820 belarus tractor help

kris smith · Mar 15, 2009

my dad owns a 820 belarus 4 wd with cab but the back wheels dif isn't working or not on ,so I was wondering where to find the differential lock lever . I'm asking because my dads forgotten where it is said he thinks it broke ,and I really need the differential lock on .
So if anyone knows where to find the differential lock for the back wheels I'd appreciate it thanks.

kris smith · Mar 15, 2009

oh I think it was made in the 70's or early 80's if that makes a difference .

vapet · Mar 15, 2009

Lower dash on left side, T handle maybe. Can't remember for sure and mine isn't close by. Anyway it is below the steering colume and connects to a cable that goes out front. Look for that cable.

kris smith · Mar 15, 2009

well this tractor has no cables left ,and I see there was some kind of cable ,as there is a few pulleys . the only thing I think the cable could of went to is a pulley/ control on the front steering box . is that the differential lock for the front ? or does it control the back to? I'm not sure what that pulley / control does. it has a few pipes into it so I know it does something just not sure what.

Anonymous-0 · Mar 15, 2009

The cable rotated a knob on steering which in turn sent oil to left brake housing. Inside brake housing multi disc clutch that locks diff. Turning brake is seperate.

kris smith · Mar 15, 2009

ok so I need to rotate that knob on the steering box the right way to get it to work. well now to figure out which way to turn that knob and how to do so while driving . does the line to the rear brake housing run outside and in the open ? if so I'll have to check for breaks in that line.

Anonymous-0 · Mar 16, 2009

The differential lock valve is near the top of steering column. Some really early one had a knob that had to be turned. Later ones had a stamped lever plate that the cable fastened to.
The pulleys are for the radiator curtain.

richardinnz · Mar 16, 2009

A cable should run to a pulley wheel on the left top of the steering bolster. Pulling a handle on the left lower part of the dash out 1/2 way and turning 1/4 turn to lock it out gives auto diff lock, pulling knob fully out gives full diff lock. The knob is connected to the pulley by a wire cable and returned to diff lock off by a spring by the pulley wheel. Another pulley wheel can be found centre top rear of the steer bolster, this is for the radiator blind. When the diff lock is activated, oil from the steering bolster flows along a pipe running along the inside left chassis rail into a diaphraham (can"t spell that!) on the end of the left side brake. This clamps 2 brake discs together locking the left diff quill shaft to the diff carrier via a shaft running up the middle of the left quill shaft.

kris smith · Mar 16, 2009

thanks I checked and found the line to the diff lock was broken. do you have to bleed the diff lock for it to work ? as I'm going to fix the line ,but I don't know how to bleed the air out ,or if thats needed ?

495man · Mar 16, 2009

I heard an 825 uses the same plates (size and part number wise) for the brakes and diff lock.

kris smith · Mar 16, 2009

ok ,but do you know how to bleed the air out of the line going to
the diff ?

richardinnz · Mar 18, 2009

No need to bleed, just repair and top up the steer bolster with oil. The diff lock line is one that is frequently opened when replacing clutches and brakes on these tractors and they never need bleeding. The brake discs in the diff lock are identical to the service brakes and the parking brake untill around 1993/4 when the size of the service brake discs was increased. By the way never ever apply the park brake when the tractor is moving as it will shear off the shaft of the park brake in the middle of the diff. Hope this helps, Richard.

kris smith · Mar 19, 2009

thanks I did that and I also cracked open the fitting close to where it enters the diff/ brake and I bled out the air that was in the line . it seems to work but only about 25% or so not 100% locked in . I'm wondering if it needs to be repaired as it is really old and it has lots of oil around the brake/ diff. but thanks for your reply

richardinnz · Mar 19, 2009

If you have a lot of oil around the diff lock housing, the seal in the diff lock cover may be leaking, to service this you remove the aluminium cover, push down in the centre of the cover with somthing like a 5/16" diameter pin punch against the light spring inside and flick out the seal ring with a pick. The seal is a standard "O" section ring, so easly obtainable locally. If gear oil is present in the housing then oil is coming along the diff lock shaft, and the diff lock unit will have to be pulled out of the tractor to replace the seals, again standard "O" section seals are used. The diaphragms very rearly fail but it is not unknown. The unit can be dismantled and the discs cleaned in petrol if they have got oil on them. Be shure that the steer wheels are in the straight ahead position when checking the diff lock or the auto function will not allow oil pressure down at the diff lock, if memory serves the diff lock disengages at around a 26 deg steer angle.

kris smith · Mar 19, 2009

ok thanks for the help

820 belarus tractor help

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