RP Rear brake cables

[AustinWood]

I think ball to backplate is the correct way round

[Tony Press]

Reverse the Austin lever so that the ball faces the backplate, or use your homemade lever, I have fitted turnbuckles for adjustment at the cross shaft end of the cable quite successfully.

Thank you Ian, I had not thought of reversing the A7 levers, I thought it would affect the angle of the lever, but the cotter must do that if put in back to front.

Roger

The brake levers should always be put on with the ball toward the backplate - the cable pull is then under the cam bush bush giving a better wearing support to the cam.

This would also put the turnbuckle in a better place- and of course your excellent design is far preferable to the presently available 'pinch bolt'  fixing which cannot be adjusted after the initial very tight fixing.

Tony.

[Robert Leigh]

Sorry, couldn't see that on tiny screen!
I would suggest actual contact is not good.
Are you familiar with the add-on cable adjusters such as the Seven Workshop supply? (BR0614) They are simple to use and fairly effective, and can be used at more or less any handy point on the cable.

Long ago (I think it was 1960) I had an adjuster of this type come off the cable when one of its hooks straightened a bit under emergency braking, so I don't use them since then. The other disadvantage is that the cable gets three bends in it which are inherently springy, reducing the positive feel of the pedal.

[Roger]

Reverse the Austin lever so that the ball faces the backplate, or use your homemade lever, I have fitted turnbuckles for adjustment at the cross shaft end of the cable quite successfully.

Thank you Ian, I had not thought of reversing the A7 levers, I thought it would affect the angle of the lever, but the cotter must do that if put in back to front.

Roger

The brake levers should always be put on with the ball toward the backplate - the cable pull is then under the cam bush bush giving a better wearing support to the cam.

This would also put the turnbuckle in a better place- and of course your excellent design is far preferable to the presently available 'pinch bolt'  fixing which cannot be adjusted after the initial very tight fixing.

Tony.

Tony,
Not having experience of A7s I just put them on as they were originally fitted!
It makes sense to put them ball first now you mention it, Ian & Jim.
I think I will revert to my home made levers and possibly remake them better, they were just a prototype to prove their feasibility.
I have a problem with the front brake cables too, they will not run straight from the levers, full lock right will kink the left side cable, and visa versa.
What is the best answer to this?
Has anyone tried an alternative method?

Roger

[Ian Williams]

A photo of your front set up will help us understand the issue, again the ball should face the backplate, this places it directly under the King Pin so that it remains in the same place as you turn the steering, facing away from the backplate it will describe an arc.

[Roger]

A photo of your front set up will help us understand the issue, again the ball should face the backplate, this places it directly under the King Pin so that it remains in the same place as you turn the steering, facing away from the backplate it will describe an arc.

Ian,
This is the best I can achieve with original A7 Lever, as you will see the cable is unacceptably stressed.

   
Photo 2 shows plan B, I decided to produce a lever using a ball & socket that I had, as an experiment.
The original was made from brass as I had some handy, steel would be better.
As you can see photos 3 & 4 show a view from exactly the same position underneath looking up, both right & left lock give a straight run to the cable. You will note the ball position does not move too much either. I may have to fine tune the angle of the lever and the position relative to the king pin centre.

The rear brakes were put on hold as whilst trying to check them I had a nasty rumbling noise from Lhs, it sounded like bearings being very rough. On investigation it turned out to be half shaft gears that felt rough because they are straight cut and the teeth could be felt meshing!
The bearings were fine.


           

Roger

[Ian Williams]

Hi Roger, it would appear you may have found your own solution. However if you wish to use Austin levers I would make a threaded socket out of some round bar to fit onto your cable, the other end would be shaped the same as a std cable end and cross drilled to accept an original end cap. I believe that would address the binding and you could be secure in the knowledge that the lever was strong enough for the job.

[Roger]

Hi Roger, it would appear you may have found your own solution. However if you wish to use Austin levers I would make a threaded socket out of some round bar to fit onto your cable, the other end would be shaped the same as a std cable end and cross drilled to accept an original end cap. I believe that would address the binding and you could be secure in the knowledge that the lever was strong enough for the job.

Hi Ian,
That was what I did initially but had to remove a lot of material from the socket to avoid the arm of the lever from contacting the socket on full lock, hence my alternative method.
I could possibly remove metal from the arm too but was concerned about loss of strength.
Thanks for you interest and suggestions, I will continue with my design and try to upgrade with next version.

Roger

[Ian Williams]

Colin, if you copy the end shape of a genuine cable exactly and use the original end cap all should be well, I have done so in the past with no issues. I do not believe it would be necessary to modify an austin arm or endocarp to make it work, some modern replacement cables have badly shaped end caps which dig into the ball perhaps this has been the cause of your problems?

[Ruairidh Dunford]

More advice and pictures on this issue here: http://pub25.bravenet.com/forum/static/s...0&cmd=show