Suspension Spring Replacement (BN2)

[microfox]

Today was rainy and freezing cold outside. Great weather for working on cars.
So I decided to go ahead and replace the suspension's front springs on the
Austin Healey 100.

The right side spring was sagging (it came that way when I bought the car). It also
has couple of those springs lifts added between the coils, so I knew it had to go.
The car was lower on that side also. I had sent for a pair of Moss Motors springs
and they came with no specification as to its compression in Pounds or Kilograms.
I called them and they didn't have that information either. They just said it was
the same as stock (whatever the spec is).

After doing my due diligence in searching the forums here and elsewhere, I made
the tools suggested by other Austin Healey folks for this task (8" all-threaded rods,
bolts and couplers). This task comes with some serious safety consideration, given
that a compressed spring has a substantial amount of stored energy in it. That
energy has to be slowly dissipated as we undo that tension by unscrewing the
couplers slowly and patiently.

It took me quite a while but I managed to remove it without any problems.
The car was placed on jack stands and also I used a separate jack to raise the
lower A-arm enough as to position it as if the weight of the car was on it.
That makes the lower A-arm nearly horizontal to allow the spring a more vertical
stance. With the suspension just dangling and the spring still under tension, it
seems to be slightly curved.

Notes:

I did not have to remove the sway bar or the brake calipers (yes, this BN2 has
disc brakes). Another thing: When I initially lifted the car to place
it on stands, it was lifted such that the wheel hub was 16.5" off the floor.
Furthermore, the suspension itself was raised 3 more inches to keep the lower
A-arm nearly level. This gave me plenty of clearance for the spring to pop
out easily. The 4 original short bolts had no washers at all, but they used
nuts with nylon inserts (not sure if that is correct). I plan on adding lock
washers when putting it back.

.

 

[microfox]

OK, it's been a week and the spring replacement is done. However, a peculiar thing
has happened that puzzled me.

After I put the front tires back in and lowered the BN2, one side sat lower than the
other. Both tires are inflated the same. Now if I measure a straight vertical line from
the ground through the middle of the knock-off up to the edge of the wheel arch,
I get 27" (68.5 cm) on the driver side and 25" (63.5 cm) on the passenger side (the
car is Left Hand Steering).

The 27" seems to be right, although I have no idea what the proper height should
be. But it follows the arch in an "even way". The springs are brand new and of the
same size. What gives?

Now mind you, this is a "nasty boy" with a small block Chevy engine. Probably a 305.
I have no idea if this engine is heavier, lighter or same weight as the original Austin
Healey engine. But I presume there is little difference in weight from the engine block
as whole from left to right. In other words, when an engine and transmission is laid on
a chassis, it should be pretty even from side to side, thus exerting similar down force
on each spring.

When I removed the old springs, the one with those lifters added to it, was of the same
size compared to the other old one. The height difference was there with them too.

My dilemma now is do I search for a longer spring for the passenger side (hopefully with
the same "bounciness" as the other)? Do I modify the spring itself to make it taller?
Or do I lower the taller side (easily doable, I guess).

PS. This car has its battery on the right side of the engine bay, but, as a test, I placed
a spare battery on the opposite side and it barely lowered that side of the vehicle,
so it is not battery that caused the excess right-side weight. I do plan to put it the
back where it belongs.

PPS. The tires are: 195 / 65 R15 on 16" wheels

Any insights?

 

[BobHaskell]

The lower A-arms can bind on the inside bushings. Loosen them and set the car on the ground. Bounce the car and see if it's level. Tighten the nuts with the car still on the ground. Will require removing the cotter pins.

 

[microfox]

The lower A-arms can bind on the inside bushings. Loosen them and set the car on the ground. Bounce the car and see if it's level. Tighten the nuts with the car still on the ground. Will require removing the cotter pins.

Thank you, @BobHaskell.

Just to clarify, this binding would be occurring on the high side, right?
(keeping it from lowering like the other [lower] side).

 

[red57]

I would suspect the rear springs are the problem - a simple test is to jack the car in the rear under the center of the cross member so the rear springs won't influence the stance and it's free to follow whatever the front wants so you can see if the front is still off.

Alternatively, find a local shop that can do corner weights (typical this is done for road racing) and see if you have similar loads on each side. (good to know your front/rear distribution anyway)

 

[microfox]

I would suspect the rear springs are the problem - a simple test is to jack the car in the rear under the center of the cross member so the rear springs won't influence the stance and it's free to follow whatever the front wants so you can see if the front is still off.

Alternatively, find a local shop that can do corner weights (typical this is done for road racing) and see if you have similar loads on each side. (good to know your front/rear distribution anyway)

Hmmm... I never thought of that. Good idea. Thank you @red57.
I will do that test, but just now, I measured the same distance and they both
(rear arches) are at 27" (68.5 cm) with all wheels on the ground.

 

[microfox]

As @red57 suggested, I lifted the rear of the vehicle and the car resting
only on its front wheels, exhibited the same stance, i.e., the right side
lower than the left (see photos). Now I am starting to think that those
lifters added between the right side spring coils were to keep the spring
from compressing too much (thus no excessive sinking). So it's not the
rear springs.

I am now going to investigate the suggestion by @BobHaskell and see
what's missing or out of wack.

 

[red57]

This may sound like reach, but have you checked anywhere besides the wheel arch as shown in your pictures? Reason I ask is the early 100-4 BN1s had a lower wheel arch in the front fenders than the later BN1 and BN2 cars. So, is it possible that someone replaced a fender sometime in the past? If you are parked on level ground, you can try placing a 3' level across the front fenders above the wheels and see if the overall body is off too.
Just a thought....

 

[microfox]

OK, I just measured it. With the front on stands located at same place in the chassis,
the car is fairly level (at the bumper, the flat area behind the bumper and on top of
the where the hood attaches). Then, measuring the highest point of the arch well,
the lower right side is 1/2" lower than the left side (the "high" one). Much less than
what I notice as the problem.

I am not sure if the arch curve was cut larger, etc. At least they seem to be fairly
even side to side.

 

[red57]

Found this on another forum - another way to check the differences between BN1 and BN2 fenders:

"The top of the wheel arch to the beading/fender welt is 9” on a BN1 and 7.5” on a BN2."

 

[microfox]

Found this on another forum - another way to check the differences between BN1 and BN2 fenders:

"The top of the wheel arch to the beading/fender welt is 9” on a BN1 and 7.5” on a BN2."

Hmm... on my BN2 is 8.25" (from the bead).

But the chassis is level, so he culprit is probably the a-arm articulation, or nearby.
The dangling wheels are also even with each other. But when the weight of the car
is put upon them, the body sag differently from left to right.

[Edit]
You know, there is another hypothesis: The springs are not equal (despite *looking* identical).
(I could not get any spec from Moss Motors on it, there are no indication on them).

 

[microfox]

OK, I finally was able to finish this task. The springs were fine. What the problem was,
as I imagined it (but hope it wasn't so) was that its perch had moved somehow and
I had to resort to making custom new "spacers". That wasn't cheap but it fixed the
problem. I did asked around and researched online for such a thing for Healeys, but
all to no avail. Now moving on to other tasks.