Thread Rating:
  • 1 Votes - 2 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Just how good should the brakes on my Ruby be?
#1
This may be an impossible question to answer, but not having any previous experience in driving my Ruby I am not sure if the brakes are simply as good as they can get for an A7 or do I have a serious problem.
In trying to find some answers I looked back over some old papers and found an article called Braking Efficiency published in the Austin Magazine dated 1936, the year of my Ruby.
In this it states “.......the Seven should be able to stop in 36 feet or less from 30 mph without skidding or pulling........Failure to stop in this distance can be taken as an indication that the brakes will benefit from from attention....”
Now I know without any doubt that my Ruby will go merrily past 36 feet before she will be brought to a stop.
I also have found an youtube a road test carried out on a late Ruby in which the braking distance when travelling at 30mph was 28 meters, which the presenter states is greater than the Highway Code requires of 23 meters.
Now these figures seem a lot closer to the performance of my own car.
The whole of my braking system has been upgraded but if 36 ft is the norm I am falling desaprately short, hence my question.
I did take my Ruby to an MOT for him to give her th once over before taking her out on a regular basis, he decided he would not put her on the roller to check the brakes, he said it would fail....!
Any thoughts would be much appreciated.
Best regards Denis S
Reply
#2
This comes up fairly regularly Dennis.
Most A7 drivers learn the art of anticipation or defensive roadcraft.

The key to passable brake performance on a Seven is
1. all parts moving freely but without play, lubricated and in the best condition they can be - sort out all those rusted bits and holes worn oval
2. set the thing up so all the levers are working at their optimal angles (i.e. as near 90 degrees as possible)
3. spend time and effort getting all four brakes to come on at the same time.

Excuse the brevity but I'm sure others will chip in!
Reply
#3
Compared to any modern vehicle the brakes on an Austin Seven, even when properly set up and working at their best are to be honest, rubbish. A good set-up is "adequate" so as Chris KC has already stated, it is necessary to drive defensively with plenty of anticipation. Accept it for what it is.

Don't forget an Austin Seven is a 1930s car built at a time when a lot of vehicles didn't even have brakes on all four wheels.

You might find that in "extremis" you will get more leverage by yanking on the handbrake as well as the footbrake, as the handbrake also acts on all four wheels on your Ruby.

However, remember the adage. Hope for the best, plan for the worst. Keep your distance and be prepared!

If in doubt, make contact with a local club and let someone else look at your car.
Reply
#4
Because of the high pedal pressure and lack of body dive Seven brakes can appear less effective than actually are. Road test of coupled models prior the Girling brakes of later Ruby were generally dismal; about 50%, some not even that, and with handbrake assistance! Many tests discreetly omitted measurements. Much better random figures appear in the Companion and later places. Present owners claim wheel locking in the dry with current linings specifically intended for the car. This indicates much better than 50% (100% is 30 ft, 50% is 60ft) . Moderns achieve 100% (and better)
 
50% braking from low speed, supposedly laden, is the legal minimum here, presumably an international standard. (Applies to those 50 ton trucks which tailgate at 100 kph!)
Curiously, older automotive books considered more than 80% as undesirable as promotes skidding! More than 50% was considered dangerous for buses with standing passengers. The later Ruby with semi Girling acheived around 75% in tests, typical of cars of the time.
 
Posts “Brakes, Whats Normal “24.1.19 and brake “Shoe Lining Materials”  2.11.18 may be of interest, and a myriad others.
36 ft is 84%!. Whoever claimed that as normal acheiveble was guilty of consumer deception.
 
Reply
#5
Another BIG factor is the type of lining that is used, modern brass woven linings are generally meant for the drums on light trucks where you have several tons of mass and servo assisted drums. I've bought more than one Giulietta Alfa with these linings, hopeless in a car weighing 850 kilograms and downright terrifying in a 7 weighing less than half of what one of my Giulietta's does.

My local brake shop re-lines my Alfa brake shoes with a very soft grey 'scooter' lining, in 25 years I've never had brake fade with these and I use my cars lots, long distance and mountain passes, never had any cause for concern and friends who have driven my cars remark how good the brakes are.

Both our single seater 7's are fitted with these soft scooter linings and our updated "Bowdenex" conversions. As Chris noted careful setting up, together with careful balancing of the brakes to ensure that the fronts come on before the rears will pay dividends.

I realize that the single seaters don't equate to a road car in braking mass, however I can get the 450/16 front and 550/16 rear wheels to start locking up on the Tarmac in the new supercharged car with the above set up and that's with less than 75 miles running-in on the new brake shoes.

Aye
Greig
Reply
#6
Hi Denis

The best my early Pearl could manage (after much fettling and tweaking) was about 50% on the MOT rollers. I noticed that the MOT man entered the car weight AFTER the test Smile after commenting that "They never had any brakes when they were new". It was only after I changed the front setup to semi-girling (rears unchanged) that on the next test it had improved to about 60%. I plan to fit a late cross-shaft some time to get front/rear compensation, which might squeeze out a bit more.

There are still quite a few Tapley meters offered at autojumbles etc which can be entertaining. On a modern, "normal" braking comfortable for passsengers peaks at about 30%, all out stop on a dry road more than 100%.

I think those period road test figures are a bit like adverts before the trades description act - semi-fiction !

I can't help feeling that the UK MOT limit was set at 50% in 1960 so that Sevens could just pass, but I believe the limit was raised to 58% in 2010.
Reply
#7
Practice shouting "Oh Shit!" with your teeth and buttocks firmly clenched...
Reply
#8
Denis - When you say that your brakes have been "upgraded", what do you mean?

With everything in really good condition and properly adjusted, it should be possible to lock all four wheels on a dry road. You have to REALLY stand on the pedal, mind you!
Reply
#9
Thanks for the comments. 
Just fyi the article I mentioned as published in the Austin Magazine dated 1936 was not what I considered to be publicity blurb, it was an article published in 2 parts giving detail of how to improve the braking efficiency.
The point was the stopping distance quoted of just 36 feet appears to me impossible to achieve with any of the A7 brake variations employed even from new.
But if the braking distance of 28 meters as mentioned in the road test (around 90 feet) is more like the norm that most owners achieve then I am sure that Ruby can achieve this and I can drive accordingly, with gritted teeth and bum cheeks.
For the record the whole brake system has been rebuilt with new bushes, cams, linings, adjustable cables, levers etc 
Thanks again
Denis S
Reply
#10
It's past my bedtime but 36ft from 30mph is 0.89g? (I'm ready to be corrected if any takers!)

Theoretically possible but highly unlikely, except perhaps on a car the works had prepared specially for the test (never underestimate what makers will do to pass tests...)

28m on the other hand is 0.35g which sounds much more realistic.

I had my car out once or twice in the past with a Mintex decelerometer but I don't recall ever getting more than about 0.5g out of her.
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)