Author Topic: New rear control arms  (Read 469 times)

Offline russ austin

New rear control arms
« on: August 12, 2017, 04:51:46 PM »
Dan made up some rear lower control arms and I am testing them out on my 63.  59-64 are the same control arm, so a lot of cars can possibly benefit from these.

Made stronger than the originals, and using urethane bushings made for a truck, these are made better than the stock pieces.

To start with, I have new springs and shocks on the rear. The original bushings are in the control links.
I had a local garage installed them, and the initial test drive was pure amazement to say the least.  The rear end sat up just a touch higher, eliminating the Cadillac saggy rear.  The Cadillac floating rear end is no longer there, acceleration, braking are crisper, and the driveline vibration at 50 is no longer there.

The new urethane bushings correctly position the pinion yolk, which directly effects the drive line angle. Why not just put in new bushings, as they are available?  To put it simply, they are junk, and do not last.  Dan had his new bushings in for 2 years, and they had failed.  These will last the life of the car.

For the price of 4 new bushings from OPGI, you should be able to get 2 new lower control arms with new bushings.

Once I am finished testing these out, the final price and where to get them will be available.

If your interested in possibly getting a set, let us know.  Dan will be the guy making them.
« Last Edit: August 12, 2017, 04:54:26 PM by russ austin »
63 series 62 4 window sedan, 63 Superior Hearse
62 Fleetwood

Tucson, AZ  USA

Offline Peter.1961

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Re: New rear control arms
« Reply #1 on: August 14, 2017, 01:45:52 AM »
That looks fantastic! I would love to install a pair of these on my car. Please put me down for a set as soon as they are available!

Can't wait to have a true bit of McNarry ingenuity in my caddy :-)

Now when are you going to build tubular arms to replace the front upper and lowers? ;-)
“If everything seems under control, you’re just not going fast enough” -- Mario Andretti

Offline 62 Coupe

Re: New rear control arms
« Reply #2 on: August 14, 2017, 05:31:15 PM »
Here are some more photos to give you an idea how the control arms are built and how strong they are. The prototypes are made from .188" (3/16") thick 2 x 3" rectangular tubing but are serious overkill. I have crunched the numbers using a tubing deflection calculator and believe that .125" would be lots strong enough but save a little weight. These ones come in at around 14 lbs each.

There are no welds perpendicular to the arms, all welds are longitudinal with the arm except the bushing sleeves and spring indexing stubs. The bushing sleeves are seamless DOM tubing so they won't prematurely wear out the urethane bushings with a rough inner seam. The spring pad is .125" as are the braces.

As Russ points out, the bushings are universal truck leave spring eye units and very tough. The front and rears are the same size for simplicity's sake.

Being prototypes, Russ's arms are very time consuming and entirely built by hand. The biggest challenge was making them identical lengths as the hole saw has a tendancy to walk a bit even though I am using a high quality Bosch unit. I have a quote from the machine shop I use for my projects and will have them CNC end mill the hole locations and the "salami" cut on the front lower end.

It looks simple enough but there is actually a lot of running around, picking up materials and cutting pieces etc besides welding, fabrication and painting. Almost forgot to mention what a pain the spring indexing stub is to make. It is the sort of tear drop shaped bit on top of the pad.

My goal is to be able to manufacture 10 sets to start based on interest. Because of the limited number costs are pretty high for me so  I would be looking for $385 USD per pair ready to bolt on, bushing included.
He has all of the virtues I dislike and none of the vices I admire. Sir Winston Churchill

Offline Peter.1961

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Re: New rear control arms
« Reply #3 on: August 15, 2017, 12:15:18 AM »
Wow, this looks perfect - exactly the way they should have come from the factory. Put me down for a pair. The price sounds very reasonable given the benefits and the workmanship involved.

Thank you!
“If everything seems under control, you’re just not going fast enough” -- Mario Andretti

Offline 62droptop

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Re: New rear control arms
« Reply #4 on: August 15, 2017, 04:11:16 PM »
awesome job Dan

a note for those of you installing them,or any bushing for that matter,make sure car is at ride height before you tighten them in place!
or you will destroy the bushings when the car is lowered back on the ground

1962 Cadillac series 62 ragtop

driven like it is stolen
broken because it was driven(still)

Offline russ austin

Re: New rear control arms
« Reply #5 on: August 15, 2017, 05:35:12 PM »
Given the price of 4 new bushings for the rear control arm, the new control arms are just a few bucks more.
63 series 62 4 window sedan, 63 Superior Hearse
62 Fleetwood

Tucson, AZ  USA

Offline 62 Coupe

Re: New rear control arms
« Reply #6 on: August 15, 2017, 06:49:51 PM »
The inner sleeve on urethane bushings is not bonded to the urethane so they can be installed in any position unlike bonded rubber bushings.

Peter, I will post on the modified forum as well and hopefully we can reach 10 sets spoken for.

Russ, an additional benefit is structural integrity. We should see if Cattle Ax still has a photo of his failed stock trailing arm.
He has all of the virtues I dislike and none of the vices I admire. Sir Winston Churchill

Offline russ austin

Re: New rear control arms
« Reply #7 on: August 15, 2017, 09:36:54 PM »
There is going to have to be a grandfather clause fee on these new control arms. These new parts are making my old parts look bad.  Who wants to buy good used control arms for half off?
63 series 62 4 window sedan, 63 Superior Hearse
62 Fleetwood

Tucson, AZ  USA

Offline russ austin

Re: New rear control arms
« Reply #8 on: August 18, 2017, 06:52:13 PM »
After a full week of testing my car, I am convinced that these new control arms are the next best thing since sliced bread.

No complaints, just improvements I'm all aspects of the car. Braking, handling, acceleration, cruising.   The back of the car sat up just a bit higher, leveling off the car. The Cadillac float and sag of the rear end is gone. A true pleasure to drive.

Get these through Dan.
63 series 62 4 window sedan, 63 Superior Hearse
62 Fleetwood

Tucson, AZ  USA

Offline 62 Coupe

Re: New rear control arms
« Reply #9 on: August 20, 2017, 02:36:21 PM »
Thanks for testing and reporting your results Russ, I really appreciate it.
He has all of the virtues I dislike and none of the vices I admire. Sir Winston Churchill