Removing 46 year old front suspension bushings - with photos
Posted: 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:
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:
I used a 3/8" drive impact wrench to tighten things up, then pour on the heat.
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 .
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
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:
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:
I used a 3/8" drive impact wrench to tighten things up, then pour on the heat.
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 .
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