Lotus Elan

Removing 46 year old front suspension bushings - with photos

PostPost by: bilcoh » Mon Sep 19, 2011 5:40 am

Hi all:

After painting up the frame (write-up still coming, as promised), next item was to get the bushings out of the front suspension arms. These are the original bushes, and I had no delusions about how reluctant they were going to be to remove. I'd planned to cobble together a small H-frame press since I already have a bottle jack and didn't want to buy yet another tool. But, I thought I'd give it one go using either my bench vise (didn't seem likely it would have the grunt) or a threaded rod with nuts/washers and the requisite sockets/pipes to press as needed. Here's what I came up with:
Tool description.JPG and


1/2" all-thread made alignment easy as it was a snug fit inside the bushing inner sleeve, as well as through the 19mm socket, which was a 1/2" drive unit specifically for this same reason. The only challenge (not really much of one) was lining up the copper coupling to rest just on the suspension arm facing. I used the 2" long all-thread couplers rather than standard nuts thinking the extra thread contact would prevent stripping of threads if the forces really got out of hand. Once the whole bundle was finger tight enough to hold all the pieces where I needed them, I clamped one nut into the bench vise:
Held in vise.JPG and


I used a 3/8" drive impact wrench to tighten things up, then pour on the heat.
Applying force.JPG and


I probably didn't apply more than 90 seconds of heat, deciding to stop when I started to see and smell smoke that looked like melting rubber. Not too bad, just got the first whiff and turned off the torch. From there, I laid into it with the impact wrench immediately and it slowly drove the bushing out. You could see steady progress as the air wrench did it's work, but it wasn't as if it was spinning the nut like a Nascar tire change. Until the bushing cleared the suspension arm, that is, at which point the wrench quickly did it's thing and I had to back off the trigger quick before everything went flying :shock: .

I didn't think to take a photo of the bushings, but while they'd clearly melted just a little bit, it wasn't a full meltdown at all. I presume that anyone pulling the bushings isn't planning on reusing them. If so, this technique could prove a problem.

NOTE: I'd read it elsewhere on this forum that one should *NOT* plunge the hot suspension arm into water to cool it. While I'm not a metallurgist, this made sense to me and I let the pieces air cool. It only took a few minutes till they could be handled comfortably.

I've only done 2 of 8, but the results with these first 2 were identical, and one had been soaked heavily with chemicals to break the bond, while the other had nothing on it. I'd say the sprays didn't do anything to help with the removal. Total cost was less than $10 US, but that's cause I already had the impact wrench, compressor and torch :? . My biggest surprise was that the copper coupling has held up. I thought it would collapse under the force, but so far, so good. And the suspension arms appear none the worse for it.

Incredibly satisfying when you find an elegant answer to a problem, hence the post to share the good news and what I hope is a simple solution for others in the future.

Dave
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PostPost by: Emma-Knight » Mon Sep 19, 2011 10:30 am

Well done, Dave.
I think I will follow your route as I have to do all bushes this year.
Keep it simple. Yes!

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PostPost by: gjz30075 » Mon Sep 19, 2011 3:25 pm

I, too, would have thought the copper would not have the strength but I'm glad it worked. I like it. Now, how do plan to install the new ones?

Greg Z

p.s. I guess I'm being too hasty. Start a new thread for installation. :-)
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PostPost by: bilcoh » Mon Sep 19, 2011 6:30 pm

Why Greg, I'm shocked :shock: . You've been around long enough to know that....

"Installation is the reverse of removal." :D

Seriously, though, just remove the copper coupling and socket, and with the nuts/washers on each end, I expect the bushing will be drawn straight into the suspension arm. "Straight" is the operative word here, so I'll need to think through how to ensure that the suspension arm hole and bushing are properly aligned.

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PostPost by: gjz30075 » Mon Sep 19, 2011 11:20 pm

Yeah, you're right; silly me :oops: Kind of a loaded question but I was thnking of putting the socket inside the copper piece to keep the bushing straight. Let us know how you did it.

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PostPost by: ardee_selby » Tue Sep 20, 2011 9:33 am

Dave (et al)

Sorry if this is one of my "specialist subject...the bl**dy obvious" posts, but Garys' thread here...

elan-f14/clonk-gone-was-defective-inner-bushes-sliding-the-arm-t23184.html

...shows that not all bushes have been created equal & wrt "so I'll need to think through how to ensure that the suspension arm hole and bushing are properly aligned"...that some light chamfering assists reassembly...

I know it refers to rear bushes, but same difference for front arms, maybe?
Last edited by ardee_selby on Tue Sep 20, 2011 10:12 am, edited 1 time in total.
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PostPost by: elansprint71 » Tue Sep 20, 2011 10:01 am

Sometimes the simple solutions are the best! :D

The only potential problem I could foresee with this is: after using the same piece of copper several times, the heating/cooling plus the compression may make the copper swell under pressure and stick inside the suspension arm. Be sure to let the copper cool naturally, rather than dunking it in water, that would anneal it and make it soft. Of course, you could just cut another bit of copper pipe!

Excellent photos and explanation.

btw, don't expect the crappy new bushes to last anything like as long. :cry:
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PostPost by: ardee_selby » Tue Sep 20, 2011 10:28 am

elansprint71 wrote:Sometimes the simple solutions are the best! :D

The only potential problem I could foresee with this is: after using the same piece of copper several times, the heating/cooling plus the compression may make the copper swell under pressure and stick inside the suspension arm. Be sure to let the copper cool naturally, rather than dunking it in water, that would anneal it and make it soft. Of course, you could just cut another bit of copper pipe!

Excellent photos and explanation.

btw, don't expect the crappy new bushes to last anything like as long. :cry:


Sorry, Pete. Point of order...don't think the cooling rate affects annealing in copper. Air cool or quench, same result. But would need to soak (time & temp) at 400C+ ...unlikely in this scenario, I'd a thunk. But, as you say, can just cut another bit of pipe if in doubt.

P.S. WRT "btw, don't expect the crappy new bushes to last anything like as long. :cry" The thread I referred to, above, had "Pat Thomas at Kelvedon is now listing bushes with polyurethane instead of rubber" Do you have any more info on these? For the rears only?
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PostPost by: elansprint71 » Tue Sep 20, 2011 11:37 am

Ah, but is "copper pipe" made of copper? I seem to recall that... oh dear, forgotten what I was going to say. :wink:

Pat Thomas's poly bushes differ from most of the others on the market in that they are a sandwich, with a steel inner tube and a steel outer tube, in other words they look like the originals but the "rubber" has been replaced by some poly-thingy material. This means that there is less of the "non-metallic stuff" than in the more common types, he said, stating the blindingly obvious. On paper this indicates that there will be less non-radial movement with Pat's bushes.

http://www.kelsport.net/parts/product_details.asp?PartID=2599&CategoryID=31&PartsectionID=26

Time for my medication, nurse.
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PostPost by: bilcoh » Fri Oct 14, 2011 7:33 am

Just a quick confirmation that after having removed additional bushings with this method, it does appear to be both safe and surprisingly effective.

Dave
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PostPost by: collins_dan » Mon Dec 31, 2012 1:56 pm

Dave, just used this approach to remove old front rubber and install new front poly bushings. Worked great! Now I need to find something to replace the copper coupling to work for the rear outer and inner bushings. Great idea, Dan
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PostPost by: collins_dan » Wed Jan 02, 2013 2:13 pm

Just an update to the post. For the rear, I needed to use a 3/8" threaded rod as the inner tube of the bushings is narrower than the front. I was able to use steel threaded couplings, 1" for outside, 1 1/4" for inside for the old bushings to be pushed into. I used an old bushing to get the inner bushings started, then a 1" socket to finish pushing them out. Dan
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