Front Sway Bar Bushings : How tight?

14894 Views 29 Replies 10 Participants Last post by Gordon Raymond, Mar 24, 2011

Lokki

Discussion Starter · Mar 19, 2011

I'm in the process of rebuilding the suspension on my 71 Alfa. I managed to burn out the old sway bar bushings (wow!) and now I'm ready to replace them with the new ones I purchased from IAP - yellow poly bushings.

However, I have a question: how tightly should the metal bushings fit on the sway bars? Should they be able to spin on the metal shaft?

The metal tubes in my poly bushings are impossibly tight on the shafts - they would have to be hammered on and would not spin at all. In fact; they'd have to be cut off like the old ones had to be.

I'd assumed that the old ones were so tight because they'd been on the shaft for 40 years (the bushing rubber was literally crumbling out).

Additionally, the yellow poly bushings are a little too big for the holes in the uhm, hangers. I'd assumed this to be normal since they should be a press fit, but I hadn't thought that the shaft and metal tubes would be tight at all.

Do I have the wrong bushing?
Should I drill out the tubes?
Other?

Auto part Fuel line

Thanks!

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msiert

· #2 · Mar 19, 2011 (Edited)

2

Can't comment on the front bushings but I replaced the stock rubber bushings on the rear sway bar with poly a year ago.......should be the same process though.

The poly bushing do have to be pressed on (just like the stock rubber bushings) I used a vise to get it started and finished off with a hammer to get them the last 1/4".

After getting the top and bottom links pressed together the links could be moved easily but did have a some resistance. That's the beauty of the poly bushing install.......you don't have to worry about pressing on the bushings at a specific angle. Well along with never having to replace them again.

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Farace

· #3 · Mar 19, 2011

I have no experience with poly, but when I replaced my front link bushings, they didn't need an extreme amount of force. Some tapping with a hammer, maybe, and after installation they were snug, but not bound. Try polishing the sway bar ends and see if that makes a difference; you might have some corrosion there standing a little proud of the surface that's binding things up.

60sRacer

· #4 · Mar 19, 2011

When new, the OEM bushings did not move at all - it took the compliance of the rubber for any motion. Fortunately there is very little rotation. The Poly's have almost no compliance, and so need some rotation. Sorry, Murray, that means the will physically wear out - just as you have experienced with other poly bushings.

They do take a lot of compliance out of the sway bar system, which means a lot more load on the very weak clamps that hold them to the body. I've had a few cracks and sheet-metal tears result. If you have any rust around the fittings, you should consider reinforcing the area. Personally I've not seen any benefit from using poly's over the OEM rubber bushings for the sway bar, either in the ends or in the body mounts.

Robert

Gordon Raymond

· #5 · Mar 19, 2011 (Edited)

I have to go with Robert on this. Old silentblocks were held in place on the OD where they were pressed in, and grabbed by the "fixture", what ever that was, with a through bolt. The rubber was designed to twist until it failed.
The Poly bushing will not twist without breaking, particularly when cold. I would go with a close slip fit to avoid wear on the inner bushing, and add a dab of Lubriplate white brake grease to be sure it does not seize on the shaft. You should have no rattles and a firm hold.
I once used Heim Joints on my '60 Spider Veloce race car, back in about '62 -64. VERY firm. ADJUSTABLE! Prone to seize up after a wet race! Noisy. FRIGHTENING! Don't do it.

msiert

· #6 · Mar 19, 2011 (Edited)

Forgot about the very important step of applying the white grease to the poly bushings before pressing things together.

Always a big debate on poly vs rubber bushings and the compliance issue always comes up along with limiting the range of motion that poly causes that's hard on the mounting points.

I like the poly bushings myself but it's hard to argue with the combined experience of both Robert and Gordon.

60sRacer

· #7 · Mar 19, 2011

Back in the late 60's and early 70's SCCA class racing, it was common for Alfas to replace every rubber bush with Heim or Unibal spherical bearings. Sway bars, links, trailing arms. Even the throttle shaft got them! Transmission mounts were replaced with solid aluminum.

This did make everything much more precise, but without an easy cure for the bump-steer that resulted from lowering the car and other geometry problems, the precision was lost in a dangerously jumpy car.

And as Gordon said it was incredibly noisy. The racing tires of those days were wide and sticky, but were bias ply with sidewalls way too stiff. You could feel your fillings rattling loose on a long race. Also, almost every joint on the car would start coming loose under the assault. Seam welding and reinforcement plates barely helped - something would break in a single season.

Compare that to a really modern Porche or BMW racer. Hugh suspension throw, really soft springs and bushings everywhere, but with precise geometry these cars just fly, yet have a ride like a highway cruiser.

Making all the rubber joints in an Alfa stiff with poly bushings brings back a lot of the old problems. Remember that street driving is on much rougher roads than are ever found on a race track. Keep all the compliance you can, work on the geometry issues that give you bump-steer problems, and you'll go faster!

Robert

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Gordon Raymond

· #8 · Mar 19, 2011

EXCELLENT! Just EXCELLENT Robert. Exactly as I remember it. Thanks!

Gubi

· #9 · Mar 20, 2011

While the benefits/drawbacks of poly in other locations might be debatable, I think poly is quite appropriate for sway bar bushing ends.

Also there's a big difference between heim joints or aluminum bushings and polyurethane. "Polyurethane" isn't one hardness: you can buy stuff that isn't much stiffer than regular rubber. If you've handled modern poly bushings it's pretty clear that they're a long way from being solid.

Anyway, getting back to the ORIGINAL QUESTION:

Lokki, when I put the poly bushings on my Milano, the metal sleeve was indeed a tight press fit onto the bar. I believe I tapped it on with a hammer. As stated, lube the outer surface of the poly bushing well (mine came with grease that basically just looked like white lithium grease).

No squeaks, no premature wear for me...just nice tight roll control. I think you'll be happy with them.

traga

· #10 · Mar 20, 2011

Murray,
I like the shot of your differential/rear suspension, beautiful. Stainless custom exhaust? One question though. Not being familiar with the late models was the mounting of the hand brake linkages on the differential changed from the earlier approach with the linkage up vs pointed down? It seems they maybe in harms way pointing down.
Regards, Al

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60sRacer

· #11 · Mar 20, 2011

Hey Murray,

Your parking brake is still upside down.

Robert

msiert

· #12 · Mar 20, 2011

traga said:
Murray,
I like the shot of your differential/rear suspension, beautiful. Stainless custom exhaust? One question though. Not being familiar with the late models was the mounting of the hand brake linkages on the differential changed from the earlier approach with the linkage up vs pointed down? It seems they maybe in harms way pointing down.
Regards, Al

60sRacer said:
Hey Murray,

Your parking brake is still upside down.

Robert

There was extensive testing done with the orientation of the parking brake mechanism during the project and it was found that with the arms down we obtained the highest HP and torque curves on the dyno........No one could explain it but after repeated runs it proved again and again that with the parking lever arms down we had the most power!

bianchi2

· #13 · Mar 20, 2011 (Edited by Moderator)

2

my parking brake parts are pointed up... yup, really can feel the hp/tq increase.. i guess it more areo that way.. nothin hangin in the wind,. much faster than a hyundia now

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Gordon Raymond

· #14 · Mar 20, 2011

With the assembly down, a high speed wind vortex is created that causes a complete disturbance of the normal air flow under the car. This assumes boundary layer airflow remains undisturbed. Thus, at specific chassis speeds, in dry air, the vortex is carried forward to the engine compartment, causing significant amplification of the under car vacuum. In turn the additional cool dry air pulled in under the hood to fill the void under the car has a dual effect. First, pressurizing the engine intake, and secondly filling this upper chassis void with relatively cool air, thus increasing mixture density. Combined with the pressurization effect, this guarantees Murray with a real world power increase over the brake assembly pointed up.
Hows that?

Gubi

· #15 · Mar 20, 2011

The power gain is offset by the fact that it's up on jackstands in every. single. picture.

**** black Spiders: garage queens, the lot of them!

Gordon Raymond

· #16 · Mar 20, 2011

3

MINE is RED. Not on stands, running in these photos.

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60sRacer

· #17 · Mar 20, 2011

Gordon - isn't this the description of a disturbance in the Force?

Murray - your parking brake may be in a Spatial Inversion Vortex.

Bianchi - I especially like the green vinyl coated fence wire extension on those Fiat springs...

Gordon II - Oooh! That's Alfa Porn. Really beautiful! I love my Duetto, but the Gulietta is so nice!!

Robert

ps - major thunderstorm with downbursts today; gusts to 50+mph; 2 inches of rain since dawn; ducks withdrawn to the mountain caves. Nothing better to do I guess........

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bianchi2

· #18 · Mar 20, 2011

back to the sway bar question. on the links press on fitting, no slop and the frame bushes , when goping down the road, suspension going up/down they should rotate, durring cornering, the resist..

60sRacer

· #19 · Mar 20, 2011

Gordon - is that a TS or a GTA head?

It looks like the fuel filter is out of circuit?

Robert

bianchi2

· #20 · Mar 20, 2011

60's. i have a covette handbrake/ parking brake on the car, do to the really COOL , SUPERLIGHT,alumiumn driveshaft , those are the return springs to relase the handbrake pressure... hey..it works...the alfa cable has a release spring, but it is in the cable itself, just a bit away from the adjustment fitting.. could not build a cable that way( a proffesional shop built it for me ).. o' yes.. not 'fiat' spring...ace hardware

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