Bushings for Type4

[Bill K.]

First, sorry I don't have drawings of how to do this. Instead you'll have to endure "a thousand words".

No, the front and rear bushings are different in flange (large diameter section) widths because the bushing carriers on the arms are different widths. The front carriers are wider than the rears. Also note that the outboard rear carrier is wider than the inboard rear carrier.

Fortunately, the front and rear pivot mounts are the same width. This makes the front/rear crush sleeves (a.k.a "metal bushing inside") the same length. Use the stock T4 front crush sleeves to determine the length. I used.750" x .375" 4130 steel tubing to make the front/rear crush sleeves.

The crush sleeves are bolted to the pivot mounts and shall not rotate. The bushings rotate on the outer diameter of the crush sleeves. The bushings shall not rotate in the bushing carriers, so the outer diameter of the bushing body is sized for a press fit to the inside diameter of the bushing carrier.

I removed the carrier inserts (thin shells inside the carrier that the stock bushings are pressed into), but would reconsider if I did it again. The carrier inserts create a uniform inside diameter in the carrier and may result in more uniform bushing outer diameter. With the carrier inserts removed, I found that each bushing outer diameter needed to be sized to create the proper press-fit.

The inside diameter of the bushings are sized for a transition fit (snug not sliding) to the crush sleeve outer diameter. This ensures the bushings pivot snug on the crush sleeve.

The width of the bushing flanges are sized according to the carrier widths (front, outboard rear, inboard rear) and the crush sleeve length ensuring the crush sleeve length is .005"-.010" LONGER than the corresponding width of the bushings inserted in the carrier. This ensures the bushings pivot snug on the crush sleeve with minimal clearance to the pivot mounts.

The overall width of the bushings are sized to leave a gap in the middle for grease application via the zerk fittings in the carriers.

I hesitate to pass on specific dimension for the bushing as this was a "make fit" project the first time through, but with the info provided and measurement of your control/trailing arms you should be able to make bushings using a lathe.

The stock bushings can be removed by lighting them on FIRE and pounding them out! After that, there's no going back!

For front camber adjustment, the front control arm pivot mount is slotted like the rear pivot mount and tabs added to keep the bolt aligned using the eccentric washers on the bolt. Sorry I don't have a picture of the slot. Spare rear trailing arm bolts with eccentric washers are used for the front.

front subframe detail.jpg

[VW 612 RS]

Thank you Ray and Bill!
Good explanations.
Then we have to go for Delrin

[raygreenwood]

Thanks Bill! You had measurements I could not provide. I did mine so long ago that when I had the bushings made by a local machine shop in Dallas I took them one of the old fronts I pressed out and they made the bushing from a sketch in two halves.

I do remember that because I did not know exact flange width at the time (i was driving it like mad every day)....I had each half of the busging left long by about 1/2" ...My first set were made of regular delrin.

Regular delrin works fine....but has less total crush strength (roughly impact resistance/density). If you don not have good or updated radius arm bushings....i would recomend using glass filled. The radius arm bushings flex with hard cornering. It eventually cracked one of the flanges from side load. More the fault of bas radius arm bushings than low strength in regular delrin.

My first ones did not have a gap in between. t made it harder to sand and fit that way....and I simply dinged one edge with a file in front of where the grease hole was drilled. On teh first set I had no grease insert. I just had a grease hole to pump with a needle.....it worked OK. Grease fitting and gap is better.

Bill found when removing the entire bushing with outer shell....the same thing I did. You will find that the bores are notround but slightly oval. Probably done this way (pure specualtion)....to make sure that there is some "load" against the pressed in bushing assembly. But either way....each bushing had to be hand sanded for a press fit.

When I gave the bushing to teh machine shop I asked for them .020" over and had to do considerable sanding two sides 180* apart to get good fit. Ray

[bradey bunch]

Any updates on this?

[Hulken]

Any updates on this?

Some....

[bradey bunch]

Looks promising!

[Hulken]

It does, but they need to be tested before mr. Strand is going to offer them for sale. At the moment noen of our cars are rolling...

[raygreenwood]

Nice! Just to be sure....you should make them slightly oversized. For Reasons unknown, every set of control arms I have pressed the bushings from have been slightly egg shaped. It is not a problem but what it entails is that almost every set of Delrin bushings will need to be hand sanded on the top and bottom for a tight fit so i would make then oversized. Ray

[dubsonjim]

im rolling! ill take a set to try

[andersonj]

Hi,

I would also without a doubt take a set for the front and rear, once you are ready to take orders.

Great work to everyone that commented, that's how its done.

[Lars S]

Im intrested in theese bushing sets, anybody making them?

/Lars S

[raygreenwood]

Im intrested in theese bushing sets, anybody making them?

/Lars S

I made my bushings and I am doing a write up on control arm refurb right now.

After looking over the wear I had on the original two part bushing set I made years ago.... to the subframe eye sockets for the radius arms......I no longer will use the two part split bushing. It seemed to handle well .....but it moves/flexes about the center too much and pounds the centering ring in between the radius arm donuts.....because the flexing allowed the radius arm to have lateral movement. in its eye socket. This is equal parts the fault of the split bushing, the radius are centering ring material and tolerance and the poor guidance/cushioning of the radius arm donuts.

But the root cause is really movement of the bushings. If I dont like how the ones I have made work....they should be fine I have seen others like then. It transfers available movement/flexing from the bushing center between the two flanged cups.,..the the outer end of the center steel bushing where the control arm flanges/yoke can exert some control of the movement.

I made my new ones of solid delrin with detached flanges at each end. In this way I can adjust each flange thickness for a tighter fit.

I also modified the radius arm donuts to generate less spring force on control arm compression and added friction reduction washers.

The delrin bushings were made with cored delrin tube that I bought that way. I then reamed the ID to a .001" interference fit and pressed in the steel bushing.

Mounted the whole part on a mandrel in the drill press and clearanced the OD with files and sandpaper forcan exact press fit into the arm.

It took about 1.5 hours per bushing and cost me about $40 for the pair.



Ray

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This is what the finished bushing looked like before pressing it in

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Here it is pressed in

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These are the side flanges. They are right at 2.25" so they have a LOT of lateral bolstering and load spreading, They fit very tight. More on the what and why when I publish my document next week.

AS a bit more on mods...and I have a whole document for this as well....here are some pics of my subframe Castor adjustment mods. The very first one I had done for me years ago....and no longer have that vehicle and should have taken the subframe....but it used a machined insert tube with an oval hole/slot and was welded in by a buddy of mine at both ends. It looked virtually identical to Bill K's.

This one looks a little rougher and used a different method ...but came out very nice, clean and strong. It looks very nice now that its epoxy coated. It will allow right up to 5 degrees positive castor if needed.

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This is the subframe attachment pad. i mounted it in a clamp and used a 3/4" bi-metal hole saw to cut through the metal, a segment of vertical bushing wall and the mounting pad. I wanted to preserve as much of the machined welded factory mounting pad as possible.

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View from the other side.

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Then I welded in a section of metal tubing to make a new bushing wall. Then welded on a flat horseshoe shaped strengthening plate on the bottom side...this is before the welds are cleaned up.

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This is the other side on the mounting pad after cleaning up the weld

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Here is the part while I am stripping paint to epoxy coat.

I will have full details of the subframe and delrin bushings and new radius arm bushings in a later document.

Ray

[Lars S]

Looks great Ray!
Not to advanced either, but to me finding the correct Delrin type over here and also tooling might be a bit of a problem.
Guess I can make the final adjustment of the outer dia and side flanges to fit the control arm on my 412 so Im still intrested in buying a pre made set if possible?

Having said that Im still looking forward to your coming document on this!

Lars S

[raygreenwood]

Actually....virtually any delrin alloy will work well because of the density of the material and our methods of installation. If you are using a solid bushing like mine.....regular delrin works great. Hard nylon will work well also ....like nylon 12.

Typically unless you are using a really heavy car.....like say amodern water cooled audi A4 ....and are using these for front control arm bushings which will by nature need to be a two part bushing....only then would I worry about using glass filldd delrin.

I will provide some alloy part #s ASAP.

I have been doing some leverage testing with the detached delrin flanges in my pictures over the weekend. Since my one piece bushing transfers any leverage side load to the flanges.....which is, great for the one piece bushing longevity.....but I dont like the denting potential I see on the flanges.

I will post pics in the am.....but I will go to either one piece bronze disc flanges....or simply go back to what I used on the original bushing which was a steel 2-3 piece thrust washer assembly....which worked very well and I 0ut many thousands or miles on. In this case....the flanges be thaley steel or bronze will be about 3" in diameter to have very wide load spreading capacity.
I will post pics soon.

I could make you a set of solid bushings like mine with steel flanges. I would leave them about .010" oversized so you could sand them to fit exactly. Ray

[Lars S]

Thanks Ray!

I am in no hurry with this, so I can wait for all info and tests until I start on it.
Im sure it has been written before but cant find it....do you reuse the inner steel crusher and how do you machine the inner of the bushing to fit the crusher.


Lars S