Topic: Front Brake line fittings for a 750K7

[M.Henry]

So I am going to make a set of custom braided brake lines for my K7. I have a buddy who is going to give me a few feet of his stainless steel braided line he got for a race truck project. It has been about 2 years since I last put together a set of custom lines for the race car team I was involved with.

So my concerns comes down to the fittings. I intend to use AN -3 for the primary choice for my fittings.

I need to replace the banjo 10mm on the brake handle end. I believe the hole is probably NPT threads, or maybe just metric threads. I plan on getting a male NPT (or whatever the threads are) to male AN -3 fitting, into the female AN -3 to line.
I will then likely just get a simple T block that has 2 male AN -3 with a female NPT (or whatever the threads of the brake pressure sensor is. I will also throw a residual pressure sensor on the line here to keep a small 2 PSI of pressure on the M.C. side of the system here.I will locate this in the same part of the front fork that the brake pressure sensor already is at.
Then I will go directly to the caliper with another male to male adapter and remove that short portion of hard line.

So what do y'all think? any feedback? recommendations? Things I may not be taking into account? do y'all know what style threads are on any of the components in the system?

[M.Henry]

I'd also be interested in a dual front brake build? Is this a fairly easy upgrade? or does it take a fair amount of modifying things? I am yet to put in the researching time I figured someone in here might know if its a pain or not.

[scottly]

The banjo bolt is not a tapered pipe thread, it's a straight 10mm thread, but I don't recall the pitch off the top of my head. The dual brake mod is fairly easy.

[754]

I think it's 10 x 1.25 but check it.
 Then get a 10x ××× to AN3 adaptor to thread into them and  calipers. .
K7 and K8 may need angle fitting.
 Your  junction can be a simple 3 or 4 way block of aluminum using 1/8 NPT tapped threads, and 1/8NPT to AN3  adaptors.
 If you go 4 way and need a cross passage in the block, use a NPT plug for the hole

[M.Henry]

hmmm. well running a straight metric thread with plumbers tape (or something of the equivalent) might be the direction to go then. if that won't be a good enough Then I guess I can keep the banjo fitting then.

Great. I will start to look into what all I need to do and get for the dual front disc build then.

[M.Henry]

K7 and K8 may need angle fitting.

What angle fitting are you saying? where would this need to be and why?

[scottly]

hmmm. well running a straight metric thread with plumbers tape (or something of the equivalent) might be the direction to go then.

NO!!

[seanbarney41]

You will need to use the banjo fitting.  Plumbers tape is not a sealant, especially when dealing with brake fluid.  Every fitting and adapter you need is available from Earle's.  I would not be fabbing brake lines unless you have access to a hose crimping machine and the training to use it correctly.

[754]

Myself I don't like using banjos  .
The K7 brake line exits caliper  at an angle, so changing angle, makes for a nicer look.
 Scott the straight thread adaptors, seem to seal up as the end of thread jams against master cylinder, at least it has for me at least 3 times.  In the caliper it can go against the seat, or seal on end ofvthread if you shorten the fitting.
 On some brakes, sometimes you can change end of thread , with NPT tap, to seal the fittings, but carefully compare sizes before you try it.

[M.Henry]

hmmm. well running a straight metric thread with plumbers tape (or something of the equivalent) might be the direction to go then.

NO!!

Ha. Yeah I guess something like that would be more of a band-Aid on a problem that really wouldn't take the pressure or hold up to brake fluids. Just using the banjo would be the proper solution.

[M.Henry]

You will need to use the banjo fitting.  Plumbers tape is not a sealant, especially when dealing with brake fluid.  Every fitting and adapter you need is available from Earle's.  I would not be fabbing brake lines unless you have access to a hose crimping machine and the training to use it correctly.

Luckily I do have experience fabbing brake lines. I do agree with you. a novice without experience does not need to be making their own brake lines cause loosing brakes is not a safety risk worth making.
I do not intend to use crimp style line fittings though. I intend to use a collar crushing a ferrule style shown in the below link. As long as you know what your doing they work just fine, which kinda holds true to crimp style too.
http://www.siliconeintakes.com/images/product/ss_install_3.jpg

[Paintedseat]

http://4into1.com/black-stainless-steel-brake-line-kit-single-line-honda-cb350-360-450-550-750/

[754]

Like I said the metric thread to AN3 adaptors seem to seal up.

[754]

2 posts back the chrome adaptor seats on the nipple in the caliper. I have used then in the master cylinder with no leaks.,,  I suppose you could run a fibre washer or copper at the MC..

[M.Henry]

Yeah, I'm now considering that 4 into 1 kit. Throw a residual brake valve at the handle and a T block with a brake pressure sensor down on the caliper end of that system.

[scottly]

Throw a residual brake valve at the handle

There is no need for a residual pressure valve; they are only used with drum brakes.
The banjo bolt thread pitch is 1.25, like Frank said. The banjo bolt is sealed by the copper washers, that fit on either side of the banjo; the one under the head of the bolt gets squeezed between the bolt and the banjo, and the other one gets squeezed between the banjo and MC. The simplest solution would be an adapter that mimics a banjo bolt on the MC end, with an AN fitting on the other end.
At the caliper end, the thread for the flare nut is the same 10mm x 1.25 as the banjo bolt, and a banjo can be used, but the flare seat must be removed first, and the surface the copper washer seats on needs to be machined flat for a good seal. Again, the simplest solution would be an adapter with a female flare on the caliper end and an AN fitting on the other.

[Paintedseat]

The 4into1 kit fits perfectly. The only issue you will have is the brake light. The stock block has the switch in it. You can buy banjo bolts with the switch integrated.

[754]

The built in switch may be a 78 only thing.
 

[Paintedseat]

Mine is a 77

[scottly]

Here is a pic of my K7 calipers modified to use banjo bolts.
Also, the biggest hassle for a dual brake conversion is the speedometer drive; this is one way to do it. 

[M.Henry]

Ah. OK. So I could run the 4into 1 line (http://4into1.com/black-stainless-steel-brake-line-kit-single-line-honda-cb350-360-450-550-750/) with their Banjo Bolt Brake sensor (http://4into1.com/universal-10mm-hydraulic-brake-light-switch/). and the system would work just fine.

I've always been taught that the residual brake sensor helps add a touch of preloaded pressure into the MC and helps give you a brake lever that is not loose at the beginning of its travel. Since I have a very wimpy and loose front brake already. I would prefer to use this to give a better feel the the front brakes. Is there anything inherently wrong with using one?

and ok. Thanks for the feedback on the dual disc. I will do some research and read a few threads ( I think i saw a new one on dual discs on the main page) and come back on a new thread for that concern.

[Paintedseat]

If you are using the stock brake/MC than you will have to use a banjo bolt with the switch. As for the switch helping with initial brake feel and lever movement that is just not true. The micro switch used in the lever applications will in no way effect lever movement or feel. You can buy an aftermarket brake/MC that has the switch integrated into the lever but there is no way to do it with the stock setup. If your lever is floppy it is because it is either not tight enough, and adjusted properly, or just worn out. I replaced mine and it is much better.

[M.Henry]

Yeah I saw it discussed in another thread, "GL1000 to CB750 front end swap", that just swapping for a stock looking MC should help with brake feel and performance a lot as well. Is this a fairly common upgrade? Is there a preferred model or brand that people usually switch to?

[M.Henry]

So I guess another major consideration to take into account is that If I intend to put dual brakes on. I will need to purchase a different MC and do the lines different anyways. At that point it may simply just be easiest to go with the custom Line I intended. Though I know now more about what fittings to go with.

[M.Henry]

Oh, And my dislike of Banjo fittings stems from the fact that they have 4 sealing surfaces and hence 4 failure points. They are popular though because of their simplicity which offsets this 4 failure point risk versus other systems which may only have 1 sealing surface, (or redundancy levels of sealing surfaces) but have inherently more complexity.

And I like the An -3 fittings because of the non-crimping style hose end fittings that you can use, as well as a constant cross sectional area. Though that constant cross section comes into account more with fuel lines where banjo restricts flow greatly.

[Paintedseat]

Not enough pressure on these systems to worry about it. I don't really understand the duel front brakes either unless you are doing a fork swap. The single works plenty good enough to lock up the front wheel.

[M.Henry]

ehh, The push for dual might just me being eager to do upgrades. It may also stem from frustrations with not getting the front brake as stiff as I want. I've done a rebuild of the MC, I put a new caliper and piston on the bottom, I've bled the day lights out of the system multiple times.

Plus I think that the front wheel looks better with the balanced look of a rotor on both sides. Especially since the mounting locations are already there on the casting for the lower fork tubes of my K7.

[754]

Not enough pressure on these systems to worry about it. I don't really understand the duel front brakes either unless you are doing a fork swap. The single works plenty good enough to lock up the front wheel.

My stock unfilled single disc sucks, if I don't hold it on in the rain..no braking..
 I suspect pads, no stopping power.
 The dual drilled stock discs with stock mc, I ran years ago were fabulous...

[Paintedseat]

Good point.

[seanbarney41]

Not enough pressure on these systems to worry about it. I don't really understand the duel front brakes either unless you are doing a fork swap. The single works plenty good enough to lock up the front wheel.

My stock unfilled single disc sucks, if I don't hold it on in the rain..no braking..
 I suspect pads, no stopping power.
 The dual drilled stock discs with stock mc, I ran years ago were fabulous...

scary #$%* in the rain when you grab the handle and it feels like the bike goes faster lol

[M.Henry]

Oh, that doe sound scary. I will admit I do engine brake and rear brake more so by habit since I have learned to ride on this bike with weaker front brakes. Especially since It had pretty much no brakes when I first started puttering her around cautiously.

After brake modes, I personally intend to rebuild the front fork cause it is way too soft with age.

[scottly]

So I guess another major consideration to take into account is that If I intend to put dual brakes on. I will need to purchase a different MC

The stock 14mm MC works fine with dual K7 42.8mm calipers; I ran this setup for years.

[M.Henry]

Did this utalize the full travel of the pedal with that stock 14 mm MC? do you feel like you could go far enough with it to lock the brakes up with full panic braking or atleast get close? I'd be concern about not pushing quite enough volume to get full potential out of both Calipers.