ZRace XG calipers- how do you bleed?

[Takiyaki]

I got a set of these- of course no instructions etc. My first hydraulic disc brakes. I have been bleeding motorcycle brakes for years w/o issue but those have a bleeder valve while this doesn't. How do I bleed them?

[neobiker]

I think trace velocity had a video explaining how for this specific model.

[OralMaster]

i recently installed these brakes, there is a thread in type adaptor i used that came with my jagwire bleed kit. its similar to the Lwtoo brake calipers where you thread the syinge into the caliper bleed port and push the mineral oil to the brifters.

[Takiyaki]

i recently installed these brakes, there is a thread in type adaptor i used that came with my jagwire bleed kit. its similar to the Lwtoo brake calipers where you thread the syinge into the caliper bleed port and push the mineral oil to the brifters.

I have an AE bleed kit with all that, I feel like I'm just not doing the right steps to firm up the lever. Usually with brakes you can open/close the bleed valve, or like on my motorcycle the bleed nipple has a check valve so I can just squeeze the lever and it pushes air out and firms up. But with these brakes it's either fully open or closed

*EDIT* OK so I pumped the lever and it firmed up + works, but has a lot of travel before it bites. Is that just the way this setup is or can I get it tighter? I might just be spoiled by my motorcycle brakes... there is no slack in them whatsoever (ZX14R w/SS lines)

This is just a "townie" bike but I would like the best lever feel possible.

[jonathanf2]

I have these brakes on my gravel bike, but they're not favorite. They don't have much rotor adjustment and they're quite finicky. They really need to be properly bled to have the best performance. Even after bleeding, you should still top off the fluid from the hoods and squeeze out any air bubbles. The only advantage they have is being lightweight. I think Shimano calipers have better performance and LTwoo calipers are easier to align.

[jonathanf2]

I have an AE bleed kit with all that, I feel like I'm just not doing the right steps to firm up the lever. Usually with brakes you can open/close the bleed valve, or like on my motorcycle the bleed nipple has a check valve so I can just squeeze the lever and it pushes air out and firms up. But with these brakes it's either fully open or closed

*EDIT* OK so I pumped the lever and it firmed up + works, but has a lot of travel before it bites. Is that just the way this setup is or can I get it tighter? I might just be spoiled by my motorcycle brakes... there is no slack in them whatsoever (ZX14R w/SS lines)

This is just a "townie" bike but I would like the best lever feel possible.

Make sure you use the brake blocks placed in the calipers. Have the funnel with a small amount of fluid inserted on the hoods. Once you feed the mineral oil into the calipers (make sure you see the fluid come through from the top of funnel), pump the brake levers until you get a firm bite. The brake blocks in the calipers are very important to have in order to make these XG calipers function properly.

[Takiyaki]

I'm honestly not sure they came with the blocks. At least not for bleeding without the pads in. I think I got them where they need to be. Glad I have Shimano on my main bike.

[Sebastian]

Do one ride and re-bleed them after that. I’ve found that the vibrations of riding the bike usually make any air left in the system travel up to the lever reservoir. That usually does the trick for me. Especially on the rear brake.

[precision6625]

Follow the instructions for the Hope RX4+ flat mount mineral oil. They're almost identical.



(note: youtube embed not working, just search "Hope Technology: How to Bleed RX4 Shimano Calipers / Brakes" on youtube)

https://www.hopetech.com/webtop/modules/_repository/1/documents/RX4Instructions_Min_EN_FR_DE.pdf

Both the ZRace XG and Hope RX4+ have the bleed port near the top of the caliper, which isn't as good as Shimano's "One Way Bleeding" with the bleed port at the bottom. But it should still be completely possible to get them to the same level, just with a bit more effort. Follow all the tips the Hope mechanic mentions.

[Takiyaki]

ZRace XG has a port at the bottom, but with how messy this is I will just take it off the bike to bleed. Def learned a "RTFM" lesson here.

[jonathanf2]

On AliEx, you can get a pair of Shimano GRX 400 calipers for slightly more than a pair of ZRace XG calipers. Way better performance and easier to adjust overall.

https://www.aliexpress.us/item/3256805058833940.html

[Takiyaki]

I honestly might just go that route if I'm not satisfied with a proper bleed. I'm usually strict about going Shimano for shifting... Looks like I need to adopt the same rule for brakes. I had a set of super light rim brakes (can't remember the name) that were terrible... I broke down and got 105s which have been great.

[Sebastian]

I’ve just build a gravel bike for the wife and paired Zrace XG with LTWOO GR9 brifters. I’ve found them quite easy to bleed actually. But yes, Shimano is definitely easier to handle.

[Takiyaki]

I did a proper bleed and it's much better. I think I wrecked the front pads/rotor with mineral oil though. Back brakes have way more grip than front. But those Hope instructions were really helpful.

[jonathanf2]

I did a proper bleed and it's much better. I think I wrecked the front pads/rotor with mineral oil though. Back brakes have way more grip than front. But those Hope instructions were really helpful.

Clean the rotors with alcohol or acetone. Torch them for a few seconds with a flame to burn off the mineral oil. Sand them down with a fine grit sound paper to rough up the surface.

For the pads you can just torch them and sand them and they should be useable again.