13 replies to this topic

[graydan]

Hi all. I have just joined this forum so I'd like to say hello to all!!!

 

I am wanting some advice.

 

I have a 1987 Mini Mayfair and I need to replace the front Knuckle Joints that sit on the top suspension arm.

 

What I want to know is what is the best method of doing this? My thinking was to remove the top arm, but would this mean that the trumpet and rubber cone would fall out? If they were to fall out, how easy is it to get them back in? Would I need the rubber cone compressor to get them back in or is there a way to do it without?

 

Any guidance, tips etc would be much appreciated.  

 

Thanks guys!!

[Dan]

Just compress the cone, you don't need to pull the top arm.

[graydan]

Thanks Dan, is there any way of doing this without the use of a compressor tool?

[bikewiz]

No you need to compress the cone. You get a little more space by removing the bottom out bumper but not enough to get the knuckle out. With the cone compressed it should take less than an hour a side.

[smev]

There are a few problems you are likely to come across. You may find that the trumpet has fused itself to the cone, or the knuckle has stuck itself up in the trumpet, and likely to have a wrecked cup too, or all three! Getting the cup out is the hardest part. If you compress the cone at least you are able to get a bit more leverage and space to beat/wriggle/curse.

[graydan]

Sound like this is going to be a bit of a pain in the you know what!!

Edited by graydan, 11 March 2014 - 11:15 PM.

[graydan]

I think I will need to invest in a compressor tool then. Are these easy to use?

[Tamworthbay]

They are as long as the threads in the cone are ok. They do have a habit of going rusty and being a pain. Make sure the tool gos into the cone a good few threads (six or seven full turns minimum ideally). If the tool let's go when you are working on the trumpet end it could be serious. For the extra hassle I would be tempted to drop the top arm if you have t done it before. That way you work on everything on the bench rather up a dark dirty hole.

[surfblue]

You can do it easily without the cone compressor. Undo the top swivel nut and break the taper. Using a long sturdy steel bar underneath the top arm and lever it upwards until the top arm is off the knuckle joint then move the hub to one side and release. An assistant is helpful but have done it on my own. So easy i rarely use my compressor.

[maccers]

I only used the cone compressor to hold the my new rubber suspension units up in the subframe while I offered up the hi-lo, knuckle and top arm while sliding the top arm pin through. Bit fiddly but you can do it without one, even if you just used it like me to hold things in place.

[greenwheels]

Looks to me there is some confusion as to which knuckle we are talking about: -

the knuckles on the hub i.e. 'king pin' knuckles   or

the knuckle under the rubber doughnut 'spring'

Reading the OPs post first time I thought it was the second but on re-reading is it the first?  No - on re-re-reading I think it's the second.

 

In which case jack the car up under the lower suspension arm until it is well up and compressing the doughnut and then put the compressor in. Remove the little bump stop under the top arm first to allow the top arm to drop a bit further. As the doughnut is already compressed a lot it will be easier using the compressor. You will probably find that the action of compressing the doughnut will force the trumpet off and it'll drop out.

 

Just be carefull the thread of the compressor is well in the doughnut - if it pops out on your finger it will crush all soft items in its path.

Also remember there are two types of thread  compressor, the early doughnuts were an imperial thread and the later metric. They are very similar and can be mixed up. Nevertheless a cone compressor is a safe tool to use, the doughnut cone is a powerful spring and the only really safe way to compress it is with a compressor.

[lewBlew]

1987 Mayfair you will almost certainly have metric threaded rubber doughnut/cone unless for some bizarre reason someone has put some NOS imperial cones into yours at some point. I bought this tool from Mini Spares:

 

http://www.minispare...sic/TOOL07.aspx

 

Does the job.

 

In theory you should be able to just compress the cone and pull the trumpet & knuckle joint out as one - pull up the rubber boot to expose the joint first - then separate and replace the knuckle. I found mole grips and twisting worked if it was stuck. Also, if you have hi los you could adjust them to their shortest setting to give you more space to work with (draw a line on them or count how many turns so you can put them back where they were again).

 

In reality, you may have issues getting the knuckle out or getting the cone and trumpet separated. Perhaps the rubber cup the knuckle sits in will have become fused to the upper arm. If you are having issues with access at this point and as a last resort you may want to remove the upper arm completely so you can replace the knuckle on a nice table instead of inside your wheel arch. I found this an absolute pig of a job due to the difficulty reaching the various nuts and bolts with a spanner. It can be done, but leave yourself lots time and be prepared to buy new pins/bolts/bushes as you break the old ones getting them off.

Edited by lewBlew, 12 March 2014 - 02:18 PM.

[surfblue]

Looks to me there is some confusion as to which knuckle we are talking about: -

the knuckles on the hub i.e. 'king pin' knuckles   or

the knuckle under the rubber doughnut 'spring'

Reading the OPs post first time I thought it was the second but on re-reading is it the first?  No - on re-re-reading I think it's the second.

 

In which case jack the car up under the lower suspension arm until it is well up and compressing the doughnut and then put the compressor in. Remove the little bump stop under the top arm first to allow the top arm to drop a bit further. As the doughnut is already compressed a lot it will be easier using the compressor. You will probably find that the action of compressing the doughnut will force the trumpet off and it'll drop out.

 

Just be carefull the thread of the compressor is well in the doughnut - if it pops out on your finger it will crush all soft items in its path.

Also remember there are two types of thread  compressor, the early doughnuts were an imperial thread and the later metric. They are very similar and can be mixed up. Nevertheless a cone compressor is a safe tool to use, the doughnut cone is a powerful spring and the only really safe way to compress it is with a compressor.

 

Ah yes, on first reading I thought it was the top steering "ball joint" rather than the suspension "knuckle joint".

You will need to use a compressor!

[graydan]

_{Thanks everyone for your replies. Very helpful indeed. I now have a compressor tool so should make things easier.}