International vari touch

[Mur Huwcun]

Hi, having bother with the hydraulics on a Bradford 276. Lift etc stopped working altogether with position lever but would work when you pushed the draft spool on top link bracket. Removed top to strip chest down, found spool sticking. Cleaned up and refit, lift now works but will lift no weight or produce pressure at tipping pipe.

Again by pushing draft spool arms will lift to top or blow relife valve if tap is closed and strain engine which shows pump is ok as is the PRV or am I missing something simple here? Have checked all linkage and the chain inside top. By now it's baffling me!!! Any help much appreciated!

 

[Tractortech]

Now Then..
What's a Bradford 276??

 

[roscoe erf]

Now Then..
What's a Bradford 276??

possibly a bomford

 

[Tonym]

McCormick International 276 built in the old Jowett factory at Bradford in the late sixties.

 

[Mur Huwcun]

Sorry, yes as above Bradford built tractors like the 250,275,276,414 and 434 as opossed to the later Doncaster built world series 74,84 series etc

 

[Mur Huwcun]

Had another play with this one over weekend, PRV must be ok as it will strain engine when it's blowing by manually moving the draft rod. If it was lift cylinder seals then I should be getting pressure at trailer tipping pipe by isolating cylinder but still can't. Any one have a manual at all for the hydraulics? The tractor workshop manual does not give much detail about the lift valve etc

 

[Rob Smith]

I’ve got a similar problem with the vari-touch on my B275. Hydraulics were slow, but now the arms will only lift with absolutely no weight - I can easily stop them with just one hand! And there’s no pressure at the tipping pipe. But like you I seem to have pressure at the pump.
Did you find out the cause of your problem - or source a manual?

 

[Pennine Ploughing]

Have you checked to see if the orifice filter is clean, as this is where your problem started,

The hydraulic system is it 2 half's, a high pressure high volume half, and a lower pressure low volume half,
When you push in the draft spool from the back, this bypasses the low pressure/volume half all together, and as you will find , it will pump oil and blow the relief valve off at full pressure, so high side is fine,

The low side is a very good design and we'll thought through valve chest, 1 of the first, if not the first, that lifts on a balance pressure, this means it will not lift the Hyd arms whatever ever the weight is on them without any drop when lifting, ,
This works like this, let's say there is 600kg on the arms, and you want to lift it from half way up, to the top, when you move the leaver up, the low pressure side comes in to force and builds the pressure up and moves the internal oil activated control spool, once the pressure is balanced it will lift the ball off it's seat, and lift the hydraulic arms without any drop, till they reach the position high selected then spool returns to neutral, and the ball sits back on its seat to hold it there,

Now if shite gets into the low pressure side, then you will have the symptoms your having, it takes next to nothing to upset it, carefully remove and renew the orifice filter, if this don't sort it, then it's a take apart and clean and good luck with that, it's not the easiest of jobs,,

An other way to clean it without taking it a part, is drain all the oil, fit new suction filter in the oil feed to pump, and put some 32 hydraulic oil mixed with diesel 50/50, and run for a while, this might flush the dirt out

 

[Mur Huwcun]

Hi, No I didn’t get much further with this I stuck a battery on the tractor this summer to move it and they seemed to be working better!!

I did strip the chest down initially to clean it, was starting to think then that it was the valve behind the feed pipe into the valve block but that did not change anything either. Your explanation of low pressure side makes sense and with mine it was a slither of silicone that I found in the main lift spool!! Will have to sort it out this winter and then finish the 275 and then re start the 250 project and do something with the 434 engine and maybe just build a shed for them all!!!

 

[Mur Huwcun]

Resurecting this thread as I have a 250 I’ve been tinkering with over Christmas. Hydraulics wouldn’t work and would slowly raise to the top when engine started, they could be pushed down but would then creep back up. Hydraulics though would not strain or pressurise the tipping pipe. Had to split tractor to fit a new input shaft seal so whipped top cover off at same time and swapped the valve chest for another one I had. Lo and behold, it’s exactly the same. Arms creep up, can be pushed down but no pressure to tipping pipe nor will the arms lift any weight! Any one with suggestions? Thank you

 

[Andy Nash]

Resurecting this thread as I have a 250 I’ve been tinkering with over Christmas. Hydraulics wouldn’t work and would slowly raise to the top when engine started, they could be pushed down but would then creep back up. Hydraulics though would not strain or pressurise the tipping pipe. Had to split tractor to fit a new input shaft seal so whipped top cover off at same time and swapped the valve chest for another one I had. Lo and behold, it’s exactly the same. Arms creep up, can be pushed down but no pressure to tipping pipe nor will the arms lift any weight! Any one with suggestions? Thank you

Pressure relief valve stuck open? Maybe unlikely on both valve chests.
Is the pump actually delivering much in the way of flow to the valve chest?

 

[Mur Huwcun]

Pressure relief valve stuck open? Maybe unlikely on both valve chests.
Is the pump actually delivering much in the way of flow to the valve chest?

I cracked open the pipe from pump and it had a bit of flow and pressure at idle. It’s odd that both PRV are stuck I admit, I’ve started stripping down the original chest that’s off now. It’s the arms creeping to top on both of them baffles me aswell.

 

[Andy Nash]

I cracked open the pipe from pump and it had a bit of flow and pressure at idle. It’s odd that both PRV are stuck I admit, I’ve started stripping down the original chest that’s off now. It’s the arms creeping to top on both of them baffles me aswell.

I’m not familiar with the 250, but am guessing it’s the same hydraulic system as my non vary-touch B275.
If so, there’s not much to it.
Have you tried isolating the linkage with the thumb wheel valve?
If so, can you trap the oil in the ram?
could the thick mounting gasket have failed?
Mine did, but it just leaked.

 

[Mur Huwcun]

I’m not familiar with the 250, but am guessing it’s the same hydraulic system as my non vary-touch B275.
If so, there’s not much to it.
Have you tried isolating the linkage with the thumb wheel valve?
If so, can you trap the oil in the ram?
could the thick mounting gasket have failed?
Mine did, but it just leaked.

Yes, exactly same as non vary touch. I have a 275 the same. The thumb screw will isolate the arms but won’t let it pressurise the tipping pipe! The gasket was all torn up so just used some RTV sealant and an oring on the oilway. Have set the non return valve grub screw as the book this afternoon but didn’t get a chance to start her up and check. Have an iput shaft seal for gearbox on the way tommorow or Friday from Repair and Maintenace so will split it quickly for that this weekend sometime.

 

[Mur Huwcun]

A quick update but still not there!! Adjusted the allen grub screw on the non return valve and now with the lever in the centre (hold) position the arms stay put but in the lower position they creep up but won’t do anything in the lift position. Going to strip one valve down tommorow for a looksy!

 

[Gapples]

 

[JuanBir]

¿Ha revisado para ver si el filtro de orificio está limpio, ya que aquí es donde comenzó su problema?

El sistema hidráulico consta de 2 mitades, una mitad de volumen alto de alta presión y una mitad de volumen bajo de presión más baja.
Cuando empuja el carrete de tiro desde la parte posterior, esto evita la mitad de baja presión/volumen y, como encontrará, bombeará aceite y soplará la válvula de alivio a plena presión, por lo que el lado alto está bien.

El lado bajo es un muy buen diseño y pensaremos en la caja de válvulas, una de las primeras, si no la primera, que se levanta con una presión de equilibrio, esto significa que no levantará los brazos hidráulicos sin importar el peso que tengan sobre ellos. sin ninguna caída al levantar, ,
Esto funciona así, digamos que hay 600 kg en los brazos y desea levantarlos desde la mitad hasta la parte superior, cuando mueve la palanca hacia arriba, el lado de baja presión entra en fuerza y aumenta la presión y mueve el carrete de control interno activado por aceite, una vez que la presión se equilibra, levantará la bola de su asiento y levantará los brazos hidráulicos sin ninguna caída, hasta que alcancen la posición alta seleccionada, luego el carrete regresa a neutral y la bola se asienta nuevamente. su asiento para sostenerlo allí,

Ahora, si la mierda entra en el lado de baja presión, entonces tendrá los síntomas que tiene, no se necesita casi nada para alterarlo, retire con cuidado y renueve el filtro de orificio, si esto no lo soluciona, entonces es un desarmado y limpio y buena suerte con eso, no es el trabajo más fácil,

Otra forma de limpiarlo sin tener que intervenir es drenar todo el aceite, colocar un filtro de succión nuevo en la alimentación de aceite a la bomba y poner un poco de aceite hidráulico 32 mezclado con diesel 50/50 y dejarlo funcionar por un tiempo, esto podría eliminar la suciedad

Buen día. Tengo un IH B414 desde hace 10 años, hace 3 años explotó la bomba hidráulica y tuve que adaptar la que compré en mi país, la puse y cuando encendí el motor parecía que todo iba a explotar así que tuve que ir a un especialista en hidraulica segun me dijo tenia que hacer piezas porque no habia nuevas......nunca funciono bien y no me pudo dar solucion y como soy muy testarudo He seguido buscando para saber como funciona exactamente el circuito y sistema Varitouch ya que tengo todas las piezas y manuales pero hasta ahora nunca una explicación de para qué sirve el famoso Filter Assy, lo cual me tuvo muy ocupado ya que logré descubrir que era el responsable de si el sistema funcionaba o no y he llenado el agujero con soldadura de estaño y he ajustado el diámetro del agujero hasta que funcione, solo que después de una hora de funcionamiento se ve que el aceite se licua y empieza a fallar nuevamente. Es una locura no saber cuál es el problema y por tanto no poder solucionarlo. Todo lo demás funciona perfectamente ya que lo que tenía que me costaba arrancar con frío se solucionó cambiando los calentadores por unos de 11 voltios. Un saludo a todos y muchas gracias por permitirme participar.