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Topic Review (Newest First)
05-01-2019 12:49 PM
Bob37pont To clarify the ride height gain, I actually gained 3" ride height with the new springs over the old springs with no air in the shocks.
Previously I ran enough air the raise the rear 2 ".
04-30-2019 03:10 PM
Bob37pont Springs arrived Thursday afternoon, busy schedule kept me tied up until today ( I'm retired, I don't know how that happened!).
Took about 4 1/2 hours, surprisingly no bolts were stuck in place.
As I got the u-bolts ready I realized,after drilling the 7/16" holes to 1/2", the brake line runs tight across the axle, with a welded hold down tab right in the center.
Pretty sure this assembly was not designed for u-bolts.
Quick trip to ACE for grade 8 1/2" bolts and everything went together smoothly.
I ended up gaining 1" of ride height with the 1 1/2" lowering blocks in place.
Put about 40#'s in the air shocks and gained another 1/2", the stance looks good. It's now 2 1/2" higher in the rear that the front, measured at the running boards.
The suspension now has some travel and a smoother ride.
Additional bonus I don't have the jack the car 12" in the air to remove a wheel, the springs don't sag with the weight of the axle!
04-22-2019 12:59 PM
Bob37pont So I keep leaving voicemail at Landrum Springs with no call back....
Called tech support at Summit and was told that generally the 'racing' spring for a specific weight is a bit softer than a 'street' spring. Given my axle weights he felt the 225# rated spring would give me a more compliant ride on my Pontiac.
Springs & shackle sets ordered, as well as a set of U-bolts!
04-20-2019 09:27 AM
Bob37pont
More weights

I went back to the CAT scale and weighed both axles with the car set pretty much centered (by eye) on the wheelbase.
Front axle: 1660 lbs.
Rear axle: 1820 lbs.
Total weight using the 2 pads of the scale: 3480 lbs
Total weight using a single pad of the same scale: 3720 lbs
I've not been able to contact the owner/tech at Landrum, I'll try again Monday.
I'm thinking the 3000 to 3500 spring will be right, But I want his opinion.
I've not been able to find a rate calculation for leaf springs based on vehicle weight, as opposed to measuring the springs themselves.
04-11-2019 01:41 PM
Bob37pont
Magic Number!

Got the car on a certified CAT scale at the local truckstop.....
She's a not-so-svelte 3,720 pounds!

Landrum lists a 225# spring rate for vehicles weighing 3000 to 3500#.
And a 250# spring rate for vehicles weighing 3600 to 3800#.
These springs with the "A" suffix have a 5" arch.
I checked under the car and with the air shocks at 75# I raise up about 1.5 to 2".
I called Landrum to get the spec on static compression for the weight, but the owner/tech guy is on vacation. I'll call him next week.
My thought is the lighter spring rate might get me closer to my stance without excessive lowering blocks, and still give me a compliant ride.
04-11-2019 10:59 AM
Bob37pont
Quote:
Originally Posted by ericnova72 View Post
I can't say for sure, but it certainly looks like they are referencing total vehicle weight with that chart.

Charts I'm used to looking at are just front or rear weights.
Looking at Landrum springs on the Summit site they state the reference is for total car weight. They also list "A" springs for asphalt use, although Summit says they are not for street use. The "A" springs have a 5" arch, while the "D" (dirt) springs have a 6 1/2" arch.
Once I get the car weight I'll call & see why they are not for street use, according to the Summit description.

Quote:
Originally Posted by S10xGN View Post
Have you got room to move the hole in the frame for the shackle rearward? Two inches there and slightly longer shackles might do it...

Russ
No, the frame gets narrower behind that hole, that's why I think the sliding shackle suggestion may work better for me.
04-11-2019 09:04 AM
S10xGN Have you got room to move the hole in the frame for the shackle rearward? Two inches there and slightly longer shackles might do it...

Russ
04-11-2019 08:38 AM
ericnova72
Quote:
Originally Posted by Bob37pont View Post
Thanks Eric, I'll get some U-bolts!
Does this spring rate chart refer to the total weight of the car?
I would assume that is the case, but better to ask, right?
I can't say for sure, but it certainly looks like they are referencing total vehicle weight with that chart.

Charts I'm used to looking at are just front or rear weights.
04-11-2019 04:53 AM
Bob37pont Thanks Eric, I'll get some U-bolts!
Does this spring rate chart refer to the total weight of the car?
I would assume that is the case, but better to ask, right?
04-10-2019 04:25 PM
ericnova72 first thing I have to comment on is the very last picture.....holy unsafe, Batman - no u-bolts around the axle tube!. The way the spring is clamped in the perch with just regular bolts is a very poor way to do it. Even when the factory started to cheap out and do this in the 1970's on Camaro/firebird and Nova they always used 1 u-bolt per side and just 2 regular bolts.

Second thing is that rear shackle angle when spring is unloaded....it should not be vertical like that, it should be straining forward almost to the point of the spring eye touching the frame(the reverse of what your dealing with when it is loaded).
My guess is the use of the convenient original bushing hole in the frame created this problem....correct use of that original frame hole would have meant the front spring hanger would have to be moved forward 3" or so, and that would mess up wheel centering in the wheel well. Correct fix here with the Camaro spring is to correctly locate a new rear bushing mount hole. Slider might be the easiest way to fix that.
The standard Camaro leaf pack is well known for going flat and sagging out, so they probably do need replaced...but to fit and function as they should you really need to do something about that rear shackle location problem.
04-10-2019 03:13 PM
Bob37pont These pics show the springs unloaded, axle hanging, rear shackle is vertical.
04-10-2019 03:09 PM
Bob37pont This afternoon I pulled a wheel to get some better pics & info. The wheel/axle drops 6" when the car is jacked up until it is off the ground.
Measuring the spring eye to center pin confirms they are Camaro, 24" from the front, 30" from the rear. Speedway offers a good selection in different weight ratings.
I still have to get the car weighed so I can calculate the correct spring rate.
It's apparent to me the front spring eye mount has been replaced, while the rear shackle is mounted in the stock frame hole.
The pics show the spring both weighted and hanging free, I did let the air out of the air shocks.
When there is weight on the axle the leaf spring is almost flat, with the rear shackle pushed back tight against the frame.
I normally run the air shocks ~ 75 lbs, this gives me about 1/2" clearance between the rear eye and the frame. Sliders might allow the spring to move a bit more.
I'm tempted to get the sliders and install them with the current springs to see how that works.
All of the speedway listed springs are described as having 6 1/2" true arch. Does this mean that is how the spring sits unloaded?
Once I get the weight I can better figure out what weight spring I need. From what Eric mentioned standard Camaro springs were either 160 or 175, I betting these are 160.
First pics show the spring loaded, axle on a jack stand.
04-10-2019 11:44 AM
Bob37pont
Quote:
Originally Posted by timothale View Post
WE have 36 an 37 Pontiac's. I have never had the 37 project up on the hoist. the 36 has springs that are narrower and more leaves than the camaro parts on the racks. some 4 X4 forums tell what bone yard springs will swap. I reversed the arch (reversed eyes) in my Model T front main leaf using a Hf tubing bender. chalk the shape then gradually work along the spring enough times. I don't know id the camaro springs would fit thru a HF tubing roller to do it faster. The 36 is stock straight 8, the 37 had a SBC and chevy pickup rear with the Pontiac wheel lug pattern
Adding a leaf along with the sliders may be the answer.
Next question where does one get a single leaf to add, a pair of junkyard to disassemble?
04-10-2019 08:27 AM
timothale
add a leaf

WE have 36 an 37 Pontiac's. I have never had the 37 project up on the hoist. the 36 has springs that are narrower and more leaves than the camaro parts on the racks. some 4 X4 forums tell what bone yard springs will swap. I reversed the arch (reversed eyes) in my Model T front main leaf using a Hf tubing bender. chalk the shape then gradually work along the spring enough times. I don't know id the camaro springs would fit thru a HF tubing roller to do it faster. The 36 is stock straight 8, the 37 had a SBC and chevy pickup rear with the Pontiac wheel lug pattern
04-10-2019 08:27 AM
rip-tide
Quote:
Originally Posted by Bob37pont View Post
Knowledge is king!
Better to learn by asking questions than throwing $$ at an issue without research!
Not to say I won't throw $$ at it, just hope to do it once!

Heard that ........ ! and wise
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