brake questions

[feralchimp]

Rear: I got the SV from zero to "more than enough" rear braking action yesterday, with what amounted to just bleeding it, but the process was strange. In particular, with the reservoir disconnected from the rear master, the fluid didn't drain out of the reservoir until I disconnected the reservoir and raised it up to pull the hose straighter. I wonder whether the raised rearsets are partially crimping the hose to the reservoir, or creating a slight J-bend in the hose that becomes a place that collects whatever air gets into the system.

Front: i get consistently good braking action out of the fronts, with one (possibly serious) exception. When I hold lever pressure hard enough, the lever slowly keeps going under I need to grab another handful of front brake. It's extremely rare that this affects me at all on the street unless I'm stuck in traffic on a hill, but definitely in the "address before taking to the track" category. Could this be fixed by a simple bleed, or does it definitely sound like an issue with the master or one of the calipers?

[MUZ720]

Hi,
The rear brake reservoir line might be pinched or is it located bellow the master? Cant remember... been awhile since I owned a SV
The front sounds like a air leak somewhere in the system, do you have fluid anywhere at any connection are you lines rubber or steel and how old are the lines if rubber?. It might just be a small leak so take a clean paper towel and check it out there should be nothing on the towel... if there is no loss of fluid your master might be the issue.. is you brake master stock and how old is it? has it hit the ground at anytime... Replace or repair it if you have any question about it.

[Petorius]

Rear: I have the original rubber hose on my rear brake between the master and the caliper. I think it is deteriorating. A few times (including the night before my first ever TD!) I have noticed that I have no rear brake. When I go to bleed it, no pressure at the bleed nipple. The solution has been to pump the shit out of it with the MityVac. After some pumping, it will suddenly 'clear' and fluid starts to come through normally. The first time I did this, visible black chunks came out. Like I said, I think it is bits of rubber from the inside of the hoses getting stuck in certain places (I rebuilt the master trying to resolve this originally, so I know its not that). I wonder if the same thing is happening to you.

[feralchimp]

This was Chip's so I'm not sure of parts ages, but the lines are steel and I think the master is aftermarket. Accossato or similar? I haven't noticed fluid anywhere but will check it out later today.

[Petorius]

If your rear issue is in fact a kinked line, you could always go this route. Thats the setup I have on my SV now.

[nhbubba]

Sounds like your front master needs a rebuild. Sounds like the seals are shot to me.

Rear sounds odd. But as long as it works..
You know there are two bleed nipples on the (single) rear brake caliper, right?
That one got me for a long while.

[Kurlon]

I have an HRC resi-delete kit if you need one.

[feralchimp]

I did *not* know about multiple bleed points on the rear, and will check that out.

There's a nice Accossato master on the front end, but Google hasn't found me rebuild kits for those.

[Kurlon]

AFAIK Accossato, like Brembo will not sell end users rebuild parts for their radial masters. They require that you send them in for rebuild.

[nhbubba]

And that's why I can't have nice things.

[Kurlon]

Beringer makes a couple SWEET radial masters, and they sell EVERY PART. They are designed to be rebuilt even if that means stripping the parts out of one master to install in a new body.

On the flip side, damn do they want ALL the money for their levers.

Shindy / Daytona branded Nissin radials are a nice compromise, low cost, rebuildable, low cost levers available.

[feralchimp]

I took the SV to work this morning, and specifically tried to make the front lever plunge while stopped at a light, but it wouldn't budge. It might only happen when the brakes heat up a lot more? Would that make any sense (and is it something that bleeding the brakes could fix)?

[nhbubba]

How old is the fluid? If saturated with moisture (brake fluid is hygroscopic) then the moisture can boil and form bubbles in the line. Gas compresses more readily than fluid and result in a spongy, soft lever.

Nobody likes a soft lever.

Drain as much of the crappy old fluid from that system. Replace with new.

[SRTie4k]

Another issue you can run into with the front "sinking" to the bar is if a piston seal is leaking. It seems some aftermarket caliper rebuild kits have seals that aren't tapered enough to make a proper seal with the pistons, and can potentially slowly leak air or fluid.

[feralchimp]

Thanks guys. I'll bleed the front lines and see how they feel over the next month or so. Couldn't hurt, and way less expensive than putting a new/rebuildable master on.

[Chippertheripper]

"they" say the real good brake fluid needs to be flushed more often because it attracts moisture in a different way.
I'd give the front a thorough and complete flushing in that case.
As far as the rears go, I can't remember how I set them up, whether I replaced lines, or had to do anything fancy to get them to work.

[number9]

AFAIK Accossato, like Brembo will not sell end users rebuild parts for their radial masters. They require that you send them in for rebuild.

I am somewhat surprised that that's legal.

[Kurlon]

I am somewhat surprised that that's legal.

There's no legal requirement that they sell repair parts unfortunately, and they can lean on liability concerns as to why they won't.

[number9]

There's no legal requirement that they sell repair parts unfortunately, and they can lean on liability concerns as to why they won't.

I guess I need to dig into Magnuson-Moss

[Mr. Kurtz]

I guess I need to dig into Magnuson-Moss

Magnuson-Moss won't force a part manufacturer to sell individual components used to build the complete unit, and rebuilding a brake master isn't "maintenance."

EDIT: I haven't read through the act in years, I used to be pretty knowledgeable with regards to it in a past life. The above is from memory, so there is, of course, a chance I'm wrong.

[nhbubba]

You go get 'em.

Ferel, we mean flush the system, not just bleed it.
Were it me, I'd pull the calipers, pop the pots out, empty and completely clean it. Then refill with new fluid. Nuke it from orbit, if you will.

[Kurlon]

There are other bits that you can't get separate on bikes. Easiest example, look at bikes with floating calipers. Normally the caliper bracket has a bolt on post that the caliper slides on. That post is a wear item. On many bikes you can't order that post, you have to either get the whole caliper bracket, or a complete caliper assembly to replace it. I'm trying to remember what other brake item I couldn't get for my CRF70 as a part that I found available separate on a Yamaha... been too long.

Moss-Magnusson doesn't actually have any details on parts availability. It covers warranty terms.

[number9]

There are other bits that you can't get separate on bikes. Easiest example, look at bikes with floating calipers. Normally the caliper bracket has a bolt on post that the caliper slides on. That post is a wear item. On many bikes you can't order that post, you have to either get the whole caliper bracket, or a complete caliper assembly to replace it. I'm trying to remember what other brake item I couldn't get for my CRF70 as a part that I found available separate on a Yamaha... been too long.

Moss-Magnusson doesn't actually have any details on parts availability. It covers warranty terms.

Yeah, I figured that it's probably not something that's in that Act. But it smacks of anti-trust to me that you can't order parts at all and your only option is send it back to the manufacturer for a rebuild.

[Kurlon]

With all the competing radial masters out there I think you'd have a hard time going the anti-trust route. A mfg is only required to support a product for the length of the warranty. It appears that Brembo specifically claims no warranties what so ever on their RCS masters, expressed or implied so... they're under no obligation to even offer to repair or rebuild them. If your bike came with them OEM, you're covered under the OEM warranty in which case they'll be replaced.

[number9]

With all the competing radial masters out there I think you'd have a hard time going the anti-trust route. A mfg is only required to support a product for the length of the warranty. It appears that Brembo specifically claims no warranties what so ever on their RCS masters, expressed or implied so... they're under no obligation to even offer to repair or rebuild them. If your bike came with them OEM, you're covered under the OEM warranty in which case they'll be replaced.

I don't know if that's legal of Brembo from a federal level, to claim that it has no warranty whatsoever. I know that in Maine there are a bunch of consumer protection laws (which I'm sure you know of) that mandate that, if a good is sold, it has to be usable for a few years, even if the good doesn't have a warranty.

Here it is: Chapter 04: Consumer Goods And Maine Express And Implied Warranty Laws.

This interests me. I'll keep digging...