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K100-forum.com » Technical, repair and troubleshooting » Need ideas for fitting SS brake line to rear master cylinder

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robmack

robmack
Life time member
Life time member
Hi,

I had a new brake line made up for my K75 rear brake (non-ABS).  One end is a straight fitting that mates to the rear master cylinder and the other is a 45 degree banjo that bolts up to the rear calliper.  When I thread the straight onto the MC, the banjo is wrong way around, meaning that I have to put a twist into the flexible line to make the banjo match up.  This is a result of the banjo being crimped to the line 180 degrees out (and I can't rotate the banjo fitting on the line).  I would need to add 1/2 turn to the straight fitting to make it work but that would require me to over-torque the fitting and risk ruining the master cylinder threads.

I need a way to torque up the straight fitting to align the banjo properly.  I have two ideas but am soliciting for more:

1. insert a crush washer into the outlet of the MC.  The crush washer would raise the level where the fitting mates, allowing me to correctly adjust the brake line.  I don't know if putting a washer in the MC is a good idea, especially if it gets jammed.
2. file off the end of the straight fitting so that it screws deeper into the MC port

Can anyone tell me which of these is best?  Is there a better way to get this accomplished?  These are brakes after all and I'm wary that I get the safety things right on the bike.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

Gaz

Gaz
Life time member
Life time member
Rob, I recently fitted stainless brake lines to my K75 (ABS) and the rear master cylinder had a banjo fitting on it from factory. Not sure if they have a different master cylinder to the non-ABS. The new line banjo was fitted as usual with a new seal washer either side supplied with the line. 

I'll try to take a photo when I get a chance.

Cheers


__________________________________________________
Gaz
1990 K75 6427509; 1987 R80G/S PD 6292136; 2010 G650GS ZW13381; 95 K1100LT 0232224
    

robmack

robmack
Life time member
Life time member
Thanks Gaz but I can't afford to buy yet another line.  This is the second one I've had built for this rear brake and I will not buy a third.  Sorry but I have to make this one work.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

Mossy1200

Mossy1200
Platinum member
Platinum member
Idd be trying a rubber O ring with same external as the banjo outside thread.
Buy 2 and trial the first. Remove after marking the mating point of the hose and inspect the O ring.
If you are happy the oring wasn't damaged install the second to the same mark using low strength Loctite on the banjo thread to ensure it doesn't come out unless removed with tools.

Don't try reduce the mating surface of the straight banjos front edge.

    

Rick G

Rick G
admin
admin
Mossy1200 wrote:Idd be trying a rubber O ring with same external as the banjo outside thread.
Buy 2 and trial the first. Remove after marking the mating point of the hose and inspect the O ring.
If you are happy the oring wasn't damaged install the second to the same mark using low strength Loctite on the banjo thread to ensure it doesn't come out unless removed with tools.

Don't try reduce the mating surface of the straight banjos front edge.
That is a very dangerous thing to do. A handfull of brake in an emergency stop and that might be the last thing you know happened.  Deadly dangerous. Never use an O-ring without a recess for it.  Quite easy to get 1000psi in a braking system.

Rob the fitting on the rear of the master cylinder should have a free turning fitting and a ball flare so the M/C end goes on first and the M/C fitting is then tightened with it in place. Similar fitting that is on the front calipers where the crossover line screwed in.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

Mossy1200

Mossy1200
Platinum member
Platinum member
RicK G wrote:
Mossy1200 wrote:Idd be trying a rubber O ring with same external as the banjo outside thread.
Buy 2 and trial the first. Remove after marking the mating point of the hose and inspect the O ring.
If you are happy the oring wasn't damaged install the second to the same mark using low strength Loctite on the banjo thread to ensure it doesn't come out unless removed with tools.

Don't try reduce the mating surface of the straight banjos front edge.
That is a very dangerous thing to do. A handfull of brake in an emergency stop and that might be the last thing you know happened.  Deadly dangerous. Never use an O-ring without a recess for it.  Quite easy to get 1000psi in a braking system.

Rob the fitting on the rear of the master cylinder should have a free turning fitting and a ball flare so the M/C end goes on first and the M/C fitting is then tightened with it in place. Similar fitting that is on the front calipers where the crossover line screwed in.


It sounds as if the fitting is not a ball flare.
O ring as per picture. I think you are assuming I was recommending it as a crush washer replacement on a standard banjo fitting.

Need ideas for fitting SS brake line to rear master cylinder Jb11

Now I have questions.
Are my brakes different from stock.

I don't have any brake pipes(solid) front or rear.
My front brakes are 4 pot and not 2.
Looks like my brake system has been changed both front and rear and don't match the manual at all.

Need ideas for fitting SS brake line to rear master cylinder 310




    

Rick G

Rick G
admin
admin
I was imagining it EXACTLY like you have drawn and that IS one of the most dangerous things I have ever seen suggested with regard to brakes. If you wish you can do that but I certainly don't recommend it to anyone.
Doing something like that is playing with your life.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

robmack

robmack
Life time member
Life time member
RicK G wrote:Rob the fitting on the rear of the master cylinder should have a free turning fitting and a ball flare so the M/C end goes on first and the M/C fitting is then tightened with it in place. Similar fitting that is on the front calipers where the crossover line screwed in.
Is it a rigid pipe with a ball flare on the end to which you refer?  If so, that I have such a line in my possession.  In fact, I had this new line made up as a replacement because I didn't have any spot on the swingarm to secure the free-end of the rigid pipe.  I felt it had to be replaced with 100% flexible line.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

Dai

Dai
Life time member
Life time member
Rob - I have no idea what the rules and regs are for Canada but I've been making my own lines for over thirty years. Depending on how much slack you have in that line, you may get away with the following. You'll also find it easier if you unbolt the caliper so you can pull it upwards.

Go to UpTheShop on ebay or somewhere similar and buy a 45-degree banjo kit. Get a packet of five spare olives too - no.3 size.
Cut off your existing banjo with a good sharp pair of tinsnips.
Chances are it will be slightly crushed - return it to round using a small pair of plier to 'crush' it the other way.
Slide the nut on.
Slide the olive between the stainless outer and the teflon inner. Be careful you don't trap any loose strands between the olive and the inner.
Push the banjo into the teflon inner.
Put the whole assembly onto the bike - the MC end doesn't need to be tight but it does need to be bottomed reasonably securely.
Start tightening the new banjo nut. If the line twists, back off to fully slack, manually twist the braided line the other way and start with the nut again. It's a bit of trial and error but the point of no return doesn't come until you have to nip the whole lot up tight and crush the olive. If you see the neck on the banjo start to twist STOP IMMEDIATELY. You're as tight as it will go without snapping the banjo but you won't have done any serious damage.
Give it a seriously good pressure test by standing on the brake lever. If it weeps, nip it up one-eigth of a turn more. If it pressurises and then goes slack later, chances are you trapped a stainless strand (yep - been there...). Dismantle, check and use a new olive.

Because of the prevalence of stupid H&S regs throughout the world I have to add the standard 'at your own risk' disclaimer, otherwise I wouldn't bother.

As regards the calipers: no, they're not standard but they are good. Someone has bought/made an adaptor to put 40mm center four-pots on the P08 mountings. It's a common Guzzi mod (done it on one of mine and got the bits for another), so I recognised it instantly. If you have the standard BMW handlebar master cylinder then with the stainless lines brake pressure should not be a problem. If you absolutely want to replace with standard P08s (but I don't recommend it) then I can do you a grateful swap for a freshly cleaned and overhauled pair!!!


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

Rick G

Rick G
admin
admin
robmack wrote:
RicK G wrote:Rob the fitting on the rear of the master cylinder should have a free turning fitting and a ball flare so the M/C end goes on first and the M/C fitting is then tightened with it in place. Similar fitting that is on the front calipers where the crossover line screwed in.
Is it a rigid pipe with a ball flare on the end to which you refer?  If so, that I have such a line in my possession.  In fact, I had this new line made up as a replacement because I didn't have any spot on the swingarm to secure the free-end of the rigid pipe.  I felt it had to be replaced with 100% flexible line.
I didn't express myself well there Rob the fitting is similar to a ball flare in that the part that screws in is not fixed to the fitting but captive on it and the end that goes into the M/C is similar.
Not sure about the K75 or K100 but my K1100 had a fitting like that on the old hose.  I had a local make some up and it was a mess so I got some venhill lines and perfecto so I have now modified the local made ones to go on the car well 2 of them anyway and one other will go on the K75 Chookie.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

Dai

Dai
Life time member
Life time member
Rick - if it's a made-up stainless line then it will have an inline fitting on it, rather than the flared end you get with a bit of solid pipe.


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

Rick G

Rick G
admin
admin
Dai wrote:Rick - if it's a made-up stainless line then it will have an inline fitting on it, rather than the flared end you get with a bit of solid pipe.
I will have one last attempt. Please read this carefully  AN INLINE FITTING SIMILAR TO A BALL FLARE. Do you understand that. Please note the word SIMILAR.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

robmack

robmack
Life time member
Life time member
OK, here's some photos to help visualise.  

Need ideas for fitting SS brake line to rear master cylinder DSC_0381

All the fittings used are manufactured by Apex Brakes and they require a hydraulic press to secure them to the SS lines.  Be aware that the fittings are machined metal and do not consist of separate parts that can rotate or move relative to each other.  When the fitting is crimped on, it is permanent and immovable.  To answer your suggestion Rick, I can't move any part of the line relative to any other.

Originally, I had the fellow make up a line consisting of Apex #7 and #9 fittings which allowed me to use the original rigid pipe from the K75.  It fit well because the flared ends on the rigid pipe allowed me to get an exact fit.  I was worried when Rick reminded me that the rigid line needs to be secured at each end otherwise it work hardens and fails over time.  This was the motivation to get the new line.  I did not count on the rigid nature of the fittings giving me so much grief.

If we examine this photo closely where the flexible line mates with the MC, we can see the type of straight fitting to which Rick refers.  Too bad Apex doesn't offer this fitting type.

Need ideas for fitting SS brake line to rear master cylinder Rear%2520brake%2520line%2520routing  Need ideas for fitting SS brake line to rear master cylinder Rear%2520brake%2520coupling


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

Rick G

Rick G
admin
admin
That is the fitting I had to use to get the alignment so it wouldn't put strain on the hose by twisting it.
I know how infuriating it can be but Venhill lines were the way to go for me. I had a special made because I could not get a straight fitting on after I built the towbar for the K1100 and I ended up redesigning the towbar attachment and mounting so I could use the straight fitting.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

Dai

Dai
Life time member
Life time member
RicK G wrote:
Dai wrote:Rick - if it's a made-up stainless line then it will have an inline fitting on it, rather than the flared end you get with a bit of solid pipe.
I will have one last attempt. Please read this carefully  AN INLINE FITTING SIMILAR TO A BALL FLARE. Do you understand that. Please note the word SIMILAR.
Oops. Embarassed


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

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