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#1
09-24-2024, 02:15 PM
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Pulling fork on disc brake bike
I need to remove the fork on my Tarmac to trim 5mm off the steerer tube.
I am thinking that I need to disconnect the hydraulic hose at the shifter and unwrap the bar tape. I am assuming I need to plug the port in the shifter to keep the hydraulic fluid from leaking out and bleed the brakes after re-attaching the hose. Can the olive be reused or do I need a new one. Thanks for any advise. 
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#2
09-24-2024, 02:21 PM
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If you don't want to do all that, depending on how long your cables are, you should be able to just:
- remove the front wheel - remove the brake caliper from the fork - unscrew the stem bolts and stem cap - remove the fork with the handlebar precariously dangling about
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#3
09-24-2024, 02:22 PM
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Quote:
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#8
09-24-2024, 02:29 PM
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Good to have a new olive on hand just in case, although you can often re-use the old one especially on the same equipment.
If you are careful, you can often open the system on one end and there will be no need to bleed when you put it back together. The fluid shouldn't go anywhere even without a cap - it's like a straw full of liquid with your finger on one end. No guarantees though!
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#9
09-24-2024, 02:31 PM
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I'd replace all the fittings you disconnect as per the service manuals for those brake systems.
The parts are cheap. You have everything apart, it costs almost no time to put a new barb/olive/whatever in while you have it apart. If you reuse stuff and you develop a leak the amount of time that will take you to fix later will be way more annoying than just making sure everything has brand new parts. FWIW my son's Trek came with a stupid setup where they did exactly this to save money on the factory install because they had a brake system that was completely assembled & bled out of the bag. They disconnected the brake lines and then put them back together without replacing the barbs/olives after routing the hoses internally. A bunch of those fittings were leaking air in the first season. Last edited by benb; 09-24-2024 at 02:33 PM.
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#10
09-24-2024, 02:32 PM
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Quote:
I don't think disconnecting the hose is a big deal as I installed and bled the brakes when building it and have all the tools.
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#11
09-24-2024, 02:35 PM
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If the brake line goes through the fork, you'll need to disconnect the line somewhere. That also means you'll need to bleed after reassembly.
I wouldn't do it up top though because you'll then need to rewrap the bar. I would disconnect the brake line at the caliper. Not much fluid will come out even though the bottom end is open - it's a closed system with the top sealed, like a finger on the top of a straw. You could further reduce this leakage risk by laying the bike on its side so there's no 'down' to worry about. Then once the line is disconnected, put a little screw or piece of plastic in the line end to ensure it won't leak, pull the line up and out of the fork, and the fork comes out. To reinstall, I would trim the line back a few mm to get a fresh end, and use a new olive.
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#12
09-24-2024, 02:35 PM
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Quote:
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#13
09-24-2024, 02:35 PM
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FWIW you won't get much fluid dripping out of the lever when you disconnect since there is no way for air to get in but you will need to bleed.
It's the same effect as holding your finger over the end of a straw that has water in it. The water won't flow unless you lift your finger off. (Same thing as opening the bleed port) But if you hit the lever it will shoot fluid out.
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#15
09-24-2024, 03:05 PM
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A few points:
Cutting the steerer without pulling the fork out of the frame may be doable, but you'll have only a small amount of steerer showing, and jigging up the fork for cutting with the rest of the bike still attached might not be easy. But if you do this, there is no need to disconnect any hoses - pull the stem and spacers off the fork, and let the handlebar dangle from hoses out of the bottom transition. There should be a minimum of 4cm of steerer exposed, as that is the typical height of a stem clamp (there'll be more than 4cm if some spacers are used under the stem). If you want to pull the fork out before cutting, this may be possible without disconnecting hoses, depending on the length of the steerer compared to the length of the stem + spacers. Remove the stem and spacers from the steerer, and if the steerer is short there may be enough slack in the front brake hose to pull the fork out. Disconnecting the hose from the from the front caliper may give you a few more inches to slack in the hose (there is about 2" of hose between the fork and the caliper, and since the olive won't fit through the hole in the for, this as much slack as you'll be able to get without cutting off the barb&olive). If that still isn't enough slack to pull the fork out, then, if the hose isn't run internal to the handlebar, you can get more hose slack by unwrapping the handlebar tape on the side with the front front brake lever. You might also need to remove the lever from the handlebar. On the other hand, if the hose is run internal to the handlebar, you'll have to disconnect the host (and probably cut off the olive&barb) and pull the hose at least partially out of the fork or handlebar. Which end is disconnected will depend on specific components used. Attach a routing cable/string to the hose before you pull the hose out, to make it easier to pull the hose back through the fork/handlebar to reassemble it. Hopefully the hose will be long enough after cutting off the old barb&olive, or you'll need to use a new hose.
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