Suspension upgrade, vented disc brakes, Porsche wheels +more

[raygreenwood]

Yes...very nice! I know the castor slots in the front subframe help alot. Also...did you happen to try the camber mod I listed for teh rear trailing arms? Ray

[Bill K.]

What strut inserts did you use? The excessive gap can very well be part of it. The harmonic rhythem of the strut damper might be slower or faster at arresting motion than the rubber bushing. They canstart an assymetrical movement between them where the bushing is moving ahead of or behind teh up and down movement of the strut cartridge and spring.

Also..if the strut cartridges used were stock....this is a symptom of worn or improperly valved rebound damping. If they are far too tight of valving far the car...a sharp up and down harmonic in one particular range of speed is simptomatic of arresting up or down motion too quikly....and the enertia transfers to flexible parts like teh bushing. Again...you are correct that decreasing that gap can alleviate a lot of that. Ray

The strut inserts are NOS Type 4 Koni adjustables (86P-1832 Special "D"), same as Wally used. I set them at full firm rebound setting - perhaps another mistake... When I take them apart to shorten the spacer, I'll back off the rebound to softer setting.

Ray - please consult your "black book" for the strut mount cap gap dimension.

[Bill K.]

Yes...very nice! I know the castor slots in the front subframe help alot. Also...did you happen to try the camber mod I listed for teh rear trailing arms? Ray

No, I plan on adding the rear camber adjustment as needed.

[raygreenwood]

I agree with that. I hate changing whats there unless necessary. For all but the most saggy type 4's...changing the rear trailing arm bushings takes care of most of the camber. The Delrin bushings will be sweet. Oh...by the way...did you use any special delrin? Not that I know if it would be better one way or the other. I just happened to use glass filled Delrin because I had it...with a turned down original steel bushing inside for the front end.

The notes I found in my black book show that the last brand new set of strut bushings with all new eeverything and delrin upper rings (where yours have rubber).....was a range of 5-7mm gap between the two parts...the outer edge of the upper "cone" and the rubbing ring below. I have a margin note that says that 10-12mm is what was described as the wear limit. Meaning....when teh gap increases to that level, the bushing donut underneath bewteen the bearing cone and the attachment plate should be inpsected for being "wallowed" out or torn.

Now...bear in mind that this is with a stock spacer tube in the center of the bearing of 13mm length....and it has a washer on top of that (in some diagrams) of about 1.5-2.0mm. I have gotten best results without a washer between upper cone and spacer tube.

Keep in mind that all of this information was "gleaned" from two or three sources....none of which was a 411/412 manual. Sveral models of the super used the exact bushing ring (as you know) which has a 412 part# prefix. Also several of certain years of golf and fox used essentially the same upper cone and wear ring. The information came from a variety of sources.

The gap you have now...allows the rubber bushuing and bearing to aquire space between them on the rebound. The solution...as you already know is to shorten the spacer. The gap between the upper cone and delrin or rubber bearing ring below is simply a travel limit to allow a range of compression and flex to the rubber donut below. Without some flex...you will damage the ball bearing. With too much...you get float between bushing and bearing or between bushing and plate. Ray

[Bill K.]

The Delrin bushings will be sweet. Oh...by the way...did you use any special delrin? Not that I know if it would be better one way or the other. I just happened to use glass filled Delrin because I had it...with a turned down original steel bushing inside for the front end.

Yes, glass-filled delrin. Ref. topic here

The notes I found in my black book show that the last brand new set of strut bushings with all new eeverything and delrin upper rings (where yours have rubber).....was a range of 5-7mm gap between the two parts...the outer edge of the upper "cone" and the rubbing ring below. .

Thanks Ray. Since you say "between the two parts" I take this to be from the BOTTOM surface of the "cone" (aka cap) to the TOP surface of the rubber ring at the outer edge of the cap. Mine are at 6-7mm, but that still looks wrong... I thought I recall tearing down a 74 412 with gaps of 1-2mm, but no notes or pictures to verify. Perhaps I'll soften the dampening of the Koni's before shortening the spacers. Plus, taking it apart and putting it back together is FUN.

The source of another rub was found and hopefully resolved. The rear quarter panel has a tab that appears to protect the fender screw from road debris. It was rubbing the tire on acceleration, hard cornering, and big bumps.



Good old grinder to rescue, both sides...


A double rear sway bar is in the plans also.

[raygreenwood]

Thats just the spec I had found and was in my notes. I think mine actually came out to be...and this is going off memory here....about 3-4mm...or right about 1/8". At one time I had it very close like 1-2mm witha thinner bushing...but that leads to hammering that top ring if you go over rough streets with lots of rebound and can lead to a rough bumping feel at times as the cone slams to ring too hard. In fact when I had it down at 1-2mm with stock struts I split the delrin rings in just a few thousand miles. There has to be enough room to move but but so much that the rubber donut comes unseated and starts getting hammered. The double rear swaybar is one of the sweetest mods you can make. It keeps the body so much more level and actually allows the front suspension to work so much better because there is not so much roll to start with. Ray

[Wally]

Extremely nicely done Bill! Mucho respect for your clean work and all the upgrades!

[Bill K.]

Thanks Walter!

I'm interested in what your "cap-to-bearing gap" is... Between lower suface of cap flange and upper surface of bearing rubber rim, mine is 6-7mm. It seems to be too large...



My other question to you was about the strut insert settings, but upon review of your topic, I found you have it set at 1/4-1/2 turn from full soft. Mine is at full hard , but that's my problem... When I step on the front bumper and release, the rebound is much slower than the compression and I think this is what is causing the bobbing of the front end at lower speeds - it doesn't recoil fast enough for the second bump and it bob's up.

Today was a big rain and I'm very happy with the grip. I can floor it and the wheels don't spin. I can crank a turn and the wheels don't slide. I can slam the brakes and the wheels don't glide. Priceless

[Wally]

Thanks Walter!

I'm interested in what your "cap-to-bearing gap" is... Between lower suface of cap flange and upper surface of bearing rubber rim, mine is 6-7mm. It seems to be too large...

I can't actually 'see' the picture, nor do I get what your asking..?

[raygreenwood]

Bill in your picture the top cone is slanted....your small gap is 6-7mm....the other side is maybe 10+. That slant is normal with all new parts. The funny part is that all literature I have seen does not say anything about the angle...even though it will be there until the bushing below compresses to shape. But the meassurement of 5-7mm that I had written down...should be the largest maximum measrurement. And...indeed that will make the low side right about the 1-2mm you were originally thinking of. It will flatten out a little as it wears in. Ray

[ubercrap]

Did you use BMW E30 318i springs?

[Wally]

Ah, now I can see the picture!
Don't worry about it, I had about the same space between those parts in my (former) 412. Superbeetles usually have too. My 1303 has it on one side a bit more than the other side. Probably to do with how new the rubber is?

[raygreenwood]

You should worry about it....but the only time to worry is when the gap is excessive enough to cause unseating of the dount bushing below on rebound. Not only will that beat out the donut in only a few thosuand miles...it will destroy the bearing also. It will usually ONLY be excessive gap when the sleeve bushing length under that top part is too long. The stock spec for 412 and "some" superbeetles is a 13mm bushing.
I say "some" superbeetles because where that fails is because so many other companies are making bearing cartridges for these things that sometimes the original stock sleeve length of 13mm is either too long or short. Too short is hard on the bearing and makes turning difficult and loosens the nut frequently. To long...and the cone sits up too high and on rebound it has a long travel to the stop/bearing ring....that rubber ring below the cone.....and can cause a "floating" action in the front strust when on rippled pavement.

Like I noted....I have a specification of about 5-7mm....but in experience its a little suspect...because I have never found the same exact dimensions on any particular brand or make of strut bearing or donut. You get variations. I think as you do that 5-7mm is a bit excessive....but I know for a fact that its servicable on most bushing sets. 10-12mm...I have found for a fact...to be excessive and damaging in the long run.

As Wally says...don't worry about it too much.....but I would make sure the spacer sleeve is at least standard spec and see what you get. Ray

[Bill K.]

Did you use BMW E30 318i springs?

Yes, the coil is 12.2 mm diameter - from a '85 2-door.

[Bill K.]

Bill in your picture the top cone is slanted....your small gap is 6-7mm....the other side is maybe 10+.

I noticed that too. The slant is about 1mm - 6mm on one side, 7mm on the other.