John deere 3400 brake noise

[Romeogolf]

Hello all,

I have a 2003 John deere 3400 telehandler. As you will all know the brakes are a bit urgent to say the least! However, I often get a noise when pressing the brake pedal, not always, but it's a noise that seems to come from above the brake pedal in that housing. The noise cannot be described as a grinding, or a squeak more a 'trump' for want of a better description. The noise also coincides with a pressure warning light on the dash.

Any help as to identifying the cause and indeed the remedy, will be greatly appreciate.

Thanks.

 

[NZ Tech]

I think they have multi plate disks in them. What are you using for axle oil??.

 

[ACEngineering]

I think they have multi plate disks in them. What are you using for axle oil??.

I think the guy is refuring to a noise under dash from brake pedal valve not axle.? Thats how i read it any way.

Last 2 i drove made funny noises from pedal valve too but no issue with warning lights.

 

[Romeogolf]

Yes, as you say the noise appears to come from where I imagine the brake pedal valve is. The pressure light only illuminates when the noise appears, when there's no noise, no light. Could a new pedal valve be an option?

Thankyou

 

[njneer]

Think it could be the brake system recharging the accumulator, will have some natural leakage over the day when using the brakes and will recharge occasionally when it reaches the minimum pressure hence when you press the brakes the minimum pressure is reached and the valve recharges the system.
Accumulator there to provide enough oil to apply the brakes if you lose power or stall etc.
It has priority from the steering circuit the reason early models were a pig to start and had to turn the steering to give the oil somewhere to go to help start them , then they fitted the dump valve which dumped the oil to tank when the key was in the start position.

Warning light will be the low brake pressure light as it has reached the minimum and will only be on momentarily as the pressure is,recharged the light naturally goes out.

Nothing to worry about I don't think unless it is doing it excessively in which case you may have an internal leak in the valve which would need looked at.

 

[Romeogolf]

Thankyou for your detailed reply. The noise is getting to the stage of occurring once in every five presses of the pedal - so would like to find a solution. Would I go about changing just the valve, the accumulator, or would I not know until further investigation?

Many thanks

 

[njneer]

Mos

Thankyou for your detailed reply. The noise is getting to the stage of occurring once in every five presses of the pedal - so would like to find a solution. Would I go about changing just the valve, the accumulator, or would I not know until further investigation?

Many thanks

most likely leakage Within the valve, the accumulator could be checked also just to be sure.
As annoying as the noise is it is probably nothing to worry about the valve is doing its job recharging the system , they did tend to do this , changed loads of them on early models as a recall for ( and wait for this !!!) excessively harsh brakes , required cutting the frame around the steering column with a 4 1/2 inch grinder to make the new valve fit .
Believe it or not the " urgent " brakes you have now are nothing compared to the early ones they were practically binary on or off.

 

[ACEngineering]

Thankyou for your detailed reply. The noise is getting to the stage of occurring once in every five presses of the pedal - so would like to find a solution. Would I go about changing just the valve, the accumulator, or would I not know until further investigation?

Many thanks

I wouldn't say there is a problem, it will charge brakes every five or so presses. It sounds perfectly normal to me others I have driven make the same odd noises from the brake charge circuit. if it works and you have brakes for half a dozen presses of the pedal with engine off then leave it alone.

 

[Romeogolf]

Thanks very much indeed, I'm very grateful for all your advice. I think I'll leave her alone for the time being, but if the problem becomes worse, I now have a fair idea of the issue!

Thanks.