Replace brake lines?

[joegeis]

Manual says to replace the brake lines every 4 years.  My 2018 is just about there (granted it only has 7k miles). How big of a job is this?  If I'm doing it, I'm going braided steel so I never have to do it again.  What was your experience like doing this job? Any tips?

[Triple Jim]

It gets a little complicated since you have anti-lock brakes.  You'll need to read about how to bleed the system.  I doubt if I'll replace mine at the four year point, but I'm certainly not suggesting you deviate from the factory recommendation.

[M. Hausknecht]

 Perhaps unless the bike has been stored outside for most of its life or otherwise exposed to high levels of ozone, I can't imagine the rubber lines have deteriorated yet. Nonetheless, the switch to braided lines makes a big difference in how the brakes feel and, along with a change to pads with stronger initial bite, the bike will will slow/stop quicker and with just two fingers. If the brake fluid is dark, it should be replaced. My guess is that the fork oil is original as well and should be replaced, at least if you want as much damping as the original units can generate. The stock shock might not be doing much damping any more either, so I'd put it on the list for replacement before a bunch of do-dads that don't effect the bike's performance.

Installing new brake lines, at least non-ABS, is fairly easy with the proper hand tools. For ABS, if there are any special tools needed or bleeding sequence, it'll be in the shop manual (which you should obtain). The toughest part is getting all of the air bled out of the new lines. YouTube features a wide array of videos on how to do it. Vacuum and powerbleeders work best but  a clean bottle with proper size clear hose can get the job done. I suggest you avoid draining the master cylinder if you can, because it can be challenging getting the last teeny tiny bubbles of air out if it.

Edited November 13, 2021 by M. Hausknecht

[Triple Jim]

3 minutes ago, M. Hausknecht said:

For ABS, if there are any special tools needed or bleeding sequence, it'll be in the shop manual (which you should obtain).

It'll require running the ABS pump.  There are special tools for that, or some guys find a gravel road or similar and go lock up the wheels to activate the pump.

[M. Hausknecht]

Oh yeah, now I remember. The ABS pump is one of things that ended up in a box somewhere with the stock brake lines and master cylinder.

[joegeis]

The rubber lines still look and feel fine to me.  I'm willing to bet the fluid and pads have never been changed though.  Perhaps I'll just do that for now and see how I like the performance in the spring.  I'm pretty handy, and I've purchased a vacuum bleeder, but not looking to do unnecessary work (especially when I could spend that money on an exhaust or suspension upgrades).

[Lone Wolf]

6 hours ago, joegeis said:

Manual says to replace the brake lines every 4 years.  

I have seen motorcycles from the 1980's with original brake lines.

It's not like they are going to "pop" and spill fluid on the road when you are trying to stop.

Do it when YOU want to do it. I wouldn't bother until other things need attention and you have a 2nd bike to ride during the down time.

I change fluid once a year. Unless you want better initial bite from HH Pads, you would NOT need to touch your pads with that low miles. I bet you could get over 30,000 miles on stock pads before wear becomes an issue. Sometimes pads can get glazed, so it's a matter of paying attention to how they are performing. But don't just toss pads that are working fine for the street.

Edited November 14, 2021 by Lone Wolf

[joegeis]

14 minutes ago, Lone Wolf said:

I have seen motorcycles from the 1980's with original brake lines.

It's not like they are going to "pop" and spill fluid on the road when you are trying to stop.

Do it when YOU want to do it. I wouldn't bother until other things need attention and you have a 2nd bike to ride during the down time.

I change fluid once a year. Unless you want better initial bite from HH Pads, you would NOT need to touch your pads with that low miles. I bet you could get over 30,000 miles on stock pads before wear becomes an issue. Sometimes pads can get glazed, so it's a matter of paying attention to how they are performing. But don't just toss pads that are working fine for the street.

Thank you.  They are definitely not glazed and I would not describe them as spongy (though again it's my first bike, so nothing to compare it to), but I would like a little more initial bite and better feel for sure. I think I will go with bleeding/replacing fluid.  I'm already budgeting for a tune, but maybe I'll put the brakes money I budgeted towards a new rear shock.  Appreciate your feedback!

[FZ not MT]

Spiegler SS brake lines and EBC HH pads made a huge difference in the stopping performance of my bike. I am very happy I changed my setup!

[firstyammerha]

my 2016 was just in the shop for the 4000 mile service and the brake system was on the list of things to do at that time. The service manager did not bring up any areas of concern and I did have a rear brake noise issue for them to address. They ran a Scotchbrite wheel over the rear disc which resolved that issue. I've never kept a bike longer than this one and  never had a problem indicating the hoses needed replacing on any of the earlier bikes. Five years and 15000 miles in my custody was the average. 

[shinyribs]

Lone Wolf is 100% correct. They're made of the same stuff as auto brakes hoses and how often do we change those? 

 

I'll just add that I've never seen where changing to stainless steel lines drastically improved the brakes of anything, unless the preexisting hose was somehow deteriorated/damaged and it was actually bulging in use. Aftermarket stainless steel lines are sometimes cheaper than OEM parts, so I'll use them. I just never saw where they did much, so I wouldn't drop a couple hundred dollars expecting big results. 

I believe your idea of budgeting for a shock first is a great idea! That's something really get a big improvement from.

Edited November 17, 2021 by shinyribs

[7fold]

9 hours ago, shinyribs said:

Lone Wolf is 100% correct. They're made of the same stuff as auto brakes hoses and how often do we change those? 

 

I'll just add that I've never seen where changing to stainless steel lines drastically improved the brakes of anything, unless the preexisting hose was somehow deteriorated/damaged and it was actually bulging in use. Aftermarket stainless steel lines are sometimes cheaper than OEM parts, so I'll use them. I just never saw where they did much, so I wouldn't drop a couple hundred dollars expecting big results. 

I believe your idea of budgeting for a shock first is a great idea! That's something really get a big improvement from.

Agreed - replacing rubber lines to braided stainless isn't going to be a night and day difference for most. The only thing it really does is improve brake feel by reducing fade under heavy braking conditions (think track day or really spirited canyon carving). For normal day to day type riding, a better bang for buck would just be some fresh pads and bleeding the system/putting fresh fluid in.

[Triple Jim]

10 minutes ago, 7fold said:

The only thing it really does is improve brake feel by reducing fade under heavy braking conditions (think track day or really spirited canyon carving).

Pad type can reduce fade.  Type of brake line can't.

[7fold]

19 minutes ago, Triple Jim said:

Pad type can reduce fade.  Type of brake line can't.

Really? I always thought the purpose of stainless brake likes was to avoid the swelling of the rubber lines from heat and pressure of hard braking. Is there just another term for that?

[Triple Jim]

Just now, 7fold said:

Really? I always thought the purpose of stainless brake likes was to avoid the swelling of the rubber lines from heat and pressure of hard braking. Is there just another term for that?

Fading is caused by the coefficient of friction between the pads and disk dropping due to high temperature.  I've  never had stock lines swell from heavy brake use.  I can see how it might seem like they are though... when brakes fade you end up pulling the lever to the bar trying to stop, with little stopping actually happening.

[shinyribs]

1 hour ago, 7fold said:

Really? I always thought the purpose of stainless brake likes was to avoid the swelling of the rubber lines from heat and pressure of hard braking. Is there just another term for that?

I used to think the same.

 

Rubber brake hoses are reinforced against swelling with braiding, but it's typically a flexible thread/textile type material vs steel. Most lines I cut in two ( easier than disassembling frozen bikes when scraping out a bike) are layered as such: rubber fluid carrying hose- braiding- rubber sheath- second layer of braiding- outer layer of rubber. I've seen a few modern rubber brake hoses that used a Teflon inner hose. 

 

Inside all stainless steel hoses are a Teflon liner. Teflon is chemically inert ( nothing effects it) so it's great to be able to be compatible with any fluid you can dream to run through it. And if you're producing aftermarket lines, anybody can use your product.  But it's fragile. It doesn't really get all that brittle with age, but it can crack easily if scratched, and it'll puncture if pinched. So they wrap it in braiding to protect it from damage. The braiding itself doesn't prevent the Teflon inner hose from swelling (it's naturally strong enough to do that alone) and it's stainless to keep it from rusting. 

Years ago, stainless braided lines didn't always come with the vinyl jacket over top and they'd scratch the hell out of anything it rubbed against. Nowadays, nobody is gonna tolerate that, so they get the vinyl jacket. The reason I mention the jacket, if you find a stainless braided hose to inspect that doesn't have the vinyl jacket locking the brading to the house, you can easily pull the braiding away from the hose. That's enough to tell us that it's not there to prevent swelling, it's just to protect the Teflon from damage.

Not all brake lines are constructed the same, so we can't make generalizations, but rubber hoses typically have a two stage crimp on connection. The first stage seals the actual fluid carrying hose to the fitting and the second crimp holds the outer jackets in place. I've yet to see a stainless braided line made that way. I've seen cheap hoses where the Teflon hose and all the other layers are smashed in to the same crimp. With enough time, they'll loosen at the crimp and start seeping. 

I'm not hating on stainless lines. I've used them plenty. Cheaper than OEM and looks cool if you're building a custom ride or flipping a bike that needs houses. I've even used one to remote mount a shock reservoir that rides right under my thigh with 200psi in it. I'm not scared of them. But I keep an eye on them. 

 

[shinyribs]

2 hours ago, 7fold said:

Agreed - replacing rubber lines to braided stainless isn't going to be a night and day difference for most. The only thing it really does is improve brake feel by reducing fade under heavy braking conditions (think track day or really spirited canyon carving). For normal day to day type riding, a better bang for buck would just be some fresh pads and bleeding the system/putting fresh fluid in.

Keeping fresh fluid in is SO important. Brake fluid wants to suck up water and only 3% water contamination can destroy the boiling point of the fluid. 

 

Once boiling, you've got steam in the line. Once you've got steam you've got dragging brakes that won't release properly, or they can lock up completely ( done it!). Before it gets that bad, the minute steam pockets give you compressible areas and there's you're spongy lever. 

Below is the brake fluid Yamaha put in my '16 FZ 09 that I bought used a couple months ago. Original owner never changed it because " it's only got 3,000 miles on it", but it's 5+ years old! Those brakes were awful riding home. Fresh fluid and they're tight now. Some of the worst I've ever saw. The bike was even stored in a climate controlled garage. 

[Triple Jim]

2 hours ago, shinyribs said:

The braiding itself doesn't prevent the Teflon inner hose from swelling (it's naturally strong enough to do that alone) and it's stainless to keep it from rusting. 

Teflon is quite soft.  I suspect that if the braid isn't tight on the inner Teflon tube, it will be later.  It has a low yield strength and a high elongation before rupture.

Edited November 18, 2021 by Triple Jim

[shinyribs]

I'm not sure. We use Teflon rings in a lot of HVAC  joint connections. I'm not talking about the flexible Teflon tape they sell for wrapping pipe joints, instead they are crush washers. Only about 1/16" thick, but they handle sustained 450psi loads under temperature fluctuations from below freezing to 150° in a matter of seconds and I've never seen one fail in the 25 years I've been at it. It's a pretty incredible material. 

I'm not a particularly weak person and I can't snap one of those little rings in my hands. If Teflon is known to elongate, there must some variation of formulas, because I've never seen a Teflon sealing ring push out or really even become deformed from being crushed in to position. But there's a first for everything.

[Julian]

I don't know anything about steel brake lines, but Teflon itself is a liquid when applied, so I would think the tube is not made of Teflon but rather of something else covered with a layer of Teflon. 

Edited November 18, 2021 by Julian

[FZWes]

On 11/13/2021 at 2:02 PM, M. Hausknecht said:

 Perhaps unless the bike has been stored outside for most of its life or otherwise exposed to high levels of ozone, I can't imagine the rubber lines have deteriorated yet. Nonetheless, the switch to braided lines makes a big difference in how the brakes feel and, along with a change to pads with stronger initial bite, the bike will will slow/stop quicker and with just two fingers. If the brake fluid is dark, it should be replaced. My guess is that the fork oil is original as well and should be replaced, at least if you want as much damping as the original units can generate. The stock shock might not be doing much damping any more either, so I'd put it on the list for replacement before a bunch of do-dads that don't effect the bike's performance.

Installing new brake lines, at least non-ABS, is fairly easy with the proper hand tools. For ABS, if there are any special tools needed or bleeding sequence, it'll be in the shop manual (which you should obtain). The toughest part is getting all of the air bled out of the new lines. YouTube features a wide array of videos on how to do it. Vacuum and powerbleeders work best but  a clean bottle with proper size clear hose can get the job done. I suggest you avoid draining the master cylinder if you can, because it can be challenging getting the last teeny tiny bubbles of air 

Question: how do you replace brake lines and not drain the master cylinder?

Thank you

 

[M. Hausknecht]

3 hours ago, FZWes said:

Question: how do you replace brake lines and not drain the master cylinder?

Thank you

 

I've got little plastic plugs with the same thread as the brake lines. I probably got the plugs with a new master cylinder at some point. Disconnect the brake lines at the master and install a plug. After connecting the new lines, I use a turkey baster to remove most of the brake fluid from the master cylinder reservoir, careful not to touch the lever, and then fill the reservoir with new fluid before bleeding.

[FZWes]

Once you remove the brake lines gravity takes over and its all she wrote, no? 

I appreciate this opertunity to learn something. 

 

[Triple Jim]

On 11/18/2021 at 4:29 AM, Julian said:

I don't know anything about steel brake lines, but Teflon itself is a liquid when applied, so I would think the tube is not made of Teflon but rather of something else covered with a layer of Teflon. 

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[Triple Jim]

I've never had any trouble bleeding a motorcycle master cylinder by just pulling the lever a whole bunch of times while keeping the reservoir full.  In fact, one of my motorcycles has the front brake line and caliper arranged so air can get all the way from the caliper, back up to the master cylinder.  I can bleed that system from empty by just squeezing the lever a couple hundred times and keeping the reservoir full.