Tech Tuesday - Bleeding Hayes Prime Brakes

Jun 12, 2012
by Mike Levy  
Why Bleed? Are your brakes feeling a little down on power? Lever throw a bit excessive? It could be time to give your brakes a bleed in order to breathe some life back into them. You may not even realize that they are down on power simply because the degradation happens so slowly over time, but spending twenty minutes on this task could be just what the doctor ordered. So, how does your supposedly sealed brake system become contaminated? It happens in a few ways, but a major factor is both air and moisture seeping past the seals over time. This is especially true of older braking systems who's seals have become more worn and brittle after years of use. DOT 4 fluid is hygroscopic, meaning that it absorbs water, lowering both the fluid's quality and its ability to deal with rising temperatures under extreme use. The result can manifest as power fade and lever pumping (the bite point moves out as the temperature in the brake system rises) during prolonged use. Contamination can also occur from the seals themselves as they break down slowly, releasing tiny pieces into the system that can gum up the brake's small bleed ports.

When To Bleed? How often should your brakes be bled? Once per year is a good rule of thumb if you ride on a regular basis, but those who spend multiple days per week at a bike park will likely have to do it more often. You'll know that you're behind schedule when you purge the system of the old fluid and discover that it is black and cloudy with gunk. Yes, a well bled brake should be able to go for quite awhile without requiring any attention, but thinking of your brakes as being maintenance free is a mistake.

What's needed:
• T10 torx driver
• 2.5mm hex key
• 4mm hex key
• 5mm hex key
• 8mm box end wrench
• Hayes Pro bleed kit
• DOT 4 brake fluid
• Pad spacer
• Clean rags
• Isopropyl alcohol
• Nitrile gloves
Some helpful pointers:
• Watch the video below before starting and make an honest decision as to if this job is out of your league. Nervous? Don't have ALL of the tools required? You'll be much better off taking the bike down to your local shop and paying the professionals to do the job correctly.
• As you should any time that you are dealing with brake fluid, place the pads and wheel/rotor in a safe place where they cannot be contaminated during the bleed.
• Instead of using DOT 4 fluide from that old bottle of yours that you've had for a long time, spend a few bucks on a new, unopened bottle that hasn't had a chance to be contaminated or exposed to air for long.
• When pushing the pistons back in with the box end wrench, be careful to not apply pressure to the edge of the piston - it can be chipped. A stiff plastic tire lever can also be used to limit the chance of causing damage.
• Performing the bleed with the master cylinder in multiple positions offers the best chance of removing air from the system, but this can be hard to do with the brake still on the bike. To simplify the process, simply remove the lever/master cylinder assembly from the bike, but leave the caliper bolted in place, and have a friend hold it for you while you perform the bleed.
• Spray the caliper down with isopropyl alcohol and give it a good cleaning before reinstalling the brake pads.

Bleeding Hayes Prime Brakes

Past Tech Tuesdays:
TT #1 - How to change a tube.
TT #2 - How to set up your SRAM rear derailleur
TT #3 - How to remove and install pedals
TT #4 - How To Bleed Your Avid Elixir Brakes
TT #5 - How To Check And Adjust Your Headset
TT #6 - How To Fix A Broken Chain
TT #7 - Tubeless Conversion
TT #8 - Chain Wear
TT #9 - SRAM Shift Cable Replacement
TT #10 - Removing And Installing a Headset
TT #11 - Chain Lube Explained
TT #12 - RockShox Totem and Lyric Mission Control Damper Mod
TT #13 - Shimano XT Crank and Bottom Bracket Installation
TT #14 - Straightening Your Derailleur Hanger
TT #15 - Setting Up Your Front Derailleur
TT #16 - Setting Up Your Cockpit
TT #17 - Suspension Basics
TT #18 - Adjusting The Fox DHX 5.0
TT #19 - Adjusting The RockShox BoXXer World Cup
TT #20 - Servicing Your Fox Float Shock
TT #21 - Wheel Truing Basics
TT #22 - Shimano Brake Pad Replacement
TT #23 - Shimano brake bleed
TT #24 - Fox Lower Leg Removal And Service
TT #25 - RockShox Motion Control Service
TT #26 - Avid BB7 Cable Disk Brake Setup
TT #27 - Manitou Dorado Fork Rebuild
TT #28 - Manitou Circus Fork Rebuild
TT #29 - MRP G2 SL Chain Guide Install
TT #30 - Cane Creek Angleset Installation
TT #31 - RockShox Maxle Lite DH
TT #32 - Find Your Tire Pressure Sweet Spot
TT #33 - Three Minute Bike Preflight Check
TT #34 - MRP XCG Install
TT #35 - Stem Choice and Cockpit Setup
TT #36 - Handlebars - How Wide Affects Your Ride
TT #37 - Repairing A Torn Tire
TT #38 - Coil spring swap
TT #39 - Trailside help: Broken Shift Cable
TT #40 - Installing a Fox Float Air-Volume Spacer
TT #41 - Replace the Seals on Your 2011 RockShox Boxxer World Cup Fork
TT #42 - Clean and Lubricate Your Fox F32 Dust Wiper Seals
TT #43 - Thread Locker Basics
TT #44 - Install a SRAM X.0 Two-By-Ten Crankset
TT #45 - VPP Suspension Bearing Service
TT #46 - Rotor Straightening
TT #47 - Finding and fixing that creak
TT #48 - Bleed and Service Magura Marta Disc Brakes
TT #49 - Cup and Cone Hub Basics
TT #50 - Install and Adjust Pedal Cleats
TT #51 - Cup and Cone Hub Rebuild
TT #52 - Converting Mavic Crossmax SX Axles
TT #53 - Cassette Removal and Installation
TT #54 - Cane Creek AngleSet Installation
TT #55 - American Classic Tubeless Conversion
TT #56 - Wider Rims Are Better and Why Tubeless Tires Burp Air
TT #57 - Pedal Pin Retrofit
TT #58 - Bleed RockShox Reverb Remote Lines
TT #59 - Cutting Carbon
TT #60 - Silence That Squeaky Disc Brake
TT #61 - Five Minute Wheel True
TT #62 - Removing Bike Rack Rattle
TT #63 - Inside Shimano's Shadow Plus Mech and How To Adjust It
TT #64 - Steerer tube length
TT #65 - Marzocchi 44 Rebuild
TT #66 - RockShox BoXXer TLC
TT #67 - Ghetto Tubeless Tire Inflator
TT # 68 - RockShox BoXXer Seal Replacement
TT #69 - Ghetto Dropper Post
TT #70 - FSA Orbit Option Install
TT #71 - How to Bleed Formula Disc Brakes
TT #72 - Crankbrothers Kronolog Cable Replacement
TT #73 - Three Ways to Save A Leaky Tubeless Tire
TT #74 - Chain Length Basics
TT #75 - Tech Tuesday: DH Helmet vs. Motocross Helmet
TT #76 - RockShox Vivid Air Tuning 2012
TT #77 - Cartridge Bearing Service and Re-Grease


  • + 23
 i want the pinkbike videos back with Richard Cunningham and Mike Levy ! yes manufacturer's videos are helpful but i like the pinkbike ones better.
  • + 17
 Shimano breaks = mineral oil = less hassle compared to DOT4 which is highly corrosive
  • - 20
flag taletotell (Jun 12, 2012 at 5:02) (Below Threshold)
 if you buy the rebuild kits and flush your entire brake system you should be able to switch from dot 4 to mineral oil.
  • + 1
 There are no lever rebuild kits for the Prime available, just complete lever assemblies and caliper rebuild kits. If you put mineral oil into a prime you would seize the entire system and essentially need a new brake. But you can run dot 5 in them, so just use 5 instead of 4 and you'll get a better feeling brake instantly anyways.
  • + 2
 Dot t could work but you would completly have to flush out any dot 3, 4 or 5.1. Dot 5 is silicon based. Dot 3,4 and 5.1 are alchol based. If you mix dot 5 with any other fluid it will turn to a gel, and destroy your system.
  • + 2
 but you need to change the rubber bits because the seals soak up the old fluid right?
  • + 4
 Just use 4 or 5.1.
  • + 2
 "Just use cantilevers" they said to whoever said "I wonder how disc brakes would work on a bike." dot 5 is a better fluid since it is not hydroscopic and the boiling point is very high. It is worth thinking about.
  • + 4
 Hayes brakes had issues in the past but now the prime brakes system is a quality item. I have found them comparaible to saint quality at a better price. I agree this makes the bleeding process seem overly complicated, I didn't do half of that stuff and didn't have an issue. Hayes is back.
  • + 2
 I agree, the primes are great! Best modulation of any brake that I've ridden. But I'm not a huge fan of Hayes bleeding, just take your old avid juicy kit and bleed it with that
  • + 1
 I hate dot 4. If you buy the rebuild kits and flush your entire brake system would you be able to switch from dot 4 to mineral oil? I was thinking of buying nitrile seals and buying the nonhydroscopic brake fluid
9dot 5) from the autopart store.
  • + 1
 you can use dot 5.1 brake fluid its basicali the same as dot 4.1 just has a higher boiling temperature.
  • + 1
 but dot 5 isn't 5.1. They are totally different animals. 5.1 is essentially the same corrosive craps as dot 4 but with a higher boiling point. dot 5 is a lot more like mineral oil. In fact, I'm not sure what the difference is.
  • + 1
 well dot 5 and mineral will expand your seals because they are not treated to survive and operate. If it says dot 4 or 5.1 just use dot 4 or 5.1 form my experience 5.1 preforms better
  • + 1
 so you tried something besides 4 or 5.1? My test brakes (avid juicy 5's) have a couple seasons with 5. The only weakness so far is how much 5 likes to soak up air and get squishy. not to terribly, but not great either.
  • + 1
 well then id rather use dot 4 or 5.1 all in all its better to have crisp brakes and change a few seals once in a while... (PS i work in a bikeshop so i have to use the oil that is recomended otherwise there is no warranty)
  • + 1
 Yeah crisp is better. And warranty is an issue I hadn't considered since I buy used. It also comes down to maintenance. You don't open shimanos for years at a time. You have to open avids at least once a year. If I could convert my elixir cr set I'd be a happier rider
  • + 1
 i have a set of cr's on my bike and maintenance? just changed the pads and lubet the caliper pistons in 1.5 seasons of riding downhill (i am a lazy son of you know)
  • + 1
 One thing I would like to add to this is, for users running Hayes Prime brakes for aggressive/DH riding- Use the T100 padset rather than the stock T103. You can find this model designation on the back of your pads. The T103 is designed to wear longer and run quieter, but the T100 gives you that bite you may be looking for if you are running Primes for DH or aggressive AM riding. T100 is the go-to padset for aggressive Hayes Prime usage.
  • + 1
 Or you can get the Stroker Ace calipers and attach them to the Prime Master Cylinders. Then you get more pad area, and still have the advantages of the Prime modulation.
  • + 1
 I agree. I have two sets of Prime brakes and I have converted them to the T100 pads. Loving them with the adjustability and modulation that other brands don't seem to have.
  • + 1
 so preferablly you should take your bars off your bike which will mean taking off grips and shifters, clamp them in a work stand and then move the brake levers loose on the bars which causes cosmetic damage. wow! i admit that apart from that it looks like they are easy to bleed but not as easy as shimano, and shimano uses mineral oil and are generally better performance wise
  • + 2
 Maintenance is a very Important issue. When I see how greasy the hands of the guy in the video are, and when I compare how easy it is to bleed Avid breaks - I don't see any argument for Hayes.
  • + 1
 I have two sets of Prime Expert brakes. I love them. Especially with the conversion to the T100 brake pads. These brakes have great adjustability and the best modulation of any brand out there. Other brakes are on or off and feel good on the showroom floor, but Hayes brakes are outstanding in the real world and out on the trails.
  • + 3
 Hope all the way for me. easy to bleed. easy to maintain. plus brilliant all rounders
  • + 2
 Couldn't have said it better. I wish Hope did a better job of marketing their brakes in North America -- I'm sure way more people would be using them here.
  • + 1
 Agree!!! I was looking for a brake upgrade 2 years ago and I saw the video on the Hope website "bleed your Tech brakes" and was sold. Connect a tube/bottle to caliper, remove res lid, open bleeder, pour...Opps! Let the cat out of the bag...I mean, these things are WAY difficult to bleed haha. I do remember the days of multiple bleedings, don't miss them a bit. I kinda like Hope being a small market in the states. I'm not running the same brakes as everyone else, I've only seen one other X2 out of 300 or so bikes. And with the ano blue res lid, lever and piston plug, it's like my own custom cnc'd brakeset, that work GREAT btw...
  • + 1
 Totally agree with ya mate. I run Mono M4's, awesomely easy to work on compared to the faff shown above.
  • + 1
 I liked my Hopes until the fluid in the lines expanded so much that the brakes locked up in the high heat. Then I switched to Formula. Haven't looked back. For the amount they cost, Hopes aren't worth the hassle.
  • + 1
 Easy fix for them cos I had the same thing happen to my front Mono M4 after a dh run, while the rear was fine. The difference? The rear has a braided hose. So gonna switch to a braided hose for the front frake shortly and see if that minimises the risk of it happening again.
  • + 1
 I don't know about the brakes but that bleed kit is crap. I see they took the hose clamp idea from avid but still use plastic squeeze bottles with press fit plastic tubing. lame.
  • + 1
 love my prime pros! best brakes i have ridden to date. But i will say this vid makes the bleed process seem overly complicated.
  • + 1
 That looked really easy, compared to avid bleeding. I use both avid and hayes, avid perfom better but I've had to work on them constanly, the hayes, not at all.
  • + 2
 Are you kidding? Bleeding Avids is just about the easiest thing in the world, with the Avid bleed kit.
  • + 1
 Have you ever tried a set of Ace's??? Those things could stop a train, let alone your puny 40Lb DH bike.
  • - 1
 Can't see the point in bleeding any Hayes brakes. They won't brake whatever you do. So a manual "How to get rid of Hayes brakes" would do much better.
  • + 2
 Hayes brakes may be perfect but DOT4 is not. That's why we need bleeding. Right?
  • - 2
 Exactly, who buys Hayes brakes anyway?
  • + 2
 I run Hope Mono M4's, so much easier to bleed than these Hayes that are being shown above
  • + 7
 Try Ace brakes. They can change your narrow-minded opinion.
  • + 1
 I'm not narrow minded mate, just konw what I prefer, having had Promax, Avid and Hopes, for me, the Hope's win.
  • + 1
 I have Hayes Aces and a Hope Tech X2 as well as old Hope Minis and I would rather bleed the Ace's 10 times before the Hopes because they are soooo much easier. Don't care for the Hope's open/squeeze/close/release ritual and now I have to install and remove (again) the diaphragm and cap in the middle of the process for the Tech? Give me a break, Hayes all the way for screw on the lever for the win. Plus with the Hayes, after you complete the bleed you can re-install the bleed screw on the lever and still squeeze a few more ml's of fluid in the line to get the lever throw as minimal as possible, my Ace levers only move about 2-3mm before the pads engage.
  • + 2
 I think the situation with Hayes is similar to Suntour - having produced some crap stuff over the past years keeps the negative opinion in users' minds. It doesn't mean there aren't any well performing Hayes' brakes (at least some of them). It's going to be hard to win the market with such opinions. I have ridden Nines some years ago and now I stick with Aces and I'm quite pleased with their performance, but I haven't read one positive review of Primes. Time will show. And the bleeding of both 9s and Aces in easy and takes 10min. Peace.
  • + 1
 For bleeding my stroker trail brakes, can i do the same process?
  • + 1
 Yes, yes you can. On You tube are videos of how to bleed the Stroker Trail brakes.
  • + 1
 Yes i kwnow that. But i'd like to give an extra power, or an extra pressure on my brakes, if you what i mean. I'd like to know if that is possible
  • + 1
 I'm not sure, what I did with mines was try different rotor sizes and a different compound pads.
  • + 1
 OM,that's the reason ,damn government.
  • + 1
 i just can't see some of the videos,y?
  • + 5
 its on youtube maybee your not allowed to view youtube videos.
  • + 1
 in the background all bikes have sram brakes Big Grin
  • + 1
 because it's a bike shop Wink . i'm guessing he's just a qualified hayes service mechanic so he did the video, but he works in the shop
  • - 3
 The process gets more and more complicated...why is that??
On the other hand...who gives a hoot about Hayes anyway

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