Member Since: 23 Oct 2007
Location: Essex
Posts: 636
MOT Failure EPB
Hand Barke has failed the MOT. Is there a fix i can do or is it a main dealer job. Said it is applying only 12% of the required braking under the guidlines. Shes an Auto.
What now?
TackCLUB DEFNER
13th May 2009 2:59 pm
SJR
Member Since: 09 Aug 2006
Location: East Manchester
Posts: 4030
Was it a dealer that did the MOT by any chance I believe that every human has a finite number of heart-beats. I don't intend to waste any of mine running around doing exercises.
Buzz Aldrin (1930 -
I think your MOT station doesn't know how to test an electronic park brake on a 4x4 I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
I'd ask them to explain how they tested it? Over 5mph (I think) activating the EPB will apply the Emergency brakes and that's the disc brakes so if they're not functioning it would fail on all brake tests The End
13th May 2009 3:03 pm
wiggs
Member Since: 03 Sep 2006
Location: Manchester
Posts: 14372
Wasent there a discussion about mot and the EPB ( or am i dreaming again)
In old days 4x4 had to be tested with some sort of device sat on the floor ( cant remember the name ) .
But if you pull the epb while moving , the car is stopped via the abs . I would like to see what method they use nowadays G4 Gone ...but not forgotten
"Brakes - condition, operation and performance (efficiency test). Suitable vehicles will be tested on a roller brake tester. Vehicles such as those with permanent 4-wheel drive will be tested either on a suitable road using a properly calibrated and maintained decelerometer or, if one is installed at the test station, a plate brake tester
As the EPB uses the main braking circuit for performing an emergency stop, they would appear to have not used the decelerometer, as to only get 12.5% would suggest your normal brakes were absolutely f ed.
1. If the vehicle is of a type which cannot be tested on a roller brake tester,
. set up the decelerometer in the vehicle in accordance with the equipment manufacturer's instructions
. drive the vehicle on a level road at a steady speed of approximately 20mph (32kph) and note the brake efficiency recorded when applying only
For Plate Brake test:
Quote:
1. Drive the vehicle forwards at a steady speed of about 4mph up to the plate tester. Just before the wheels are on the plate high friction surfaces, apply a light constant pressure to the brake pedal. Do not stop on the tester. Note the way in which the brake efforts fluctuate.
2. At the same steady speed of 4mph, again drive the vehicle forwards onto the plate brake tester. As soon as the wheels are on the plate high friction braking surfaces, apply the service brake progressively until maximum effort is achieved.
3. Repeat 2 above using the parking brake.
As the EPB takes a second or so before engaging, I'm thinking it would fail a plate brake test on a new-from-factory car. I can only surmise from this that the only effective way to test is to use a decelerometer?I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
Electronic park brakes
Several manufacturers such as BMW,
Renault and Jaguar now utilise electronic
operations for the park brake. Though these
park brakes are progressive, their operation is
constant until fully applied. This can cause
the vehicle to pull out of the rollers quite
sharply, so ensure that the area around the
vehicle is clear. It is important to know that
many of these systems will utilise the service
brake if the vehicle is being driven above a
set speed so should not be tested using a
plate brake tester or a decelerometer.
These vehicles have not presented any real
problems to date but manufacturers may
have different methods of application.
We have already covered some vehicles in
Matters of Testing, and in some instances
extra information has been added on VSI to
help you (you may have to scroll down the
screen to see this). If you are still unsure of
how to operate the park brake, consult the
vehicle’s handbook or call the help number
at the bottom of the VSI screen.
As you see above, EPBs shouldn't be tested by a Plate Brake Tester or a decelerometer, yet from what I've read so far these are the accepted methods for a vehicle with all axles driven full time (perm. 4x4) ?
I'm confused I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
Sorry to be pulling this together like this. Posting as I find stuff.
From Motester.co.uk forum:
Quote:
try testing a range rover with electronic parking brake , you have to put the parking brake into "bedding mode" before it can be tested on the rbt .
this involves a strange sequence of pedal & button presses , the vsi gives the information on the screen but does not print it on the vt40
So anyone out there got access to VSI and able to briefly talk us through this? The forum suggests it's not a great process to follow. I'd put good money on the tester having screwed up somewhere along the line.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
13th May 2009 4:02 pm
wiggs
Member Since: 03 Sep 2006
Location: Manchester
Posts: 14372
Do you want to know the bedding in procedure
or what an MOT'er is told to do G4 Gone ...but not forgotten
What an MOT tester is told to do, because you can bet your bottom dollar they aren't doing it right to get 12.5%!
From what I understand, if both rear wheels lock there is a "wheels locked" box that should be ticked and no value entered for the brake efficiency test. That in itself is a pass on park brake testing.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
13th May 2009 4:28 pm
stapldm
Member Since: 11 Sep 2006
Location: Swine Town
Posts: 2330
Nodo$h, the first time I tried using the bedding in procedure to fix my ineffective EPB, I ran out of road using the EPB to stop the car and had to use the footbrake : http://www.disco3.co.uk/forum/post398557.html#398557.
I was only doing the recommended 20MPH but after 100yds of EPB braking without slowing down much I was at risk of running into a building. As such I can easily believe this 12% figure. If they' tested it 5 times it would have probably got a lot better each time and passed Dr. Ian Malcolm:
"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."
Transgenic tomato anyone?
If we can get full details of the VSI requirement we can see if the requirement is open to being misinterpreted and a fail given due to tester not following the instructions.
As you can't print the instructions from VSI, it follows that more complex procedures are going to be very difficult to follow correctly.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
13th May 2009 4:58 pm
stapldm
Member Since: 11 Sep 2006
Location: Swine Town
Posts: 2330
True, but you'd also need to find out what procedure the tester took to compare it with.
It'd also be worth finding out the state of the brake shoes too; Tony, if you find a safe deserted flat road/carpark, and pull and hold up the EPB switch to halt the car, you should get:
"bong bong bong ABS ABS ABS EPB Car-Halts"
When you do this do you get the above or
"bong bong bong ABS ABS ABS EPB EPB SCREECH" without stopping well?Dr. Ian Malcolm:
"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."
Transgenic tomato anyone?
13th May 2009 5:10 pm
Tony686
Member Since: 23 Oct 2007
Location: Essex
Posts: 636
Reading the replies I think I will leave my tools in the box for now. TBH most of what you have posted has blown my head off. The MOT centre was not a main dealer. How do I know what is right or wrong, I assume he has tested it correctly, I do not have the front or especially the knowledge to start questioning the man that did it.
Option is, do I take it somewhere else to have it tested?
TACKCLUB DEFNER
13th May 2009 5:18 pm
wiggs
Member Since: 03 Sep 2006
Location: Manchester
Posts: 14372
I would go back and ask him to explain how he tested it . That way you will have an idea if it was done correctly ( or post his reply on here and someone else will )G4 Gone ...but not forgotten
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