Ask the experts

[John_B]

If you swap the syringes does the leak happen at the master cylinder end?

[Gunder]

Hmm okay. That's a little disappointing given that both the brakes and the bleed kit are brand new.

This is the adapter I have:
Attachment 462044

Looks cheap. Proper bleed adapters usually have a shoulder and an oring.

Did the bleed screw have an oring on it when you removed it? If not then you will have one in the port and it’s bad. Use only brass or a plastic pick to remove. If you scratch the bore those breaks will never be proper again.

[Toddball]

If you swap the syringes does the leak happen at the master cylinder end?

I'll try this when I bleed it next.

Looks cheap. Proper bleed adapters usually have a shoulder and an oring.

Did the bleed screw have an oring on it when you removed it? If not then you will have one in the port and it’s bad. Use only brass or a plastic pick to remove. If you scratch the bore those breaks will never be proper again.

Pretty sure there was not an O ring on the bleed screw when I removed it. Assuming the Dominions have O rings in there (and I sure hope they do), I think the O ring stays inside the bleed port; it doesn't sit on the shoulder of the bleeds screw like on a Shimano brake.

[Gunder]

I'll try this when I bleed it next.



Pretty sure there was not an O ring on the bleed screw when I removed it. Assuming the Dominions have O rings in there (and I sure hope they do), I think the O ring stays inside the bleed port; it doesn't sit on the shoulder of the bleeds screw like on a Shimano brake.

That makes sense. You should replace the oring in the bleed port.

[Dantheman]

I've done a lot of Dominion bleeds. I've never had the leak you describe. I'm pretty sure there is not an internal O-ring on the bleed ports (none shown here on p. 23-24: https://b2b.gepard.bg/docs/Dominion%...ed%20Guide.pdf) and they rely on precision machining to seal. The only O-ring in the entire caliper assembly is in the transfer port. It's possible you may not be quite fully tightening the nipple (though it is a distinct "hard stop" and I've never given them more than my best finger-tightening) or you got a bad bleed nipple or caliper. Hayes will probably warranty either if that's the case. Hopefully it's not and you just need to get things a little more snug.

[One (+) Sentence]

Hmm okay. That's a little disappointing given that both the brakes and the bleed kit are brand new.

This is the adapter I have:
Attachment 462044

I have experienced this exact thing when bleeding Dominions with the correct Hayes kit. It still works fine, but use SRAM syringes/fittings if you don’t want any leaks at the lever while bleeding.

[Andeh]

Interesting. Yeah, I've also had air bubbles in the syringe at the MC when pulling with the Hayes kit. It's never stopped me from getting a good bleed though. I basically stop pulling when I see the little bubbles. Didn't think to try the SRAM kit.

[Toddball]

I ended up bleeding again, same leak at the master cylinder syringe, but just finished the bleed with several rounds of pushing only. Seems okay now. Thanks all for the help and insight.

[XXX-er]

The vids i watched suggested to keep pulling the DOT at the caliper in/ out a few times until there are no bubbles pulled into the syringe,

There are alway bubbles in suspension SO i shake the fuck out of the DOT fluid container to release them all before filling the syringe and 1/4 filling the top cup

it seemed to work

[One (+) Sentence]

Interesting. Yeah, I've also had air bubbles in the syringe at the MC when pulling with the Hayes kit. It's never stopped me from getting a good bleed though. I basically stop pulling when I see the little bubbles. Didn't think to try the SRAM kit.

Yeah, the SRAM kit works better on Dominions than the Hayes kit.

[Stuntmonkey]

New whip, anything I need to add or just go shred? Lol.

[rideit]

Bigger rotors?
Looks pretty dialed.

[g_man80]

Nice looking ride!

-Confirm the tires are set up tubeless.
-Make sure the brake pads are bedded in before dropping into the first steep descent.
-Slap some clear film on the rear triangle if you care about that stuff.
-Remount the tires so the logo is aligned with the valve stem

[XXX-er]

IME that SC design thro's a lot of smoo on the rear shock so i zap strapped one of hose mini fenders to the rear triangle

[Sandbox]

New whip, anything I need to add or just go shred? Lol.

Nice bike, colour combo is solid. Hightower or Tallboy??


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[Stuntmonkey]

Hightower carbon. R-kit. Not a fan of the NX drivetrain but that's upgradeable.

Is there a specific process to bedding the pads? Def need to invest in some frame wrap protection of some kind.

[XXX-er]

One can alwys spend mo money

I have NX on a bullit for > 2 seasons, I was also wary but it works as well as the XT on the last bike even under the load of a motor

To cure very noisy brakes on nothr bike I scuffed the padz & got driven to the top of a long/steep hill to do panic stops all the way down but you can probably just do some panic stops on flat ground

I been using a 25$ roll of 3M for my wraps , it doesnt cover everything but I just do the area's that will get hit
top of toptube/ bottom of down tube/ sides of stays

I do like the SC product a lot

[Dee Hubbs]

Is there a specific process to bedding the pads?

The purpose of bedding in brake pads/rotors is to evenly transfer pad material onto the rotor, and remove any asperities of the rotor.

The proper bed in procedure has a few key takeaways:
-Start with a clean rotor, and clean pads. Rubbing alcohol or brake cleaner and lint free rag.
-Ride on a flat surface (not bumpy) to prevent material from transferring in a bumpy manner.
-pedal at a speed around 15-20 mph, and drag the brakes until you’re slowed to walking pace, and then release the brakes. This speed allows the brakes to get up to temperature to allow material transfer.
-do not come to a complete stop, as this will deposit more material at the stopping point, release the brakes at the walking speed. (Magura says otherwise, but Shimano, SRAM, TRP, and Hayes say so)
-doing one brake at a time helps create an even surface, as it avoids weight transfer in the stopping/slowing process.
-repeat at least 10x, most brands ask for 25+ times for each wheel, some brands say 50x per wheel!
- the larger the rotor the longer/more times are required.

There are some pro mechanics that suggest you pour clean (distilled) water over the pads between stops. Some say don’t cool them down, keep the heat in the rotor.

The world pro team mechanics, for road bikes, have been building brake bed in machines where they place the bike on a motorized drum to get the wheels up to speed, and drag the brakes to bed then in. The DH guys have been using them for just over 2 years now.
Pro motor sports have has these machines for years.
I first saw one of these machines on a Jumbo Visma mechanic Insta page when disc beaKES Started to get popular in road racing.
There are now some comercially available units to buy. I’ll post some links in the next post.

I have a mechanic buddy who works in a shop beside a parking garage. They would take the bikes in the elevator, and come down 7 stories in the parking garage while bedding in brakes.
They do 4 elevator laps with 5-6 bed ins per lap on their high end bikes they sell. Those bikes brakes are strong and silent from day 1.

[Dee Hubbs]

The world pro team mechanics, for road bikes, have been building brake bed in machines where they place the bike on a motorized drum to get the wheels up to speed, and drag the brakes to bed then in.
Pro motor sports have has these machines for years.
I first saw one of these machines on a Jumbo Visma mechanic Insta page.
There are now some comercially available units to buy.
I’ll post some links in the next post.

If you really want to nerd out:
Bonas Labs has a bed in machine, and Pinkbike, and bikerumourus did a write up about it.

CycleOn (a dutch company) has one.
Unior has one in development that the pro teams are using, they are working on an app and bluetooth for the mechanics to input specific setting for pad material, rotor size ect.
Here is Instagram of it in use:
https://www.instagram.com/reel/Chur7..._web_copy_link

I can go on, but my inner "bike tool nerd" is showing a bit too much, and I'm just a home mechanic.....

[J. Barron DeJong]

Dee has you covered, but regarding stopping/not stopping, not stopping is correct.

The vast majority of ‘warped rotors’ in cars are from pad material building up in one spot due to coming to a complete stop either during initial bedding in of pads/rotors, or an emergency stop where pads got very hot and then came to a full stop.

You’re looking to get an even transfer of pad material building up over the whole rotor surface.

[Stuntmonkey]

If you really want to nerd out:
Bonas Labs has a bed in machine, and Pinkbike, and bikerumourus did a write up about it.

CycleOn (a dutch company) has one.
Unior has one in development that the pro teams are using, they are working on an app and bluetooth for the mechanics to input specific setting for pad material, rotor size ect.
Here is Instagram of it in use:
https://www.instagram.com/reel/Chur7..._web_copy_link

I can go on, but my inner "bike tool nerd" is showing a bit too much, and I'm just a home mechanic.....

Perfect thanks, this is exactly what I wanted. I'll do that as soon as it stops raining!

Probably going to grab the ride wrap kit, and then buy a nice tuning rack.

[Falcon3]

Ok back on the Zeb issues.

I released all pressure and then took the top cap off. The fork is very hard to push down and springs back up even with no air? All compression was full open. It's reasonably hard to push down and especially so in the last 2-3 inches of travel. Not sure what this means.

[toast2266]

Ok back on the Zeb issues.

I released all pressure and then took the top cap off. The fork is very hard to push down and springs back up even with no air? All compression was full open. It's reasonably hard to push down and especially so in the last 2-3 inches of travel. Not sure what this means.

Did you bleed the air out of the lowers? It kinda sounds like there might be a bunch of air stuck down there.

[Falcon3]

Did you bleed the air out of the lowers? It kinda sounds like there might be a bunch of air stuck down there.

I didn't, is that just taking a zip tie and burping it in full compression? I think I might just pull the lowers anyway and do a quick service.

[toast2266]

I didn't, is that just taking a zip tie and burping it in full compression? I think I might just pull the lowers anyway and do a quick service.

Yeah, assuming your zeb doesn't have the little bleed buttons.

I doubt it's going to make a huge difference, but it'll at least give you a clearer picture of how tight things are down there.