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Discussion Starter · #1 ·
Renewing both lower control arm bushings. As part of a sub-frame R&R figured that there would be no better time than when the arms are on the work bench.

Couple of questions:

1. As I look at the after (rear) bushing, the wings of the "butterfly" are not in the same plane as the horizontal surface of the control arm. With the arm flat on the bench and looking forward along upper surface. Instead of the wings being in the 9 o'clock to 3 o'clock index, they appear to be closer to the 10 - 4 oclock plane. I have never seen a proper, new installation so I am wondering whether this the right angle. Is this to provide a certain degree of pre-load? Should I just replace it as it is now?

2. The torque spec for the nut that locks this bushing unit in place. The bolt that protrudes out towards the rear of the vehicle (lower arm to rear bush mounting bolt) is only 37 ft/lbs. Can this be correct? Is that sufficient to clamp that bushing permanantly in place at the correct angle and pre-load?

3. Should I even bother doing this job at all? The outer surfaces of the bushing look mint. Is there a spec for allowable play? Something to the effect of - an applied force of 20 lbs on the outer edge of the wing should cause a deflection of not more than 1/2"? In other words - how do you know if you have a played rubber insert?
 

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Discussion Starter · #2 ·
As far as I can determine, the angle (and thus the degree of pre load), is set by the design weight of the front end. The bushing is mounted on to the threaded shaft and the washer and nut are brought up only hand tight at that point.

After every thing is back in place and all other fasteners have been torqued to final spec, lower the car down off the jack stands. This allows the weight of the vehicle index the bushing on the through bolt. It is at that point that the nylok nut is made up to 37 ft/lbs.

As for the 2nd question - I didn't realize that the rubber insert in the bushing was so supple. Given that and the relatively small degree of rotation that the control arm can make, I can understand why the bushing won't twist out of it's set point. So 30-40 ft/lbs would be plenty.

BTW - I am going down to the local machine shop as soon as it opens and have them press the front bushings out. They might charge me $10 - if that - but it will be a hell of a lot better than making up a special tool and struggling with that all morning.
 

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When I replaced the rubber butterfly bushes on my 9k with PU ones using Powerflex bushes and blank bush housings from PFS's competitor, I looked at the position of the old bush on the mounting shaft of each control arm, installed the replacement at about the same position, and torqued up the nut with the control arm off the car.

Otherwise access to the nut is very difficult.

Craig.
 

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Discussion Starter · #4 ·
Yeah you're right - KISS is usually the best way to go.

I was going to either grind the cheeks off an open end wrench or cut a notch out of a box end. But as I got to looking at it - it didn't seem all that critical, as long as the control arms on both sides are at the same degree of slope.

So, I torqued them (rear bushings) on the bench. BTW I never did even have the forward ones changed, they were tight and more importantly, OEM.

The control arms are ready to bolt on after I lift and hang the sub-frame.

Couple of questions (remember this is the first time I have even looked under the Saab)

1. Those control bearing supports - what is the material? Appears to be aluminum or some kind of pot metal - are they intended to be sacrificial? All of them - on both the wrecked subframe and the replacement - were nothing more than a shell. Some of them were wasted away to nothing.

2. Sway/stabilizer/anti-roll bar - is it a struggle to install with the subframe in place? Just wondering because I am working alone and when I go to lift the frame up I want it to be as light as possible. I don't want any jack in the way - you know so I can scoot around under there. I am thinking of using threaded rod (in the corners) and ramp it up that way.

3. Bolt grading - what convention is Saab using? I need to replace a few bolts that either got destroyed in the accident or got lost while the uni-body was being stretched back into place. I am familiar with the SAE system of radial marks and the metric 9.8.... But the 2 most important bolts I need to replace have what appear to be an arrowhead or something. What is that?
 
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