Topic: '76 550k upgrade to Stainless Steel brake line, help me plan my upgrade

[danielg]

I've got some brake questions.  Don't worry, I've done my searches.  In fact, I've probably spent way too much time at work today researching this.

My front brake on my '76 CB550K has developed a terrible squeal.  I'm already planning on cleaning up the piston in the caliper and the seal.  That's now what this post is about.  There's enough info for that problem on these forums to... kill a horse.  (say what?)

I'm here to discuss braided steel brake lines.  My lower rubber line is cracked and dry-rotted--definitely in need of replacement.  I figured why just replace it?  Why not go braided?

There are two options I'm considering.  I've outlined them both below.

Plan 1:  Bypass the pressure sensor
I can get 1 stainless line to run from the master cylinder to the caliper bypassing the pressure sensor and the hard line.  To do this, I'll have to get a banjo bolt with a built in sensor (like the one here: https://helusa.worldispnetwork.com/secure/banjobolt/m10x125.htm).  This is a simple, and seemingly clean setup.  Fewer place to trap air bubbles, too.
I'll just need to buy 1 line, 2 banjos, 1 regular banjo bolt, and 1 sensor-banjo bolt.

Pan 2: Upgrade both rubber tubes
I can get 2 stainless lines to replace the two rubber lines.  I'll still bypass the solid metal line near the caliper since it seems like a strange component to fit to braided lines.  This way, however, I'll need to purchase 4 banjos and 1 or 2 banjo bolts.

I've already planned out the parts I will purchase from Z1 (http://www.z1enterprises.com/catalog.aspx?pid=MFGO0)

So what have others done?  What would you do?  It sounds like plan 1 will cost less, but will require some electrical work.  But Plan 2 is more stock.

Any thoughts?

Thanks for reading and giving any advice you may have.

[Bodi]

I got a single line - russel component line with banjo fittings - and a sportbike m/c with built-in mechganical brake light switch. I think the pressure switch tee traps bubbles and causes sone sponginess, and with repeated back bleeding by pumping the caliper waaaay out then pressing it back in I have a rock-solid lever feel. The sportbike m/c has a bigger piston bore than stock and I think the stock one would work stronger, but I can still get the front tire to howl on stops. The banjo switch would be a good alternative - I lost the right mirror mount but haven't used a right mirror in 44 years of riding anyway.
The banjo will fit right on to your caliper IF you get the right threads on the bolt AND make sure it isn't too long AND you may need two crush washers underneath to raise the banjo above the counterbore in the caliper. I machined off that counterbore, removed the steel insert flare seat and threaded the full depth with a bottoming tap so I didn't need to worry. The threads are deep enough to hold securely even with the seat in, but you have to ensure your banjo bolt doesn't bottom out. You may have to file the end down a bit. I like the Russel line because I could pass the line through the original bracket grommet for the hard line and then attach the banjo end, the banjo would not fit through there if I had a preassembled line. The Russel stuff is also fully certified for street use, many premade lines are not: these are still definitely safe and stronger than the rubber OEM lines but being DOT certified may count for something if there's an accident and some insurance company is out to screw you.

[danielg]

Am I correct that Honda uses 10mm Diameter x 1.00mm Thread Pitch  NOT 1.25mm Thread Pitch?

[danielg]

based on my searches "all SOHC 750s use 10 mm x 1.25".  So I was wrong.  Good thing I didn't order yet.  I assume (hope!) the 550s use the same?

[danielg]

I ordered the following (from z1 

   
TU03-6053  Brake Hose 10MM 35 DEG BANJO FITTING  1   $9.59   
TU03-6239  Brake Hose 10MM X 1.25 MALE TO MALE ADAPT   1   $7.86   
TU03-6125  Brake Hose Stainless Steel 30" Clear Coated   1   $22.69   
KS12-0010  Brake Light Switch Banjo Bolt   1   $11.86   
Total w/shipping     $58.16

[mystic_1]

Don't forget new sealing washers.  You'll need two per banjo fitting.

cheers
mystic_1

[cbass*gxc]

Daniel I just ordered my custom single hose from Spiegler Monday so hopefully it will be here before the weekend.  I used your first method of getting one hose with a banjo bolt with light switch.  I didnt really like the factory switch so I went the single hose route.  I will try to get it hooked up this weekend and post some pics.  The nice thing about mine is they have a fitting (#520) that goes on the end of the hose and connects straight into the caliper, replacing the hardline coming out of the caliper.

[danielg]

That is the same method I'm using.  I did some searches and guessed at 30" for the SS line.  It turns out that using the current routing, my measurements came out to 36-38"!  Yikes.  How long was the one your ordered?

I plan to bypass the hard-line and go directly into the caliper, too.  I'm using this part to do it, just like the "520" you ordered.

I just pray 30" is long enough.  If not, I'll be returning it and going for something longer.  BTW score one for Z1. Ordered yesterday and I'll have it tomorrow or Saturday, and just paid an extra $8 for priority USPS shipping.

And thanks for the sealing washer tip.  I'm pretty sure the banjo bolt comes with two.  If not, I can pick those up locally.

[cbass*gxc]

I did 30" as well so hopefully mine is long enough.  I ran ice maker hose from the master cylinder to the caliper and measured twice.  Mine is lowered about 5" and the handlebars are quite a bit lower than the stock bars are too so I should be good.  I will let you know what I find out when they come in.

[danielg]

I did 30" as well so hopefully mine is long enough.  I ran ice maker hose from the master cylinder to the caliper and measured twice.  Mine is lowered about 5" and the handlebars are quite a bit lower than the stock bars are too so I should be good.  I will let you know what I find out when they come in.

I just modified my order to a 36". 

[Shenanigans]

Don't mean to hijack but...

I have a double banjo bolt from a early Night Hawk 650. I cant seem to find the thread/pitch of it anywhere and was wondering if it was the same as used on the 550?

[danielg]

Sorry, I'm not sure.  But based on my searches, all old hondas use 1.25 mm thread pitch.

[Shenanigans]

Sorry, I'm not sure.  But based on my searches, all old hondas use 1.25 mm thread pitch.

Thanks, but sure enough when I was in the bike junkyard today I came across a 750 front end that had been dual disked! (If anyone is looking for that set up PM me and I will tell you where it is) and I snagged the double banjo bolt.

Both the bolts are pretty much the same except the nighthawk bolt is shorter by about a quarter inch and has a quarter inch less thread. I think both would work in the pressure switch. If anyone cares to know...

[MJL]

I've thought about the SS lines myself, and bypassing the pressure switch seems doable. I rarely ever use the front brake alone, and usually have some extra play in the rear lever so I can activate the brake light while downshifting if I don't exactly need the brakes.

[cbass*gxc]

Well Daniel I got mine in and installed this evening after work.  Went together very easy and the banjo switch works great.  30" was perfect for me so if you are running stock I would say 36 or 38 would be good.  Anyways here are some pics.

HD Master Cylinder w/ Black Banjo Fitting and Banjo Bolt w/ Light Switch. 
Bigger Image - http://jaypage.com/pics/motorcycle/Front%20Brake%20MC.JPG



Honda Caliper w/ 520 Fitting from Spiegler.
Bigger Image - http://jaypage.com/pics/motorcycle/Front%20Brake%20Caliper.JPG

[danielg]

very nice.  I should have some pics of mine Saturday or Monday!

[danielg]

Well my parts arrived Saturday, so I got to work.

The 36" cable, routed the same as stock, probably could be 2 inches shorter and still work.  I think I could've actually used the 30" by routing the line in front of the fork, but I went behind and used the same path the hard line did.

The pressure banjo bolt is perfect!  The male-to-male part that goes into the caliper was a bit long, so I stacked three crush washers to make it work.  The result is a very stiff lever and much better braking performance.  Now if I can only stop the squeal upon application.  I'm still planning on rebuilding the MC and getting new pads.  I thought it was the old banjo bolt fitting that was leaking, but now it is apparent that is the MC.

Likes:  good feel, reliable line
dislikes: I wish I got a black covered line (I got clear coated) so it would look more sock.  Also, I really should shave down the male-to-male fitting that goes into the caliper so I don't have to use 3x crush washers.  Lastly, I don't like that I had to put the banjo bolt with the pressure wires up by the MC fitting.  The area is just too busy now.

Perhaps I'll snap some pics this week.

[Helo229]

I'm currently doing the exact thing with my brakes, more or less with the same shopping list from Z1.

The TU03-6239  10mmX1.25 Male to Male Adapter was the only bolt I tested on the bike, and it seems to be a tight fit. I don't have a thread guage, but it seems like a 1.00 pitch might be a better fit. The stock banjo bolt slides right in, but the male-male adapter goes in about 1 or 2 turns and is snug.

Before I tighten all this up and pressure test, can anyone verify that the front caliper on a 750F is indeed a 10MMX1.25?