Most motorcycle problems are caused by the nut that connects the handlebars to the saddle.

banjo torque

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jerryfudd
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banjo torque

Post by jerryfudd on Fri 27 Feb 2015, 7:53 am

hi,

just fitted HEL SS lines and having problems bleeding the brakes - there always seems to be air so must be drawing in from somewhere.

the Haynes/honda manual says 35nm! which I did once (with no joy anyway) but seems really excessive.

also are people using the HEL fittings? the bolts are slightly shorter than OE? in also using a Pro-Bolt SS bleed screw but have just notice that the PB has a point at the end that sits in the caliper whereas the Honda is flattened off?

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Re: banjo torque

Post by Guest on Fri 27 Feb 2015, 9:20 am

From my experience. On the standard banjo bolts indeed 35Nm did the job, both on the calliper and the master cylinder (front). Mind I did replace the two metal washers. I've heard they will go on and off a few times only. Getting the air out did take a while, after purging until no more air escaped all that was needed was a ten minute manipulating of the brake lever until no more air showed up in the reservoir and the grip got gradually firmer and firmer.
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Re: banjo torque

Post by jerryfudd on Fri 27 Feb 2015, 11:08 am

Thanks, I've been trying to get the brakes working for a couple of days with no joy and I'm running out of ideas on how to get it working or pin point where the problem is Sad

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Re: banjo torque

Post by Guest on Fri 27 Feb 2015, 11:25 am

Moonfleet41 on youtube has a few video's about working on brakes I found educating.
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Re: banjo torque

Post by Ayep on Fri 27 Feb 2015, 11:39 am

In my experience, bleeding the brakes on that bike is not as simple as it seems initially. How sure are you that the brakes were bled correctly, initially? (i.e. are you sure it's a leak?)

I've wasted many hours trying to figure out why my brakes wouldn't work, after changing banjos ; as in most cases, it ended up being bad purges.

Personnaly I've found the best way is to pump liquid, via an aquarium type tube full of DOT, into the brake caliber, and fill the master cylinder bottom up. Also, using that technique (with a bicycle pump), you tend to pressurize the liquid a little, and will notice many bubbles resurfacing in the MC. Using that method, brakes will be operational right away after a banjo change.

Just my two cents - not sure how familiar you are with bleeding brakes.

Tony
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Re: banjo torque

Post by jerryfudd on Fri 27 Feb 2015, 12:07 pm

thanks, the bike is being rebuilt so the system was in pieces - calipers have been rebuilt and MC serviced aswell as adding the HEL lines.

bad purges?

I initially tried to fill it bottom up via the bleed nipple with no success. I then tried the conventional method of open bleed, pull lever and then shut bleed screw and repeat but again no joy. I also saw a tip about submerging the caliper banjo in the MC tank and pull lever till no bubbles appear and then tie lever back and re-attach the banjo to caliper and then bleed conventionally but still no joy.

How do you use the bicycle pump????

I also tied leaving the lid off the tank and the lever tied back for 12hrs.

The best result I've had from anything I've tried so far is pulling the lever and getting a little resistance and bubbles rising from the MC tank but then on every pull after no resistance and no bubbles but then leave it a min or so and id again get the minimal resistance and bubbles.

I did wonder if it was my MC rebuild but I'm also struggling to bleed the rear and I didn't rebuild that one.
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Re: banjo torque

Post by eternally_troubled on Fri 27 Feb 2015, 2:06 pm

Did you use new copper washers on the brake banjos? (I bet you did) The 35Nm is all about squashing those copper washers. Once they have been squashed you need to buy new ones or re-anneal the old ones (with a blow torch!).

I didn't have a problem last time I bled my CB500 - I do it the old skool way and use windscreen washer tube from the bleed nipple into a jam-jar with a bit of fluid in the bottom. I also plan to use lots of fluid, so I use a clean jam jar (no jam left!) so I can pour it back into the bottle if required.

I essentially keep pumping steadily until fluid reaches the bottom of the system (i.e. you can see something in the bleed hose). This can take a while as the there is only so much fluid that can enter from the reservoir into the bore during each stroke of the piston.

I then proceed to pump lots of fluid from the reservoir to the jam jar - even after I have stopped 'seeing' bubbles coming out - I've seen almost microscopic bubbles still coming out long after you might have thought you were 'done'.

I then usually do the 'tie the lever back overnight' thing to finish it off.

I have also previously used a big syringe on the bleed nipple (with a short bit of pipe) to suck brake fluid through the system which makes the first part (filling the system) rather quicker.

Good luck!
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Re: banjo torque

Post by jerryfudd on Fri 27 Feb 2015, 2:09 pm

do you nip the banjo closed between pumping the lever?
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Re: banjo torque

Post by eternally_troubled on Fri 27 Feb 2015, 2:13 pm

Nope, not always. I did try that (thinking that the fluid will just flow back in and undo the good work), but it doesn't always seem to make things quicker.

I have tightened/undone it nearer the end to try and trap some of the air bubbles outside the line.

Generally I try and get a good flow going (out of the res. into the jam jar), which indicates the system is full of fluid (or at least, mainly fluid and few bubbles) before I start to worry about screwing the nipple.
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Re: banjo torque

Post by jerryfudd on Fri 27 Feb 2015, 2:21 pm

Thanks, ill try (again) tonight.

Still can't help thinking that something isn't right - is there anyway of telling if I have done a poor job of rebuilding the MC or the caliper?

In answer to your question I did use new copper seals and 35nm (the first time) but after failing and having the line off re-used the seals as I had no others but have more on the way.
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Re: banjo torque

Post by eternally_troubled on Fri 27 Feb 2015, 2:23 pm

@jerryfudd wrote:

In answer to your question I did use new copper seals and 35nm (the first time) but after failing and having the line off re-used the seals as I had no others but have more on the way.


I wouldn't worry too much about re-using them.  You shouldn't do it, but...  you will notice if it leaks onto your new paint work!

I suspect that if re-using copper banjo washers meant instant crashing then there would be a lot more motorcycle crashes.


Last edited by eternally_troubled on Fri 27 Feb 2015, 2:24 pm; edited 1 time in total
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Re: banjo torque

Post by Ayep on Fri 27 Feb 2015, 2:24 pm

@jerryfudd wrote:thanks, the bike is being rebuilt so the system was in pieces - calipers have been rebuilt and MC serviced aswell as adding the HEL lines.

bad purges?

I initially tried to fill it bottom up via the bleed nipple with no success. I then tried the conventional method of open bleed, pull lever and then shut bleed screw and repeat but again no joy. I also saw a tip about submerging the caliper banjo in the MC tank and pull lever till no bubbles appear and then tie lever back and re-attach the banjo to caliper and then bleed conventionally but still no joy.

How do you use the bicycle pump????

I also tied leaving the lid off the tank and the lever tied back for 12hrs.

The best result I've had from anything I've tried so far is pulling the lever and getting a little resistance and bubbles rising from the MC tank but then on every pull after no resistance and no bubbles but then leave it a min or so and id again get the minimal resistance and bubbles.

I did wonder if it was my MC rebuild but I'm also struggling to bleed the rear and I didn't rebuild that one.

Hmm, the problem with the whole rebuild (MC / calibers) is that it will indeed make things harder to rule out.

The slightest bubble is enough to disrupt the whole thing. Hard to say what's happening here.

About the bike pump - I use that instead of a syringe, same principle. I hook up some aquarium tube (1m ) on the caliper bleeding nut (open), make sure I have a good fit (cable tie, and obviously tube has to be the right diameter); I fill it with DOT liquid, keeping it vertical. (MC lid stays off.) I then hook up the tube to a bicycle pump (the tube fits in the car valve type pumps), with a good fit. A bit of pumping sends the DOT liquid straight up the caliper and MC. Without a doubt the quickest method I've had experience with. Takes me 10min to get a fully functional brake... Hard to explain, I'll see if I can draw a schematic if it's unclear.
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Re: banjo torque

Post by eternally_troubled on Fri 27 Feb 2015, 2:25 pm

Ah, so you used the bike pump as a syringe to push the fluid up the system?
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Re: banjo torque

Post by jerryfudd on Fri 27 Feb 2015, 2:27 pm

ah, got you. I used a syringe when I tried it.
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Re: banjo torque

Post by HomeBrew on Sat 28 Feb 2015, 8:58 am

The pro bolt bleed screw- can you show a link or pic? If the end isn't the same as the honda it isnt going to seal, the end mates with the caliper to cut off the flow. If you open the bleed screw too far air will get in along the threads too. 

This tool vacuum pump makes bleeding brakes fast and easy.
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Re: banjo torque

Post by jerryfudd on Sat 28 Feb 2015, 9:32 am

Firstly some good news - the front is working.... I'll get to why but just for reference these are the HEL and PB bleed compared to OE (and it is working with them).



Problem was in the master cylinder - when I dismantled awhile ago after a little tug the piston came out with a boiiiiiiing and so did the parts which meant I was looking for a diagram of it. The diagram in the Haynes and in the main Honda book looked to cover the Nissen MC - not the Brembo I needed and these are the bits I was working with...



I found a picture in the Honda T-V amendment but it was a crappy picture and it seemed to go back pretty well. All the parts were in the diagram bar that little black piece of rubber (guess where the problem lies!).

So it seemed self explanatory where it went and I attached it as I 'believed' it came out in a cap like fashion on the end of the piston and together it went.

(insert all the problems described earlier here)


Then yesterday I looked at the diagram again and noticed a little protruding lip which i've arrowed



That little lip there implies that the 'cap' washer was actually a cup like washer.

So here's the problem......



and here's the correction.....







PHEW!

now need to figure out what i've sodded up on the rear - which could just be a bad bleed as I didn't dismantle the rear MC.

Thanks for everyones help, in the end I did the reverse bleed and then a conventional bleed for good measure and it firmed up a treat Smile
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Re: banjo torque

Post by Ayep on Sat 28 Feb 2015, 12:54 pm

Excellent news!

Actually I remember hesitating about which way around that rubber part goes on last time I restored an MC. I checked on a Honda parts website... Glad you found the problem. (The banjo torque did seem to be an unlikely cause for such leaks.)

As for the rear, no need for it anyway, just use the engine braking  Laughing
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Re: banjo torque

Post by ashcroc on Sat 28 Feb 2015, 2:49 pm

Glad you've sorted it. Hope you're remembering to wet down anywhere brake fluid could spill. It's a fantastic paint stripper!
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Re: banjo torque

Post by eternally_troubled on Sat 28 Feb 2015, 5:56 pm

Great!  Good to hear you got it sorted.

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