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I have a new frame coming tomorrow, used Revel Rascal. I am competent at frame swapping, easy job. Except brakes. I really like my TRP Slate4 and I can just about remove the lever, use the tiny hex insert to block the hose, thread in the frame and reconnect to the lever without losing much fluid. I also have the basic TRP bleed kit which would help getting rid of air and add a little fluid. I have spare barbs and olives.
BUT, I am confident my existing hose will be too short. The previous owner is sending the frame with a long enough hose from a SLX brake set.
Can I use that hose?
And if so how to I disconnect my caliper to the TRP original hose without losing much fluid ? And how do I connect the SLX hose to it?
Thx for any help.
I don't know whether the Shimano hose will work with your TRP brake. If you get a new TRP hose use a RockShox Barb Connector to join the two hoses and pull the new one through the frame with the old.
Thank you. The internal routing is guided so not an issue inserting a new hose tool less if needed. I just don't know how to connect to the rear caliper.
They use mineral oil like Shimano. The levers look like Shimano ones, so I'd guess that a Shimano hose will fit. Just compare the internal and external diameter of both, although TBH bike brake hoses are pretty small so any difference is going to be minimal and the olive/barb should take up any tiny difference.
Sorry forgot to say. The banjo connector just un-bolts. There will be a small rubber washer each side (caliper and bolt) to seal it. In theory you need new ones but you can probably re-use the old ones. Easy peasy. However I would do a full bleed on them after installation.
Cheers. I failed at the first hurdle anyway. How do I remove the old olive? Or am I supposed to just cut the "old" line? (almost new)
Yep, you'd need to cut the old olive off. They get crushed into the lever when the nut is done up, so shouldn't be used twice. If the hose isn't long enough, it's likely you'll need to source another TRP hose as the caliper end fittings are usually a sealed unit - my son had some TRPs briefly and IIRC they had a banjo fixed on the caliper end. So you'd unscrew this from the caliper and screw the new hose banjo in it's place, then feed through your frame, join up to the lever and bleed/fill the mineral oil.
Like These?
Having said all that there are hose suppliers who include a banjo kit for all brakes. eg Goodrich (if they're still doing MTB kits). They might have what you need.
Quick check on ebay, there are TRP hoses available on there
I used a Shimano hose on a TRP caliper/lever. I bought a banjo connector off AliExpress and fitter it to a straight hose which was much cheaper than buying a hose with a banjo connection. It all worked fine and doesn't leak
Some TRP brakes use larger diameter hoses but I think most are 5mm same as Shimano. I think I used a TRP barb at the lever but a Shimano olive as the TRP olive was slightly too narrow to get over the hose.
Regarding cutting of the hose, yes you have to cut the olive off to be able to get the nut and plastic cover off the hose to enable internal routing. If you want to preserve cable length the it's possible to cut an olive off very carefully and not damage the hose but it's a faff
This is one of those things where there's an exact right answer but mostly, you don't need it to be that exact right answer. Like, you should never reuse an olive, that's the right answer. I've reused olives a bunch, as long as they compress a little more each time it's fine. But if you overtighten you'll break the lever or caliper! So it's messy.
Reusing olives on a different hose is pretty impractical because they'll be compressed onto the hose, very rare you can actually phusically reuse it. The barbs are indefinitely reusable, easiest way is to crush the olive off (it'll break if you squish it with pliers at 90 degrees a couple of times) and then cut the barb out carefully with sidecutters along the length of the barb (they'll cut into the hose but slide off the metal. This works with everything but steel braids, but since steel braids are absolute pointless nonsense it doesn't matter)
Compatibility is...intentionally mysterious. Because no brake company wants you to use any parts but their own, and they all want to sell you a 1p bit of brass for £10. As long as the hose thickness is the same, and the olive and barb shape more or less the same, it'll usually work. And once you get into the aftermarket you see variation come in thick and fast, suddenly you see the same barb and olive on parts that are sold for dozens of different brakes. But you never know when you'll run into that one weird brake that's really specific, where they've actually managed to design in incompatbiility.
Fluid compatibility as far as I'm aware is a complete nonissue, I don't believe there are any quality bike brake hoses that can't do mineral and dot, in the world. But, you might not want to mix used hoses.
Update and many thanks.
The existing hose is too short even if I had managed to remove the olive which I didn't.
But the frame was delivered with an empty Shimano hose which is the perfect length and with a (presumably Shimano) banjo at the end. The other end has nothing but I have a new TRP insert and barb.
Both hoses are 5mm (original TRP and Shimano)
How do I connect this spare hose to my caliper? Do I need a barb and insert for that too or anything?
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Just saw your post thanks. They are TRP Slate4 but non evo.
Don't I need a seal if I swap the banjoed hose on the caliper?
The banjo bolt just unscrews and can go back through the new banjo/hose. Just check you have the o-rings in place as there is one on each side of the banjo
Yeah, as dc1988 says, hopefully you can unbolt the banjo fitting from the caliper, (leaving it attached to the hose) and bolt the new one on in its place. I'm not 100% sure Shimano and TRP banjos are the same, but you'll soon know if the Shimano one doesn't fit snugly onto the caliper.
(You can online chat with Total Bleed Solutions to check for sure on that link I posted to the brakes.)
^ thank you so much!
I have successfully connected all the hardware. It feels secure and tight, banjo thing is compatible I think.
So I got carried away. I tried to bleed the system.
I think the lever and the caliper had fluid but obviously not the new hose.
I tried the TRP youtube guide with the kit but it didn't work so I used the syringe to add oil. The thing exploded when I pressed and I have oil all over the bike and my walls 😂.
I think I was trying to push air that had nowhere to go.
Not sure what the next step is. A bridge too far for me?
You should just need to bleed the brake, they're quite easy iirc so not quite sure what you've done. If you've opened the bleed ports on the lever and caliper then you should be able to push new fluid through the system and clear the air out the hose.
I didn't open anything on the caliper 😂. My friend is going to do it for me tomorrow. Hopefully I'll learn! Perhaps 😂. Thanks all.
That would be it then, it's a very simple process once you know how and with mineral oil there's not a lot of danger
Sounds like bleed port was still closed. I've done that before! hopefully you haven't wrecked the seals 😲 (or the brake pads!)
Yes I was thinking about the seals. I have a new spare caliper and lever as they're only £30 on Merlin as they are continental, like me.