Soft brakes after bleed

[AVI8_636]

Hmmm... Youtoob has our back:

Good find.

BACK BLEED. You will be rock hard. LOL

I understand how the backbleed works now on that type of bike, but what about something with dual front brakes? In the video he sort of touches on the subject, but doesn't show how it's done. Is it basically the same method?

[nhbubba]

I imagine you start with the longest leg, probably the left side caliper. Then repeat on the other side. Depending on where the junction in the lines is you may end up pushing a lot of fluid to do a full swap. My situation is even worse as the Y is right before the calipers but way after the ABS pump and miles of hard lines going to-from it.

[Paul_E_D]

I imagine you start with the longest leg, probably the left side caliper. Then repeat on the other side.

Correct.

[jasnmar]

Try it with this...

[nhbubba]

Any advice for 'reverse' bleeding a system with ABS and the bunch of plumbing that comes with it?
I'm thinking speed bleeders may still be a better bet for my setup as I can push the old fluid out of each caliper without having to flush the rest of the system twice.

For the non-ABS and non-linked brake bikes that seems like the ticket though.

[AVI8_636]

So basically, I'm pushing Air/fluid out of the front left caliper first, towards the split that is in the right caliper (at least on my bike), and then up to the master? If there's air in the right caliper, will that get bled out in this process, and if it's not, what's to stop that air from going back through the split into the left caliper once I start bleeding the right side?

[Paul_E_D]

Pressure and the tendency for air to rise are what make this work.

This is NOT a way to flush your whole system. Just a way to get stubborn air bubbles moving to the top of the system.

Like I said earlier, alternate a few times back then forward.

[AVI8_636]

Been super busy so I haven't had time to reverse bleed the brakes, but where in the hell do you find a plastic syringe?? I've literally been to every store/pharmacy in the area, and the only thing that I've found close, is a plastic injector (syringe) for babies that holds about 2tsp of liquid. It was between that, or an $8 food injector. I keep seeing pictures of these big plastic syringes and I can't seem to find them anywhere.

[jasnmar]

http://www.amazon.com/gp/aw/d/B000HI...&robot_redir=1

[carsick]

http://www.tractorsupply.com/en/stor...city-pack-of-2

[ZX11D]

You can use a mighty vac with the lines reversed also. Same principle as the syringe with 60cc capacity.

[AVI8_636]

So update, did the reverse bleed and zip tied the lever overnight. MUCH better than before. The lever is still softer than I'd like, but the brakes definietely do their job now. With the reverse bleed, I actually watched a bunch of tiny air bubbles come out the reservoir. It was a bit messy but not difficult at all! Thanks for the suggestions!

[Stromper]

When you apply pressure to the system]]

The bubbles shrink according to boyles Law from 1 atm to hundreds of psi

Additionally if this is pulsed then the bubbles can detach from surfaces and rise

It is easier for tiny bubbles to move up

[nhbubba]

I've been having problems bleeding my V-Strom as well.

I'm so frustrated with this POS.

This weekend I installed speed bleeders. I like those, they make bleeding easier and less messy.

A friend had suggested taking the calipers off and tying them to the handlebars. Naturally, on the V-Strom this means dismantling half the plastics. I tried this and was unable to get anything close to all the air out. Once I put the calipers back on the forks and bled again I at least got some bar feel back.

I did notice that some of the lines on the system are braided. This makes me think that throwing a line kit at this thing won't help anything. All the lines look good and have no weeping fluid or anything. No cracks, no evidence of bulging. Nothing.

Maybe there's a loose fitting letting air in somewhere? But then I'd expect the lever feel to get worse (and worse) over time. Lever feel starts meh and stays meh.

I'm going to try a traditional bleed once more with a different brand of fluid. Although I honestly think the crap lever feel is a byproduct of the cheap(er) V-Strom components. Maybe the calipers? The master? I don't know.


Do you think I can back-bleed an ABS system?

[jasnmar]

As you know, I know shit about V-Stroms...

There has been a long standing issue with "some" GL Brake systems (which have been around for more than a dozen years) which recently a solution was discovered for.

Turns out there is a brake line that runs up and over the engine. In some cases when air gets trapped in this particular line it can't (at least easily) be bled out as it is at a local "high point" in the system. A guy, having fought with this for years, found a fitting on this line, cracked the fitting open (just a bit) and was able to bleed air from this line after having repeatedly tried to bleed the system per the factory recommendation. Just a little psssssst, cleared up a problem he'd been chasing forever.

I'm not saying the V-Strom has anything like this or that it is your problem. Something to look for.

[nhbubba]

Yeah. There are two soft lines going over a hump in the frame from the distribution block under the steering yoke. From there they connect to hard lines that run down the frame to the ABS module under the seat. I wouldn't be surprised if that was a high point where air got stuck. Tying the calipers up to the bars was supposed to fix that.

I'm honestly starting to think that it is as good as it is going to get.

[Viper897]

I was having issues bleeding the brakes on my 99 track sv650. Same thing, soft lever, air, very spongey. Solution, clean your calipers, I cleaned mine and bleed the system again and now it has a solid lever.

[Billy]

Interesting. I've never done it the way the YouTube video showed. Makes a lot more sense to do it that way now when you think about it. I'll have to keep that in mind for my next one.

[nhbubba]

I can't quite imagine what dirty calipers would do to lever feel. I would expect dirty calipers to bind and either be extra stiff or not release correctly.

Either way, I cleaned the calipers with brake cleaner, a tooth brush, and some steel wool for the nasty deposits on the cylinders. I did this before my bleed session yesterday. No dice.

My pads are getting thin. Seems like performance pads are pretty darn thin these days anyway. But I think mine are nearing the end. Cylinders are extended quite a bit. I topped off the reservoir with the pads in contact with the rotor.

[Paul_E_D]

New pads will likely do it. Cheap bastids have squishy brakes!

[nhbubba]

I don't share your enthusiasm. But what the hell. Never loved these Galfer pads anyway. Time to try something else.

[Paul_E_D]

I don't share your enthusiasm. But what the hell. Never loved these Galfer pads anyway. Time to try something else.

My dirtbike brakes get squishy as the pads get worn. Almost all do, actually. but you also have that overly complicated (and budget) system working against you.

[TheIglu]

I can't quite imagine what dirty calipers would do to lever feel. I would expect dirty calipers to bind and either be extra stiff or not release correctly.

Either way, I cleaned the calipers with brake cleaner, a tooth brush, and some steel wool for the nasty deposits on the cylinders. I did this before my bleed session yesterday. No dice.

My pads are getting thin. Seems like performance pads are pretty darn thin these days anyway. But I think mine are nearing the end. Cylinders are extended quite a bit. I topped off the reservoir with the pads in contact with the rotor.

Did you actually open the calipers up, take out the seals, etc?

Or did you just clean the outside of the system?

One is like doing an oil change in a dirty engine to make it run smoother. The other is like washing the outside of the engine.

[nhbubba]

Outside. I did not rebuild the calipers. Never imagined such a thing would be required unless the seals were leaking. (Mine aren't.)

[TheIglu]

Hard deposits build up behind the seals in the caliper making them ever tighter. Combine that with seals that harden and shrink over time and it makes for a bad combo of odd performance/function.

Dentistry tools work well to scrape the oxidation/sludge out once you pull the seals. Just like any other seal, always new ones go in (for me). I'm not interested in doing a job like that twice.

Did you also pull and clean/lube the slide pins?

As said before, you still could simply just have a bulging brake line. Soft lever feel/lots of travel can be many many things unfortunately. Rebuilding calipers/pins and giving a good bleed is the cheapest step.