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KevG
Super Moderator
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Posted: Thu Aug 13th, 2009 08:29 pm |
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DB. Yes. Same as Mk 1 Discoveries. A very good Idea.
Kev.
PS youve got a massive write up in MOT TESTING magazine
well done.
Kev
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Dynamic Balance
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Posted: Thu Aug 13th, 2009 07:34 pm |
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You guys may disagree, but the Austin Metro or was it the Rover Metro had one of the best hydraulic braking systems, which was known as a "Triangular System", and for anyone who is unfamiliar with this type of system, I will briefly explain it.
The service brake pedal when depressed applied the hydraulic force to all four wheels, as the normal dual line system does, however, on the triangular system the hydraulics are designed to supply four pot brake calipers at the front and then the normal brake expanders at the rear, the difference being, if a leak occured in say one of the front circuits, then braking would still be available to both front calipers and one rear brake expander. If one of the rear hydraulic brake circuits failed, then both front brakes and the remaining rear brake would still function as normal.
In summary then;
Any hydraulic brake circuit fails at the front, the brakes still have full braking capability at the front, and one rear brake still functions as normal. Unless the brakes developed a leak in both independent systems at the same time, which is very unlikely, then with a leak present, ie one brake pipe burst, the brakes still have at least 75% of the brakes working on the vehicle.
The instrument display advising the driver with a warning lamp when the level of fluid in the reservoir drops towards or below the manufacturer recommended minimum level. Now that must be a good brake system design
DB
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KevG
Super Moderator
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Posted: Thu Aug 13th, 2009 05:23 pm |
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| Well said Spongebob
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Spunkymonkey
Member
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Posted: Thu Aug 13th, 2009 12:21 am |
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jonnyjohnson wrote: Car doesn't crash with all occupants killed, thanks to dual circuit braking system that brings the car to slow but effective halt!
Not all cars have dual circuit brakes. I mentioned an aquaintance elsewhere with a Daf 55 which recently passed its MOT with an advise of just over 50%* braking from its single circuit brakes (Tapley meter cos of the belt drive so no real chance to fail for individual wheels).
He was aware of fluid leaks from two of the wheel cylinders but "wiped them off" before the test. Remember, it could be you driving down a main road when one of those faulty wheel cylinders gives up as he approaches from the side. As long as you have motorists like that on the road, the MOT is the only chance there is of stopping them.
It ain't perfect - in the "good old days" before all this computer stuff I've known testers who would have failed it anyway (and possibly lied about the readings in the process) because they knew the results were way too low for the car - but it's the best we've got and it does force irresponsible owners to attend to their cars at least once a year!
* by comparison, my Daf 33 (drums all round and no servo) scores a fairly respectable 85% in the dry before the (cheap) tyres start squealing.
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Spongebob
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Posted: Wed Aug 12th, 2009 11:05 pm |
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jonnyjohnson wrote: Car doesn't crash with all occupants killed, thanks to dual circuit braking system that brings the car to slow but effective halt!
What happens when you need to stop suddenly though? your potentially 50% inoperative (at least) braking system will not bring you to as effective a halt as the 38 tonner that's just slammed all on in front of you. You will find that despite having dual circuit brakes not every car will have sufficient reserve pedal travel to fully engage the other circuit. I'm thinking peugeot in particular and one or two other manufacturers also come to mind.
Just a thought is your self appointed role on this forum to question every aspect of the MOT or does it just come across that way?
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Wesley
Trade Member
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Posted: Tue Aug 11th, 2009 11:45 pm |
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jonnyjohnson wrote: The MOT Testing scheme save lives every day...How can you make such a claim, if this was the tabloids I could understand it, but prove or disprove if you can.
"Logged On", and Have already noticed an excessively corroded brake pipe, Dangerous, continue and start to carry out an RBT.
Whilst carrying out the RBT, Brake Pipe Bursts!
Test "Abandoned"
Full Retest after repair.
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Dynamic Balance
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Posted: Wed Aug 5th, 2009 07:14 am |
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Whatever made you think that kev?
Did you think I could use the present marketing ideas and trade her in under the new four year scrappage scheme
DB
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KevG
Super Moderator
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Posted: Tue Aug 4th, 2009 09:37 pm |
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Educated Guess drawn from 27 years of experience.
(its a figure of speech)!!!
Just out of interest DB. Im Guessing your not married?
Kev
Last edited on Tue Aug 4th, 2009 09:39 pm by KevG
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Dynamic Balance
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Posted: Tue Aug 4th, 2009 08:32 pm |
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love to know how you calculated the time scale to be seconds from disaster for the two vehicles kev
DB
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KevG
Super Moderator
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Posted: Tue Aug 4th, 2009 07:34 pm |
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I Scrapped a Micra this week and a Fiesta, Both were seconds from disaster!
The UK Germany and Holland have 3.1.1 Testing.
Rest of Europe have 5.2.2 or similar.
Guess which 3 countries have the least per capita road deaths?
Our System is used Globally as
a template for testing.
KevLast edited on Tue Aug 4th, 2009 07:35 pm by KevG
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Dynamic Balance
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Posted: Tue Aug 4th, 2009 06:45 pm |
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jonnyjohnson wrote: The MOT Testing scheme save lives every day...How can you make such a claim, if this was the tabloids I could understand it, but prove or disprove if you can.
It's very easy to make that claim. One just has to look at vehicles condition based on experience. many years ago we used to have vehicles like the Mini, "Old Type" which had front ball joints that fell out of their sockets and the suspension would collapse on the side of the road.
We have had many track rod end ball joints which have had many problems, and flexi brake hoses which would bulge under pressure just to name a few.
Each time an mot test is carried out a catalogue of faults are seen and recorded. The results are then in a national data base where those failure points and componts can be looked at and information sent back to the vehicle manufacturer who can then look at that type of defect, which then can be redesigned so that component becomes more reliable in the future.
Now please do tell me that vehicles have not become more reliable over the years, and that all those components which were changed at service and mot testing times have not diminished a considerable amount.
DB
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kev1975
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Posted: Tue Aug 4th, 2009 06:24 pm |
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jonnyjohnson wrote: The MOT Testing scheme save lives every day...How can you make such a claim, if this was the tabloids I could understand it, but prove or disprove if you can.
what proof would you like ?
it could be argued that when a brake pipe bursts on the rollers instead of on the road someones life could have been saved .
or when the balljoint that is practically hanging out gets failed & the owner responds by saying either that they never heard or felt anything unusual , or that they wondered what the funny noise was .
or a car gets failed for having tyres in a dangerous condition , such as the immaculate 34000 mile 06 punto i failed yesterday , one front tyre was down to 0.5 mm of tread & the other was heavily worn on the inside edge with cords & wires showing .
nobody can say that someone driving that car would have had an accident & been killed , can't say they wouldn't either .
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jonnyjohnson
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Posted: Tue Aug 4th, 2009 06:10 pm |
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The MOT Testing scheme save lives every day...How can you make such a claim, if this was the tabloids I could understand it, but prove or disprove if you can.
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