Swaybar bushing

[hulken]

Has anyone swapped the inner (front) bushing of the swaybar for the front suspension?

No longer available fra VW of course, any other source?

[raygreenwood]

Yes. Long ago I swapped mine as they were shot.

At the time I used standard cylindrical urethane ones from Energy suspension components. The sway bar on the early models is 15mm and the later are the 16.5mm.

I had to buy a generic sway bar bushing and widen the inner hole and narrow the outside diameter slightly with a Dremel tool and a sanding drum. They worked well. They needed silicone grease not to squeek.

What I ordered and used were not actually sway bar bushings. They were 5/8" ID generic shock absorber eye bushings. I think it was part # 9.8116G from energy suspension components. In the long run you would be better off with Buna rubber instead of urethane.

If you start with that part # and google....you can find that Energy suspension components has many different parts numbers that are similar.

If memory serves.....you may have to find shock eye bushings that have a 9/16" ID and widen that slightly and a thick enough OD to be slimmed down a little if need be.

Many auto parts stores also sell generic replacement shock eye bushings in normal rubber.

I need to source new ones because after more than a decade...since urethane hardens up a few percent per year.....literally shattered when removed.

I may actually make a few. I do not know what options you have where you are.....but I can order rubber tube from McMaster Carr industrial supply. It is Buna N at 75 duro....sl8ghtly harder than stock.

It can be bought with 5/8" ID.....which is almost perfect....and 1" OD. If I cut it to length I can mount it on a mandrel in a drill press and sand the OD alightly to create the flanges and reduce the OD so it will fit the clamp.

A 6" length is about $6.50.
Ray

[hulken]

Could some of these be useful?

http://autobua.no/understell/powerflex/universale-foringer

[hulken]

Powerflex got one that measures 16mm inside diameter and 25,5mm outside diameter. Length is 50mm. Sounds like a good match?

https://www.powerflex.co.uk/road-series/products/Parallel+Bushes-2790/1.html

[raygreenwood]

Two problems with those:

1. If these are for the front end....they need to be round.....with no flat side so that first one will not work. They will however work on the rear sway bar if they are the correct size

2. That second bushing will not work because it needs to have side flanges or it will walk out of the clamp.

Even a powerflex slope sided shock eye bushing can be made to work with a small amount of sanding.

Google the Powerflex lower shock bushing for a Saab 900 and you will see what I mean.

Our front sway bar bushings are virtually identical to a shock eye bushing. Round, tubular and with a collar on each end.

The other problem I found with urethane is that the OD will have to be very close to perfect in size because the split clamp used on our cars is not rigid enough for the clamping bolt to compress urethane without bending the clamp. Ray

[hulken]

So the part inside the split clamp is 25mm, or the outside diameter on side flanges?

Is the side flanges ar 25mm, I was thinking of using the round "barrel" type bushing, and Dremel it down in senter so it should fit the split clamp.

This is the exact one I was thinking of, ID 16mm and OD 25,5mm;

http://www.ebay.co.uk/itm/PF99-110-Powerflex-SPECI...1985675321

[raygreenwood]

[raygreenwood]

OK...some pictures and measurements:

First the location. You will notice that they do not show the bushing in the bracket above it...and nowhere I can find in the parts book..even in the chassis welded parts section...do they show the top bracket.
Also one thing is clear from my car is that the top bushing ..at least on mine...was not split. It was solid but identical in dimensions to the lower bushing in the clamp that went around the sway bar. The upper bushing was installed with the inner tube bushing inserted through the eye bracket in the body and then swaged at each end permanently.

To replace the bushing, the new upper one will need to be split or I will remove the upper tube bushing and install a clevis pin with a cotter pin and washers so when I remove the sway bar..I simply pull the clevis and the bracket and bushing assembly stays on the bar itself.

part number list

The part and part number...this is for the earlier 15mm bar

The part with dimensions

The part in the split sway bar clamp...and right here you can already see the issue. This bar has been run with Urethane lower sway bar bushings for about 30K miles.

So when clamped together this is one possible fit on the top bushing...the tongue fits in the slot so the clamp cannot slip sideways......WHICH I HAVE HAD HAPPEN AND IT IS VERY DANGEROUS!

This is what is happening at the other end...barely engaged. In reality once both bushings are in this clamp...both ends are barely engaged.

This illustrates he issue. The clamp fit from the factory is not a perfect tongue and groove mesh fit...but these clamps have been stretched by using a urethane bushing in lower bushing position.

This further illustrates how wide apart the parts have been spread.

You need to make sure the OD of the part...if you use urethane....is just large enough as needed...and pay attention over time to see if the clamp is stretching and correct it.

This can be corrected by taking each half of the clamp...mounting between two boards...and squeezing it slightly in a vice to flatten the clamp slightly.

I will say that using urethane bushings definitely makes a slight improvement in handling. You can see how much torsional load is put on the bushings by the fact that it stretches the clamps.

The factory stock bushings are approximately 50-55 durometer. You can get Buna rubber hollow tube...in 75A durometer...which is very similar to basic urethane....but does not have some of the energy rebound issues.

In fact in modern cars like my Golf...when buying performance front suspension bushings like strut mounts on ECS tuning's site....75 Duro high pressure cast rubber mounts are the in between performance level between stock and urethane. Ray

[hulken]

To make it easier in the future I have decided to change the mounts. The inner mount will be a universal swaybar mount, the same as I will be using to doublestack the two rear swaybars. I will have to cut away original mount, and make a new mounting plate.

Outer mount is Porsche 944 frount outer swaybarmount

[raygreenwood]

Nicely done! I will keep wtching this! Please keep us in the loop.

One auggestion. I have used the same method for the front outer links that you did uskng parts from some water cooled VW/Audis
I took it off....because it was far too soft with standard 50-55 duro donut on each side of the control arm...AND a rubber bushing for the sway bar end to go into. It waw more of a flexibility and misaligment issue under load. Very squishie.

But the "type" of outer link is a good idea. The stock outer link "block" of the 411/412 was actually excellent as it was very rigidly linked to the control arm but had enough cushion in the rubber of the block.

My suggestion is to replace the top donut on the outer link....with urethane.. and leave the bottom black rubber. This will give less flexible misalignment....but still give flexibility Ray

[hulken]

Thank you for the input Ray, will order a sett of poly parts. When going rear double-Stack swaybar, should ai replace the rubbee there too?

[raygreenwood]

[hulken]

I have a set of Porsche 944 front swaybar links I will be using in the rear, like Bill K sugested over at another forum. They are thicker and more suited when double-stacking swaybars. But I guess I will stay with rubber bushes in the rear, due to your experience.

[raygreenwood]

[raygreenwood]

To be more clear.....I will post some pictures shortly of some outer links that will work but need some slight modification to work.....but point the direction to what is needed if you are to use the double sway bar safely.

Ray

[raygreenwood]

So...here is what I have been playing with years ago...and also...to a good extent Bill K is correct about the Porsche 944 link....but a couple of warnings.

By the way..thank you Hulken and Bill K for that information. At least at a glance without measurements the front outer links for a Porsche 944 are virtually identical to the rear of a 411/412.

So the 411/412 parts in question:

Part group # 12

Here is the problem I experienced with upgrading the original type 4 outer links:

Here is a crude sketch of what the outer link looks like looking sideways toward the wheel. The sway bar is pinkish. The blue rubber donuts....were 50-55 durometer Buna-N rubber from the factory.

I replaced them with 70 durometer urethane discs/donuts. This is a big problem on the stock outer links that we will get to soon.

This is what happens when you do cornering in the car and the trailing arm pivots. The linkage pivots on its bushings and creates compression which is normal and how it works. But....it creates very high pressure impingement points shown by the red X's.

Before I snapped one of these links...I had warnings that the urethane bushings were too much. While the handling was AWESOME....about every 2-3 months one of the thick dished steel washers on each side of the bushing donuts needed to be replaced because it was warped... ...should have been a warning bell.

BUT.....what people forget...and what I forgot as well.... is that these bushing donuts are being used as SPRINGS and vibration dampers all at one time.

As an elastic spring....urethanes have far, far, far...more compression loading and rebound than Buna, Neoprene or EPDM rubber. This is why they are used as industrial elastomer springs.

For example:
50-55 durometer Buna-N (factory...has between 1500 and 2500 psi compression. The 60 durometer urethane has 4100 psi ...and 70 durometer urethane has 5,000+ psi of compression and rebound.

So...when loaded at an angle and "pinched"....I think I calulated a while back that a 70 durometer, 13mm thick donut can generate something like 20-30,000 psi of resistance.

It bent the pin attached to the tube/collar of the link....and snapped the pin off!

Here is what we need:

The one on the left is from a Mk-2 golf and has a 12mm thread and 10mm pin.
The one in the middle is 411-412 and has an 8mm stud. Other than that they are quite well made.
The part on the right is from an Audi...I think. It is tough as nails and if it had attachments it would be superb. Just here because its in the collection.

The problem with the Golf Mk-2 part is that it is slightly shorter. Too short...until I find the right bushing thickness for it.

You need to have enough length on the linkage that with a nut, lock washer, flange washer and bushing on top of the trailing arm and a bushing and flange washer below the trailing arm...it must be long enough that the sway bar does not contact the trailing arm at any angle.

It "can" work...but the top bushing must be very thin....and to work very thin...it mus be very tough (urethane)....and it leaves little room for angle compression under the washer.

A little more detail.

The Porsche 944 front outer link...stolen from the Pelican parts site.

This looks very promising. It would be nice to know what the thread diameter is.

I would make the busing inside the eye....buna rubber...or it will squeak going over every bump unless you can find a poly-graphite bushing.

If the bushing in the eye is urethane would make the donut bushings Buna-N for some give.

If the bushing in the ye is Buna-N...i would make the top of the trailing arm donut of Buna-N and the lower donut of urethane...probably 60-Duro.

With the proper outer links...the double swaybar modification is one of the most important and high performance handling mods you can make for the 411/412.

With just factory level single swaybar...going through curves the rear of the car tries to do the steering. The double sway bar prevents this. Ray

[hulken]

I will order a pair of the Golf 2 links, might be the best Solution for the front swaybar. And the 944 could handle the rear doublestacking.

Type 4 on the left and the 944 on the right.

[raygreenwood]

Ah!.....thats nice to know. So the 944 part is 10mm. That should do a good deal better.

The stock one is fine.....but its just on the fringe of being strong enough. The 944 part should be strong enough. Ray