Brake line question for techs

[monkey]

Is there any difference between a 2 line set up (on the front) and a 3 line set up apart from alightly more brake fluid in the system? I'm not sure what the bike curently has but basically the two line kit is cheaper from HEL. If it has the 3 line is there a simple junction in there somewhere? ('98 ZX6R). Am I correct in thinking that with the two line I use a 2 way banjo at the master cylinder and feed one line to each caliper?

I should add that they're being swapped for braided as they don't appear to have been changed ever. I may be wrong but I'd rather spend my fettling time first on making sure the brakes are ok before anything else. I plan to pop out the pistons and check/overhaul the calipers. Rear brake is fine.

Finally can I have a quick explanation of the DOT rating i.e. what's the difference between 3, 4 and 5.

Thanks in advance.
:)

[lukemillar]

Is there any difference between a 2 line set up (on the front) and a 3 line set up apart from alightly more brake fluid in the system? I'm not sure what the bike curently has but basically the two line kit is cheaper from HEL. If it has the 3 line is there a simple junction in there somewhere? ('98 ZX6R). Am I correct in thinking that with the two line I use a 2 way banjo at the master cylinder and feed one line to each caliper?

I should add that they're being swapped for braided as they don't appear to have been changed ever. I may be wrong but I'd rather spend my fettling time first on making sure the brakes are ok before anything else. I plan to pop out the pistons and check/overhaul the calipers. Rear brake is fine.

Finally can I have a quick explanation of the DOT rating i.e. what's the difference between 3, 4 and 5.

Thanks in advance.
:)

Yep that is correct. The system is sealed so an amount of pressure applied at one end (the master cylinder) should result in an equal pressure at the calipers regardless of line length.

I have seen people post things like the advantage of a 2 line system is that both calipers move at the same time, whereas 3 lines, one caliper moves, then the other. This is carp. Advantages of a 2 line system are A: cheaper B: Less brake line + joints for air to get trapped/ areas to fail.

I would give the calipers a proper overhaul - off the bike dismantle, new seals and a good clean. Use red rubber grease on the seals and pistons.
You are also correct with the double banjo at the master cyl and then the a line to each caliper.

Not sure about the specificas of DOT rating but use manufacturer's guidelines - Most likely DOT 4. Don't get confused with DOT 5 and 5.1, they are completely different.

HTH Luke

[embee]

In simplest terms, the DOT system describes the temperature capabilities of the fluid. It's also associated with water absorption etc, but all you really need to know is that for normal road use in a bike, any of the DOT4 specs will be fine (there are standard and super type specs, all OK).

You can use a DOT5.1 if you wish, but DOT5 is, as said earlier, a different product really intended for competition use with frequent changes, it doesn't absorb the water so it can form droplets or plugs in the lines and can potentially either boil or freeze depending where it is.

Most important thing is to change it regularly, annually is nice, 2 years tops really. This is why I like to use a Mityvac because although it might seem like an overkill and unnecessary expense, it makes fluid changes so easy and reliable that you tend to do it more often.

Downside is that any of them other than 5 will damage paintwork very quickly, so wash splashes off immediately with plenty of water.

[muffles]

Piggyback time...any tips for brake bleeding? I just changed to braided (last night) on my CBR...just very briefly filled the system (bottom up) but it needs bleeding properly (it's no better, in fact slightly worse, oh and I changed to a supposed better M/C).

However from my previous experience of it I'm not very good :lol: but trying to learn! About the only method I know of is "crack open bleed nipple, depress brake lever, close bleed nipple, release" repeat ad infinitum. Should I see air bubbles coming out, generally, or will it appear to be solid fluid (but actually be removing air)?

Any other methods I can use (I have a syringe for piping it in via the nipple if that helps, it's how I filled it last night)?

[embee]

My tip (http://www.mandp.co.uk/productInfo.aspx?catRef=533338), other sources are available.

Big advantage is that you can empty the reservoir first without draining it all through the system, top up with fluid and let it stand for a minute to let air bubbles rise, then you get a continuous flow when pumping vac onto the catch bottle which pulls air through better than pushing intermittently using the brake lever.

Just my opinion, however humble.

[muffles]

My tip (http://www.mandp.co.uk/productInfo.aspx?catRef=533338), other sources are available.

Big advantage is that you can empty the reservoir first without draining it all through the system, top up with fluid and let it stand for a minute to let air bubbles rise, then you get a continuous flow when pumping vac onto the catch bottle which pulls air through better than pushing intermittently using the brake lever.

Just my opinion, however humble.

Looks good, and easy to use, but £35 - don't think I can justify it...if I can get it done well enough with the tools I have right now...

e.g. why can't I attach the syringe on the bleed nipple and use it to suck brake fluid through (topping up the M/C beforehand)? Same principle, no?

[yorkie_chris]

Yes you can do that. Might be easier to push fluid in to the bottom though, after all air will naturally flow upwards...

Oh yeah 2 line setup is IMO superior as it's simpler, easier to bleed, cheaper, lighter...

I have heard tell of the over the mudguard setup wearing one set of pads out faster than the other, it seems unliklely but I wouldn't comment either way.

[niccollotto]

Hel call the 2 line sysytem 'race' because most racing regulations require separate lines and no 'cross-over' between calipers, thinking behind this is that if you lose the front mudguard its not gonna take your brake line with it

[Dangerous Dave]

2 line setup is IMO superior as it's simpler, easier to bleed, cheaper, lighter...
+ 1, no real performance benefit on the road.

[Grinch]

+ 1, no real performance benefit on the road.

Yep, both my SV's had 2 line setups.

[muffles]

Yes you can do that. Might be easier to push fluid in to the bottom though, after all air will naturally flow upwards...

Cheers, will try this again then. It's how I filled the system so just more of the same, I guess...

[yorkie_chris]

Yup pretty much, you can get bubbles stuck in the banjo fittings so try crack those off and bleed a little through.

[muffles]

Yup pretty much, you can get bubbles stuck in the banjo fittings so try crack those off and bleed a little through.

Will that not cause fluid to leak out through the banjos though? Or can you loosen them a little without that happening...

Since I also replaced the M/C is there anything special to do to clear air bubbles out of that?

[yorkie_chris]

Yeah you need to let some leak to get the air out, that's the idea.

M/c doesn't need bleeding.

[muffles]

Yeah you need to let some leak to get the air out, that's the idea.

M/c doesn't need bleeding.

Ok, cool...thought I had heard someone saying they got an air lock in their master (different forum). Will give that a go!

[yorkie_chris]

It's possible I suppose but there's very little space in there at the end of the stroke, so it's unlikely.

[muffles]

It's possible I suppose but there's very little space in there at the end of the stroke, so it's unlikely.

Won't worry about it then :D

[yorkie_chris]

Oh yeah if you've pushed fluid up from bottom then there definately won't be an airlock there.

[muffles]

Yep, all done from the bottom so far...sounds good...

[monkey]

Thanks chaps. The 2 line system it is. I can say I've got race spec brake lines then too! He he. Just need a race spec rider now.

With new lines is it acceptable to keep pumping the same fluid through when the bubbles have settled in the catch bottle at the bottom to make sure I've got a solid line of liquid in there? Also with 2 lines am I right in thinking I can simply do them one at a time? Is the main point of bleeding to get any trapped air out of the calipers?

[yorkie_chris]

Yes can do them 1 at a time, but you won't get firm lever untill both are bled.

Bleeding is to remove air, yes.

Don't use same fluid, use all fresh to get old water contaminated crap out of there, you won't use more than 200ml anyway and it's not massively expensive.

[monkey]

I'm gonna use new fluid I just wondered whether I could pass it round the system more than once to save a bit of time standing waiting for possible bubbles to reach the m/c and to make sure it's a solid liquid line or is it not worth the bother?

[muffles]

I'm gonna use new fluid I just wondered whether I could pass it round the system more than once to save a bit of time standing waiting for possible bubbles to reach the m/c and to make sure it's a solid liquid line or is it not worth the bother?

I would think you could do that? Only problems I could see are that you'd need to flush the system completely first so you don't mix the 2 fluids (otherwise how do you know when you've got to the new stuff), and also there might be a risk of getting bubbles in the fluid that's come through, as it comes out into whatever container? (I say that cos I've been told to leave the bottle still overnight to let it settle, and remove air bubbles - but sounds like YC knows his stuff, can probably advise whether that's really a problem)

[Dangerous Dave]

I'm gonna use new fluid I just wondered whether I could pass it round the system more than once to save a bit of time standing waiting for possible bubbles to reach the m/c and to make sure it's a solid liquid line or is it not worth the bother?
Do it when you are not going to ride the bike for a few hours, then when you are finished bleeding zip-tie the brake lever back (I do this overnight).

[monkey]

Okey dokey. Cheers techy peeps.
:)

[muffles]

Just got in from re-bleeding my lines, found quite a good technique - well, it's made the lever pretty stiff, but need to take it out for a shakedown run still.

I have a brake bleeding kit I bought off Ebay for £6 all in - basically it's a couple of syringes (little & big) and 2 bits of plastic tubing for each (short & long).

I filled the large syringe with fresh fluid (oh, bear in mind my system was filled with this fluid yesterday, so it's all fresh), and connected it to the bleed nipples one at a time. Then I slowly pumped it through until the M/C reservoir - lid off - was full (note: have to do it slowly apparently, HEL's web site suggests you may pop the seals otherwise - master cylinder I think?). Then I sucked it out again, and repeated a few times.

By keeping the syringe elevated in such a way that air won't go into the system (sensible really!) the movement of the fluid through the system cleared out a lot of the air & thus the sponginess.

Btw if you do take this route, when you first connect the syringe to the bleed nipple, elevate it and gently push and release the syringe to remove the air that gets trapped in the plastic tubing near the nipple, as a result of you putting it on the nipple. The air moves into the syringe and you'll only push fluid into the system, which is what you want.

[muffles]

Lever tested out in anger - very firm now! Still not 100% happy with the initial bite/grab - though I suspect that is because I'm comparing them to K8 GSX-R750 brakes, it's never going to live up to those without serious modifications. These are non-radial brakes with a non-radial M/C, and I'm not sure about the state of the pads/discs - possibly going to look at changing to some EBC HH pads or similar.

Anyway enough of the derailing...be interested to see your experience TM.

Lever tied back for the night now :D - one note on that, loosen the M/C reservoir cap and just put it on top - it's to allow the pressure to escape I think, but you need the cap actually sitting on there to prevent moisture getting in. I did it without doing this the first time, it didn't work, but when I then loosened the cap it worked wonders.

[monkey]

One MORE question. Is it ok or not adviseable to use brake new brake fluid from a bottle that's been opened (about a year ago)?

Nice method Muffles. Think I'm gonna stick with the length of tubing I have and the old soy sauce bottle for now.

[yorkie_chris]

Initial bite is more related to pad than hydraulics

[muffles]

One MORE question. Is it ok or not adviseable to use brake new brake fluid from a bottle that's been opened (about a year ago)?

Nice method Muffles. Think I'm gonna stick with the length of tubing I have and the old soy sauce bottle for now.

Np...if you get stuck you know what you can try, at least. I had a brake bleeder like that - stick the tube on the nipple, put fluid in the reservoir and pump through....awful really...didn't work well at all. Lemme know when you want to spend £6 I'll point you at the auction ;)

On the fluid...if it's been sealed (no moisture got in), it might be OK? Brake fluid is relatively cheap, though, may as well get some more for the price. I got a 250ml bottle, all I needed for the front, hardly any fits in the system - it'll be enough for the rear I have too (pointless, I know, but it was a set of 3...).

Initial bite is more related to pad than hydraulics

Aha, cheers - pointing more and more towards a set of new pads then :D

[ThEGr33k]

Already posted this on another thread but this one seems a little more alive...

Anyway I did what Muffle's did but with a squeezy bottle (does the same thing basically...

I think I may have got some oil on my disc's, I cleaned them off with brake cleaner, or tried but the bite seems pretty bad, Ive done 2 runs on it since doing the change (to Hel 2 lines) and it got a lot better since the start of the first run but it isnt back to the initial bite I had before the change. It also seems better once they were used hard and warmed up.

So basically im asking how long might it take for any crap that might have got in there to get burnt off... I suppose it might be that the pads need bedding in again though?

Sigh. :rolleyes:

[yorkie_chris]

Shouldn't take too long to burn any crap off. Take it for a good run and use them.

[Dangerous Dave]

I cleaned them off with brake cleaner
Don't use brake cleaner on the discs....

Shouldn't take too long to burn any crap off. Take it for a good run and use them.
+ 1, just go gently with them to begin with.

[ThEGr33k]

Don't use brake cleaner on the discs....


+ 1, just go gently with them to begin with.

I see. Fair enough, ill be getting new pads soon anyway since the ones I have in are getting a little low :(. I guess this should help :D

[muffles]

When I got WD40 on my rear disc (don't ask!) it took a while to return to full power, but did it progressively. I had to drag it along the whole ride home though, not sure if you are dragging your brakes or not? Which might explain the longer time required - though as YC says it shouldn't take that long, and of course front brakes can be on harder than the rear...

[Blue_SV650S]

Point1: The system is sealed so an amount of pressure applied at one end (the master cylinder) should result in an equal pressure at the calipers regardless of line length.

Point2: I have seen people post things like the advantage of a 2 line system is that both calipers move at the same time, whereas 3 lines, one caliper moves, then the other. This is carp.


Point1 is not entirely true as there is still some flex/swelling even in braided hoses.

As for point2 - it depends on the joint layout really doesn't it ...

[yorkie_chris]

Yes point 1 is true. Pressure is in this case static so any flex in the hoses jsut results in greater lever travel to produce that pressure, there is effectively no flow, so no pressure drop in the lines. (unless lever is going back to the bars, but really, how f***ed were your standard lines to cause that?!?)

Also it "should" be the same pressure in both calipers, regardless, but I have heard of this occuring. I won't comment on the matter because I don't know. Except to say get a 2 line kit as it's easier to bleed.

[ThEGr33k]

It will be the same pressure on both callipers, its just some pistons may move easier than others...

[monkey]

Stop!

[muffles]

Stop!

Hammertime!

[monkey]

:cool:

(You read my mind!)

[muffles]

:lol:

I like that this thread has become about everyone else's brake problems :p

[ThEGr33k]

:lol:

I like that this thread has become about everyone else's brake problems :p


Not like you can comment! :p

[lukemillar]

Hammertime!

Close, but no cigar!

The answer you were looking for was:

"collaborate and listen"

;)

[yorkie_chris]

Don't use brake cleaner on the discs....

Why not?

[muffles]

Not like you can comment! :p

:smt043 - true, but my problem/question is resolved now, so I can absolve myself of blame :p

Close, but no cigar!

The answer you were looking for was:

"collaborate and listen"

;)

Wayyy too sensible ;)

[ThEGr33k]

Hammertime!

Close, but no cigar!

The answer you were looking for was:

"collaborate and listen"

;)


Wayyy too sensible ;)


All wrong :p

It is "GO!"...

Ok im leaving. :(

[monkey]

Why not?

+1?

[monkey]

Well I've got myself a set of two HEL braided lines from M and P for the promised £40! I think they only do the standard clear although they did send the stainlessbits in the colour I wanted. All the bits look the right way round too.
:)

[Flamin_Squirrel]

Don't use brake cleaner on the discs....

Er, that's what it's for?

[Dangerous Dave]

Er, that's what it's for?
Er.... no, at least 99% of the products I have seen or used are for cleaning the calipers not the discs!

[yorkie_chris]

So if you've got some grease or other crap on the disc how are you going to get it off? Pi$$ on it?

The stuff I've got is a mixture of chemical nasties, comes in a steel 5l can and eats mostly anything. It evaporates quickly leaving no residue, which to me suggests it's perfect for cleaning the discs.

[Flamin_Squirrel]

Er.... no, at least 99% of the products I have seen or used are for cleaning the calipers not the discs!

Any decent company that sells a product called 'Brake Cleaner' is providing what YC says - a chemical spray that evaporates quickly, ideal for using on or near any brake components, including discs. Been using the stuff for a few years and never a problem.

No idea what stuff you've been buying, but if it screws your brakes, it isn't brake cleaner.