Experience with SNG replacement leaf springs?

Yesterday was a big milestone for me: the body is finally back on the chassis for the first time in 30 years. The mating went better than expected, but it confirmed what I had suspected before. The rear end sits way too high on the replacement leaf springs I purchased from SNG. I am not trashing SNG here. What I would like to know is if anyone has specific experience with these springs and how much I might expect them to settle once the car is back on the road. I don’t want to throw more money at this issue if it is not necessary, but I also don’t want to finish the car and have the rear end jacked up like a 60s dragster. Right now the rear end sits about four inches too high. It will drop a little when the tank is full, the spare is in the boot and the interior installed, but i suspect it will still be several inches too high. That seems like a lot to expect from the springs settling in. Does anyone have experience with these and what is your counsel?

Did you compare them with the arch of the old springs?
Are they well greased?
Could the shackles and front bolts be too tight?
Figure a spare tire weighs 50 lbs and a full tank of gas weighs 100 lbs.

I Have replacement leaf springs on both my XK140 and XK150 Both from SNGBarratt.
Both cars have the right ride height, very pleased with them.
They will settle down when your car is fully assembled and you take it for a spin.

The new springs supplied by all do make the cars sit too high at rear.
Certainly your car will drop down when finished etc but you will find it will be to high see the pic of this car restored by jaguar and it is way to high at rear.
The Xk140fhc above lovely colour I would say is about right at rear but from front seems to be a smidge to high?
Whether lowering front on torsion bars will raise the back which then would make it to high.
Terry
photo shortly

If you have installed the springs, preload the rear ( I used bags of play sand) and bounce the car multiple times to settle the springs. If that does nor change the ride height you can take the springs to a spring shop and they can change the curvature of the springs. On mine I had a set made to order for no dip on high speed cornering because the original set was too soft.

Thanks for the input guys. My old springs were not original and did not match each other. The new springs had enough arch that I had to flatten them with clamps just to install them. Before the body was installed I used my body weight (considerably more than 150 lbs.) to bounce the chassis without getting much movement from the springs. I will check the shackles and front bolts as Rob suggests. Peter’s car looks about right to me. I always thought the tires and fender openings should form concentric circles when all was set up correctly. Unfortunately, leaf spring shops are becoming rare birds. I would have to remove the springs and send them out of town to rearch. If it comes to that, I question whether it is worth throwing additional funds at this set which never impressed me with their quality.

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Ground clearance is 7-1/8" measured at the front mounting structure of the rear springs.
image
Here is my 7-1/8" measurement device. I made 4 of these.
Ride Height Blocks 003
Ride Height Blocks 002
Front suspension height I adjusted first with these at the rear and the rear wheels off. Then I could put the rear wheels on and check the rear, knowing the front was already right.

I took my springs apart and re-arched the top leaf to 5-1/2" by setting it across two blocks and jumping on it. Then did each successive leaf the same way until they matched the curvature of the top leaf.
image
It worked.

Jumping on the leafs sounds cheaper than having them rearched. I just hate the idea of taking them out since they were such a pain to mount. I will use your method to set the front height since it takes the exaggerated height of the rear out of the equation. That just leaves the alignment of the front wheels to worrying about while the rear decides to settle in.

You jumped up 'n down on 14 different leaves?!..got any videos of THAT?

Sorry, it wasn’t that dramatic, wouldn’t win an oscar. On the other hand, people put some pretty stupid things on social media. :laughing:

Think tik-tok…