Triumph Sprint ST 955i Restoration Project. Vid 3b: Brakes - Front Caliper Overhaul

I know many bikers can relate to the deep nostalgia I feel for classic sport-tourers—machines that had character, soul, and a perfect blend of performance and comfort. For me, the Triumph Sprint ST 955i from the early 2000s is one of the finest examples of this golden era. Maybe you have your own bike that sparks this feeling, but this one? This one does it for me.

I was lucky enough to find this 2001 Sprint ST for sale in Brisbane in late 2024. It had seen better days, but under the wear and tear, I saw something worth bringing back to life. This latest video continues my restoration work on one of the most critical systems on any motorcycle—the brakes.

A properly functioning braking system can mean the difference between life and death on the road. This Sprint ST hails from the pre-ABS era, relying on dual hydraulic discs up front and a single disc at the rear—fully independent of each other. In this video I'm overhauling the front brake calipers. On the front, Triumph employs a Tokico four-piston fixed-style caliper, providing strong stopping power but requiring regular maintenance due to their susceptibility to corrosion and piston sticking. I encountered several of the pistons sticking worryingly, which can result in uneven pressure on the brake pads and hence the disc - resulting in uneven wear and unbalanced forces leading to damage and bending. During this overhaul, I clean and inspect the pistons, replace the seals, and flush old brake fluid. Using a TRK Braking seal replacement kit, I replaced all the old rubber seals - hopefully helping to prevent future leaks and improve braking efficiency due to uneven piston pressure from sticking. I thoroughly clean every component to ensures smooth piston movement, which is what we all want....preventing drag and poor braking feel. And finally, apart from seeing-off potential upcoming component failures and causing smoother operation, I'm committed to regular servicing to extend the life of the calipers. I'd much prefer to spend the time and effort to conduct regular services rather than just repair motorcycle systems after they've failed... because they'll probably fail just when you need them the most, and possibly with catastrophic results.

Still to come in following videos of this series on the braking system:
Rear caliper overhaul
Master cylinder overhauls (front & rear)
New brake lines & full system bleed

If you're planning or in the middle of a similar project, I hope you’ll find these videos helpful. And if you’ve tackled this before, I'd love to hear your tips, experiences, and any suggestions in the comments!

My ultimate goal? To bring this Sprint ST as close as possible to how it looked and rode when it first rolled off the Hinckley production line in 2001. A lofty ambition, I know—but that’s the dream! Wish me luck, and if you're into classic sport-tourers and hands-on motorcycle restoration, hit subscribe and join me for the ride.

Apologies for the long video, but I think its important to cover all aspects in detail, and the chapters below can help you short-cut this and jump straight to what interests you....

Chapters in this video on the front braking system:
0:00 Introduction
2:07 Cracking all the caliper bolts while still mounted on the bike
4:10 Removing a caliper from the bike
4:25 Removing the brake pads
5:00 Using brake line pressure to extract the pistons as far as possible
8:27 Disconnecting the brake line
9:56 Splitting the caliper into two halves for servicing
13:07 Removing the pistons
16:46 How does the caliper work - components
18:12 Extracting the old piston seals (pressure seal and dust seal)
19:52 Old seal inspection and caliper bore inspection
21:35 Caliper body flush-out and clean - what should you clean with?
24:01 Clean up and inspection of the pistons
28:37 Removing other side caliper and extracting pistons after you've disconnected the brake line
33:09 Inspection and assessment of the second caliper
33:47 Some further comments on cleaning and flushing the caliper body
35:18 New seals installation
42:40 Reinstalling the pistons
47:02 Installing new bleed valve
48:24 Replacing the conveyancing seals
50:12 Assessing the pad spring and the old brake pads for re-use
50:52 Reassembling the calipers
54:04 Assessing the front disc wear
55:22 Remounting the calipers on the bike and torquing to specification
58:18 Summary and conclusion

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