Can't remove bump knob on Bolens BL110 trimmer

jimhokie

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After the bump knob fell off twice the first time I used the trimmer, I tightened the crap out of it. Now I can't get it off to add more string. It actually rotates with a lot of torque, but is not actually unscrewing. I thought the plastic cover was just rotating on the stud, but I pried the plastic cover off, and the square head of the bolt also turns with a wrench without unscrewing. I seems to turn in a set increment, so I don't think the threads are stripped. I suspect the entire flex transmission cable is rotating, and not the threaded part of the bump knob. I'm looking for some guidance on how to take it apart enough to see where the bump knob threads in, so hopefully I can hold that part still while trying to unscrew the knob. Any ideas?

Jim
 

ILENGINE

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If you the bolt and shaft is turning while holding the outer spool then that means the outer spool is also stripped and will need to be replaced. Curved shaft trimmers can be a challenge when things go wrong. Straight shaft trimmers normally have a slot just above the cutting head to insert a screwdriver or some other small rod to prevent the gears from turning when removing the head.
 

jimhokie

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Thanks for the response, ILENGINE. I finally got a chance to try to fix it today, but could not figure out how to remove the outer spool. Is the bump knob bolt threaded into the outer spool? It looks like it would be from the picture of the part. I removed the shaft from the motor and pulled the flexible drive shaft out...the bump knob bolt still turns in 90 degree increments still. There are 4 holes on the top of the outer spool, where you can see the plastic stops that the inner reel engages, but I see no means to remove the outer spool. What is the trick?
 

possum

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What is the unit? Now there is a trick.
 

possum

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The bolt that comes through the outer spool has a little stop washer on it. You will have to pry it down with a screwdriver. Clean the area out and you should find it. A new one will come with the new outer spool.
 

ILENGINE

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This is basically the ryobi setup of trimmer from years past. the bump knob threads into a extended nose coming through the outer and inner spools. the outer spool has a square hole at the top which will wear with time or from damage. the problem is you can't remove the outer or inner spool with the bump knob bolt attached to the trimmer. But can't remove the striped bump knob bolt because you can't prevent the shaft from turning do to the striped square on the outer spool.
 

possum

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Well if that is the case then buy the shaft portion plus the complete head. Or, start sawing off parts of the head until you can remove it from the shaft and buy a new complete head. Or, toss the weedeater in the trash and get another one. Or, all three.
 

jimhokie

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ILLENGINE, I think you gave me the key bit of info I couldn't figure out from the exploded parts diagram...the square hole in the top of the outer spool. That hole being stripped explains how the bolt seems to turn in 90 degree increments. So maybe if I can figure out how to grip the opposite end of the flexible drive shaft while trying to unscrew the bolt, without overtwisting the drive shaft, that may work. The square end of the drive shaft is recessed inside the shaft somewhat, but I may be able to lock a vice grip on it and hold that still while turning the bolt. Otherwise, it sounds like I'll be cutting the head of the bump knob bolt.

Possum, I'm hoping to avoid replacing the entire shaft and head assembly after looking at the price of all the parts. I just bought this model last summer to replace my 20+ year old Ryobi trimmer and have only used it 5 or 6 times. Two of which, the bump knob came off while in use and one of those took me 2 hours to find the damn knob again, which prompted me to tighten the crap out of it, leading to my current problem. As disappointed as I am with the design of the head, I'm not ready to scrap this trimmer yet!

Thanks to everyone for the advice and suggestions...I think I know enough now to fix it!
 

Suzannta

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After the bump knob fell off twice the first time I used the trimmer, I tightened the crap out of it. Now I can't get it off to add more string. It actually rotates with a lot of torque, but is not actually unscrewing. I thought the plastic cover was just rotating on the stud, but I pried the plastic cover off, and the square head of the bolt also turns with a wrench without unscrewing. I seems to turn in a set increment, so I don't think the threads are stripped. I suspect the entire flex transmission cable is rotating, and not the threaded part of the bump knob. I'm looking for some guidance on how to take it apart enough to see where the bump knob threads in, so hopefully I can hold that part still while trying to unscrew the knob. Any ideas?

Jim

DID YOU EVER REMOVED THE BUMP HEAD?

I am having the same problem and I can't get it off. It keeps rotating and I can't seem to find the hole to insert a screwdriver to hold it while I try to remove it. Barely new too.
 

shiftsuper175607

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DID YOU EVER REMOVED THE BUMP HEAD?

I am having the same problem and I can't get it off. It keeps rotating and I can't seem to find the hole to insert a screwdriver to hold it while I try to remove it. Barely new too.


Some of these trimmers have left hand thread.

Check to make sure you are trying to turn it the correct direction.
 
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