PontiacBonnevilleClub.com

Has anyone else noticed that the solid subframe bushings from a Fiero fits our subframe/cradle perfectly?
I've been going through some trial and error and finally nailed what I can replace my subframe bushings with. This will apply to all 86-99 h-bodies.
Stock replacement wasnt an option because:
1-stock rubber
2-expensive
3-rubber

Its been tried and tested with S-10 mounts, but buying 1 set only comes with 4 of the 6 required mounts, thus making you have to buy 2 sets = expensive, unless you can find cheap used ones. As well the fitment wasnt as tight as OEM. Here is someone who used the S-10: http://www.bonnevillepro.com/forums/vie ... 36&t=14937 Lee, I'd PM you because I just found this thread, but lesabret.com seems to be down again.

I stumbled across some Fiero pictures for what ever reason and noticed the subframe holes looked similar to ours. Sure enough they make poly and solid aluminum.

So I tried a set of poly from a 84-87 fiero, but they ended up being to large for our metal washers and didnt seat properly/making the assembly too tall for the bolt to engage full. Throughout that process I found out that the fiero cradle bolts were the exact same length, so sourcing out some metal upper and lower washers from a Fiero would make it possible but also a nuisance to have to find 6 sets of the washers.

So I knew the solid aluminum ones would work, being that they dont require the use of the washers...
Contacted the owner of a Fiero store and had some shipped to me.
I might have confused the hell out of most of you, but heres the results, solid aluminum fiero mounts work! heres the pictures for proof:
Stock, S-10 poly, Fiero Poly, Fiero aluminum

S-10 fitment:

Fiero poly fitment:

Fiero aluminum:


The whole lot:


All locations fit except for this one driver side front...pass front fit perfect which makes me wonder if this would vary from car to car:

Ground down the edge, took all of 5 minutes:

Perfect:


Just thought I'd share my findings and wondered if anyone else put this together?
I can now get my cradle and suspension bolted up!

Nice find on the fiero mounts. I was the one who told Justin (Nighthwk) about the s-10 mounts.

I would be more interested in the Fiero poly than the soilds but it soulds like I would be sourcing all the fiero associated parts.

This sounds good and I'm in need of replacing my sub frame bushings.

But I'm wondering wouldn't the aluminum transfer the road vibration into the cabin (just too harsh)?

On the other hand you're giving the car a more solid mount for power transfer and hold front end alignment better.

Make sure you can grease em some how. That aluminum would get pretty squeeky IMO. Hell polys cam get all squeeky too.

95naSTA wrote:I would be more interested in the Fiero poly than the soilds but it soulds like I would be sourcing all the fiery associated parts.

agreed but finding 3 fieros to strip the washers from is unlikely here, and buying new washers is probably 20 a piece(same as an h-body i'd imagine), and you'd need 6, making for another 120 bucks for poly application to work.

Bing wrote:But I'm wondering wouldn't the aluminum transfer the road vibration into the cabin (just too harsh)?

You are absolutely correct on the harshness assumption. This is probably not recommended for a daily driver. Unfortunately it's going to be 6 months until an actual road test...

01bonneSC wrote:Make sure you can grease em some how. That aluminum would get pretty squeeky IMO. Hell polys cam get all squeeky too.

I planned on using die-electric grease on them to start being that I bought some because I thought I was going with poly S-10 mounts. Don't know if thats ideal for aluminum, but I'll be doing some research on whats best. There are some M6 holes on the sides of the collars, which I am going to see if I can find some grease fittings to fit, which would help on the maintenance side.

Hmmm the Fiero connection makes me wonder.... IIRC the 84-87 Fiero was basically a T1000 (Chevette) front suspension up front, and the rear cradle was tweaked from the front end of the X-Bodied Pontiac Phoenix (AKA Citation).. I wonder if the descendants of the X-Body (mainly the A Bodies 6000 etc) has compatible bushings or related parts

Looks good, but this is definitely not the solution for a daily driver. You'd go insane.

So let me get this right, if I want to make the poly Fiero bushing work with my 99 Bonne sub frame I need the upper and lower metal washers from the Fiero bushings?

If this is the case I've got a junkyard run to do. The yard I frequent has 6 or 8 Fieros just waiting to get picked.

Bing wrote:So let me get this right, if I want to make the poly Fiero bushing work with my 99 Bonne sub frame I need the upper and lower metal washers from the Fiero bushings?

If this is the case I've got a junkyard run to do. The yard I frequent has 6 or 8 Fieros just waiting to get picked.

I think these are for his 88 lesabre.....

It's the same subframe, at least mounting wise, 86-99.

YAY!!! Poly bushings for the LeSabre!!!

00+ prease?

I've never seen a 00+ subframe, nor do I know if they retained the same mounting style/configuration.

As for the poly fiero mounts, the only issue I see with them, is that they do not have a metal collar like the S10s and oem mounts. Don't know if this is an issue at all, and whether or not the sub frame would end up cutting through the mount. They'll work, but don't know for how long.

I wonder if the collar could be transferred or if its bonded to the bushing?

The OEM collars are bonded to the bushing:

and the OD of the OEM and Fiero Poly is the exact same:


Youd have to burn the OEM collar free and then carefully grind down the Fiero poly mount to fit the collar... wayy too much work for what I'm interested in.

Just for some peace of mind for those that dont care about the collar and want confirmation that you need the Fiero hardware, heres a shot of how our upper and lower hardware works with the Fieros poly:

Fiero on the left and S-10 on the right. Keep in mind that the subframe has to get wedged in there too.
Heres a Fiero subframe with the hardware, you can see how the upper washer/spacer wraps over the bushing, unlike ours pictured above:


Also keep in mind that if you buy the Fiero polys it comes with both front and rear bushings. We only need the rears. So when talking to a vendor, see if they'll sell you a set of 6 for the rear. Otherwise you'll end up with a bunch of bushings you cant use else where.

Thanks for the extra pics and explaining everything out for me, and others as well.

No problem, I just hope it makes sense. I sometimes have troubles keeping things linear when it comes to multiple configurations like this.

If you want any more pictures of anything let me know.

I'll be posting all my extra bushing in the for sale section shortly.

If thats some of the poly feiro bushings let me know and I'll shoot you a PM for them. I'll be the crazy one and make them look and work like the Bonne ones.

So were the feiro bushings a better fit than the s-10s? As you know (thanks again) I have the s-10s but based on your pics the fieros might fit a little better.

BTW have you been able to get on lesabret.com?

PM sent.

Lee, the polys are definitely a better fit, but the cons are the lack of metal collar and retrieving Fiero hardware. I've managed to locate new lower washers at $11/ea but cannot located the upper one, thus requiring a JY run or buying from GM.

I think the S-10s will be fine so long as you shim the gap like the Nighthwk did in the link. It'd be nice to hear from SteveX what his S-10s are like. Judging from his building quality, he probably didnt put anything to fill in the gap. Then again he seems to have fallen off the face of the planet.