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30-09-2020, 09:58 PM
(This post was last modified: 30-09-2020, 10:00 PM by Zetomagneto.)
Rupert, that is clearly a result of poor engineering.Looks like an alignment problem .Using flat strip metal in compression is not a good idea either.
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I quite agree, the entire system was so flawed that I can't see how it ever could have operated satisfactorily even when brand new. I strongly suspect that it is the reason that the car sat in a lockup since the 60's until I got my hands on it. I persevered for far too long trying to get it to work in a reliable manner before realising it was a lost cause!
Joined: Aug 2017 Posts: 1,647 Threads: 23
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Location: The village of Evenley
Car type: 1934 Austin Seven RP Deluxe
I’ve converted two Sevens with hydraulics back to the standard set up because I wasn’t happy with the engineering and in both cases, the braking was as good if not better!
Joined: Nov 2017 Posts: 21 Threads: 1
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Just to add my personal findings and this relates to an A7 chassis with Ford E93A/E83 axles.
The standard pedal set up from a 100E is very robust and quite light and an ideal mount for the master cylinder, multiple choices of bore can be found, I think the last ones came from Demon Tweeks. the current version is dual circuit.
If you are going to do any kind of trials my preference is to retain single leading shoe front brakes (the car will be able to stop going backwards!)
On the front I used Ford Transit rear cylinders (sorry cant remember what year) and these were machined to fit the E93a back plates.
The original adjusters do not take up all the movement so I modified some automatic adjusters (not now automatic and adjusted with a screw driver through a hole in the back plate), this mechanism bears on the brake shoes immediately below the wheel cylinder, the wheel cylinder then moving up under spring pressure to take up the movement.
On the rear axle I retained the cable mechanism and "tree" with an additional lug/eye. I then used a Range Rover clutch release cylinder to push the tree to operate the rear brakes, this system allows the retention of the original handbrake mechanism, its not an original thought and a similar system was used on early A40 Farinas.
the bore of the front cylinders, range rover clutch cylinder and the master cylinder will all have a bearing on the effort required.
I found I needed a larger bore master cylinder to obtain the required movement but obviously that then requires more effort at the pedal.
I had a concern that there would be an imbalance between front and rear axles so fitted adjustable valves in each brake line, to date I have had no need to use either adjuster.
I used parts that I thought would be easily available in the future (I did start on the project 20 years ago).
It should be remembered that the brakes on both A7's and E93A's were considered fairly useless even back in the day and just converting to hydraulic will not radically improve them.
Sorry I do not have any photos of the work but when I next take the drums off I will photograph and put on here.
Best wishes to all
Joined: Mar 2015 Posts: 5,445 Threads: 231
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Location: Scotchland
Thank you for all the message on here and off-line.
To be clear, it is not my car and I don't have any Sevens that are converted to Hydraulic systems (I did, but converted it back to cable over a decade ago). I am just trying to help a friend who does not use the Forum identify what he has - some serial numbers he found yesterday have identified them correctly.
Many thanks.
Joined: Aug 2017 Posts: 226 Threads: 9
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Location: Edinburgh/Lothians
Car type: Seven Special
Hi Othopetra,
Although not really connected to the original post I do not entierly agree with your statement: 'It should be remembered that the brakes on both A7's and E93A's were considered fairly useless even back in the day and just converting to hydraulic will not radically improve them'.
Its all about the engineering. If all aspects of the conversion are properly considered a hydraulic conversion on a 7 should give excellent results.
Way better than the standard rod/cable system.
I fear many conversions done over the years have not been well considerd and it is therefore no surprise that a myth has grown that its a waste of time.
Of course it all depends on what you want to get out of it, what you use the car for etc, and therefore whether its worth doing.
Joined: Feb 2018 Posts: 367 Threads: 14
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Location: Western Brittany (France)
Yes Paul I agree with you. As I said before I already implemented such conversions, not on A7 but the difficulties are the same. Apart from a good ratio of diameters between the master cylinder and the wheels cylinders, there's the right pedal to master cylinde rlever ratio to consider and, very importantly a huge rigidity of all the pedal and master cylinder mount. I know because I first did not take that sufficently into account and that last point can and does ruin all the rest.
Joined: Nov 2017 Posts: 21 Threads: 1
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Hi Paul
I think if you read my words again you are agreeing with them
And yes I concur with your thoughts about set up and what you want to achieve
Best wishes to all
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My AG tourer was converted in the 60's to early (50's) Morris Minor hydraulics with a VERY substantial bracket holding the M/cyl to the chassis!
When it came out of it's Ohio barn it was found that the whole system apart from the backplates & drums was unusable. however a kit of parts & new pipes (cheap & easily available) was fitted and the brakes are terrific! even the handbrake used MM cables (& a bit of ingenuity!)