13 replies to this topic

[miniyellowmini]

I'm planning on removing the front trumpets on my 1984 Mini Sprite or at least one of them as one of the rubber covers that protects the knuckle joint has split and I want to replace it.

I know I will need to compress the cone to remove the trumpet but can anyone tell me the size of the thread in the rubber cone? I think it may be 14mm and if so would that be a standard M14 thread as I was going to have a go at making a compression tool myself with some bits and pieces I have laying around the garage and have some M14 allthread I may be able to use. Cheers.

Edited by miniyellowmini, 14 January 2013 - 11:32 PM.

[KernowCooper]

That age should be metric yes, I believe after 1976 they went to 14mm metric so if you have some studding try it and see how it feels but due to the compression load on the thread it should be a good quality material otherwise it may just strip its thread or damage the internal thread on the cone.

[miniyellowmini]

Cheers thanks KernowCooper. I'll give it a go. The the bar I have is high tensile steel so should be ok I reckon, but I'll take care with it all the same. Guessing there'll be a lot of stored energy ready to go bang if it snaps!

[KernowCooper]

Snapping is one thing jumping the thread is another problem I have seen cones which have jumped the thread and then you have to damage the alloy trumpet to get the cone out, as per other threads here.

[MRA]

We all want to save money and make tools etc..... however this is one job you really should NOT attempt without a proper tool, there are some suppliers that have this tool made and the same applies....

THIS IS A SAFETY ISSUE !!! You could very easily lose a finger or more..

[MRA]

Allthread is not high tensile

[Spitz]

oh...and just replace the whole knuckle assembly.....cheap...cheap...cheap preventative measure. Cup, knuckle and rubber seal.
( unless you originaly meant you're replacing the whole joint )
The plastic cup may be nearly worn through, if not already, and you'll just have to pull it all apart again to change it

[Cooperman]

I have a 'proper' compression tool and it still scares the crap out of me when I have to really compress an old cone in case the thread strips in the rubber cone at maximum compression just when my fingers are taking the trumpet out.
The original 'Churchill' tower tool was great and I have one of those, but it is only for the early cones with the imperial threads. Now that is a substantial tool and easy to use.

[miniyellowmini]

Snapping is one thing jumping the thread is another problem I have seen cones which have jumped the thread and then you have to damage the alloy trumpet to get the cone out, as per other threads here.

We all want to save money and make tools etc..... however this is one job you really should NOT attempt without a proper tool, there are some suppliers that have this tool made and the same applies....

THIS IS A SAFETY ISSUE !!! You could very easily lose a finger or more..

oh...and just replace the whole knuckle assembly.....cheap...cheap...cheap preventative measure. Cup, knuckle and rubber seal.
( unless you originaly meant you're replacing the whole joint )
The plastic cup may be nearly worn through, if not already, and you'll just have to pull it all apart again to change it

I have a 'proper' compression tool and it still scares the crap out of me when I have to really compress an old cone in case the thread strips in the rubber cone at maximum compression just when my fingers are taking the trumpet out.
The original 'Churchill' tower tool was great and I have one of those, but it is only for the early cones with the imperial threads. Now that is a substantial tool and easy to use.

Cheers for the advise Sounds like this may not be a good idea after all and I will just buy the proper tool for the job. £20 saving or whatever it is isn't worth loosing any fingers for LOL. Can anyone recommend any good tools or are they all pretty much the same regardless of where they are bought from? I've been looking at the Minispares one below but may hang on a couple of weeks and see if I can get one at Bingley and save on postage costs as it's unlikely I'll be doing this job till sometime next month anyway.

http://www.minispare...ch/classic/cone compressor.aspx

I will be replacing the whole knuckle joint as the one with the split boot looks slightly rusty inside and betting the other ones not much better and like you say they are so cheap anyway it's not worth taking it all to pieces and not changing them.

[minilee94]

I got given a compression tool with my car when bought and it was brand new im box and it stripped while compressing so i chucked it in the tool box and done it with out you don't need a tool

Well i didnt use one and i done mine abit of banging and smashing yourself etc was done

[Cooperman]

Snapping is one thing jumping the thread is another problem I have seen cones which have jumped the thread and then you have to damage the alloy trumpet to get the cone out, as per other threads here.

We all want to save money and make tools etc..... however this is one job you really should NOT attempt without a proper tool, there are some suppliers that have this tool made and the same applies....

THIS IS A SAFETY ISSUE !!! You could very easily lose a finger or more..

oh...and just replace the whole knuckle assembly.....cheap...cheap...cheap preventative measure. Cup, knuckle and rubber seal.
( unless you originaly meant you're replacing the whole joint )
The plastic cup may be nearly worn through, if not already, and you'll just have to pull it all apart again to change it

I have a 'proper' compression tool and it still scares the crap out of me when I have to really compress an old cone in case the thread strips in the rubber cone at maximum compression just when my fingers are taking the trumpet out.
The original 'Churchill' tower tool was great and I have one of those, but it is only for the early cones with the imperial threads. Now that is a substantial tool and easy to use.

Cheers for the advise Sounds like this may not be a good idea after all and I will just buy the proper tool for the job. £20 saving or whatever it is isn't worth loosing any fingers for LOL. Can anyone recommend any good tools or are they all pretty much the same regardless of where they are bought from? I've been looking at the Minispares one below but may hang on a couple of weeks and see if I can get one at Bingley and save on postage costs as it's unlikely I'll be doing this job till sometime next month anyway.

http://www.minispare...ch/classic/cone compressor.aspx

I will be replacing the whole knuckle joint as the one with the split boot looks slightly rusty inside and betting the other ones not much better and like you say they are so cheap anyway it's not worth taking it all to pieces and not changing them.

If we knew where you live you might find someone on here who would lend you one.

[Spitz]

The compressing scares the hell out of me also....now
Several years ago I was compressing a cone. After I made the last turn and was about to reach in underneath....there was an almighty BANG.
The threads had not stripped on either part. The "nut" on the spring itself and the metal it was attached too let loose! My fingers could have been somewhat hurt.

As it turns out my supplier had supplied me with some of the "imitation" springs ( doughnuts )...not the proper Dunlop ones.

[A-Cell]

To the OP, good decision , get a tool. The Minispares one s good. Put some copper slip grease on the tool thread before inserting it into the cone. When doing it think that the tool could become detached so always keep this in mind when your hands/fingers are underneath and position them with this in mind. Only compress the cone enough to allow some upward play in the top arm, remove the top arm as this will make the job easier.
Also, as the cones wear, also deteriorate with age, consider whether it might be worth fitting new cones at the same time. Good luck, be careful.
I can't understand why anyone would struggle to do he job without a tool....

[Cooperman]

The correct tool is about £20. How much do you value your fingers at?