The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: Simon59 on 26.05. 2018 13:57

Title: Plunger column removal
Post by: Simon59 on 26.05. 2018 13:57
Hi All. Am I missing a trick or a technique to extract the columns (89-4041) from my plunger rear suspension? I’ve removed the top plugs and the pinch bolts and opened out the lugs. I’ve bought the right tool that screws into the top of the column, but neither columns are budging at all. I’ve used some heat and penetrating fluid too. Any experiences or thoughts?  *conf* Thanks, Simon
Title: Re: Plunger column removal
Post by: Rex on 26.05. 2018 16:57
And the bolt through the rear of the slider?
Title: Re: Plunger column removal
Post by: Greybeard on 26.05. 2018 17:07
Off the top of my threadbare head: The pinch bolts must be removed, not just loosened. I can imagine that if the columns have been in for a long time they may have ledges where the trunion goes, (but I'm not sure). Mine were tight; I had to drive them out with a long rod from the top, (and knocked out the bottom fixed blanking piece in the process  *work*). Probably not a great idea to drive on the top edge as it will likely belly out and get even more stuck. Leave it for now, go and get a drink and when you come back they will simply fall out!
Title: Re: Plunger column removal
Post by: morris on 26.05. 2018 19:56
Same as GB here. But I remember turning up an aluminium threaded piece on the lathe to screw in instead of the plugs and giving the columns a good wack to shift them before drifting them out completely.
Alternatively you could use the plugs themselves and knock them with a plastic hammer. The plugs are widely available and don’t cost much if ever you damage them in the process.
Title: Re: Plunger column removal
Post by: Rex on 26.05. 2018 21:08
I used the plugs to knock the column through but they needed the flange grinding-off first. Didn't matter as they rusty anyway.
Title: Re: Plunger column removal
Post by: Greybeard on 30.05. 2018 13:45
Hows it going Simon?
Title: Re: Plunger column removal
Post by: duTch on 31.05. 2018 10:24

 Yeah Simon ??

 
Quote
And the bolt through the rear of the slider?

 If you mean the front, that's just a pinch bolt for the axle lugs, and doesn't affect the shaft- otherwise maybe it wouldn't all slide at all....as GB says "  The pinch bolts must be removed, not just loosened. "     The shafts/columns have locator grooves scalloped out
Title: Re: Plunger column removal
Post by: Simon59 on 31.05. 2018 12:16
I'm on holiday in Scotland this week so no chance to have another go. I can confirm that the pinch bolts are definitely out, the lugs have been opened out and the special tool threaded into the top of the column. I've studied a cut-away drawing of the plunger suspension system and I can't see what might be stopping me from drifting out the column, but both are stuck fast despite reverting to Very Large Hammer. If it was just one I might think it was a one-off problem, but both?  *conf*

I'm back home tomorrow so I hope they've 'loosened' in my absence! 
Title: Re: Plunger column removal
Post by: Simon59 on 02.06. 2018 17:02
Just an update - one plunger column has been removed! But not without nearly destroying the service tool and getting plenty of exercise for my right arm. Definitely not the 'tap' that the BSA service sheet and the Haynes manual suggest. I can't see any obvious reason for the very (very) tight fit, so I'm going to take the column and sleeve to work on Monday to measure them, before I tackle the second unit. Still, one down, one to go!  *smile*     
Title: Re: Plunger column removal
Post by: Greybeard on 02.06. 2018 17:05
Just an update - one plunger column has been removed! But not without nearly destroying the service tool and getting plenty of exercise for my right arm. Definitely not the 'tap' that the BSA service sheet and the Haynes manual suggest. I can't see any obvious reason for the very (very) tight fit, so I'm going to take the column and sleeve to work on Monday to measure them, before I tackle the second unit. Still, one down, one to go!  *smile*   
Well, that shows proof of concept anyway. Good luck with number two!