question on installing lower Mustang II control arms

[Ed ke6bnl]

My question is that I have mustang II with tubular A arms on my 50 F1 pu.. I am under the impression that the arms should be tightened when the truck is sitting at ride height. I am not sure how they function. Are they tight enough that they move around the rubber bushing or I have to assume they move up and down on the metal sleeve in the bushing and the rubber bushing is for shock absorbing. There is a washer on both side of the bushing, two for each bushing. And how much torque is used to secure the lower a arm to the crossmember.. Hope I didn't confuse with my question thanks ED

[enjenjo]

If they are working right, there will be no actual movement outside of the rubber distorting. That the reason to tighten at ride height. 65 to 70 ft lb if they are 1/2" bolts.

[Ed ke6bnl]

If they are working right, there will be no actual movement outside of the rubber distorting. That the reason to tighten at ride height. 65 to 70 ft lb if they are 1/2" bolts.

Are you saying that the tubular A Arm will move with the rubber bushing?  The arm will be turning on the sleeve in the rubber bushing. Thanks and they are 1/2 bolts. Thanks Ed

[Learpilot]

My lower tubular A-Frame have 5/8" bolts.  I changed from stock A-Frames to tubular ones and had to drill out the crossmember to 5/8"and weld the extensions and gusset. I have a 1/2" drill motor with a lot of torque and it mashed my little finger. It hurts but no blood.

[jaybee]

If they are working right, there will be no actual movement outside of the rubber distorting. That the reason to tighten at ride height. 65 to 70 ft lb if they are 1/2" bolts.

Are you saying that the tubular A Arm will move with the rubber bushing?  The arm will be turning on the sleeve in the rubber bushing. Thanks and they are 1/2 bolts. Thanks Ed

Kind of.  He's saying that the outside sleeve of the bushing is pressed into the arm.  The inside sleeve has teeth on the end so it's locked in place when tightened down as well.  Movement is accomplished by flexing of the rubber.  If you tighten everything with the suspension in droop the rubber will be flexed at normal ride height.  That will provide a little extra spring rate, sometimes enough that the car will sit unevenly if the two sides were tightened in different positions.  The extra stress on the rubber can also cause it to wear prematurely.

Of course the alternative is polyurethane bushings. Since poly doesn't flex like rubber they work a little differently.  Some people who've used them say they rode just about like rubber, others say the ride was bone jarring.  For them the key is in the trial fit.  The bushings need to be a slip fit on the inner and outer sleeves and in length so it can move freely.  That last part is where it sometimes goes wrong.  If the poly is just a little too long everything looks fine on test fit, but once you tighten it down the bushing is clamped firmly in place and free movement is compromised.  This also means that it's important to use silicone grease on the inside, outside AND ENDS of the bushing.  A lot of the squeaking complaints with these come from not greasing the ends, only the inside and outside diameters.

[enjenjo]

What he said.

[Ed ke6bnl]

What he said.

you guys are the first place I go for the real answer, and I thank you all for the explanation. I do understand it now and was fortunate I did it correctly the first time without a real clear knowledge on how it works.  Hope I can pitch in and help some at sometime but it is hard with the wide knowledge base on the site. Thanks ED