rubber hose itself is compatible across all of them.
How often should I replace rubber brake hoses?
We recommend replacing replace rubber brake components whenever damage or deterioration is noted. On a 50-year-old Honda, if the original hoses are still installed, they're deteriorated. Visual signs include cracking at the fittings, swelling under pressure, or fluid weeping from the banjo joints.
What brake fluid should I use?
DOT 3. That's the factory spec across this brake family. Don't mix DOT 3 with DOT 5 (silicone) — the two are not compatible and mixing them will damage the seals.
Do I need to replace the hard line too?
Inspect it. The hard line runs from the junction block down to the caliper. If it's pitted, bent, or corroded, swap it while you're in there. We stock replacement hard lines in both late-style and early-style for the CB450 K3–K4 and CB750.
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Last updated: April 2026
