Vet65te

I've put maybe a hundred miles on my '61 since I got it running again and so far, so good. I will be replacing the semi-metallic brake shoes and pads shortly but I had noticed that the rear radius rod bushings looked quite wasted and figured I'd get those done soon. No real odd sounds out of the back end (but with the solid lifter cam/headers/40-series Flowmasters that's not much of a surpise). Reached in to check the 'looseness' of the rods and found the drivers side to be still fairly snug. Then...I reached in on the passenger side and 'oh brother'. Check out the pics.


Not a big deal to fix but then I saw something that just might not be right. Check out the next pic of the frame bracket for that passenger side radius rod. I know I shouldn't ask this because I might not like the answer but is there supposed to be a 'slot' at that forward end in order to aid installation or is it supposed to be a circular hole?

Thanks,
Mike T.

mike coletta

Hey Mike,
I'm not 100%, but I think that the "slot" is correct. I haven't done an original frame in years, but I seem to remember that it was slotted to help with installation. My 2 cents!! Mike Coletta

BTW, you really got your moneys worth out of that bushing!!

Plasticman

Forward radius rod mounting hole is slotted (I removed my radius rods when I added Traction Masters traction bars).

There should be a special serrated tooth washer that ensures the stud does not slip in the slot, when torqued properly.

Plasticman

Vet65te

"Whew", that's great news. I'll bet you guys could hear that 'sigh of relief' in Florida. That's one issue cleared up. The other is that the old bushings only seemed to have an inside steel sleeve unlike the replacement bushings which have an inner and an outer. I first thought they were the same as midyear rear strut rod bushings but after laying them side by side, the midyear bushings are a bit longer.
As for traction control, I first thought the car had a set of Traction Masters till I looked closer and found hex rods with heim ends. Add them to the 5 leaf springs and 'air shocks' (to keep the wheel well lips from hitting the 255-60's) and I almost need a hardhat to keep from banging my head on the inside of the hardtop when I hit a bump. I will be putting on some smaller tires and tucking them inside the fender lips in order to get rid of the air shocks.
Here's a couple shots of the traction bars the PO's Dad installed.
Got to admit, there is no 'squat' when you hit the gas.


Mike T.

AZDoug

Put the radius rods on the shelf. With those lower links and the radius rods, you have locked your rear end up solid, resulting in the super rough ride. You can have one or the other, but not both.

Your ride will still suffer,a s the front half of the spring isn't totally free to flex, but it will be better.

Slapper bars will stop wheel hop and allow spring movement, but they hang lower.


BTW, looks like the radius rods brackets were torn off once in the past, look at all the gobbed up weld attaching them back to the frame
Doug

Plasticman

I agree with Doug. Either the Radius Rods or the Traction Bars, but not both! When I put the Traction Bars on about 1.5 years ago (already had the stock 62 Radius Rods), the ride was firmer and I did not need that. Took the Radius Rods off (leaving the new Traction Bars on), and I swear the ride is now better than when I had just the Radius Rods.

And the previous wheel hop issue is now gone (it would also hop bad when hard shifting into 2nd, and 1st gear was a leaf spring or 2 waiting to fail!).

One question: Are your front Traction Bar mounting plates allowed to pivot, or are they welded in one spot? I see they have the leaf spring bolt at the top and the traction bar bolt at the bottom, but I found on mine that I needed to weld the plate solid to the front leaf spring perch, in order to prevent it from pivoting fore/aft, and causing some squirrley handling under hard throttle, besides they would clunk loudly when they pivoted forward and contacted the spring perch (again, under a hard launch).

One forum member (DZAUTO - Tom Parsons) has his plates allowed to pivot, and does not report any issues such as I had with mine (before I welded them).

Plasticman

Vet65te

P-Man, the front traction bar plate is definitely welded to the front spring perch/hanger, no flexing at that point.

I have read through that other post on Traction Masters (still have it bookmarked) and did read that a number of people with traction aids had eliminated the upper radius rods.

So, would most of you consider the traction master-'like' setup that I have now minus the radius rods on top to be better than just the radius rods on top and allow a bit more differential travel?

Also, in the stash of parts, my '61 came with a pair of Traction Master Rods, minus the bushings. Would there be that much of a difference between the semi-solid heim joint setup I have now and Traction Master Rods with rubber bushings?

Thanks,
Mike T.

Plasticman

Mike,

I certainly would never go back to the Radius Rod setup, now that I have the Traction Masters. The only benefit I can see of Radius Rods the potential for preventing wheel hop under very severe braking conditions is far better with the Radius Rods (but the leaf springs are inter-supporting when the rear end torque is "front downward anyway)". Since I have installed the Traction Bars (and deleted the Radius Rods), I have tried one set of tests (at lower speed around 30-40 mph) of hard braking and saw no wheel hop.

As for the Heim joints vs. the rubber (actually the new Traction Masters I purchased 1-1/2 years ago came with plastic bushings (won't call them poly-urethane, since they have almost no deflection), I can only think there would be slightly better positioning control with the Heim joints, but also more potential for ride stiffness/harshness and eventually wear of the joints).

Plasticman

Viking427

..and a couple extra notes;

"I first thought the car had a set of Traction Masters"
-Actually it did at one time. Those are original TM brackets (cast rear mount + weld-on-frame front mount tab) and the reason you found TM rods in with your parts. The PO musta swapped the TM rods for that adjustable heim joint setup thereafter. Perhaps to address the same binding/harshness concerns as well. This "6-Link" setup might have also accelerated the deterioration of the upper radius rod bushing(s) and/or self-removal of the upper radius rod frame tab, as noted above. You could replace the worn bushings in all the rods (OEM & TM) put it all back on and test each combination out to see what works best for your preference, but I suspect you'll find what the others have noted, that the ride is just too harsh and may cause premature deterioration of bushings. I also suspect Traction Master's original target market -drag racers- placed wheel hop well above ride harshness & worn bushings on the priority scale

62Jeff

That car competed extensively, and successfully, for years in National Council of Corvette Club (NCCC) events in the Classic Stock class. It competed in drag races, low speed and high speed autocrosses.

No doubt that the PO's dad put all the suspension kibbles in place to address handling and traction issues on one or all of those event types.

Vet65te

In the hundred or so miles I've put on the car, mostly easy driving with no shock to the driveline, I can definitely say it has a harsh ride. When I first saw the car at the sellers house, I noticed the 'Bird-Stuff' weld all over the frame brackets for the radius rods and suspected it was done by one of the PO's but had heard that some of the factory welds weren't exactly pretty either. In the case of my front brackets, they must have thought 'if a little is good, a lot is better'.

While I'm not going to replace the 5 leaf springs with 4-leaf versions, I'm going to take out those radius rods and the air shocks are next on the list (and to trim those super long u-bolts that hang down too far). While those first two changes won't make it ride like a Cadillac, I expect the difference should at least be noticeable.

Thanks all for the help.
Mike T.

62Jeff

You plan to do anything to make it faster than a cadillac?

Vet65te

Hi Jeff, well I think right now I could leave a Cadillac in the weeds...as long as it's a '41 Cad

If I had to race your new CTS-V with it's 500+ horsepower I'd need at least a 20-car lead and that'd be in an 1/8 mile race. Let's see now, an 1/8-mile track is about 660 feet long and 20 times about 15 feet is 300 feet. On second thought, make that a 22-car lead
Mike T.

Plasticman

Mike,

I would not be so eager to trim the long U-bolts all that much. I recently removed my rear anti-sway (due to more oversteer than I want or need).

In doing so, I had to undo the long U-bolts to get at the anti-sway bar end brackets that are sandwiched between the 2 mounting plates under the leaf spring. I too had visions of shortening the long U-bolts, but then realized that as the nuts were released down the U-bolt threads, that I used most of those threads before everything became "loose". And therefore, I would need most of that thread to reinstall the nuts easily.

However, my U-bolts look somewhat shorter than yours and you could trim "some" of that excess off. My U-bolts measure 2-1/4" from the bottom of the plates to the end of the U-bolts, and 1-1/2" from the bottom of the nuts to the end of the U-bolts.

And I think you will be pleasantly surprised at the ride without the Radius Rods (I was). Note that I also have the 5 leaf rear springs (with urethane bushings), and am using old Gabriel Strider shocks (3 way adjustable that are no longer available).

Plasticman

mashinter

The heim joints reduce rear roll stiffness compared to the traction master bushings. (The traction masters, with stiff bushings, act like torsion bars when the car rolls.)

Reduced rear roll stiffness reduces oversteer. I found my '59 with the factory stiff springs needed more oversteer for autocross, so I'll guess he did the heim joints for better launches at the drag strip (and autocross).

Plasticman

That would dovetail with why I felt too much oversteer when I added the Traction Masters (and still had the rear anti-sway bar).

Did not realize that the Traction Masters would add rear roll stiffness, but now it makes sense.

Lot better now, with the rear anti-sway bar removed!

Thanks,
Plasticman

Vet65te

Plasticman - Just measured the 'excess' length of my u-bolts and are 2 3/4 inches below the bottom of the TM plate so they are about a half inch longer than the ones on your '62. Since the lowest part of that cast plate with the heim joint connection is nearly 2 1/4 below the plate, I'd really only need to cut off around a half inch of length to clean them up.

Mike T.

DZAUTO

That is correct!

Tom Parsons

DZAUTO

On my 56, I have:
5 leaf springs
60 axle housing
59-62 radius rods
60-62 rear sway bar
Original style Traction Master bars with new bushings
ZERO problems or issues, and no more wheel hop on hard launches or hard braking.

The forward attaching bracket for the TM bars is secured with the big nut for the front spring eye bolt, not welded.
The rear of TM bars is attached somewhat differently on 60-62 cars than it is for 53-59 cars. The 60-62 cars have a rear sway bar bracket below the anchor plate, thus, the TM attachment for those cars requires longer U-bolts and 4 spacers, which drops the TM rear plate down about 1 1/2in lower on 60-62 cars. Obviously, this changes the geometry of the TM bars for 60-62 cars. So, what is the resultant effect of the different TM angle on 60-62 cars vs 53-59 cars? Heck, I don't know. But I'm much happier with the elimination of wheel hop now.
By the way, my original style TM bars were GIVEN to me about 30yrs ago, I put them in the attic and said that someday I'd clean them up and do a trial fit/test. Finally, about 2-3 yrs ago, I dug them out, ordered new bushings from TM (only because someone here mentioned that TM was still in business and new bushings were available from them), put them on, and now they're staying on!

Tom Parsons

Vet65te

Tom - Since you had your 56 running with the 5 leaf spring and later model Radius Rods for a fairly long time before you added the TM bars to the mix, did you notice a change in the ride 'after' adding the TM bars?