Tech Tuesday - Switch Hoses Without Bleeding Your Brakes

Jul 16, 2012 at 1:51
by Richard Cunningham  
Say you trashed your race bike in practice and had to borrow one for your race run - but the front brake is on the left and you ride moto style. Time is a ticking. Do you risk missing your start time and bleed the brakes, or is there another way? In this Ghetto Tech Tuesday we show you a method used to switch brake hoses left to right at the levers which, in all but a few cases, eliminates the need to bleed the system. The trick is to remove the wheels, pump fluid from the lever's reservoir into the caliper, switch the hoses, and then replenish the fluid into the reservoir and evacuate any air bubbles by spreading the brake pads. The technique is frowned upon by brake makers, but it can get you back into the game in a pinch.
Note: If your brakes can be flip flopped (like the Avid Elixirs used in this demonstration), then it makes no sense to switch hoses - just unscrew the perches and flip the lever assemblies. Pre 2012 Magura brakes do not have enough reserve fluid in the lever's reservoir to execute this procedure. We have successfully used the following technique on Shimano, Avid, Formula and Hayes.

Danger: This is a temporary technique to switch hoses in a pinch. If you complete this procedure and the levers feel soft or less than firm and responsive, you'll need to properly bleed the air from the system before riding the bike. Always check to ensure that the brakes are functional and that the levers feel firm when squeezed repeatedly BEFORE you ride and then do a trial ride to ensure that the system is working before setting out into the real world. Some brake fluid is usually lost in the process. After your ride, check the fluid levels in the master cylinder reservoirs, or give the system a proper bleed.

The only major tools you ll need are a clean flat-bladed screwdriver and an eight-millimeter open-end wrench.
The only major tools you'll need are a clean, flat-bladed screwdriver and an eight-millimeter open-end wrench.

What You'll Need:
• A clean towel to wipe brake fluid from the lever and to protect the floor.
• Eye protection is always important when dealing with compressed fluids.
• An eight millimeter open end wrench.
• A clean, flat-bladed screwdriver.



How to Switch Hoses Without Bleeding Your Brakes


Remove the wheels and hang the bike or put it in a stand.
Step 1 -Remove the wheels and hang the bike by the saddle, or put it in a stand.

Pump the brake levers until the pads close as far as then will go. There will be about a one-millimeter gap between the pads.
Step 2 -Pump the brake levers until the pads close as far as they will go. There will probably be about a one-millimeter gap between the pads.

slide back rubber covers to expose nuts.Loosen with 8mm wrench.
Step 3 -Slide back the protective rubber housing to expose the compression nuts. Loosen both sides with an eight-millimeter open-end wrench.

Pull hoses out and switch sides then tighten by hand.
Step 4 -Unscrew both of the compression nuts by hand and pull the hoses free from the levers. Quickly switch the hoses and then thread the compression nuts in hand-tight.

tighten nuts and replace rubber covers.
Step 5 -Tighten the compression nuts snugly (don't overdo it), wipe off any spilled fluid with a towel and then replace the rubber caps.

Using a clean flat-bladed screwdriver carefully pry the brake pads apart until they are completely retracted This should push the bubbles out of the line and into the master cylinder reservoir.
Step 6 -Using a clean, flat-bladed screwdriver, carefully pry the brake pads apart until they are completely retracted. This should push the bubbles out of the line and into the master cylinder reservoir.

Replace the front and rear wheel. Secure the axles to the maker s specifications.
Step 7 -Replace the front and rear wheel. Secure the axles to the maker's specifications.

Pump the brake levers to reset the pads against the rotors. The Levers should feel firm. If a lever feels springy there is air trapped in the system. Pull the wheel out spread the pads again install the wheel and repeat. No Then bleed the brake properly before riding.
Step 8 -Pump the brake levers to reset the pads against the rotors. The levers should feel firm. If a lever feels springy, there is air trapped in the system. Pull the wheel out, spread the pads again, install the wheel and repeat. No? Then bleed the brake properly before riding. Test ride the bike in a safe environment to ensure the brakes are functional before setting out.



Did you find this week's Tech Tuesday helpful?






59 Comments

  • 66 0
 I can see this being used as a prank, switching your mates hoses...the effort would be worth the outcome Razz
  • 5 2
 Now Im wishing I clicked yes instead of what was the question. Great idea bennyy4x
  • 3 1
 Comment of the month! lol
  • 2 1
 at ryanreishripper, you know you can switch back your answer right?
  • 1 4
 i dont get it, how would that be a prank? unless im missing something in the prank, i wouldnt really care if my friend switched my hoses.
  • 1 2
 bikeracer.. switching rear to front.. or as the Brits sometimes say "righty fronty".
  • 4 0
 Usually I just cut the hoses if I want to do a prank.
  • 1 0
 Aeoneal that made me lol hard xD
  • 1 0
 Bikeracer. If your friend switched your brake lines and you didn't know it you would probably eat shit by going OTB. that's why it would be a prank. I mean seriously. How often do you check to make sure your brake cables are in the right place?
  • 1 0
 ooohhhhh!!! i get it now!!! i see! i thought benny meant just like, putting different colored hoses on. i gotcha now though!
  • 24 0
 Haha! First time I read this I thought it said switch whores without bleeding..
  • 13 1
 ... but we all know that is not possible!
  • 13 2
 would it not be easyier to just swap the levers as you would with any avid brake? all this seems pretty pointless to me
  • 4 1
 yeah pretty funny they showed this technique on an Avid, 30 sec with an allen key without removing any wheels or risking air in your hoses would have been my method.
  • 1 0
 Not in my case... HOPE Brakes w/ Matchmaker clamps. In fact, if you're running matchmaker clamps you may not get things lined up how you like again.
  • 1 0
 I cant switch my avids levers cause my hoses are the perfect length. so nice 1 pink it was a good tech point for avid
  • 1 0
 Mnorris you can with shimano, back in the day i ordered the wrong levers with my brakes, ran them both upside down, worked faultlessly
  • 10 2
 Seriously? You really want even more air getting into your avid elixir brakes? Oh well, at least when the lever pulls to the bar mid descent you can pretend it's because of a dodgy lever swap rather than the fact that it's an avid elixir brake!
  • 2 1
 Ive been running elixir 3s for about a year, no problems. cant say the same for the code 5s I had though.
  • 9 1
 Its funny because Elixirs are one of the few brakes that you can just switch the brakes over without any difficulty.
  • 2 0
 Yeah, I used Elixir brakes because that was the bike I had Laying around. If the brakes can be flip-flopped, like Avid, Magura etc, it makes no sense to remove the hoses - just unscrew the perches and switch them. For Shimano and the few that can't be switched, however, it works great in a pinch. RC
  • 5 0
 "Note: Pre 2012 Magura brakes do not have enough reserve fluid in the lever's reservoir to execute this procedure."

BUT, both olive oil AND water will work as top up fluids in older Magura brakes... Right now I am running almost entirely
virgin oil in my rear brake! Good Luck Kiddies!!!
  • 3 0
 i dont have maguras, but that is a very interesting fact!
  • 10 3
 Or you could just switch the levers to the other side of the bars
  • 3 2
 Not possible with shimano, I think Avid are one of the only companies that run flippable levers.
  • 1 0
 Exactly! The only time I could imagine this being useful is if you were running your brake lines so tight it couldn't reach the other end of the bar, but who does that?
  • 2 0
 Every major brand except Shimano now run flip flop levers.
  • 1 0
 Flip flopping the levers may be easier, but I've seen hoses get pinched close to the compression nuts and this may be the quick solution for that problem. Cool tech Tuesday!
  • 2 0
 I do this all the time at our shop to shorten hoses that are too long. It works 95% of the time.

One additional thing I do however, is to angle the lever so the hole for the hose is pointing a little upward, then I pour fluid into where the threads are. This displaces the air and you just need to use a rag when inserting the hose to catch the overflow.
  • 2 0
 Just did this with my M775. The levers felt a little bit spongy (not by much) so I'll be topping off the fluid.

*Instead of having the pistons pushed out and then pushing them back in to send air bubbles up, pump the lever a few times.
** After unscrewing the connecting bolt, you have to pull the hose (with a bit of force), which will expose the olive.
  • 1 0
 Yeah, I still don't see the point. Why would you switch the brake lines in the first place, and even if you did, would you REALLY trust your brakes with the possibility of air bubbles before you launched down a hill or tech section?
  • 1 0
 RC, bad idea. If you pump the pistons out, you draw fluid out of the reservoir, putting the diaphragm in a vacuum state. The second you remove the brake line from the master cylinder, that diaphragm is going to expand and in doing so suck air into the master cylinder. When you hook the line back up and push the pistons in you may purge the air from the master cylinder bore and into the reservoir, but it'll still be there, and it can still get drawn back into the system during use or storage, resulting in an inopportune brake failure. If you really want to do this, you should remove the pads and push the pistons back into their bores first, and then remove the brake line. This will keep the diaphragm in a neutral state so it will not suck air back into the system.
  • 2 0
 It's so easy to bleed latest shimano brakes (can't speak for avid, not using them for years), but if it works for you I guess it's ok.
  • 2 0
 will this work on Shimanos M596? someone in the comments says you can't do this becuase you trap air in the diaphragms?

this safe or what?
  • 2 0
 just for an urgent situation because the air bubbles are very dangerous in downhill
  • 2 1
 That hand in photo of Step 8 looks like a hand of some voodoo-shaman with that ring and stuff, making some magical moves on Elixirs.
  • 1 0
 There's a Shimano doc on this somewhere, I done this when I bought my XT brakes from rose and they came with the levers on the opposite sides to what I'm used to.
  • 1 0
 Just done this now, no probs at all, and no sponginess..... easy does it
  • 2 0
 Oh god! I guess that's the best Tech Tuesday I've ver seen! Thanks! Going to try that!
  • 2 0
 You can also use this technique to trim a hose without bleeding, worked fine for my Shimanos.
  • 1 0
 except you also need a new olive, if doing that
  • 1 0
 I was about to do the other method of bleeding the brakes because I have to sell my friend my back brake but my leaver is bent and I was going to switch it with the front
  • 2 0
 Most brakes these days flip flop....so you can put them on either side.
  • 2 0
 I just love ghetto technology. lol
  • 1 0
 that was easy, now I know how to do it! will try it with my friends hydraulic brakes for trialSmile
  • 1 0
 Magura's new composite bodies scare me.....but i wonder how well this would work on them?
  • 1 0
 Richard Cunningham loves old Volvo station wagons?
  • 1 0
 My father is a hippie too and wears the same cooper shaman bracelet
  • 2 1
 Hayes have flippable levers.
  • 1 0
 This is why they make lock-on grips
  • 1 0
 love the avid, i flipped mine when the ike came out of the crate.
  • 2 2
 hang on, it tells you about swappipng the top end, but nothing about the bottom end :S
  • 1 0
 Won't work from the caliper end, Te Trick that makes the swap work is that the few bubbles and tiny bit of fluid that you lose when you remove the hoses near the lever are evacuated when you spread the caliper pistons and force fluid back into the lever's reservoir. There isn't enough fluid displaced to safely evacuate air bubbles from the caliper end of the hose, all the way to the brake lever. RC
  • 1 3
 Using a screwdriver to pry the pistons back in with the pads still fitted, will shag your pads. Well done PB, well done.*

*Sarcasm - americans will probably need to look that up in something called a dictionary.
  • 1 1
 Something smells like a burnt butt hole?
  • 1 0
 I scrolled down for a video :L Not happy
  • 1 0
 Do both of your brakes work after this?
  • 1 0
 Ohhh. ..
  • 1 0
 Perfect timing, thanks.

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