Hey guys, I am planning to do a leaf spring swap in my 71' and I want some opinions about which to get. I can get the cheaper summit leafs with rubber bushings or the more pricey Hotchkis sport package with urethane bushings. Is the extra money worth the more pricey option? Also, is there a link to a DIY for the install? or any heads up tips for the install? Thanks!

 

I bought the Summit, but I also bought a urethane bushing kit as I was installing all new front and rear suspension bushings, so I tossed the rubber bushings.
Don't know of a DIY video, but leafs are pretty basic. Couple things you might run into when swapping springs. The shackle bolts might not come apart, and I ended up cutting mine with a sawzall and just replacing them with shackles I built. Saved a lot of time fighting them by just cutting alongside the spring, through the bolts.
The front spring mounts need to drop down to get the crossbolt out of the spring eye. Those 3 front bolts on each perch often are rusted into the captured nuts, and might be a bear to get off. Might even require cutting an access hole in the rear seat area to get at the nuts to hold them, or cut them if they're too rusted. Hard to get any penetrant at the threads to help from the bottom side. Mine came right out with ease, but mine were pretty rust free.

 

The shackle bolts may require dropping the tank as well. The rubber bushings are fine. If you want a bushing upgrade try delrin. www.customworksproducts.com
Keith can talk you through any question you may have concerning bushings.

 

Have you tried delrin bushings before? I haven't, nor would want to. Delrin is a plastic, and is harder than polyurethane bushings.
Poly at least has some give to it, delrin doesn't, which spells a harsher ride.

 

Thanks for the heads up on the rusted bolts/nuts! hopefully I won't need to cut them or drop the gas tank....I have to check out the sending unit for the gas gauge any way, so if I do have to drop the tank...I can kill two birds with one stone. Thanks again and I will post pics when finished...going to check out the Pomona swap meet on Sunday and see if I can get a deal on some springs (among other things)

 

With 11 Cincinnati injection molding machines in my shop, 36 at my old shop. Yeah I know a bit about Delrin. As for using it in the car. The suspension guys I take my ques from like it because it has almost no deflection. THEY say poly shouldn't be used in a situation where the component rotates. THEY also say its not the best for body mounts. I say they because I don't really have any practical experiance building a car that corners, so I have to listen to the manufacturer of my suspension when it comes to how to set it up.

As far as what I have. My upper and lower control arms both have Delrin bushings. One step down from solid which I would have run if they he could have come up with some type of seal to keep the dirt out and the grease in. On the leafs I have poly in the spring and rubber on the frame side of the shackle. There is a reason for that that sounded completely logical when described to me, but I can't remember why now. The upgrade for this is Delrin and then some pretty sweet solid spring eye bushings upgrading from that. I was instructed to ditch the poly spring pad I had because they can cause the rear to slide around during hard cornering. I was told to run rubber or steel shim. I've read up on all of the mods and I haven't heard of anyone complaining of a harsh ride. I haven't spoken with anyone using solid control arm/leaf spring bushings though. Many have said they can't tell the difference with solid body mounts and Delrin in the control arms though.

So to answer your question. No I haven't tried Delrin. But my car has Delrin already. I know my situation is completly different than the OP's. I just wanted to describe what I've got under the car and why.

 

As with anything you do when putting a car together, it depends on your intended use. And, talk to a handful of suspension guys, and you're sure to get tons of conflicting opinions.
I mean, some will even tell you that poly bushings are overkill for a (mostly) street car, and that rubber is the way to go.

 

I agree totally. Conflicting opinions, on the internet? No way.

 

I still don't understand all the negative towards poly bushings? They all have metal inserts, so it's not poly against a bolt that can create an issue, it's metal against metal, with poly in between. The part of the poly bushing that's in direct contact with metal is not meant to move anyway, so unless the metal seizes it wont be an issue. If the metal does seize you've got bigger problems than bushing material.

 

The way it was explained to me made sense. I couldn't for the life of me repeat it though.