Spring plate bangs on lower stop

[johndl58]

So as I drive my 70 standard class 11 wannabe more and more now that its sort of road worthy, Im finding some things that need to be addressed. One is an annoying "bang" that occurs when rear suspension extends after a decent size bump. Im assuming its the spring plate hitting the stop. Right now the rear is indexed for a few inches of lift. Im running 225 75 15s. At rest the spring plate is on the stop. Is this correct? How do I eliminate the "bang"?

[PhillipM]

Lower the car back down.

You've got far too much preload and no droop as a consequence. Try running stiffer bars with less preload, but if you're running on the stops at ride height you're going to have an issue anyway.

[johndl58]

Just a disclaimer- I did not do the re index job on the rear. It was like that when I got it and never changed it. So basically I need to reindex the rear lower. How much? I'll see if I can post a pic of how it sits at rest. How far off the bottom stop should the spring plate be? It has dual plates by the way.

[johndl58]

[Bashr52]

You may need to notch the spring plates.

[PhillipM]

[johndl58]

Its pretty high for what it is(stock). I could bring it down a little. I'll post a pic of the car.

[endobear]

I like to be 1/4" off the stops at ride height.
Once there ill jack it up to rest on the stops and add limit straps. Then cut off the stock stops.
Same idea with the bump stops.
No more clanking and banging through the whoops.

[johndl58]

I am definitely going to drop it a little bit. I would really not like to do it several times though. the problem is that I don't know how much preload there is on it right now. so I don't know how many splines to lower it.I was thinking I was going to start with one on the inner since I think that will give me about an inch to an inch and a half. I'll do one side and see how it sits and if its enough then I will do the other. If it's not enough then I will take it apart again and do another spline. its going to be a real PiA.

[johndl58]

after looking at the chart I obviously can't just do the inter spline and only get an inch to an inch and a half. I'll have to sit and do the calculations beforehand. I'm thinking if I lower it approximately 2 inches or so it might get me to where I need to be. that's assuming the spring plate is just resting on the stop right now. if for some reason there is more preload than that then I will have to adjust accordingly I guess.

[johndl58]

Do I need to unbolt the trailing arm from the frame get the clearance I need to adjust the spring plates? I worked on it a bit yesterday and it seems that I do. What a pia if that's the case.

[dustymojave]

It's only 4 bolts and that is the easy part of the job. It can get dangerous after that. Be sure to read up on re-indexing the rear torsion. When the spring plate slips off the stop, it can maim you. Beware!

Do a search in this forum.
_________________
Richard
Offroading VW based cars since 1965
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SoCalBajas Member
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[johndl58]

I totally understand the power involved here. My Jack isn't even powerful enough to compress the spring to unseat it. What I'm asking, and I did a quick search and only found one mention, is do I need to take out that big Allen bolt on the frame along with the 4 bolts on the spring plate to be able to move the trailing arm out of the way? Or is there another trick in dealing with dual spring plates that I missed somewhere?

[Sandjunky]

No, you don't have to remove the trailing arm from the torsion housing. You will have to unbolt the trailing arm from the spring plate. You can tie the trailing arm up and out of the way while you are indexing the spring plate.

[johndl58]

That's what I was hoping to hear. I only messed with it for short bit the other day and was trying to push it down to clear. I will tie it up on my next session. Thanks for the advice.

[johndl58]

Got a chance to mess with it today. Passenger side went very smoothly. Moved it one spline on the inner. Plate is not resting on the bottom stop anymore. Moved on to the drivers side figuring I'd bang it out and give her a test drive. WRONG! Started out very harmlessly. All bolts came out no problem. Got plate past stop no problem. Adjusted one notch no problem. Go to put cover back on torsion bar..PROBLEM. No matter what I do I can not get the holes to line up to get bolts back in. Jacked up, down. Tension, no tension. Hammer, screwdriver, c clamp, etc.I get the rear bottom bolt in and that's it. Ran out of light and broke my new phone in the process as well. Any tips, advice? I couldnt even use a longer bolt since the holes don't even line up. Very frustrated.

[B Ramsey]

I use ratchet straps wrapped around the part of the spring plate that holds the torsion bar. Pull the spring plate in the right direction to get the bolts in. Longer bolts will help too.

[72Pstroke]

The easiest way I have found to get the cover plate bolts back in it to put 3 of the bolts in with the trailing arm hanging down below the stop.
With those 3 started, raise the arm in just enough to get the last (lower rear) bolt started.
After they are all started, raise the tailing arm up and get it on the stop. Then you can tighten all 4 bolts down.
Tim

[johndl58]

72pstroke- so engage the spline where you want it, then place cover and start bolts, then jack plate up to stop height. I will try this tomorrow when I get home from work. Still shaking my head how easy the other side was.

[johndl58]

72pstroke was on the money. worked like a charm. only prob now is that it doesnt sit level. I only went one spline on the inner on both sides but the driver side is definitely lower than the passenger side. now I have to do the math to figure out the make up on inner and outer to raise the drivers side about 1". what a pia. I guess I didnt notice the difference when it was super jacked or it wasnt evident when it was riding on the stops. Shouldve used the protractor rather than trust I was starting with both sides equal.