16 replies to this topic

[newenglandmini]

I have just removed my rear suspension trumpets.  The rubber springs are stuck on the trumpet ends.  What is the best way to remove them?

 

The swivel balls are also stuck.  How are these best removed?

 

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[alex-95]

Get a big screwdrive and put it between the two you can the hammer it moveing around the cone and trumpet till it's off.

 

You may be able to get a long bar down the trumpet and tap the knuckle joint out, if not then grip the knuckle joint in a vice (probably best to put 2 flats on it) and twist the trumpet to loosen them and hammer the trumpet off.

[M4TTD05794]

I'm currently in the middle if changing my suspension, I found out that my trumpets are cast all in one and I'm unable to get them apart.

[alex-95]

I'm currently in the middle if changing my suspension, I found out that my trumpets are cast all in one and I'm unable to get them apart.

What do you mean by all in one?

[finch661]

i ended up hitting the trumpets with a hammer and after a few blows the cones came off

[Tamworthbay]

I use a blunt chisel between the rubber and alloy. Penetration oil also helps. They can be well stuck so take some abuse. The knuckle joints can be a pain as well, I leave then with penetrating oil overnight then clamp the small ball in a vice and turn the trumpet. If you need more leverage a strap type oil filter remover is perfect.

[M4TTD05794]

The knuckle joint is cast onto the trumpet

[alex-95]

The knuckle joint is cast onto the trumpet

Are you sure, it's probably just stuck in there.

[M4TTD05794]

There is no visible 'seam' (is the only word I can think of) which gives me the impression that it is just a cheap casting (which really doesn't surprise me with the other bodges I've found)

[Tamworthbay]

No it won't be one piece, they can corrode in so bad they look like they have always been together. They will come apart but it might take a lot of effort.

[M4TTD05794]

It doesn't really matter anymore because I've bought a set of adjustables and knuckle joints. But I'll know for future reference.

[Stu.]

The joint on mine is stuck too. I tried clamping the ball in my vice and it broke the vice casting   I now plan to thrash it vigorously with a stick until it gives up 

[Guess-Works.com]

or just warm it up, as aluminium expands at a different rate to the steel of the knuckle.... thus breaking any corrosion bond between the two....

 

back to the OP...

 

Removing the cone from the strut is a little more tricky, same again it's a corrosion interface between the steel metal cup which is in the middle of the cone and the aluminium of the trumpet/strut. If the cone has a captive thread through the middle then screw a bolt into it and clamp that in the vice and not the cone, You then have more leverage on the trumpet and again with a little warmth, the joint can be released.

 

When putting them back together, the liberal use of copper grease is suggested.

Edited by Guess-Works.com, 03 January 2014 - 11:58 AM.

[newenglandmini]

I had already removed the cone from the radius arm prior to making this posting.  One of the ball seats had disintegrated in service, the remnants of which are wrapped around the ball.

 

Clive, I'm going to try a different approach to the rubber.  I'm going to heat the bond using my heat gun.  I'll report any success (or failure) thereof.

[dklawson]

As Guess-Works said, heating the dissimilar metals helps.  Though it seems like these parts will never separate, repeated heat cycles, particularly with the joints wet with penetrating oil, will help.  Rather than a direct hammer method, someone suggested to me years ago that after repeated heating and cooling cycles, grab the trumpet like it was a club and bash the rubber cone against the ground or a tree.  This truly primitive looking behavior does help.  But give it time.  Repeat the heat cycles, oil, and bashing over a few days and it will come off.

 

As for the knuckle joint itself, once you get the cone off, the trumpet becomes a funnel.  Heat the old steel knuckle and then spray penetrating oil down the funnel of the trumpet to quench it.  Repeat the heating and quenching cycles and the oil will get wicked into the joint.  Eventually you will be ready to drive the knuckle joint out.  Use a drift down the center of the trumpet and a big hammer and you will be able to drive the old knuckle out.  Be sure to apply more oil as necessary as you drive the knuckle out.