VoSA modified their interpretation of secondary brake performance requirements some while ago. Which vehicles do still have a separate hand valve operated secondary brake?
cav551:
VoSA modified their interpretation of secondary brake performance requirements some while ago. Which vehicles do still have a separate hand valve operated secondary brake?
The old Bedford MJ if my memory serves me right
From the HGV inspection manual:
IM72 Secondary Brake Performance – The requirement for the testing of secondary brake performance on both HGV and PSVs has been reviewed as part of the process for test simplification.
One recommendation was for early adoption of the requirements of Directive 2014/45/EU. The Directive removes the need to test secondary brake performance on vehicles where the designated secondary brake is the split system.
For these vehicles, DVSA will overrule any brake printout with a secondary brake failure and will ignore any prompt to look for an alternative secondary option.
Vehicles where the designated secondary is separate from the service braking system (typically via a hand operated brake control valve) will continue to be tested in the usual way. The exception to this is when the result is a failure for secondary performance. In this case, the failure will stand but no alternative secondary brake will be considered.
The computerised brake programmes will be updated at the next available opportunity to reflect these new requirements.
Read the updated inspection manuals
HGV inspection manual
What is means is that vehicles where the Dtp code ask to perform a separate secondary, they still are considered. (certain Scania’s and MAN and others)
The parking brake valve functions on these vehicles as a Secondary brake control valve (the area before the lock)
If the vehicle Dtp code doesn’t ask for a separate operation of the secondary, you can ignore the secondary.
For example most DAF’s only use the split as secondary brake system, in the case it pass the normal brake test, and fails the secondary you can ignore that.
And the vehicle will pass.
Every operator who has a brake tester, should use them instructions for their intermediate brake test.
However from a repairer/ operator point of view, it shows that something is not working properly, and I certainly would like to find out why.
Thank you, so there are some current vehicles still using the parking brake valve to operate the secondary brake.
Yes there are, in principle every truck with air operated brakes.
But for your MOT test, Mainly Scania, MAN, some Volvo’s, the odd Mercedes all depending on what the manufacturer put in their Dpd number
cav551:
VoSA modified their interpretation of secondary brake performance requirements some while ago. Which vehicles do still have a separate hand valve operated secondary brake?
All HGV /PCVs have a secondary brake.WTF you talkin about?
They give you a reading on secondary systems at test all must reach 25% or lock up to pass.
Try reading that again and then THINK. Of course HGV have a secondary brake. The question was asking: what do you have to do to operate it, use the hand valve or the footvalve? Others seem to have understood that point and also that not all manufacturers go about doing things the same way. Now with your infinite knowledge of everything maybe you can answer the question, Daf hand or foot? Renault hand or foot? etc. The clue being whether the tester asks for the secondary brake to be operated on RBT.
cav551:
Try reading that again and then THINK. Of course HGV have a secondary brake. The question was asking: what do you have to do to operate it, use the hand valve or the footvalve? Others seem to have understood that point and also that not all manufacturers go about doing things the same way. Now with your infinite knowledge of everything maybe you can answer the question, Daf hand or foot? Renault hand or foot? etc. The clue being whether the tester asks for the secondary brake to be operated on RBT.
Secondary brake is the application of air to all chambers before the hand valve is fully applied.
When the hand “brake” is fully applied air is dumped from the spring brakes.
The secondary brake is in reality using the hand valve as a footbrake.
Thats why the hand valve only exhausts as you pull it over the lock point.
Try it.
Bking:
cav551:
Try reading that again and then THINK. Of course HGV have a secondary brake. The question was asking: what do you have to do to operate it, use the hand valve or the footvalve? Others seem to have understood that point and also that not all manufacturers go about doing things the same way. Now with your infinite knowledge of everything maybe you can answer the question, Daf hand or foot? Renault hand or foot? etc. The clue being whether the tester asks for the secondary brake to be operated on RBT.Secondary brake is the application of air to all chambers before the hand valve is fully applied.
When the hand “brake” is fully applied air is dumped from the spring brakes.
The secondary brake is in reality using the hand valve as a footbrake.
Thats why the hand valve only exhausts as you pull it over the lock point.
Try it.
I dont think its as simple as that between the different makers.
As an example Daf on the pit footbrake on then apply handbrake = release of air.
Scania on the pit footbrake on then apply handbrake no air at all just the click noise the handbrake being applied
Daf 4x2 tractor up to 63 plate on the RBT no secondary, Daf 4x2 Euro 6 64 plate onwards on the RBT secondary on drive axle only.
Scania 4x2 tractor on the RBT 65/66 plate no secondary either axle.
Merc 4x2 tractor on the RBT secondary both axles and a royal pita to get a pass first go!
Plus it doesnt stop there as different chassis/wheel configs and markets all have different specs, also changes between model years soemtimes in the same year.