Bowdenex Brakes

[Ian Sly]

I would replace the flat plates with 1" by 1" angle for a bit more strength.

[Speedex750]

Hi Malcolm,
My experience matches the other guys closely. In addition, especially if you're fitting a set and have to drill the cross member, mount them as high as possible so the outer cable is just under the cross member. I find that the flat strip brackets can be improved by counter boring the holes so the outer cable lodges tightly in the strip keeping it square and the cable straight. In addition, as per yours, there's quite a bit of excess material on these strips below the outer cable, you can dress it back, taking off the corners as well, almost back up to the cable hole. All this gets you back about 1" of ground clearance. The strips need bending slightly so the cables point directly at the swingle tree 1/2" bar. The bent brake levers are for the front brakes, note they are handed, and the straight ones for the rear. There's a fuller explanation, including the standard levers, on the old Speedex website here; http://myweb.tiscali.co.uk/speedex/index...ge2288.htm

Dave

[Ruairidh Dunford]

Be careful to make sure the correct one is correct to everything else you have.

Mixing does not work (guess how I know).





I had other examples but have given them away - no photos, sorry.

Which is which?  Stuart, over to you...

Despite my reservations about the system shown above, my post is entirely serious and I admit to hoping that someone would be able to identify the various permutations and how to match them to the various set ups that exist.

I understand that you must have all matching parts correct.

[Malcolm Parker]

All good advice, many thanks.    My Bowdenex system came off a complete axle assembly and I suspect it had not been touched since it was fitted 50 years or so ago.   The brakes are Girling and the cranked levers are the third one down on R's photo.  The bowed axle was seriously bent in two planes, either the Bowdenex brakes worked far too well or were bl**dy useless!  Regarding the flat mounting strips, these have been fitted to the cables before the ends were crimped on so are not removable without sawing a slot in them.  Likewise, fitting a different mounting bracket would involve a slotted arrangement which would be fiddly.
I have restored one cable by hanging it up in the out-house and heating with a blow lamp.  Once the old grease was out I fed WD40 into the cable through the grease nipple midway along and the cable now operates with minimum friction.   Alas on looking at the second cable very carefully, there is a crack in the threaded end that feeds through the steel rod on the swingle arm, so this will need attention before I can progress any further.  Has anyone got a spare cable they do not need? 
One outcome of this thread is that I have read Stuart Ulph's book 'Would suit enthusiast' again. Available from the PWA7C bookshop in time for Christmas!
Shameless plug but why not?

[Reckless Rat]

WD40 isn't really a lubricant, it's a water dispersant (hence the initials) For lubricating your cables Malcolm, I'd try some PTFE based lubricant used for cycle chains.

[Dennis Nicholas]

Hello Malcolm
People seem to have mixed views on Bowdenex.  The main advantage is that it removes the "anti servo" effect of front axle twist experienced with the earlier lighter pattern front axle, and removes the effect of steering lock on braking. 

The kits (From Super Accessories ?) included longer levers for the front, plus a matching set of longer levers for the rear so pedal pressure was reduced (in theory) in exchange for a longer pedal travel and more frequent need for adjustment. The disadvantages are extra weight and cable friction especially if full of old grease ( Some say that oil should be used ).  
Hope this helps

John Cornforth

The kit was made by a little engineering shop in Ottery St. Mary in S Devon.  They also did the IFS with twin front springs in place of the axle beam....I have photos of their "drawings" of the IFS that they sold to me and gave permission for me to show around.   (ok A7CA archive I haven't forgotten to send you copies....still fathoming out how to copy and send!!!)

Use molybdenum grease sparingly on the cables (Molyslip)  CV joint grease usually has it in it. Moly rubbed well into cable.  Moly is difficult to remove from anything you get it on so will last well.  Another tip is to wet a cloth with Moly (as in oil additive) and rub it well onto the lips of lip seals to provide a lubrication that will lessen friction and thus wear on seal and shaft.  Also rub onto seal faces in hydraulic circuit seals including all rubbers in disc brake pistons.

It is very worthwhile providing compensation between the two cables as it saves endless adjusting and ensures equal force to each leaver.  My 7 with hydraulics used to be a pain using Bowden type cables for the hand break with similar set up of rod through leaver tail and cable through hole in each end of rod therefore no compensation.  Then I changed to using short rod to swivelling compensator with cable at each end of the swivel......transformation was wonderful.  I think it was an Allegro swivel that I used (from the breakers) but anything similar would do.

Dennis

[Speedex750]

Malcolm ParkerAll good advice, many thanks.    My Bowdenex system came off a complete axle assembly and I suspect it had not been touched since it was fitted 50 years or so ago.   The brakes are Girling and the cranked levers are the third one down on R's photo.  The bowed axle was seriously bent in two planes, either the Bowdenex brakes worked far too well or were bl**dy useless!  Regarding the flat mounting strips, these have been fitted to the cables before the ends were crimped on so are not removable without sawing a slot in them.  Likewise, fitting a different mounting bracket would involve a slotted arrangement which would be fiddly.
I have restored one cable by hanging it up in the out-house and heating with a blow lamp.  Once the old grease was out I fed WD40 into the cable through the grease nipple midway along and the cable now operates with minimum friction.   Alas on looking at the second cable very carefully, there is a crack in the threaded end that feeds through the steel rod on the swingle arm, so this will need attention before I can progress any further.  Has anyone got a spare cable they do not need? 
One outcome of this thread is that I have read Stuart Ulph's book 'Would suit enthusiast' again. Available from the PWA7C bookshop in time for Christmas!
Shameless plug but why not?
Hi Malcolm,
I forgot to mention in my previous reply that a small Jubilee clip just fits between the eyes of the cross shaft lever on the 1/2" swingle tree and prevents it migrating to one side. There's usually enough wobble in the swingle tree to give some compensation, get a fine adjustment on the cable threads so both sides lock at the same pedal pressure. You can replace the inner cables with early Mini handbrake cables, shortened, and an A7 adjustable cable end. It looks like the one in your photo is broken anyway, it's usually about 3" long? The Mini ones are 1/4"UNF but I'm sure you can accommodate that. You mention you're fitting these to a Girling set up? I'm not clear if they were designed (if they were designed) to do that, although I've seen a number like this. The cranked levers, while longer than the 'Austin' ball levers, are actually shorter than the standard Girling lever and may not have the desired effect, see the Speedex site write up. I've found the best way is to rotate the Girling back plates so the adjuster is at the back and fit the really long 4" levers with a shortened inner and outer cable. This has worked well with standard semi Girling rears or, as on my Opal, standard rod Girling rears.

Dave

[Malcolm Parker]

It looks as if the threaded ends on both my inner cables have broken as they are only about 1 1/2" long.  If it is a case of replacing them, I would look at doing away with the steel mounting brackets, by having the ends of the outer cables retained by the chassis cross-member.  I would also arrange for the cables to be compensated.  Lots to think about!

[Philip Ball]

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Malcolm Parker pid='2077' dateline='1506622920']It looks as if the threaded ends on both my inner cables have broken as they are only about 1 1/2" long.  If it is a case of replacing them, I would look at doing away with the steel mounting brackets, by having the ends of the outer cables retained by the chassis cross-member.  I would also arrange for the cables to be compensated.  Lots to think about!

Hi Malcolm

Attached are some pictures I've just taken of the Bowdenex set up under my car (sent low size and res). They were taken with flash and the camera was struggling to focus as it was so dark under the car. I could do better pictures on Saturday when I'll have it out in the daylight. You should be able to get the idea of the set up and see that the steel bar on mine has bent in use. I intend to put angle in to deal with this when I rebuild them. In the meantime they seem to work pretty well. I can lock up all four wheels on a loose surface and stop quickly on tarmac - once or twice, I assume if I used them a lot the brakes would get hot and fade.

Philip

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It looks as if the threaded ends on both my inner cables have broken as they are only about 1 1/2" long.  If it is a case of replacing them, I would look at doing away with the steel mounting brackets, by having the ends of the outer cables retained by the chassis cross-member.  I would also arrange for the cables to be compensated.  Lots to think about!

Hi Malcolm

Attached are some pictures I've just taken of the Bowdenex set up under my car (sent low size and res). They were taken with flash and the camera was struggling to focus as it was so dark under the car. I could do better pictures on Saturday when I'll have it out in the daylight. You should be able to get the idea of the set up and see that the steel bar on mine has bent in use. I intend to put angle in to deal with this when I rebuild them. In the meantime they seem to work pretty well. I can lock up all four wheels on a loose surface and stop quickly on tarmac - once or twice, I assume if I used them a lot the brakes would get hot and fade.

Philip

Apologies ended up attaching some of the less useful pictures here's the others

[Steve Jones]

   

All this talk about Bowdenex brakes prompted me to dig out some cables and parts that have lain, unseen, under one of my floor racks for, probably, 25 years or so. I've always thought they were Bowdenex bits but never had any interest in them but here they are. Look like many of the bits in the various photos - and none of the cables are seized! 

Steve