Valtra 8150 brakes

[Giles1]

Replaced the brakes on the above as the old ones were worn and not holding properly. New ones don't either! The correct oil is being used, the system has been bled with new fluid twice, but the brakes wont hold a load much more than 8 tonnes or so and you have to press the pedal pretty hard to get effective braking even without load. (Our 6350 brakes are way more effective). This leads me to think the old brakes wore because something in the system was not functioning correctly rather than just through use,and still isn't so the new ones will wear prematurely too. We are stumped,any ideas?

 

[davidroberts30]

sounds like the trailer brakes don't work

 

[Green&Steam]

How well does the tractor stop when it's on its own ?

 

[Giles1]

Trailer brakes are fine, round here they need to be! Even with nothing on the back, stopping is nowhere near what it should be. New brakes were soaked for 2 days in the right oil before fitting as well.

 

[Giles1]

The brakes do groan and bite just before you stop.

 

[Giles1]

You are just about standing on them at that stage.

 

[Mur Huwcun]

The brakes do groan and bite just before you stop.

Sounds like they’re warped already, are they multiplates?

 

[Pebd99]

The master or slave cylinders will be wrong. Have you fully adjusted at the slave cylinders? Dot 4 fluid?

 

[Giles1]

Thanks all for the help, hope they're not warped,barely done 20 hours since renewal. Correct fluid in there,will check slave cylinder adjustment again. The cylinder seals seem to be ok as it's not losing fluid.

 

[Pebd99]

The cylinders can semi seize up over time with rust.

 

[Giles1]

Probably not the cylinders as the handbrake doesn't hold too well either ,and that I understand uses a different system.

 

[Macsky]

Probably not the cylinders as the handbrake doesn't hold too well either ,and that I understand uses a different system.

Are the pivot pins on the levers that the slave cylinders push free? (Ones with grease nipples on them)

 

[james ds]

Probably not the cylinders as the handbrake doesn't hold too well either ,and that I understand uses a different system.

Did you try tightening down the two 19 mm nuts a couple of turns. To pull the brakes a bit tighter.

 

[wdah/him]

Did you try tightening down the two 19 mm nuts a couple of turns. To pull the brakes a bit tighter.

as said the slave cylinders will rust, and you don't really notice. also don't over tighten the brakes up as we did that and warped the second set in a short enough time but more than 20hrs. we now run at 3/4 pedal so the plates have enough room to separate and allow oil in between.

check your handbrake cable as we have had few snap

assuming that the 8450 is very similar to our 8400, ours is a bit of a bitsa, some parts are 50 series some are 8000 series

 

[Giles1]

Ok thanks, will check those things out. Tomorrows looking like a washout/workshop day!

 

[Macsky]

How did you get on in the end?

It looks like I am needing to change the brakes on my 8150, left side is grabbing harshly, like they're warped and down to metal or something. Did you do the job yourself? Big job?