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Boom suspension trouble l180f
- Thread starter mrcowboy
- Start date
Ben Witter
Senior Member
Does the boom drop all the way or just sag a little? You can unhook the lines to the boom suspension valve and plug/cap them to verify the issue is in the boom suspension.
It could be the accumulators need charging or rebuild/replace. Or you could need to reseal the valve.
It could be the accumulators need charging or rebuild/replace. Or you could need to reseal the valve.
Mark250
Senior Member
- Joined
- Aug 30, 2015
- Messages
- 1,243
- Location
- victoria,Australia
- Occupation
- heavy equipment technician
Hi mrcowboy, check that hyd oil is not bypassing the lift cylinder seals. when the BSS is on, the valve V1 opens the rod end of the lift cylinder to tank, if you have a faulty cylinder or seal it will allow the boom to drop.
with the BSS off the rod end of the cylinder is blocked at the control valve with the valve in the hold position. so the boom will not drop even with a faulty seal but you may notice that that it is a bit slower than normal
Mark
with the BSS off the rod end of the cylinder is blocked at the control valve with the valve in the hold position. so the boom will not drop even with a faulty seal but you may notice that that it is a bit slower than normal
Mark
Ben Witter
Senior Member
Yes what Mark says is often the cause. Look at the bottom side of the cylinder barrel for any damage also. Often debris gets under them and on top of the frame which distorts the barrel when booming down all the way.
Mark250
Senior Member
- Joined
- Aug 30, 2015
- Messages
- 1,243
- Location
- victoria,Australia
- Occupation
- heavy equipment technician
that's because your BSS is disabled when not running
there a few ways to check your cylinder seals. be sure to remove any residual pressure from the tank and cylinder lines
1/use a heat gun when you retract or extend cylinders to there limits and hold against relief
2/support load frame when extended and remove hose from rod end of cylinder. cap hose off and operate control as if to raise boom and check for leakage from cylinder connector. lower the load frame as far as it will go and remove hose from head end of cylinder and cap off .operate control as if to raise machine off the ground. check for leakage
there are quite a few other ways to check seals as well
there a few ways to check your cylinder seals. be sure to remove any residual pressure from the tank and cylinder lines
1/use a heat gun when you retract or extend cylinders to there limits and hold against relief
2/support load frame when extended and remove hose from rod end of cylinder. cap hose off and operate control as if to raise boom and check for leakage from cylinder connector. lower the load frame as far as it will go and remove hose from head end of cylinder and cap off .operate control as if to raise machine off the ground. check for leakage
there are quite a few other ways to check seals as well
Might be totally different but had a similar problem on L90E and I think it was one of the 2 solenoid coils on the BBS valve . I had a spare coil because previously it burst the solenoid valve body and I had to get a new coil with it .
From my experience it's either a BSs solenoid or you have bad packings in one of the cylinders. You should be able to swap the solenoids out with each other. If a accumulator was bad you would feel a thump when BSS is turned on but have no softness in the boom. And your boom would not drift down.
From my experience it's either a BSs solenoid or you have bad packings in one of the cylinders. You should be able to swap the solenoids out with each other. If a accumulator was bad you would feel a thump when BSS is turned on but have no softness in the boom. And your boom would not drift down.
Check for volvtage at your bss solenoids.
Ben Witter
Senior Member
If MA9103 is faulty or not receiving power it is possible for the boom to drift down when boom suspension is activated. You can check for power and ground at the coil when boom suspension is activated and resistance across the coil.
You can also cap and plug the hose from the MCV to the BSS valve and try to see if it still drifts
You can also cap and plug the hose from the MCV to the BSS valve and try to see if it still drifts
Shagga
New Member
What was the outcome mrcowboy? I have same issue with L220g. No cylinder leakage and all new coils and posts. Losing hair real fast.....