58 rear upper control arms

[Frango100]

Is there someone with a 58 Bird who still uses the original spring setup who can measure the length from the rear upper control arms, bushing center to bushing center? I just would like to confirm that my control arms are the original ones (with the correct length)

[Frango100]

No one with a 58 who can measure the length of the rear upper control arm?

[OUR5T8BIRD]

No one with a 58 who can measure the length of the rear upper control arm?

I have a '58 with original rear coil springs .May take a bit of effort to get it up and go under for measurements . Do not have a hoist .

[Astrowing]

Mine are off. I'll measure Friday.

[Frango100]

Mine are off. I'll measure Friday.

That would be great Jim, thanks. Did you go with leave springs on the Bird?

[Astrowing]

I'm going back with new bushings and the coils. All the bushings and shocks were toast.

[Astrowing]

I measure 10 3/4 inches center to center. I turned the arm to get a perpendicular measurement through the center axis of each bushing

[Frango100]

I measure 10 3/4 inches center to center. I turned the arm to get a perpendicular measurement through the center axis of each bushing

Thank you very much for that Jim. Tomorrow morning i will check the measurement of my Bird.

[Frango100]

Just checked the arms on my Bird and they are exactly the same size. Still confused (or maybe even more now) why the clapper is far more open than it should be (and the diff housing pointed more down than it should).
Lower arm and axle seem to be original as well.

[Astrowing]

Great! If the big U bolts have been off, the differential might rotate. I don't know if there is a key to ensure they are positioned correctly.

Got left lower arm off today. The big clapper bolt on right arm didn't cooperate with my impact wrench so will probably resort to cutting the bolt. I can't believe it wouldn't break it free. Lots of PB blaster on it to no avail.

[Frango100]

Interresting that you mention the U-bolts. I wondered why they are there, since on my axle the bracket is also welded to the axle. So on your Bird only the two U-bolts hold them together? That could be the reason that the clapper doesn´t close enough on my Bird.

[Astrowing]

The clapper separation is determined by the bushing between them. It is approximately 1 inch thick. I don't know if the axle is welded. The diagram only shows ubolt.

[Frango100]

On my Bird the clapper separation is determined by the fixed length of the lower and upper control arms. I can close the gap of the clapper by fastening the vertical bolt, but this will put a lot of (unneccessary) strain on the control arm bushings. As soon as the axle is back from the welder, i will put it back in and check what the clapper separation does over the travel distance. There must be something not normal on my Bird.

[simplyconnected]

On my Bird the clapper separation is determined by the fixed length of the lower and upper control arms. I can close the gap of the clapper by fastening the vertical bolt, but this will put a lot of (unneccessary) strain on the control arm bushings...

As I posted in prior threads, that 'clapper' MUST have free range of motion.

The '58 T-bird rear suspension is basically a parallelogram. If you tighten the clapper, you will snap one or more upper control arms or one of the welded mounting nuts will break. Why on Earth should an upper or lower arm break? All they do is pivot, right? In all my years I have NEVER heard of axle arms OR mounting nuts breaking, especially in a luxury car.

The best way to see 'range of motion' is by removing the springs. Then, you can manually raise and lower the axle while observing the moving parts. If the axle binds, you can easily find out where the bind is. Usually, it's in the clapper (from being restricted).

The axle housing has upper bumpers and the shocks stop the axle at the lower limit. Everywhere in the middle, the axle should move freely.

This axle is strange by all accounts. Ford never used it (the clapper system) before or since, which explains why no parts are supported. No other car company used it either.

I believe the axle system was designed by Budd, Ford engineering signed off on it (for production), and Budd built it. Ford quickly dropped this axle after one short model year, and went back to leaf springs in the '59 & '60. Warranty problems and complaints were overwhelming. That is why I suggest you retrofit a leaf spring setup. - Dave

[scumdog]

I read somewhere that initially Ford intended to run an independent rear suspension in the '58 Thunderbird but changed their mind at the last minute hence the 'clapper' system as a substitute.