Standard or heavy duty leaf springs?

desdain · 06-15-2009

I'm in need of new leaf springs for my '66 fastback as the old original ones are really sagging.

My question is is I should get the standard springs or the heavy duty springs? I rarely have anyone in the back, but sometimes I carry some heavy luggage in the trunk if we're going on a road trip. I don't drag race and I prefer ride comfort over curve handling.

What do you think?

MizzouMike76 · 06-15-2009

I think you've answered your own question with the ride comfort over handling.

I went with a pair of stock leaf springs, and I was amazed how much better my car handled and how much less it sagged after a suitcase was tossed in the trunk. Even a set of stock springs will be a drastic improvement over what I can only guess are stock worn out sagging springs.

Are you doing the work yourself?

Michael

desdain · 06-15-2009

Yep, I'll be doing the work along with a buddy. Anything I need to know about?

MizzouMike76 · 06-15-2009

Yeah, you need to know it really sucks putting leaf springs on a car!

The biggest challenge was getting the front eye bolt out/off. It is very likely you will need to cut the bolt on either side of the leaf spring, a tricky job since the space is narrow and it's a very tight fit. I used a combination of cutoff wheel and Sawzall (reciprocating saw) and it was ugly ugly work. It doesn't sound like a big deal, but it was!

Be sure you take care not to have springs hitting you in the face; I jacked the car to take the weight off the springs, then I had a jackstand under the front of the spring for added protection. Also, since you're under there, this might be a good time to clean up the rear axle and paint it, and install new shocks should you need or care to do those things.

Your efforts will be worth it the first time you drive after putting in new springs; they'll improve handling, acceleration off the line, and stopping; overall, the car will feel more agile than before. You will be pleasantly surprised.

Oh, and make sure you have a good supply of Finnish vodka on hand to keep your buddy interested (or do y'all drink whiskey now like the Russians?)

Michael

racin_ryan · 06-15-2009

I replaced my fastback springs with standard, because like you, I wanted the comfortable ride. The originals would sag when you sat in the car or pushed down on the rear. The new springs raised the rear 3". I had to put lowering blocks (1.25") in to bring the rear back down to where I wanted it. I drive around with my wife and the kids in the rear and it is a night and day difference. You no longer feel the car sag in the rear and you can't push the rear down by hand.

Like Mike said the only thing that sucks is the front bolt. 45 years of rust and grime add up to not wanting to come out. I took an air chisel and I was able to wedge it between the frame and bolt. After getting a small gap the air chisel hammered it right out. It was the first pair I've ever removed and it wasn't too bad.

Hopefully you have replaced the front coils or are planning to. New shocks all the way around and new shocks (620's up front) at all four corners make it ride like a new car. Used to lean like a boat in water in a turn. Now it turns like a newer car. I'm wanting to upgrade the front sway bar and add a rear for more improvement.
Good Luck,

desdain · 06-16-2009

Well, the car was completely restored a couple of years ago, and at that time the springs didn't appear to be too bad. Also, as the build was going way over budget, we had to reuse some of the parts that were in "decent" condition.

Now I see the error of my ways and I will replace the leaf springs (the front end is new and upgraded). The good thing is that all the bolts are new and I shouldn't have any problems with ~45 years of rust and dirt build up.

The vodka is at hand ;-) (it's still Koskenkorva vodka, or Kossu, as the Finns call it, that is the predominant booze of choice)

TrialbyError · 08-11-2009

Hi there, I was looking at tackling my rear suspension this winter as well. Do any of you have any pictures of your rear suspension setup? Desdain, can you take some pictures when you do yours? I'm looking to do 4.5 leaf spring with mid eye, b/c that's what I've seen many people do w/ their classic, but I want to make sure I know what it looks like etc? I asked the local mustang parts dealer and they didn't know what I was talking about, hah!
Racin Ryan, are lowering blocks an easy thing to purchase? Like you, I'd like a lower profile car.

stars · 08-11-2009

Guess it depends on the car, I had zero trouble doing the leaf springs in my ’68 fastback (just liquid wrench and elbow grease). I went with the heavy duty springs and was grateful for the firmer ride in back (the ones I got didn’t raise the car much over stock), but that’s a personal preference. The thing that made the back really ride too hard was KYB shocks (those things would knock your teeth out on a rough road), and I ended up switching to another brand.

TrialbyError · 08-11-2009

Quote:

Originally Posted by stars

Guess it depends on the car, I had zero trouble doing the leaf springs in my ’68 fastback (just liquid wrench and elbow grease). I went with the heavy duty springs and was grateful for the firmer ride in back (the ones I got didn’t raise the car much over stock), but that’s a personal preference. The thing that made the back really ride too hard was KYB shocks (those things would knock your teeth out on a rough road), and I ended up switching to another brand.

Which brand did you switch to?

stars · 08-11-2009

This was about seven years ago, so my memory’s a little fuzzy, but I think it was Monroe’s that I switched to. They were a little soft, but better for general street use than the overly stiff KYBs (especially with how beat up the roads are around here).

TrialbyError · 08-11-2009

Quote:

Originally Posted by stars

This was about seven years ago, so my memory’s a little fuzzy, but I think it was Monroe’s that I switched to. They were a little soft, but better for general street use than the overly stiff KYBs (especially with how beat up the roads are around here).

Thanks!
How many leaf springs are in your heavy duty pack? My setup has 4 total (I think, maybe 5), but if the longest one is estimated at 4' (feet) then the next one is 3', then 2', then 1' if that makes any sense???? I'm not sure if they are all supposed to be around that 3-4 foot marker or tapered like mine? That's why I'm looking for pictures. I'm not sure if I need to upgrade. I'll post some pictures tonight.
I have air shocks right now and I'm not too thrilled about having them so I want to go to a regular shock. I was thinking about the KYBs but I think I'd probably have to go KYBs with a regular leaf spring setup maybe? Or go Heavy Duty and then have a softer shock (like you)?

If I'm going to take the shocks out, I figure I may as well do the leaf springs at the same time...

stars · 08-11-2009

The leafs that I got had four segments, one more than the stock springs that were on there. I was quite happy with them, as I always felt that the stock leafs were a bit too weak for the application. They were designed to maintain the stock ride height too. Unfortunately the company I got them from has gone out of business (another victim of the economy). There’s probably other sources for similar items though.

TrialbyError · 08-11-2009

Well I've attached some pictures. I'm not sure if these are original or newer, or whether they are 4.5 leaf...or mid eye (whatever that means)

It looks like I have 4, but they get shorter as you get closer to the ground. My rid height isn't too bad, but I also have air shocks so even when they are deflated the ride height doesn't look to bad. It passed a provincial inspection last year...

Did yours look like this, or were they all full length?

Thanks again!!!

66 restomod · 08-11-2009

I am really happy with the ride and performance of the 4 1/2 mid eyes we installed. Can put 2 people in the back seat with a full tank and not bottom out on a big bump. Car stays flat in turns. But it does not ride rough, just firm.
Here are pictures of the rear end and leaf springs:
Photo Page/6 Pictures

Good Luck and be safe
Ron

TrialbyError · 08-12-2009

Oh, I just figured out that it's you and your son's website, hah, very good site! I also figured out what Mid Eye means. The leaf spring attaches to the middle of the eye bolt housing as opposed to the bottom. Mine are not mid eye. The new ones you've installed look like mine in terms of the leaf spring setup / staggeredness (if that's even a word). Thanks so much for the help Ron!