Plastic Add-a-leaf question

[jaredbenz]

I was getting ready to rebuild my front spring packs on my '76 Suburban, and I was thinking about putting some kind of full-length plastic uhmw spacers to make them slide more easily, and it occurred to me that I could use the plastic almost like an add-a-leaf that wouldn't really change my spring rates. Am I crazy to think this? This seems like a cheap, easy way to add 1"-2" of front lift without the danger of blocks. I understand that there is no easy and cheap way to keep the brake lines and steering safe, but with a small lift, that shouldn't be a problem. I am more just looking for thoughts on what some of the problems with this may be, and why no one seems to have ever tried it.
The article on here about the 52" front spring swap was kind of what got me thinking. He does the same thing with .060 uhmw poly, why not with .250? My dad used to work with this stuff, and it is almost indestructible if kept out of the sun. He used it for wear plates on farm equipment.
Would it change spring rates? What are other possible problems?
I would appreciate any thoughts/input.
Thanks
Jared

 

[BGKYK5]

My worry would be the plastic block splitting in half and falling out. Don't do it, get a set of Easy Inches or Zero Rates instead.

I did however use 0.60" UHMW PE between my leaves and would recommend it.

linky

 

[1976Blazer76]

I'm also putting the thin UHMWPE in between each leaf. I work with this stuff everyday, I wouldn't use a piece of it as a lift block. It more than likely won't split in half but it will "squish" a little and allow the axle to possibly move which could bring on another list of issues. I would stick with using metal for this application.

 

[6.2Blazer]

There is no benefit to installing UHMW the full length between springs in regards to friction. Remember the springs are bolted together so the only "sliding" they do against each other is really towards the tips.

However my first concern would be how flexible the stuff was......would it last being flexed back and forth with the springs?

 

[1976Blazer76]

However my first concern would be how flexible the stuff was......would it last being flexed back and forth with the springs?

It shouldn't have any issues with being flexed back and forth with the springs. It is self lubricating and abrasion coming from spring movement would have little to no effect on the UHMWPE.

 

[BGKYK5]

There is no benefit to installing UHMW the full length between springs in regards to friction.

I agree, but I had enough to do it that way and it was just as easy.

Mine is adhesive backed and seems to be on there pretty good. I haven't wheeled it hard yet though. The truck is still not all put together.

 

[Blue85]

Using UHMW poly for height is a bad idea. Also, I would rather have the thick teflon pads at the ends of the leafs that the thin sheet of plastic all along.

If you need a small boost in front, hit up the junkyard for some old leafs that have fallen out of spring packs. Cut them down so they are only 6" long or so and bolt them into your spring pack for like 1/4"/each. Old overload springs are good for 1/2"-3/4". I wouldn't try to add any more height than that using this method in the front.

You can always get another 3/4" or so from longer shackles, but you will probably need a degree shim then. One of those add-a-leaf kits will stiffen the ride, but it's good for 1-1.5" and isn't super expensive. If you need more height than this, it's really time to swap springs.

 

[4X4HIGH]

My worry would be the plastic block splitting in half and falling out. Don't do it, get a set of Easy Inches or Zero Rates instead.

I did however use 0.60" UHMW PE between my leaves and would recommend it.

I'm sure you meant .060" not .60"?

 

[BGKYK5]

Uhh, yeah.

 

[jaredbenz]

Thanks for all the input guys. I am not looking for a lot of lift. I actually have a 1949 Ford (gasp, I know) F-3 on the '76 Suburban frame, and it will easily clear the 35's that I want due to huge fender wells and having what amounts to a body lift to make things work fit-wise. I don't really need the lift, and I am not a hard core trail guy, I was just curious about people's experience with this. I have 3 leaf springs with an overload pack, and I was just thinking about adding maybe 1/2-3/4" of Poly for my application. I am really surprised that you had trouble with this stuff breaking. My dad used it for protecting shanks on field cultivators (basically it gets drug through the dirt and beat on with rocks), and 1/4" uhmw way outwears the actual 1/2" spring steel shanks. The stuff he used was flexible even in extremely cold weather. I can see the center hole possibly being a weak spot, but I don't see a lot of risk for myself because I don't do much besides mudholes and mild trails. I may try it and write up how it turns out.
Thanks for the thoughts.