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Time to Rebush all Front Suspension Rubber
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Pepperbilly
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PostPosted: Tue Feb 11, 2025 4:40 pm    Post subject: Time to Rebush all Front Suspension Rubber Reply with quote

Next project is to replace all the old original 127,000 mile front end rubber bushings on Goldie. I do have a shimmy/shake through the steering from 40 to 50 mph and is getting worse in the cold winter weather drives. It is also accompanied by a fair amount of squawky creaks over larger bumps at any speed. It is coming from the front suspension for sure. The rear end is nice and quiet.

In the interest of simplicity it would be nice to find all the bushings and donuts at the same time. But we all know it usually is not just “that” simple on these cars. Wish it could be one stop shopping somewhere and maybe it is today. I would rather that this project not take too awfully long. I really enjoy driving Goldie because she is in all other aspects such a sweet running ‘73 wagon.

Bill
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raygreenwood
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PostPosted: Tue Feb 11, 2025 6:09 pm    Post subject: Re: Time to Rebush all Front Suspension Rubber Reply with quote

I may not have enough time to complete this comment tonight.

First, lets look at what all rubber there is.....what is available/not available...and what has to be done to replace it.

As for available....about the only thing rubber that is available to actually buy without needing work or modification are the upper strut mounts, a newer design of sway bar outer links and inner sway bar bushings and the idler arm bushing.

First....the shimmy. What causes it? Any one of the parts I am about to list if its moderately bad can cause the shimmy alone. But in most cases there is no one part that is moderately to totally bad. Its a general level of wear across several parts that act together to cause the shimmy.

Rubber Parts starting at the top:

1. Strut bushing/bearing assembly. This creates its own harmonic if the strut units themselves are moderately worn. There is a little play inside of stock strut tubes. Its generally not an issue if everything else is good. But you get sloppy strut mounts/bearings and some rattle from other components downstream of the struts and it can cause that little bit ofspace to rattle.

Action: Go through the struts. Audi mod or there have been some Spatz, Bilstein or Koni offerings here and there.

2. The ball joints (bonus). If they are really sloppy they can cause some of this but its usually more of a handling issue going over bumps and less of a simple shimmy.
I have a HUGE how-to coming out soon with answers once and for all to get ball joints if they are unobtanium. I already have answers for new boots as well. I have literally been working on it for years.

3. The rubber bushings on the sway bar outer links. Typically these are so massive that even if they get a little crusty around the edges, the inner core is just fine. They will harden up a little but you can spray them with a graphite lube and squeeks will g oaway. I will post part # that is easy to find later.
The only issue is if the steel hoop/strap on these rubber outer links is rusted through or broken. If thats the case....instead of looking for exact replacements, there are many common rod and hoop style outer links that will bolt right up.

One that looks just like this (I have to check the bushing diameter but they are available in many sizes) will work fine and this is $12

Image may have been reduced in size. Click image to view fullscreen.


4. The sway bar to body bushings: These are a bit of a pain only because when you remove the bar, you discover that there is a captive rubber bushing that is permanently affixed to the body. Its easy to find one that fits...and I took a dremel to the swaged in tube its mounted on...tapped it out with a mallet....put new rubber on it and put a simple clevis pin back in the hole. Looks more nice and makes it instantly removeable for service.

Same thing with the rubber bushing that connects to the sway bar. I will have a part number you can by on line shrtly. I think I posted the measurements about 3 months ago somewhere in here.

5. Control arm bushings. Technically they rarely wear out, but they commonly get a little loose. The rubber becomes unbonded from the steel tube in the center and they slip fore and aft and make grinding noises as they grind against the subframe. This also causes wear to the radius arm donuts and centering rings.

Action: If you can push or drive the center bushing tube back to where it is centered in the bushing (about 50/50 on this), I have measurements for simple nylon rings made out of slices of nylon tubing that slip on each side of the center tube and keep the control arm bushing pinned, centered and make it wear free on the sub frame.

If in rare cases you can look at the center steel bushing and see that the rubber has sagged toward the top side of teh steel tube its cast into....you need new bushings.

The very easiest way to do this is press the center tube out of the rubber. If it will not come out, cut the outer tube wit ha hack saw, peel away the sheet metal tube...and get after therubber with a wire wheel or razor blade. It took me 10 minutes each to get them clean of rubber.

The object is to save those nice thick tube bushings. Then I can give you a cheap part # for a one foot long, thick wall tube of either delrin or polypropylene from McMaster Carr. Maybe $20.

I cut two pieces exactly the width of the yoke where tehcontro larm bushing goes. I did a little sanding with a drill on the inside of the tube and a little on the steel bushing tube.

I used my bench vise to press the steel bushing into the Delrin tube. Measure the bore in the control arm. I put a piece of all thread through the bushing, tightened down with a nut, chucked it into a drill and sanded the outside for a bout five mintes each and used the vise to press it into the control arms.

Center it, then install the same cheap nylon rings I describe above to keep it centered. They are better than stock, will last forever and I got away for maybe $35 for the pair.

6. The radius arm donuts. These rarely wear out. Lets look at yours first. They get a little crusty around the outside edges but they rarely wear out. If they do....I made new ones in like 10 minutes.

I will furnish a part number for 3/4" thick rubber sheet from McMaster Carr. You can buy a 6" x 6" square. You can use Neoprene, Buna-N or Viton... but I would keep to about 40-45 durometer hardness. Out of these rubber types, in order...Viton, Buna-N and Neoprene for oil resistance.

Viton is too damn expensive. Neoprene is thecheapest but you have to be careful of the grease you put on it. For about $10 more...the best choice is Buna-N.

I used cheap spray glue and glued my 6" x 6" square sheet onto a block of plywood (temporarily). I used a 2.5" hole saw from home depot and cut for plugs on that 6" x 6". Using the same pilot hole from the drill, I used a 3/4" hole saw to drill out the center. Lube it with water while you work.

Peel them off and clean off the glue and they are ready to use.

7. MOST IMPORTANT: the centering rings that go between these two rubber radius arm donuts. Thise being missing or shot are a big part of the shimmies.
On 99% of cars these are lost or worn away. I will furnish part nymbers for simple nylon flange bushings...many hardware stores, box stores or Mcmaster carr. About $8 for a bag of about four. Take a razor saw or hack saw and cut off the flange with about 1/4 extra left on it...sand it to length with the dremel while trying it for fit in the ears of the sub frame. When they fit you are done.

I have a how to for this as well. You can use nylon, delrin or polypropylene.

8. The center link is a big part of the shimmy issue. Either get and NOS one which will last about 30-40k miles.....or I have a how to for rebuild better than stock for about $25 in parts and two hours with basic hand tools.

9. The idler arm bushing. Huge part of the shimmies. The stock rubber one is flat out defective in design which is why the Super beetle eventually went to a solid bronze bushing. They are avalable new for the same price as the rubber one ...about $50. I will post links to that thread.

Ray
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Pepperbilly
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PostPosted: Thu Feb 13, 2025 4:29 pm    Post subject: Re: Time to Rebush all Front Suspension Rubber Reply with quote

AH HA! Discovered I never installed my steering damper when I put the front suspension back together. Dug out my stock BOGE and put it back on. Years ago I did replace it so this one has probably 40 to 50,000 miles wear. Did a hand bench test and responded good… no leaks either. I gotta say the only shaking was between 40 to 50 mph without it. Really pretty impressive.

Vastly improved now but not completely. Still just a tiny bit of shimmy at the same speed range. I am still going ahead on rebushing and possibly replacing the struts. The struts do pass the bounce/rebound test…they seem good… no leaking there either.

So this part in the photo, it needs to go back on the car, LOL!

Bill


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raygreenwood
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PostPosted: Fri Feb 14, 2025 8:39 am    Post subject: Re: Time to Rebush all Front Suspension Rubber Reply with quote

Laughing ...and THAT is the part I forgot

Yes...the steering damper masks quite a bit! Over the decades, I have pretty much come to the conclusion that the steering damper does less to mask oscillations and small shocks that your wheels/tires encounter...and more to mask the oscillations of the small gaps and tolerances within the parts of your suspension that start a harmonic in reaction to the jostling from the road and tires.

Other quick low hanging fruit that make big a difference with the shimmy...would be the idler arm bushing and the centerlink. Those two are the biggest causes outside of struts.

If your steering damper got rid of 80-90% of your shimmy....replacing the idler bushing and cneterlink will usually do the rest. Ray
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Pepperbilly
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PostPosted: Fri Feb 14, 2025 1:16 pm    Post subject: Re: Time to Rebush all Front Suspension Rubber Reply with quote

raygreenwood wrote:
Laughing ...and THAT is the part I forgot

Yes...the steering damper masks quite a bit! Over the decades, I have pretty much come to the conclusion that the steering damper does less to mask oscillations and small shocks that your wheels/tires encounter...and more to mask the oscillations of the small gaps and tolerances within the parts of your suspension that start a harmonic in reaction to the jostling from the road and tires.

Other quick low hanging fruit that make big a difference with the shimmy...would be the idler arm bushing and the centerlink. Those two are the biggest causes outside of struts.

If your steering damper got rid of 80-90% of your shimmy....replacing the idler bushing and cneterlink will usually do the rest. Ray



Yes, the tires are new and the best rims are up front and it’s all been dynamically balanced. I believe during these cold weather drives the rubber/bushings shrink a bit and also get harder. So the cold promotes these faults. I think you are right saying replacing the marginal rubber will eliminate any unwanted movements and take away the shimmies that remain.

As to the struts, RockAuto has the Bilstein B6’s. Their text indicates it is a direct fit for 412s and the stock springs up front. To me that would be the way to go…I really want to stay with the stock setup. Have you or anyone else had experience with these? By the way, I checked the ball joints for any unusual movement and they passed the test. They look good. They are the originals.

Bill
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Hawker
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PostPosted: Sat Feb 15, 2025 3:18 am    Post subject: Re: Time to Rebush all Front Suspension Rubber Reply with quote

Hello Bill,

The B6 insert by Bilstein would certainly be an easy replacement option, but what is its valving like???? That is the big question because our cars have a very light front end, unless loaded and I believe that the original valving on the VW front shock absorbers caused the front end to pump up higher.

If the valving is correct, then it saves a lot of work, but who is going to try them out?

BR,

Rob
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raygreenwood
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PostPosted: Sat Feb 15, 2025 9:05 am    Post subject: Re: Time to Rebush all Front Suspension Rubber Reply with quote

Hawker wrote:
Hello Bill,

The B6 insert by Bilstein would certainly be an easy replacement option, but what is its valving like???? That is the big question because our cars have a very light front end, unless loaded and I believe that the original valving on the VW front shock absorbers caused the front end to pump up higher.

If the valving is correct, then it saves a lot of work, but who is going to try them out?

BR,

Rob


I have been wondering this same question.

If you go by what the Bistein designations are for their series.....onemight "think" that the B6 series would be too much. One would think the B4 would be better.

But....thinking about this for just a second, the factory 411/412 valving....while it makes a great ride and seems to be spot on for comfort on the down stroke/compression stroke.....is actually barely adequate on the extension stroke....when the dampers are NEW.

Put 50k miles on them and they become inadequate on extension stroke ....and rough pavement can cause double bouncing to the front end which is horrible for everything.

Then let's think about how well the low pressure gas Audi strut cartridges work on 411/412. Yes, they are a moderate update in compression and about 2X in extension. They work great.

So, if I was doing the Audi mod and buying the Bilsteins....I would most certainly use the B4 series because the stock valves Audi struts are perfect as is. Going to Bilsteins is just changing the brand. We still want the stock Audi 4000 valving.

Back to the Bilsteins.....if Bilstein is really tracking with exact stock valving for 411/412.....and there is no reason to think they would NOT know the exact stock valving for 411/412 because chances are they made some of them back in the day and they are an excellent shock manufacturer ......then if we are staying with the definitions that Bilstein publishes for their shock series.....I would most certainly think we would want the B6....because if we had B4's....they would have exact, exact valving to the factory strut and would therefore have the same problem with the extension stroke valving.

Here is Bilsteins definitions:

https://help.fcpeuro.com/hc/en-us/articles/2494737...noQAvD_BwE

Ray
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Pepperbilly
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PostPosted: Sat Feb 15, 2025 10:39 pm    Post subject: Re: Time to Rebush all Front Suspension Rubber Reply with quote

Well, that’s where I’m at. Has anyone out there installed the B6s? Anyone?

Bill
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raygreenwood
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PostPosted: Sat Feb 15, 2025 10:53 pm    Post subject: Re: Time to Rebush all Front Suspension Rubber Reply with quote

Pepperbilly wrote:
Well, that’s where I’m at. Has anyone out there installed the B6s? Anyone?

Bill


In this thread, Jeremiah said he ran some. I would contact him!

https://www.thesamba.com/vw/forum/viewtopic.php?t=773988

Ray
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