C2 front control arm bushings

[Christopher R.]

Re: Threaded rod...

Geez, you guys are scaring me now.

I picked the threaded rod method because I thought it was safer than spring compressors, which didn't appear as substantial, and had moving parts. The rod seemed more fail safe to me.

But what's really fail safe and appealing is a back up. Previous posts mention a chain. How does that work? What else could be used as a back up to either a threaded rod or a spring compressor?

[Joe L.]

Re: Threaded rod...

Chris-----

The chain simply goes through and around one of the spring coils and is otherwise fastened around something solid (like the frame or a-frame).

With an internal spring compressor, there is no back-up possible other than the safety chain. If the threaded shaft on the spring compressor fails, all you have to rely on is the safety chain. So, you want the single shaft compressor to be as absolutely reliable as possible.

I won't even use a "loaner" or "rental" version of one of these because I don't know the history of them (i.e. how much abuse that they've sustained at the hands of "klutzes") or the quality of the tool, in the first place.

For a 63-82 Corvette front spring (I don't know about C1s) to be removed or installed with an internal spring compressor, the spring has to be nearly fully compressed with the coils "touching". At this point of compression, there is a LOT of potential energy present. I take NO chances with this.

[Mike McKown]

Re: C2 front control arm bushings

Gene:

I don't own a spring compressor. I have never borrowed one. I removed the front springs fromt my '65 a number of years ago to paint the springs and around the spring area.

I know I jacked the car up and supported it on the front of the frame rails behind the front wheels. I think the next thing I did was loosen the lower ball joint nut several rounds and smacked the spindle where the ball joint went through with a two pound ball peen. This jarred the balll joint loose from the spindle without damage. As I remember, I put a floor jack under the lower a-frame and raised it enough to take the ball joint nut loose. I then lowered the bottom a arm slowly with the jack until all the tension was off the spring and it fell out on the floor. Yes, I did have it tied off with a safety chain.

I have changed out front springs on '57 Chevy, 62-67 Chevy II's, '65 Corvette and '69 Nova and Camaro. The '57 is the only one that gave me a problem. I had to collapse it a little and tie it off with a chain to get it short enough to get back on top of the control arm and in the pocket.

As far as I am concerned, the two things to watch here are to chain the spring so in case it gets loose, it won't fly out and take your head off (or a fender)
and keep your fingers out of the way in case the spring expands suddenly, mashing your fingers. This is one reason I like my method. I don't have to fool with a coil spring under tension while I'm handling it. Just another way to do it.

[Joe L.]

Re: C2 front control arm bushings

Mike----

The method that you described works well; I've watched Mike Allen (of Allen's Exhaust) do it this way several times with no problem, whatsoever. I've never tried it myself, though. I guess that I've been "chicken".

The trick to this method is that when you install the spring using the reverse procedure, the spring usually doesn't seat properly in the tower of the frame. Mike Allen just took a long drift and, through the upper shock hole, one "whack" and the spring was moved into it's proper seat. That's the "art" of the whole thing---knowing just how to give it that one "whack", because one "whack" is all you get!

[Mike Cobine]

Re: Threaded rod...14,000 psi enough?

I think you guys are far too cautious here.

According to http://raskcycle.com/techtip/webdoc14.html
SAE 2 no marking bolts low carbon has a tensile strength of 74,000 psi. Calculate the area of a 5/8ths bolt (Pi * (5/8)^2) gives roughly .3 sq in. That times 74,000 psi gives over 22,000 psi.

Even allowing that outside diameter and the root diameter is different, even HALF of 22,000 would be more than enough.

According to http://www.hobson.com.au/mild_steel.htm
Allthread of 5/8ths diameter has 14,190 psi tensile strength. 1/2 inch has 8660 psi.

Even with HD springs of 460 lb/in, and the springs with the suspension at rest is typically only compressed an inch and maybe 2 inches of the new "too long" reproductions, you are looking at 920 lb of force.

With the car on the ground, weight on wheels, you have 3600 lb / 4 wheels * 21 inch arm / 9 inch arm-to-spring = 2,100 lbs. However, you aren't removing the spring with WOW.

I think a 5/8ths rod will hold it, don't you?

If you really want a backup, remove the three bolts holding the A-arm pivot bar to the frame with full-thread 6 inch bolts. Run the 5/8ths rod down the shock opening and snug the nuts. Then loosen each bolt and nut a turn at a time until the spring is loose in the pocket.

Heck, my F41 springs were barely in contact (enough to keep them from moving) when the suspeninon was hanging fully extended on the race car. My '63 springs were loose when the pivot was 2 inches from the frame but they had a spacer pad under them.

I think the problems is that some think you compress the spring and pull it out of the pocket which isnt' much room with the A-arm in place.

The safe way is to use the big rod to lower the A-arm so the inner pivot drops down from the frame until the spring falls out by gravity as the spring is at rest and not compressed and the only danger is it falling on your hand or head if you are under it.

It is like the service manual does with a hydraulic jack, but a jack can fail by slipping, falling over, or the seals just blow. (otherwise, no one would recommend jack stands all the time.) You are just using a threaded rod instead of a jack to lower the A-frame.

Don't do it by removing the ball joint first. That is asking the spring to fly out at you.

[Harmon C.]

Re: Threaded rod...14,000 psi enough?

Mike You did a great job of explaining the way I do this job. If you also use a chain you have three ways to control the energy. If one feels their method is unsafe they should hire it done. I have seen many hooks and pullers that have flew off by people not paying attention. What ever one uses to do the job be smart and alert to problems. I will use the bolt thru the spring as when you take the nut off the ball joint I don't like the engery being clamped only with the tool and a chain. Lyle

[Eugene B.]

Re: Thanks & another question

Members,
Thank you all for your input and sharing your experiences. I will look the situation over carefully when I get to the control arms.

Here's the additional question: In this forum or in the Restorer Magazine, I seem to remember seeing an article about control arm bushings. The article stated that some control arm bushing are longer? that the OEM ones.

Does anyone remember seeing this article and where should I plan to purchase the bushings to get the correct ones?

Thanks for all the great advice.

Best regards,
Gene

[Joe L.]

Re: Thanks & another question

Gene----

The upper control arm bushings changed in about 1973. Before this time, the configuration of the upper ones was just like the lower ones that were used for 63-82 and are still available in SERVICE in exactly their original configuration. The 63-73 upper bushings had an approximate 1/4" rubber extension on the inner end. For 73-82 upper contol arm bushings and current GM SERVICE for all 63-82, the outer shell of the bushing extends all the way to the inner end and there is no exposed rubber.

Reproductions of the original style are now available for about $10 each. Volunteer Vette introduced them, but I expect that most of the vendors have them by now.