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Hydraulic drum brakes

Diogenes

Well Known and Active Website User
Non-VOC Member
17 July 1958 there was a description in 'The Motor Cycle' of converting Vincent rear brake drums to hydraulic operation. The standard 'one leading and one trailing shoe' design is retained, useful for providing effective braking in both directions, especially on a sidecar outfit.

See file in

http://tinyurl.com/9hc3rc


http://autos.groups.yahoo.com/group/stevenageworld/files/Brakes/

It looks OK though the wheels are no longer as QD as the standard bike wheels.
[ That disadvantage might be overcome by using quick release couplings in the hydraulic pipes, such as smaller versions of those used on tractor hydraulics. ]

Does anyone know how this scheme worked out in practice?
It might be an alternative to those who, for whatever reason, do not want to fit disks or 2LS drums.
It appears better suited to sidecar outfits than to solos.
In principle it would also be applicable to the front brakes.

I do recall reading in an old MPH of someone [ Pat Hendra? ] fitting hydraulically operated 2LS to the front drum brakes of a sidecar outfit, which were reported as working well.
 
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Tom Gaynor

Well Known and Active Website User
VOC Member
Hydraulic brakes

I don't know if it worked on a Vincent, but I know that someone converted his Sunbeam S7 front brake to hydraulic application (using Mini bits) and reported a dramatic improvement, presumably just because far more actuating pressure could be applied. His reasoning was that the Sunbeam rear brake, which has a huge leverage compared with the front, was perfectly capable of locking the rear, so "more leverage" would perhaps lock the front. Since Sunbeam rear brakes CERTAINLY don't lock because the powerful (standard) front has lifted the back tyre off the tarmac, he was probably right.
17 July 1958 there was a description in 'The Motor Cycle' of converting Vincent rear brake drums to hydraulic operation. The standard 'one leading and one trailing shoe' design is retained, useful for providing effective braking in both directions, especially on a sidecar outfit.

See file in

http://tinyurl.com/9hc3rc


http://autos.groups.yahoo.com/group/stevenageworld/files/Brakes/

It looks OK though the wheels are no longer as QD as the standard bike wheels.
[ That disadvantage might be overcome by using quick release couplings in the hydraulic pipes, such as smaller versions of those used on tractor hydraulics. ]

Does anyone know how this scheme worked out in practice?
It might be an alternative to those who, for whatever reason, do not want to fit disks or 2LS drums.
It appears better suited to sidecar outfits than to solos.
In principle it would also be applicable to the front brakes.

I do recall reading in an old MPH of someone [ Pat Hendra? ] fitting hydraulically operated 2LS to the front drum brakes of a sidecar outfit, which were reported as working well.
 

Diogenes

Well Known and Active Website User
Non-VOC Member
"I do recall reading in an old MPH of someone [ Pat Hendra? ] fitting hydraulically operated 2LS to the front drum brakes of a sidecar outfit, which were reported as working well."
That was in MPH 136, May 1960, pages 17, 18.
 

peterg

Well Known and Active Website User
Non-VOC Member
Howdy Chaps,

Wow, just the added leverage I need to consumately shatter a pair of fragile elektron front brake backing plates.

Sort of a braking version of the Jaws of Life used in vehicular accident victim extraction I'd think.
 

Alan J

Well Known and Active Website User
VOC Member
Brakes.

Wow, Peter! brakes is for stopping!! on my outfit, eventually!! I believe it is fairly straight forward to fit a late "Bonnie" back wheel with disc to assist retardation.:(:(
 

peterg

Well Known and Active Website User
Non-VOC Member
Howdy Alan J,

As this thread lead off with reference to conversion on the front brakes, and my initial excitement of discoversing NOS elektrons among the bucket of parts with my Shadow basket tempered by warnings of inevitable cracking from others, and having observed the steel Rap ones deflect when the brakes are applied, couldn't help making an observation on that one.

Coincidentally, I've already got the cracking elecktron syndrome out of the way. As found at time of purchase, a Norton Int'l trans was acting as a cork stopper to seal the box these plates were in. The top shelf where it had once been collapsed and it plummeted 5 ft downward and put a thin 3 inch crack in the outer perimeter of the left side plate. AARGH!

Thankfully away from any pivots/mounting points, but I shall keep an eye on it nonetheless.
 

clevtrev

Well Known and Active Website User
VOC Member
Howdy Alan J,

As this thread lead off with reference to conversion on the front brakes, and my initial excitement of discoversing NOS elektrons among the bucket of parts with my Shadow basket tempered by warnings of inevitable cracking from others, and having observed the steel Rap ones deflect when the brakes are applied, couldn't help making an observation on that one.

Coincidentally, I've already got the cracking elecktron syndrome out of the way. As found at time of purchase, a Norton Int'l trans was acting as a cork stopper to seal the box these plates were in. The top shelf where it had once been collapsed and it plummeted 5 ft downward and put a thin 3 inch crack in the outer perimeter of the left side plate. AARGH!

Thankfully away from any pivots/mounting points, but I shall keep an eye on it nonetheless.

If you can see your steel plates moving, you had better put your thinking cap on, and work out what is going on.
 

Tom Gaynor

Well Known and Active Website User
VOC Member
Cracking electron plates

I raced a late 50's 350 Manx with its original electron brakes until four years ago. It is still being raced, same brakes, although we had to replace the electron crankcases, cracked around the main-bearing housing on the drive side about 15 years ago. Electron brake plates are more likely to crack than steel or ally, but it is a possibility that after 50 years they'll crack, not a certainty. However, electron or no, Vin brakes are still just two 7" single leading shoe brakes on a 100 mph, 460 lb dry, bicycle, and even British bikes had largely moved over to twin leading shoe 30 or 40 years ago. Better off, IMHO, with 2ls. You can't pull the shoes into contact half as well as they can servo themselves into contact.

If you can see your steel plates moving, you had better put your thinking cap on, and work out what is going on.
 

peterg

Well Known and Active Website User
Non-VOC Member
Howdy clevtrev,

Thankfully not mine and thinking cap still relegated to the shelf collecting dust.

At this risk of being overly verbose...and acknowledged bad habit, didn't want to mention circumstance of flexing backing plates, etc. But at a recent very large vintage event over here observed a machine with the rear brake arms standing straight up at rest (I'm a strong proponent of the pull-towards-the pivot not away for safe leverage multiplication, especially on weak single leading shoe types) and couldn't resist giving the lever a prod with my foot. Both backing plate cocked noticeably to one side.

And Tom, agree with you on TLS, some are almost too good to a fault as far as self servo action. Let the shoes on the front of a /2 wear to thin and as mentioned previously regarding leverage rise with shoe application/drum contact angle compared to shoe pivot location, they become grabby to the point of being unsafe.
 
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peterg

Well Known and Active Website User
Non-VOC Member
Howdy Clevtrev,

Well actually it already has, years ago that it is.

I once stared at some Vin brake parts at a swap meet with an eye towards making the worn out shoes on offer cores for trade in when getting new linings - that is until I started arranging re-ligning here locally - many of they had worn cambered when viewed in cross section from uneven loading on the lining face which in turn had even worn the pivot bores on a few.
 

Albervin

Well Known and Active Website User
VOC Member
Think again, and wonder why the plate is moving nowhere near where the load should be applied. Now does that give you a clue ?
I am guessing that you are saying things are not parallel & perpendicular? :confused:
I tried to fit "lightning" plates to my "B" & I just got squeals & broken springs. Put the old steel plates back & no problems. I then noticed the plates "distorting" under load. A few measurements later & I realised my Bramptons are less than perfect. They track well at speed but below 32 mph they have a slight wobble. Have to fix it some time as it is a pain in stop/start traffic!
 
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