Jcb brakes

[Tomtrac]

Hi have any of you noticed your loadall brakes fade / go if engine stoped
Ie you put your foot on brake to talk to someone stop engine and then two- four minutes later machine starts to roll
My brother broke his back he was parked on a road and a car came so he reversed down a slight hill on road at speed some how the engine stalled and he couldnt start it ( probably in panic didnt pull handbrake on to activate start switch) he went for foot brake and nothing happened on second or third use and he went over a wall dropping eight to ten feet into a field
I believe the brakes are hydronic and the accumulator runs out.
similar to the smooth ride set up
I was working on a farm and experienced the brake fade as yard on a hill and if you stoped engine with out handbrake on after two three presses of the pedal brakes would go so i got jcb to re fill/ fit new accumulator
So ok now
Has any one els experienced same problem
I personally think its a dangerous set up

 

[njneer]

It's a characteristic of " high pressure brake systems" as the title suggests they work on high pressure from the hydraulic pump.
If the engine is not turning you have no rotation of the hydraulic pump and therefor no hydraulic flow and no hydraulic pressure .
The system is designed to pre charge an accumulator, in conjunction with a check valve ,to trap oil under pressure, in order to store enough oil so that, in the event of a stall, you have enough oil stored in the accumulator to bring the machine to a safe stop and apply the handbrake .
If you have a leak in the brakes somewhere , or repeatedly press the pedal , you can easily use up the stored oil to the point there is not enough to adequately apply the brakes and stop or hold the machine.
Bigger machines with higher weights and speeds have forced high pressure brakes upon us as fully mechanical brakes no longer have the efficiency required .

You will also find that almost ,if not all , manufacturers are required only to provide enough stored oil to stop the tractor / handler with little if any consideration for any implement or machinery attached to it.
Understandable as they cannot know which of the infinite number of machines you may have attached but little help when a stall occurs.

Have seen , and experienced it , first hand with a tractor stalling beside the forager then taking off backwards as the driver panicked when a couple of presses of the pedal failed to hold it on the hill and he couldn't get it started again quick enough .
Ended up jack knifed with the trailer on its side and the tractor back wheels 6 feet off the ground, driver requiring new pair of boxers and half a day lost righting it again.

The system is , what it is, designed to work under high pressure with a minimal failsafe built in .
Problem is the situation very rarely happens but when it does the operator is not prepared for it and is focussed only on trying to get it restarted again but is then utterly distracted by the realisation that they are still moving and all attention is then drawn away , from starting , to trying to get it stopped .
The combination of factors ends up with the operator neither able to get it started or stopped with unfortunate consequences , which unfortunately sounds like the situation your brother ended up in ( do hope he is ok by the way) .

 

[Tomtrac]

It's a characteristic of " high pressure brake systems" as the title suggests they work on high pressure from the hydraulic pump.
If the engine is not turning you have no rotation of the hydraulic pump and therefor no hydraulic flow and no hydraulic pressure .
The system is designed to pre charge an accumulator, in conjunction with a check valve ,to trap oil under pressure, in order to store enough oil so that, in the event of a stall, you have enough oil stored in the accumulator to bring the machine to a safe stop and apply the handbrake .
If you have a leak in the brakes somewhere , or repeatedly press the pedal , you can easily use up the stored oil to the point there is not enough to adequately apply the brakes and stop or hold the machine.
Bigger machines with higher weights and speeds have forced high pressure brakes upon us as fully mechanical brakes no longer have the efficiency required .

You will also find that almost ,if not all , manufacturers are required only to provide enough stored oil to stop the tractor / handler with little if any consideration for any implement or machinery attached to it.
Understandable as they cannot know which of the infinite number of machines you may have attached but little help when a stall occurs.

Have seen , and experienced it , first hand with a tractor stalling beside the forager then taking off backwards as the driver panicked when a couple of presses of the pedal failed to hold it on the hill and he couldn't get it started again quick enough .
Ended up jack knifed with the trailer on its side and the tractor back wheels 6 feet off the ground, driver requiring new pair of boxers and half a day lost righting it again.

The system is , what it is, designed to work under high pressure with a minimal failsafe built in .
Problem is the situation very rarely happens but when it does the operator is not prepared for it and is focussed only on trying to get it restarted again but is then utterly distracted by the realisation that they are still moving and all attention is then drawn away , from starting , to trying to get it stopped .
The combination of factors ends up with the operator neither able to get it started or stopped with unfortunate consequences , which unfortunately sounds like the situation your brother ended up in ( do hope he is ok by the way) .

But the point i was making was that now i got the new accumulator fitted it works fine and i havnt notice a brake fail since it should have a warning light or gauge to let you know the accumulator is US and to let people know to replace it

 

[Speedstar]

Hi have any of you noticed your loadall brakes fade / go if engine stoped
Ie you put your foot on brake to talk to someone stop engine and then two- four minutes later machine starts to roll
My brother broke his back he was parked on a road and a car came so he reversed down a slight hill on road at speed some how the engine stalled and he couldnt start it ( probably in panic didnt pull handbrake on to activate start switch) he went for foot brake and nothing happened on second or third use and he went over a wall dropping eight to ten feet into a field
I believe the brakes are hydronic and the accumulator runs out.
similar to the smooth ride set up
I was working on a farm and experienced the brake fade as yard on a hill and if you stoped engine with out handbrake on after two three presses of the pedal brakes would go so i got jcb to re fill/ fit new accumulator
So ok now
Has any one els experienced same problem
I personally think its a dangerous set up

what age is the machine as there was brake problems with them from 13 to later 14

 

[Tomtrac]

They where both
JCB TM300's one o3 and an05
i am just making people aware of the need to get checked /replace the accumulator but if your yards not on a slope as us up here in cumbria call it but some may call it a hill lol if your yards are flat you will not realise
I thought there was something wrong one day so i parked on a slope killed the engine (having made sure i had a run off) and let my foot of the brake a couple of times and it just set off the pedal didnt do out just straight to floor hell i been pulled in cars etc when the servo isnt working and you have a pedal but just not power and hard to press but this problem just goes so nothing ahh a lot of weight to stop by pulling hand brake on not much stopping

 

[ACEngineering]

They where both
JCB TM300's one o3 and an05
i am just making people aware of the need to get checked /replace the accumulator but if your yards not on a slope as us up here in cumbria call it but some may call it a hill lol if your yards are flat you will not realise
I thought there was something wrong one day so i parked on a slope killed the engine (having made sure i had a run off) and let my foot of the brake a couple of times and it just set off the pedal didnt do out just straight to floor hell i been pulled in cars etc when the servo isnt working and you have a pedal but just not power and hard to press but this problem just goes so nothing ahh a lot of weight to stop by pulling hand brake on not much stopping

Exactly same on the manitou mla accumulator fails and no brakes at all if engine stopped.
All the rigid machines still retain some braking just not assisted as they have a different set up.

 

[njneer]

But the point i was making was that now i got the new accumulator fitted it works fine and i havnt notice a brake fail since it should have a warning light or gauge to let you know the accumulator is US and to let people know to replace it

The brake system will work on a set pressure and there will be a pressure switch to inform the operator that the minimum required pressure has not been met.
Once the accumulator is filled to that minimum pressure the brake light goes out.
A failed accumulator will still fill to that pressure , and put the light out ,but will not store much oil if the diaphragm is burst as there's no gas behind it to push the oil out , hence why you lose brakes quickly after engine stops.
The new accumulator , with good diaphragm , holds oil,and the gas behind the diaphragm pushes it out when you need it.
The only way to notify of an accumulator failure would be to have a pressure switch,or gauge , on the gas side of the diaphragm to inform of the status of the gas charged pressure.
I don't know of any machines that have this, as you say perhaps they should.

 

[Cowabunga]

It's a characteristic of " high pressure brake systems" as the title suggests they work on high pressure from the hydraulic pump.
If the engine is not turning you have no rotation of the hydraulic pump and therefor no hydraulic flow and no hydraulic pressure .
The system is designed to pre charge an accumulator, in conjunction with a check valve ,to trap oil under pressure, in order to store enough oil so that, in the event of a stall, you have enough oil stored in the accumulator to bring the machine to a safe stop and apply the handbrake .
If you have a leak in the brakes somewhere , or repeatedly press the pedal , you can easily use up the stored oil to the point there is not enough to adequately apply the brakes and stop or hold the machine.
Bigger machines with higher weights and speeds have forced high pressure brakes upon us as fully mechanical brakes no longer have the efficiency required .

You will also find that almost ,if not all , manufacturers are required only to provide enough stored oil to stop the tractor / handler with little if any consideration for any implement or machinery attached to it.
Understandable as they cannot know which of the infinite number of machines you may have attached but little help when a stall occurs.

Have seen , and experienced it , first hand with a tractor stalling beside the forager then taking off backwards as the driver panicked when a couple of presses of the pedal failed to hold it on the hill and he couldn't get it started again quick enough .
Ended up jack knifed with the trailer on its side and the tractor back wheels 6 feet off the ground, driver requiring new pair of boxers and half a day lost righting it again.

The system is , what it is, designed to work under high pressure with a minimal failsafe built in .
Problem is the situation very rarely happens but when it does the operator is not prepared for it and is focussed only on trying to get it restarted again but is then utterly distracted by the realisation that they are still moving and all attention is then drawn away , from starting , to trying to get it stopped .
The combination of factors ends up with the operator neither able to get it started or stopped with unfortunate consequences , which unfortunately sounds like the situation your brother ended up in ( do hope he is ok by the way) .

This is a problem on some John Deere six cylinder tractors. A local contractor stalled his engine while towing a tanker and starting off up a main road with traffic lights. He couldn't hold it with the footbrakes and it went back into a car I believe. Not good.

'Mother regulations' for machines built from January 1st 2018 will have forced manufacturers to address this issue, but whether it applies to handlers, I have no idea.

 

[Angusfarmer]

what age is the machine as there was brake problems with them from 13 to later 14

I have a 13 JCB, having big problems with my brakes....do you know much about the problems? Not getting any help from the dealer, changed the master cylinder had the front axle off and changed seals but still not working, next thing to check is the vacuum pump to servo.... can't think of anything else. Any advice appreciated

 

[startinghandle]

Last year a lady was killed when her son stalled his manitou and she could not get out of way quick enough.... the machine is impounded at Richard York near Newtown

 

[Fendtbro]

These systems sound totally dangerous and sub-standard. Why not use air operated brakes? in fact just use commercial lorry drums and air.. they would last forever and be cheap as chips to fit to the machine and service.. Ah but the manufacturer can't rip you off for parts if you can just go down to your local motor factor!

 

[ollie989898]

Christ alive, I did not know this kind of thing could happen, I guess most of us can count the times we have stalled a modern machine on one hand so it would be an usual situation to be in that you might be unprepared for?

If these accumulators are so safety critical why don't dealers taker them off and have them exchanged or tested every 1000-2000 hours or so?

Trouble is a lot of kit like this just does not get the maintenance specified in the manual. Tractors with iffy handbrakes are one thing, but no brakes in the event of a loss of engine power is scary.

 

[Speedstar]

I have a 13 JCB, having big problems with my brakes....do you know much about the problems? Not getting any help from the dealer, changed the master cylinder had the front axle off and changed seals but still not working, next thing to check is the vacuum pump to servo.... can't think of anything else. Any advice appreciated

Have you changed the full brake valve block as I think this was the main problem,our one was so bad it when back have a 15 plate one now which is better but not as good as our 02 plate one was

 

[Nav man]

I have a JCB 320S Pivot. Is there anyway i can test brake accumulator before i waste money on a new one. I have no brakes after engine switched off. Ta

 

[Cowabunga]

I have a JCB 320S Pivot. Is there anyway i can test brake accumulator before i waste money on a new one. I have no brakes after engine switched off. Ta

If it used to work and doesn't now, that's as good a test as any isn't it?
Get a price from JCB but also get a price for a Kramp one of the same litres and pressure from your local tractor dealer or repairer. I got a couple a few months back for my Quicke loader and saved about 50%.

 

[Nav man]

If it used to work and doesn't now, that's as good a test as any isn't it?
Get a price from JCB but also get a price for a Kramp one of the same litres and pressure from your local tractor dealer or repairer. I got a couple a few months back for my Quicke loader and saved about 50%.

only owned machine for past year or so (2014 model) not sure if ever worked but have a habit of swapping parts which are perfectly fine. £150 for accumulator is painful if there's nothing wrong with old one hence question

 

[Cowabunga]

only owned machine for past year or so (2014 model) not sure if ever worked but have a habit of swapping parts which are perfectly fine. £150 for accumulator is painful if there's nothing wrong with old one hence question

Aha! It's difficult if you are not sure whether you have a fault or not. Someone will be along presently to help that has experience with this model I'm sure. However, if it has an accumulator, then it certainly isn't working and does need to be changed or charged in my opinion.
I have another pair that have failed recently, again ones for a suspension system rather than for retaining energy. Been very lucky with ones fitted to transmissions and brakes over the years.