I took my wagon for its’ MOT today and was listening to an od who had his lorry failed on a brake test, even though he’d had it tested at another garage earlier this week (apparently).
So he said, that the wheel in question actually exceeded the percentage required.
Could it just be sods’ law that something failed just prior to test? Iffy test at garage or could’ve the od just not kept the pedal pressed correctly, keeping the red in the box on the test screen?
Muckaway:
Could it just be sods’ law that something failed just prior to test? Iffy test at garage or could’ve the od just not kept the pedal pressed correctly, keeping the red in the box on the test screen?
Yes something can fail even between being tested at the local garage and being driven down the road to the test centre. My wife even had something fail during the MOT. She took her car for a MOT one year, all the brakes passed visual and leak inspection then when it was on the rolling road brake tester it blew a flexihose which had just been inspected and deemed OK. Garage were very apologetic and I just replied I was glad it failed on the brake tester and not when she was driving down the road.
I always insisted our fleet went for a voluntary brake test at the test centre immediately before the actual test, or if we couldn’t arrange that, the voluntary check was on the same day as the actual test and the truck went nowhere in between.
However - we had a couple pass the voluntary on ‘lane 1’ then be called to ‘lane 3’ for the actual test and fail - by a very small amount. The lesson learned was if it passes the voluntary test by a small margin - cancel the actual test, take it back to the workshop and fix it properly.
Unfortunately many trucks pass their MOT brake test by a vary small margin - those operators should be getting them back in the workshop and pulling the brakes down to get them back up to standard. This isn’t what happens and over the next 6 weeks or so the brakes deteriorate and drivers are put at risk.
It sounds like the guy you refer to passed the brake test at some workshop somewhere but by a very close margin. The tolerance between different roller brake testers meant a fail on the day. It only needs A 2% DIFFERENCE.
shep532:
I always insisted our fleet went for a voluntary brake test at the test centre immediately before the actual test, or if we couldn’t arrange that, the voluntary check was on the same day as the actual test and the truck went nowhere in between.However - we had a couple pass the voluntary on ‘lane 1’ then be called to ‘lane 3’ for the actual test and fail - by a very small amount. The lesson learned was if it passes the voluntary test by a small margin - cancel the actual test, take it back to the workshop and fix it properly.
Unfortunately many trucks pass their MOT brake test by a vary small margin - those operators should be getting them back in the workshop and pulling the brakes down to get them back up to standard. This isn’t what happens and over the next 6 weeks or so the brakes deteriorate and drivers are put at risk.
It sounds like the guy you refer to passed the brake test at some workshop somewhere but by a very close margin. The tolerance between different roller brake testers meant a fail on the day. It only needs A 2% DIFFERENCE.
My firms fitter always sends us off for a brake test after he’s done any brake work , I went for 3 one week
Do MOT failures still affect ocrs scores?
When I used to take our trucks for MOT, roughly one every week and all eight wheeled tippers or powder tankers, I took them with about 15 tonne on to get good brake readings. To do the ‘lock to lock’ over the pit the tester usually raised the second axle to take the weight off a little, however this one time he didn’t and when turning the wheel I felt something ‘go’ on the steering! The tester emerged from the pit drenched in red power steering oil, the pipe end had blown off of the ram! To say he was unhappy was an understatement, and of course he failed me. So a phone call, and a fitter came out with a new connector and I got my pass, after that they always jacked the axle up. 
Had a few brake diaphragms blow during brake roller tests so I carried a spare with me just in case and I also had an electrical fire that burned part of the dashboard out but they just tested what still worked and again a fitter came out and we rewired it, they passed it then.
Pete.
i always get the air back to max before trying the next axle no matter how long it takes .
VBT is always interesting with the MAN, takes ages to build the air back up after each axle, sure the mech thinks i’m taking the ■■■■.
merc0447:
Do MOT failures still affect ocrs scores?
For Goods Vehicles yes they do. Even more so if is warrants a prohibition at the same time. A high first time MOT pass rate is an excellent way of helping maintain a good OCRS
PSVs however - MOT failures don’t normally affect OCRS.
Even if the brakes pull the required effort this is not a pass.
The brakes have to be free of flutter (warped discs or oval drums) they have to be in balance across the axle and they have to not flag up any bind.In general the higher the effort reading before lock out the less efficient the brake.The machine will shut down at lock up.
If you get a reading of say 1000kg then lock out this is a far better reading than 2000 kg then lock out or max retarding force recorded and no lock out.
Brake temperature can make a big difference. If he had the vol test at the end of a working day and then turned up cold next morning for annual test that could account for it.
shep532:
I always insisted our fleet went for a voluntary brake test at the test centre immediately before the actual test, or if we couldn’t arrange that, the voluntary check was on the same day as the actual test and the truck went nowhere in between.However - we had a couple pass the voluntary on ‘lane 1’ then be called to ‘lane 3’ for the actual test and fail - by a very small amount. The lesson learned was if it passes the voluntary test by a small margin - cancel the actual test, take it back to the workshop and fix it properly.
Unfortunately many trucks pass their MOT brake test by a vary small margin - those operators should be getting them back in the workshop and pulling the brakes down to get them back up to standard. This isn’t what happens and over the next 6 weeks or so the brakes deteriorate and drivers are put at risk.
It sounds like the guy you refer to passed the brake test at some workshop somewhere but by a very close margin. The tolerance between different roller brake testers meant a fail on the day. It only needs A 2% DIFFERENCE.
Particularly on the park brake there’s plenty of brand new trucks that will only be a few % above pass that will see no benefit from extra hours in the workshop. Voluntaries are easy if the truck is being looked after by somewhere that’s ATF it’s a pointless timewasting faff otherwise entirely caused by the, in my view, flawed thinking behind the OCRS scheme.
VOSA prefer roller brake tests yet and consider electronic tapley meter type testing the lesser because it doesn’t measure on individual axles. However, it’s a much more real word result than the actual MOT.
I used to have ‘fun’ with the transmission handbrake on Fodens, just a drum mounted on the rear diff worm. They were either soaked in diff oil or siezed solid, that one drum was expected to hold 30 Tonnes+ on a hill and they couldn’t be tested on rollers so I had to drive them part laden up the test slope at the testing station and swing my legs out of the cab to prove that I wasn’t pressing the footbrake. I took a length of pipe with me to lengthen the handbrake lever and stood up in the cab to get extra leverage, the problems came when I had to try and release it again!! 
Bedfords and LandRovers were a similar set-up but mounted on the gearbox output shaft (if the prop or halfshaft sheared then there was no handbrake) and more efficient being a much lighter vehicle, thank goodness spring brakes came into fashion!
Pete.
windrush:
I used to have ‘fun’ with the transmission handbrake on Fodens, just a drum mounted on the rear diff worm. They were either soaked in diff oil or siezed solid, that one drum was expected to hold 30 Tonnes+ on a hill and they couldn’t be tested on rollers so I had to drive them part laden up the test slope at the testing station and swing my legs out of the cab to prove that I wasn’t pressing the footbrake. I took a length of pipe with me to lengthen the handbrake lever and stood up in the cab to get extra leverage, the problems came when I had to try and release it again!!Pete.
LOL being ex military I remember the good old bedfords and landy …on the landy it was basically on the gearbox output and on bedfords it was on the diff.My favourite bit is how people where confused when you jacked them up and the wheels would still turn
Some of the old buses I take for test entail quite a performance when it comes to the RBT. The vehicles have power hydraulic brakes. The normal operating line pressure is only about half the available reservoir pressure. To achieve a pass considerable extra effort has to applied to the pedal, this then compresses a spring in the footbrake valve and full reservoir pressure is available. However this shuts off the return line to the tank which risks a pipe bursting if the engine is running. It is necessary to build up hydraulic pressure between each wheel, however to do this the brakes have to be pumped several times to deplete the pressure enough for the cut out valve to start recharging. That is the easy bit, there is an interlock fitted which prevents the engine being revved if the gearbox is in neutral unless the engine has been turned off and the ‘ignition’ isolated first. In addition the handbrake has to be on for the starter to engage. Having got through all that rigmarole an additional brake test is required to prove that there is still braking available when the low pressure warning starts to operate.