Dubstep Shep

I'm looking for a replacement bushing for the rear lower shock mount on a 2007 Z06.

I bought a used PFADT polyurethane bushing kit and it didn't come with a replacement for that particular bushing.

Does anywhere sell those individually? I emailed PFADT (AFE Control) about it to see if they would sell me just those bushings but I wanted to see if I had other options.

froggy47

Is it damaged?

Some well respected racers on the forum suggest leaving that one rubber so you don't end up with too little compliance on the rear corners. That's why some poly kits do not come with that one.

Dubstep Shep

In short, I removed the OEM ones without realizing that the kit I bought doesn't have the poly ones in it.

I'm a little confused as to why the rubber would help anything there. It's just going to hinder the coilovers from doing their job.

This is for a race car, not a street car. I get the whole NVH argument for street cars.

froggy47

Got it, I am not really sure, just was passing on the info, maybe does not apply to a race car . Wish I had more to offer.

Matt_27

Never seen that one in poly. You could machine some Delrin for it. The rubber does seem to be high durometer so it doesn't hurt much to leave it.

ZZebes

http://afepower.com/shop/details_new...L&&brandID=142

That's the spherical replacement for it... Best solution but certainly not the cheapest

phipp85

I had to replace the spherical bearings in mine about a year ago. I have the old Pfadt lower shock mounts. I could not find a direct replacement so I machined some housings to accept a more readily available bearing. Only downside is having to use a 1/2 bolt for the lower shock instead of the factory sized 5/8 bolt.
I'm not sure if the poly kits ever included a lower shock bushing. I though they kept the oem rubber bushing.

el es tu

Yes the Pfadt kits come with the lower shock mounts; the part number is 3333. BTW their poly bushings are made by energy suspension.
Energy makes a rear only kit with the bushings but youll have to provide your own sleeves.

I recently replaced my pfadt poly rear shock mounts to the pfadt spherical - the difference in operation was huge - after a few years the poly binds like crazy and creates massive sideloads; now I can smoothly move the shock around by hand

Dubstep Shep

Well I appreciate the input nonetheless!

I've considered it. Delrin isn't expensive and I know the dimensions I need. The machine time would be the difficult part as I don't own a lathe.

I talked to Mark with aFe Control and he informed me that when I do go full solid bearing, that kit comes with the shock mounts and there's no option to buy the kit less the shock mounts. So if I go spherical shock mounts now, I'll have an extra set later. That's less than ideal. I'd rather get by for now and do all the sphericals later.

The PFADT poly kits come with a lower shock bushing.

Awesome! I already emailed energy suspension about it, but I may call them today. Fortunately I already have the sleeves.

Honestly I only need these bushings to last a year or two before I go full spherical.

Dubstep Shep

aFe came through on a set of extra bushings, so I'm all set!

sperkins

I could make that for you if you give me the dimensions. Wouldn't take long at all.

Dubstep Shep

Here you go. This is inferred from what I measured on the control arm.

This is without a metal insert for the center of the bushing, which it would need. The only dimension that would change would be the ID of the bushing though.

el es tu

you might want to put some taper in that design; with spherical bearings you can see the shock turn on the lower mounts. With poly and rubber you have some flex, however with delrin you could run into bind issues

Dubstep Shep

I'm not sure why it would matter? The shock itself can spin freely. No reason for the mount to spin as well.

el es tu

The rearmost facing side of the shock fork has a tendency to turn toward the inside of the car which indicates that the rear geometry could be negatively influenced by a solid mount that only moves in one axis.

froggy47

My shocks turn all the time unless I tighten up the (pin top) nut into the bushings so it stops the spin. I can tell because the schrader valve moves. Inverted shocks/JRI.

There is definitely some twisting torque going on. If this is what you guys are discussing?

Dubstep Shep

What you're saying is that when the control arm moves up, it doesn't move in a straight up and down arc, but rather at an angle.

From what I can gather, it sounds more like a bending force than a twisting force...

But by the shock spinning at the bushing because of a ball joint, it doesn't transfer a bending moment like a cylinder could.


This is a tough conversation to have via internet haha. I feel like some diagrams would work wonders.

froggy47

Yes, not a pure twisting force (of course) but an observable force that turns the shock under it's operation.

el es tu

yep

Im running hardbar/banski delrin spherical upper mounts which probably exacerbate it but Id still suggest anyone developing a lower mount to take this into consideration

froggy47

How do you "tell" that the fork turns inward? It's in a fixed attachment?