Rear leaf springs, new or rebuild old ones?

[BULLITT65]

nice. Let me know how those work out. Looks and install wise. thanks

[X33RS]

Bullitt, I haven't used Heartbeats kit but I've rebuilt a handful of rear leafs for other cars.  It's pretty straight forward and easy, inexpensive too.

[Mike S]

Read somewhere, probably here, CHP commented about Camaro Specialties being spot on.

Good reading also:https://www.eatondetroitspring.com/

  Unfortunately their mono springs are not spot on  That applies to Eaton and Camaro Specialties (I suspect they get  them from Eaton). It lacks the correct horizontal taper width. I don't think that applies to multi-leaf springs however.

Mike

[janobyte]

Not sure about mono's. I sort of suspect, like all these parts, to obtain "spot on" meant possibly an old set of springs re-arched/restored or just a good old set of springs where sold. I thought there was some difference in the multi leaf from Eaton also. Somewhere on the site they even go into detail about the difference in leaf thickness. Can't remember off the top of my head, too much lacquer thinner fumes today ! lol

[dale_z28]

Bullitt, I haven't used Heartbeats kit but I've rebuilt a handful of rear leafs for other cars.  It's pretty straight forward and easy, inexpensive too.

If I may ask, what is used between the springs right in the center where the pin/bolt draws them together? Like I showed in my picture, there's some type of separator in there, but I haven't been able to figure out what it's made of. I'm considering UHMW so it'll withstand the pressure yet "slip" a bit so it won't squeak or have friction issues. Thoughts?

[69Z28-RS]

Bullitt, I haven't used Heartbeats kit but I've rebuilt a handful of rear leafs for other cars.  It's pretty straight forward and easy, inexpensive too.

If I may ask, what is used between the springs right in the center where the pin/bolt draws them together? Like I showed in my picture, there's some type of separator in there, but I haven't been able to figure out what it's made of. I'm considering UHMW so it'll withstand the pressure yet "slip" a bit so it won't squeak or have friction issues. Thoughts?

There were rubber isolators used above and below the spring assembly for multileaf springs.  Here is a link to an NOS set (but nothing was used between the spring leaves to my knowledge at the center).
http://www.ebay.com/itm/NOS-GM-1968-1969-Camaro-Multi-Leaf-Spring-Pad-Kit-part-3930052-nova-firebird-/131553443151?hash=item1ea1323d4f:g:ujsAAOSwPcVVnsX-&vxp=mtr

The 'anti squeak/sliders' were used at the ends of the springs (between leaves) and were a hard plastic 'friction reducer'.  Here is a link to a reproduction set.
http://www.ebay.com/itm/68-69-CAMARO-NOVA-4-LEAF-SPRING-REBUILD-CLAMP-KIT-/252231800744?hash=item3aba2fd7a8:g:3AQAAOSw0vBUaiiU&vxp=mtr

[X33RS]

On the GM multi leaf springs I've done, there have only been rubber isolators right in the center of the springs on either side, just as 69Z28-RS describes, and the end of the leaf has plastic anti squeak pads along with your clamps and small rubber for those.

Ultra High Molecular Weight Polyethylene or UHMW is pretty cool stuff, comes in a roll, and could work as a substitute on the ends of the leaf if you don't want to buy the spring refurbish kit with anti squeak pads, but I can tell you the UHMW costs 3 times more than a spring refurbish kit does.  I'm not aware if UHMW comes thick enough to substitute for the center rubber isolators.  Those are fairly thick.

I'll be rebuilding my rear springs on the Z, and just plan to use the simple rebuild kit, probably try Heartbeat.  I'd guess the kits are similar.  I did a 61 vette a few years back and used what Corvette Central had, worked fine, and did a 67 mustang and a 65 Comet last year and used what NPD had and replaced all hardware as well, which was a mixture of Scott Drake and AMK.  Worked excellent.

[dale_z28]

I've been "assuming" (and we all know what that means!) that there is something in between the springs at the center location, and I'll find out soon enough if that "something" is dirt, or some sort of material. The more I look into this, the more it sounds like the anti-friction pads are the only thing used, and only on the spring-ends. I've got the upper and lower isolators and the new T-bolts and U-bolts, new J-nuts and screws. Just wanting to make sure there isn't actually something in the middle - and it's looking  like there is not.

[69Z28-RS]

The springs really don't 'slide against one another' at the center; they are clamped tight at that point.  At the ends of the leaves is where they move, and that's where the anti-friction pads are located. 

If I were assembling a set of multi-leave springs I'd use the stock isolators and friction pads, and I might be tempted to use some heavy grease between the springs at the center- more to keep out water than to reduce squeaking..

[X33RS]

Correct, they don't move in the center, just the outer ends move around as the spring compresses.

When I assemble them I use the new stock plastic pads and apply graphite grease on the surfaces.

There is also a paint called "Slip Plate" which I believe is a graphite based paint that is also said to work very well.  I haven't tried that yet but I might in the future.

[X33RS]

If it makes you feel better Dale, I guess you could put pieces of UHMW between the leaves in the center.
   The only thing that pops into my mind is that spacing each leaf in the center with UHMW could possibly change or affect the spring rate in some way. As the leaves are separated more in the center then the ends of the leaves don't make as much contact pressure.
     I think that UHMW comes as thin as .015" or .020" thick, but with 3 of 4 pieces of that in the center of the spring it could add up to .050" or more.

I might be splitting hairs here with that thinking, and it might not make one bit of difference, I'm just thinking out loud.   

[dale_z28]

A new question has come up in my rear-spring refurbishment. My lower leafs (the shortest ones) are offset in opposite directions (comparing) right to left. The right side leaf has more going out the back of the axle than the left side. Is this like the staggered shock method of reducing wheel hop or binding springs? I first noticed this when I saw the end of the leaf on one spring being nearer to the clamp then it's partner spring.
My bodyman was very careful in the disassembly and reassembly, making sure not to mix right parts with left, or letting the leafs turn end for end.

[69Z28-RS]

Dale,

It's been 3.5 yrs since I had my differential out cleaning it up, but I don't recall seeing anything like that...  yours doesn't look *right* to me; maybe someone exchanged the short leaf in the past?  I will look again at the photos I took while they were out and see if I can see anything to shed better light on your question...

OK..  I found a photo of my springs after I'd removed them and cleaned them.  They were not disassembled, just cleaned and re-corrosion protected.  The plastic sliders were present and in good shape, so I felt better by leaving them as they were.  I didn't remove the front bracketry to ensure they went back on the same side they came off.  I can't see any differences from the photo..  Does your springs have additional 'clamps'?  My original springs only had one clamp forward and one clamp rearward.

[dale_z28]

Yes, one clamp holding 2 leafs and the other end holding 3. In thinking about this, the holes in the short leafs are 1-1/2" off-center (the leafs are the same length as each other). If one leaf is opposite and the spring packs laid side-by-side, as mine are, then you see a difference of 3". The wear marks in the adjacent leaf (the ones above) shows a distinct wear pattern, there's no mistaking the original location. Now I'm just wondering if the significance is so small, the assembly line workers may not have cared or been able to tell if they flipped one during the build

[x77-69z28]

Check for inter granular rust. My 70Z springs were almost fused.
Buddy