1936 Ford - Axle Wrap Problems - Parallel Springs

Have you tried putting the spring clamps in the correct locations on the front half of the springs?

 

With the holiday this week I did not have much time to work on the car or get online but I managed to mess around with it again this weekend. My pinion angle is wrong and is pointed down 2 degrees. I will need to adjust this and bring it up to a positive (pointed up) 2 degrees to match the level of my motor/trans. I messed around with different shims to correct the pinion angle and it still has the spring wrap issues.

I removed all the blocks and shims once again to make sure I wasn't imagining things and tested it. It did not have any noticeable spring wrap with the blocks out. I crawled under it while my dad worked the clutch and it does seem to jump around a bit more than it should even w/ the blocks out of it. There is however, no vibrations in the car like before. Unfortunately the car sits up WAY too high with out the blocks.

I am led to believe that the blocks are just accentuating the problem and maybe it is not the springs or pinion angle at all. My next step is to look into the clutch set up once again. Everything is new there except the fork and linkage. I will try to adjust my linkage and see if that changes anything. My driveshaft is all new along with new U-joints and was built by a very reputable shop, so I do not think that is the problem. If worse comes to worse, I guess I'll be making some trac-bars for it and cross my fingers.

Not sure what the correct locations are? These springs are straight from Ch***is Engineering, and the clamps came in those positions out of the box. I did try to shim under the gaps in the clamps to see if that would help, and it did nothing.

 

The spring packs have 4 leaves. Between me and my dad, we have 3 cars with this same set up and they all have 4 springs per pack.

I talked with Ch***is Engineering and they do sell an Add-a-Leaf that I am considering. I am concerned it will make it ride like a dump truck though.

 

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I measured the skew of my driveshaft going to the pinion and it is only off by one inch. I checked a few other cars running a 9" axle and it seems that this is pretty standard due to the offset design of the carrier.

I need to correct my pinion angle, but like I mentioned earlier, the problem did not go away when I used temporary shims to put the pinion and motor on the same plane.

I am going to try and adjust the clutch to where it is not releasing at the very end. There should be enough adjustment in the linkage for this. The throw out bearing has about 1/2" of play before it makes contact with the forks of the pressure plate.

I am agreeing with you that the problem may very well not be the springs and rather something in the drivetrain.

 

Dan, Have you measured how your pinion angle changes with and without the blocks.

If 2 degrees down works without the blocks, it seems like you would need a larger negative (down) angle as you add the blocks. Raising the differential relative to the trans, reduces the angle, so you would need to compensate for that, plus a little for the added torque that the lowering block give.

The reduction in angle plus the longer lever arm that the blocks create may be causing it to bind under the initial load, and then it springs back into a tolerable angle under normal driving forces.

Just thinking out loud here.

 

I am also having what I would describe as a leaf spring wrap-up issue. My pinion angle is set perfectly (checked with an inclinometer/angle finder, I can't remember what the actual numbers are but it is set so they cancel each other out ... if it is 2 down at the trans then it is 2 up at the pinion, absolutely no vibration from this setup). I am running Jeep Cherokee leafs with a couple leafs removed, homemade solid steel 2" lowering blocks, and a T5 trans behind a stock 305. I drove this car with a 350 and a TH350 trans with absolutely no issues. I changed out the tired 350 for a fresh 305 and swapped the TH350 for a T5 and now I have, what I can only describe as an axle wrap-up problem, that was not there before. My feeling is the automatic trans put a lot less stress on the leafs compared to the stick and I believe that the lowering blocks also contribute to my issue (the lowering blocks were also present when I ran the automatic, I just don't believe the "leverage isssue" came into play at that point because of the automatic trans being "easier" on the suspension).

The issue itself is hard to explain but I will try. It only happens when pulling away in first or when I shift into second and not every time, it depends on how "smoothly" I work the clutch, and how much gas I am giving it. Once I am moving at a good clip it does not happen ever. The car kind of "jerks" or "pulses" (think "wha...wha...wha...) before it smooths out. I believe what is happening is the leaf springs are wrapping up ... springing back ... wrapping up again ... springing back again ... wrapping up again ... and that is what is causing the "smooth" jerking (it is not violent at all, not clanging, banging or anything). The car does not sway side-to-side, it does not try to turn itself, it just "pulses" or "smoothly jerks" in a forward motion. I am confident that it is spring wrap up, caused by two things ... lowering blocks that increase "leverage" on the springs, and the standard trans. It (in my opinion and my case) has nothing to do with the clutch itself or the pinion angle. I am going to fabricate some links that will prevent (or at least minimize) the change of pinion angle when under load (which will also prevent the leafs from wrapping up), I jjust need to stop driving the car long enough for me to make up the links. I like the picture posted earlier of the two links directly under the leafs, that attach just below the front spring eye but i would actually prefer to run something similar to a mid-eighties Camaro/Firebird "torque arm". Same as the original poster, my car will sit too high without the lowering blocks.

One more thing, my driveshaft does "jog" or "skew" slightly because I have centered the engine and trans in the ch***is, but the rearend I am using does have some pinion offset, I do not believe for a minute that that has anything to do with causing my issue. I ran a ladderbar equipped Nova a couple of years ago with a SBC and a stick and never had this issue, the ladder bars do not allow the rear to "wrap-up". The Nova also had driveshaft "skew". In my opinion, as long as the engine and trans are installed "straight" in the car (not "****eyed") and the rearend is also located correctly, there is nothing wrong with some driveshaft "skew", as long as the angles cancel each other out.


Keep this in mind ... this is my opinion of what is happening to my car. I have yet to prove it because the issue is not that big a deal and I can't seem to stop driving the car. Once the "slop" of winter hits the road I will get around to making up those links, but I am confident that spring wrap-up is what I am experiencing.

 

Heres a '62 Vette with upper and lower bars. If it were my car and I didn't want the look of the lower bar I would install the top bars first. He races this Vette hence the top and bottom bars, in your case you are not racing, not running huge power or rubber on rear and the '36 is a light car. Vette owners will tell you that the top bar is for wheel hop when braking but I have used this set up for both problems. The top bar is standard on atleast the '62 maybe other older models as well.