Diff bush void fillers

RS2000 · Postby **RS2000** » Tue Apr 24, 2018 12:58 pm

Anyone tried the SuperPro diff bushing void fillers SPF2875K ?
They look easy to fit, just by lowering the diff a little, & should add stiffness to the factory rubber bushes.

ManiacLachy · Postby **ManiacLachy** » Tue Apr 24, 2018 1:36 pm

Why not just go to full poly bushes for the diff?

hks_kansei · Postby **hks_kansei** » Tue Apr 24, 2018 1:40 pm

Not used them, but looks to be a good idea to add a little more support without the vibration etc of full poly bushes.

And for $50 it's also half the price of full Polys, or having a brace welded up.

Magpie · Postby **Magpie** » Tue Apr 24, 2018 2:43 pm

ManiacLachy wrote:Why not just go to full poly bushes for the diff?

Delrin?

ManiacLachy · Postby **ManiacLachy** » Tue Apr 24, 2018 2:50 pm

I'd argue delrin might be a bridge too far for street. Honestly I noticed no difference to NVH when I went to poly.

EDIT: I admit my car isn't exactly low on NVH to begin with. It's not a race car, but it's not a Rolls either.

RS2000 · Postby **RS2000** » Tue Apr 24, 2018 3:31 pm

ManiacLachy wrote:Why not just go to full poly bushes for the diff?

I assume for full bush relpacement, that the diff has to come out. These void fillers require just undoing the nuts & lowering the diff just enough to allow the small top filler to slip in.

hks_kansei · Postby **hks_kansei** » Tue Apr 24, 2018 3:39 pm

RS2000 wrote:
ManiacLachy wrote:Why not just go to full poly bushes for the diff?

I assume for full bush relpacement, that the diff has to come out. These void fillers require just undoing the nuts & lowering the diff just enough to allow the small top filler to slip in.

Correct, re removing old bushes.

You'll need to take the diff out, and also pull the shafts out, then either press the old bushes out, or cut/burn them out.
Then press in the new ones (probably not too bad since it looks like the Superpro bushes are two piece)

Personally, i'd happily give these fillers a shot, $50 and maybe an hour of labour max.
Seems like a cheap way to lengthen the life of older diff bushes that may not be as firm as they used to, or to give a little more support for minimal outlay and effort.

noobee · Postby **noobee** » Tue Apr 24, 2018 4:45 pm

when I had the diff out while changing to a torsen at the start of this year I cut 4 donuts out of flat poly sheet I had and fitted them top and bottom.made a visible difference in movement while jacking the car,not sure if I noticed a difference driving it though because I changed a couple of things while I had it jacked up high.
Mick

and1 · Postby **and1** » Wed Apr 25, 2018 1:17 pm

RS2000 wrote:Anyone tried the SuperPro diff bushing void fillers SPF2875K ?
They look easy to fit, just by lowering the diff a little, & should add stiffness to the factory rubber bushes.

I have them on my SE. Super easy to fit. Seems to locate the diff a little more. I think NVH increases a little but I'm not sure because I have poly engine mounts as well..

RS2000 · Postby **RS2000** » Sun May 27, 2018 9:38 am

I fitted these bush void fillers, & thanks for all replies.

I had to remove all under body bracing & exhaust to allow the diff to drop enough.The only difficulty was getting the diff cradle to realign with the studs, when still attached to the ppf/transmission. Lying on the floor, using a pry bar, a mirror, & operating a jack at the same time by yourself is not easy!!

I'd been having problems with wrong gear selection on the track, but no problems yesterday at SMP North (also have fitted Mazdaspeed engine mounts).
I am hoping that axle tramp on hillclimb starts is also cured.
Cheers.