Journeyman
"And this one is just right" ~ Goldilocks
Here's what your clutch fluid looks like at 20,000 miles....
There was sludge at the bottom. Replacing the fluid is part of the 20,000 mile service.
Other information on that can be found here...
www.r3owners.net
Warning, this goes long.... Once you've removed the radiator replacing the fluid is straightforward and easy.... Unless, you're a dummy like me and accidentally allow the level to drop below the reservoir. No problem I thought, it'll give me a chance to clean the gunk out of the bowl and I'll just bleed the air out- should take an extra 15 minutes, right? Wrong!
I fought what seemed like a losing battle for two days running two quarts of Dot 4 through the system, but could not restore pressure to the lever. What the he11? If you make the same mistake (don't!), or need to open up the system to change a line, for example, then the rest of this post is for you.
First of all, many thanks to @Rocket Scientist and @TURBO200R4 for their advice over those two stressful days. I am convinced that either of them, had they actually had the bike in front of them, would have figured it out waaay faster and with far less brake fluid going to waste. Some of the tips they gave I'll note here (below), as it could be useful for restoring a brake systems that feels spongy.
As with other issues I've come across performing the 20K service, such as measuring the valve clearances, the service manual doesn't go over any of this. You're on your own. Long, long, story short (gravity bleed, reverse bleed, syringe suction, compressor system suction, compressing the slave cylinder, other voodoo techniques, etc., etc.), here's the actual fix....
The sealing screw (#1 in first diagram) is removed along with the fixing to separate the bowl from the master cylinder. They are both submerged under brake/clutch fluid when full. It turns out that the "sealing screw" is really a bleeder for the master cylinder. If you've lost pressure you need to remove that screw and slowly work the lever. Air will come out and fluid will travel in. Reinstall the screw and then bleed below at the slave unit, as usual- just like a brake system. Repeat that until you have no air bubbles from either end. I also used a rubber mallet to bang on the banjo bolts and tapped on the lines to help move any trapped air along.
The result, finally, is a firm lever- "blue steel, cat can't scratch it."
So, turns out in my attempts to restore pressure that I probably didn't need to tear into the master cylinder looking for crud fouling a seal, but I did and it's clean now. Btw, I can't find a rebuild kit or any replacement parts, should they ever be needed for the hydraulic clutch system, through Triumph.
Here's a look at the innards, if you're interested...
Here's those tips from @TURBO200R4 and @Rocket Scientist I mentioned that may come in handy with brake issues clearing a stubborn air pocket.
@Rocket Scientist suggested removing the lever and pushing on the piston directly- this allows you to push it in further which gives you some extra "umph" moving fluid through the line. I used a small socket driver covered with a plastic end cap....
Diagnosing the problem I was having was hard (not knowing about the submerged MC bleed valve). @TURBO200R4 suggested isolating the master cylinder to make sure it was working. To do so I needed a way to remove the brake line and seal that opening. To make the seal I put a nut in place of the brake line with washers on each side. Worked!
When I did this I had a rock hard lever, telling me that the MC was not the issue- well, it was, but it was air, not a bad seal, etc. This is when I discovered the purpose for the "sealing screw."
Finally, a bit of advice- after two days of frustration, beginning to lose all hope, and your brain is starting to fry.... and you have taken your clutch parts with you to find crush washers and maybe even matching piston seals (ha ha
) to several auto parts stores, and you get back to your bike, ready to put it all together... that *irreplaceable* piston, the one not listed in the parts catalog, that you now can't find anywhere (oh, fvvvvck me!) will be on the floor under the rack for crush washers, 30 minutes away at AutoZone! Just say'n.
There was sludge at the bottom. Replacing the fluid is part of the 20,000 mile service.
Other information on that can be found here...
A look at the 2.5 Innards - DIY 20K mile service, including valve clearance check and shim replacement
So are you putting the exhaust cams back in to check those clearances before reassembly in case they are out of spec. It would worry the crap out of me wondering what the clearance on those exhaust valves were. Seems like a good time to check those again. Oh, yeah- waiting on the tool I need...

Warning, this goes long.... Once you've removed the radiator replacing the fluid is straightforward and easy.... Unless, you're a dummy like me and accidentally allow the level to drop below the reservoir. No problem I thought, it'll give me a chance to clean the gunk out of the bowl and I'll just bleed the air out- should take an extra 15 minutes, right? Wrong!
I fought what seemed like a losing battle for two days running two quarts of Dot 4 through the system, but could not restore pressure to the lever. What the he11? If you make the same mistake (don't!), or need to open up the system to change a line, for example, then the rest of this post is for you.
First of all, many thanks to @Rocket Scientist and @TURBO200R4 for their advice over those two stressful days. I am convinced that either of them, had they actually had the bike in front of them, would have figured it out waaay faster and with far less brake fluid going to waste. Some of the tips they gave I'll note here (below), as it could be useful for restoring a brake systems that feels spongy.
As with other issues I've come across performing the 20K service, such as measuring the valve clearances, the service manual doesn't go over any of this. You're on your own. Long, long, story short (gravity bleed, reverse bleed, syringe suction, compressor system suction, compressing the slave cylinder, other voodoo techniques, etc., etc.), here's the actual fix....
The sealing screw (#1 in first diagram) is removed along with the fixing to separate the bowl from the master cylinder. They are both submerged under brake/clutch fluid when full. It turns out that the "sealing screw" is really a bleeder for the master cylinder. If you've lost pressure you need to remove that screw and slowly work the lever. Air will come out and fluid will travel in. Reinstall the screw and then bleed below at the slave unit, as usual- just like a brake system. Repeat that until you have no air bubbles from either end. I also used a rubber mallet to bang on the banjo bolts and tapped on the lines to help move any trapped air along.
The result, finally, is a firm lever- "blue steel, cat can't scratch it."
So, turns out in my attempts to restore pressure that I probably didn't need to tear into the master cylinder looking for crud fouling a seal, but I did and it's clean now. Btw, I can't find a rebuild kit or any replacement parts, should they ever be needed for the hydraulic clutch system, through Triumph.

Here's a look at the innards, if you're interested...
Here's those tips from @TURBO200R4 and @Rocket Scientist I mentioned that may come in handy with brake issues clearing a stubborn air pocket.
@Rocket Scientist suggested removing the lever and pushing on the piston directly- this allows you to push it in further which gives you some extra "umph" moving fluid through the line. I used a small socket driver covered with a plastic end cap....
Diagnosing the problem I was having was hard (not knowing about the submerged MC bleed valve). @TURBO200R4 suggested isolating the master cylinder to make sure it was working. To do so I needed a way to remove the brake line and seal that opening. To make the seal I put a nut in place of the brake line with washers on each side. Worked!
When I did this I had a rock hard lever, telling me that the MC was not the issue- well, it was, but it was air, not a bad seal, etc. This is when I discovered the purpose for the "sealing screw."
Finally, a bit of advice- after two days of frustration, beginning to lose all hope, and your brain is starting to fry.... and you have taken your clutch parts with you to find crush washers and maybe even matching piston seals (ha ha
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