Wheel hop options

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Read the Mopar Performance Suspension Manual. This is a WELL known fact for leaf spring suspensions. We've had this discussion before. It's a FACT. If CalVert engineering told you to lock leafs TIGHTLY together, "somebody" made a mistake.
 
In Canada we put a snowmobile in the back of the truck and it fixes the wheel hop issue 8 out of 10 times.
 
Someone should mount a camera under the rear of a mopar and draw a vertical line with a silver sharpie between the ubolts (torqued to factory 45ft-lbs). This would show how much relative movement the leafs have directly under the axle. I'm guessing 0-none, but I have no proof.
 
RustyRatRod said:
Read the Mopar Performance Suspension Manual. This is a WELL known fact for leaf spring suspensions. We've had this discussion before. It's a FACT. If CalVert engineering told you to lock leafs TIGHTLY together, "somebody" made a mistake.
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Are you talking the u-bolts or the clamps? The clamps I get....if the u bolts, what is the area than needs to be able to move between the perch and the plates? I don't have that book....is there something that I can search or some links?

One thing to consider is that once the u-bolts get a bit rusted, then a given nut torque is not going to the give the same clamping force as when the threads are new and clean. So is cleaning threads a part of this?

Edit to add: I am searching threads here....
 
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nm9stheham said:
Are you talking the u-bolts or the clamps? The clamps I get....if the u bolts, what is the area than needs to be able to move between the perch and the plates? I don't have that book....is there something that I can search or some links?
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The U bolt nuts. The torque spec on them on the Mopar CARS is 45 LB FT. Always has been. As I said, I don't know what it is for trucks, but the principle is the same, so I would imagine they are not supposed to be super tight.
 
The Mopar Performance manual makes it clear that if the nuts are over torqued, the rear suspension will not be allowed to work correctly, and it is correct. I have made the mistake of torquing them to 100 LB FT when I was a kid and the rear suspension dang near would not compress at all. With no other changes, I went back and retorqued to 45 when I found out the problem and everything worked fine.
 
nm9stheham said:
Are you talking the u-bolts or the clamps? The clamps I get....if the u bolts, what is the area than needs to be able to move between the perch and the plates? I don't have that book....is there something that I can search or some links?
Click to expand...

I'm just guessing here, but some of the cars came with rubber isolators for added ride comfort. Perhaps the 45ftlb number is to keep from crushing them. My FSM does say 45 ftlbs for U bolts.
 
OP.. If you haven't tried clamping all the front spring segments together, do so.

It has the effect of making the front spring sections a solid piece, so they can't wrap, and cause wheel hop, same effect as Caltracs, slapper bars etc..

Then no-one will mistake your car for a chebbie or ferd.. lol
 
RustyRatRod said:
The Mopar Performance manual makes it clear that if the nuts are over torqued, the rear suspension will not be allowed to work correctly, and it is correct. I have made the mistake of torquing them to 100 LB FT when I was a kid and the rear suspension dang near would not compress at all. With no other changes, I went back and retorqued to 45 when I found out the problem and everything worked fine.
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Thanks for the info. I'm a'gonna have to think this one through; sounds like the leafs need to move all the way through.... which seems unusual for a leaf spring pack. Perhaps the leafs move/slide a bit as the car's weight sets down on the springs, allowing them to settle to the normal height setting, or 'adjust' to different vehicle loading, but does not move all that much in normal movement. With the variations in actual clamp force versus nut torque as mentioned, the 45 ft-lbs has to be well below where the leafs can slip some.

There almost has to be some slight curvature to the perches or the plates for any relative leaf movement to occur in the center area.
 
I don't buy the 'required movement of leafs' being the reason for the low torque value in the Mopar books.
Moving leafs will break the spring's center bolt very quickly, and maybe even the leafs as well.

My guess is Mopar used a low grade metal for their U-bolts and to prevent stripping or twisting the U-bolts, they were conservative with torque values in the manual.
As with most fasteners, next to the lubricant used, the metal grade will dictate the torque value.

1/2"-20 thead U-bolts would at least require 65 ft/lbs to me, unless the metal is softer than a Grade 5 orso.

Did Mopar ever used taller nuts on the U-bolts?
I recall aftermarket kits are supplied with 3/4" (?) tall nuts, that the extra internal threads prevent stripping.
 
Firm Feel makes a quad shock kit that is supposed to eliminate wheel hop under acceleration and braking. Same kit fits any rear wheel drive mopar, so doesn't matter what one you look up.

Firmfeel Mopar Suspension and Steering

Also the axle location on the leaves are different between cars and trucks. On the truck the axle is mounted closer to the middle of the leaf spring, the car axle is mounted so that about 1/3 of the spring is in front of the axle and 2/3 of the spring is behind the axle.
Better traction with how the car springs are mounted compared to how the trucks are.
 
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I never said the leaves move. Someone else brought that up. I said simply that if you overtighten the U bolt nuts, the rear suspension will bind. That is an indisputable fact. This is just one more reason also, to torque all main suspension bolts and nuts with the weight on the tires.
 
You may want to consider putting a pair of shocks longitudinally connected to the top of the axle al'a HiPo Fox body Fords. Did wonders for calming their dancing ways.
 
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