View Full Version : Changing rear springs
07-02-2017, 04:36 PM
So the new rear coil springs came in this week and I started the removal of the old springs. But when trying to remove the upper control arm bolt from the frame, the bolt head turns, but doesnīt get loose. It seems that there is a loose nut behind it, but I donīt see any way to access that nut. Is there any secret to remove the bolt, or is there suppost to be a fixed nut behind it?
07-02-2017, 05:13 PM
You may have the manual already.I cant see that a fixed nut is present.
07-02-2017, 05:23 PM
Thanks for the reply newyear. Page 4-12 only mentions to remove the upper arm at the body side, it doesnīt mention any special way to do so. I can remove the bolt from the axle side, even though it requires more removal, but the bushings from the body side seem to be in a bad state, so at some point I will need to remove those bolts.
07-02-2017, 08:30 PM
Gentlemen, the rear suspension issues are pervasive with everyone who has a '58. Some of our members dissected their axle system just to improve the operation and the bushings situation.
Anders gives us the most comprehensive and detailed project, all the way from Europe.
I suggest you check where your upper control arm front bolt goes into the frame. You might have a big issue there. Or perhaps the bushings in your control arm is gone, as mine was. Thatīs where it all started....
Click on the small (blue) arrow next to Ander's name and it will bring you to his thread. He explains just about everything because he had all of his new urethane bushings custom made. - Dave
07-04-2017, 08:44 PM
Thanks for that Dave. I went through the whole story from Anders and have a better idea how this whole rear suspension should work. I now also know that the upper control arm front bolt should have a welded nut inside the frame. A repair procedure was mentioned, by making a hole under the rear seat. I will leave that for now, since the front bushings are still in reasonable shape and have no radial movement. The upper arm rear bushings are shot. They attempted to fabricate some bushings with copper center tubes. These tubes seems to be made from water line, completely incompatible with the forces which are put on it. On both sides the tubes are broken and the rubber worn away. I have some bushings left over from my jeep, which i can use here.
I have the new coil springs in and they are a lot softer than the springs previously on the Bird. Now i have to re-install the upper arm aft mounting bolts, which is quite a PIA. I would have expected that they would go in without too much effort, but no. I did already remove both vertical bolts (the ones from the isolators), to be able to rotate the axle a bit to align the bolt holes, but today i couldnīt finish this. I will have another try tomorrow.
07-04-2017, 10:37 PM
Ok, so WHY are these upper arm mountings breaking? To me, that's the big question. After all, they are only a pivot point, right?
No, not necessarily.
The entire rear suspension is basically a parallelogram system. If ONE joint is held solid, the whole arm will flex and break. That is what happens when (what I call the 'clapper') is screwed down solid. My comments are in Ander's thread. - Dave
07-05-2017, 08:23 AM
In my case the upper arm rear bushing was some home made crap which could never resist the forces applied to it. But also the "clapper" insulator rubbers are quite hard, which will probably cause the suspension to bind and put excessive forces on the suspension bushings.
Also strange that on my Bird the thick insulator rubber is on top and the thin one at the bottom.
07-05-2017, 11:44 AM
You can learn a lot by taking the springs out. Let the axle hang by the shock absorbers and watch, as you put the axle through the whole range of motion. It should move freely. ANY binding is bad. Simply leave the bushing issue until last, after you discover why the bushings and mountings went bad. - Dave
07-05-2017, 08:50 PM
The upper pivot bolts do have a welded nut in the frame that sounds like it has broken loose. There is a service bulletin that describes how to access it from inside the car behind rear seat.
I got mine out Monday thankfully. The right lower bolt had frozen to bushing so had to cut bolt with cutoff wheel. Several hours of work.
I also got the Monroe shocks Dave suggested from Rock Auto. Had to cut crowfeet in bottom mounts with cutoff wheel
Lower arms are another weekend project. Springs looked great on my car. Same length exactly.
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