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-   -   Learn how to Flip IRS trailing arms for an ultra low stance (http://volksrods.com/forum/showthread.php?t=10217)

FONZY March 7th, 2006 11:25 AM

I wanted to lower the rear of my IRS beetle beyond the normal '2 notches' but one problem encountered with this is 'Ze Germans' engineered in a few degrees of camber in the rear suspension, so when you drastically lower it, the rear wheels lean in at the top very much like a swingaxle suspension. What this is basically boiled down to is a slight built in angle in the leading pivot for each trailing arm. To counteract this effect, I'm using a neat trick which entails swapping and flipping the trailing arms from side to side. At normal ride height the top of the rear wheels will then spread away from each other, but when lowered, will pull in to a vertical position. This is actually a pretty simple modification that could easilly be done in a weekend, with the body on or off.

First things first, a bit of teardown and clean up. Stripped the trans, axles, brake lines and whatnot.

http://i26.photobucket.com/albums/c1...ear/rear21.jpg

Now off with the trailing arms... the inner pivot uses the same size allen head as the transmission filler plug.

http://i26.photobucket.com/albums/c1...ear/rear18.jpg

http://i26.photobucket.com/albums/c1...ear/rear19.jpg

...then the spring plate arms... after removing the spring retainer plate, you will want to be extremely wary of the spring plate... it is under a load and will release as soon as you bump it off it's stops. I used a couple love taps with a small sledge to persuade them out...

http://i26.photobucket.com/albums/c1...ear/rear17.jpg

http://i26.photobucket.com/albums/c1...ear/rear16.jpg

Since were swapping the trailing arms side to side, the lower shock mounts and bump stops will need to be cut off and reattached upside down and swapped from one trailing arm to the other, from stock...

http://i26.photobucket.com/albums/c1...ear/rear13.jpg

http://i26.photobucket.com/albums/c1...ear/rear12.jpg

You can even weld them back on the same place you removed them from...

http://i26.photobucket.com/albums/c1...ear/rear11.jpg

Now with the bump stops, I opted to scavenge some off of an early swingaxle since I can shorten them up more than the stock IRS bracket, gaining a precious bit of extra travel in the lowered suspension before bottoming out.


http://i26.photobucket.com/albums/c1...rear/rear7.jpg

A bit of trimming and careful alignment (it doesn't sit 'square' to the trailing arm) and I cut off all but an inch of the rubber stops, again for a bit more travel... still effective and cheap:)

http://i26.photobucket.com/albums/c1...rear/rear5.jpg

http://i26.photobucket.com/albums/c1...rear/rear4.jpg

In addition to the trailing arms, you have to swap the spring plates from side to side so the holes will line up again. Also made a notch in the top edge of the spring plates so they don't bottom out as early... Note that you don't want to go nuts removing material here since it will drastically weaken the spring plate. Also, make sure you cut the correct spring plate on the correct side...

http://i26.photobucket.com/albums/c1...ear/rear15.jpg

http://i26.photobucket.com/albums/c1...ear/rear10.jpg

http://i26.photobucket.com/albums/c1...rear/rear9.jpg

Also had to notch out a small corner of the trailing arm bracket where it attaches to the spring plate to clear the 'stops'...

http://i26.photobucket.com/albums/c1...rear/rear6.jpg

http://i26.photobucket.com/albums/c1...rear/rear3.jpg

One more spot you can do a bit of clearancing is right above the lower shock tower mount. I shaved off and rewelded the factory flange where it will hit the underside of the stop.


http://i26.photobucket.com/albums/c1...rear/rear8.jpg

Now time for some assembly... I went ahead and rebuilt the brakes / E-brake assemblies, new bearings, seals, bushings... For you guys who take the brakes apart and don't remember how it goes back together...

here ya go

http://i26.photobucket.com/albums/c1...ear/rear14.jpg

a bit of sanding, primer and gloss black rustoleum...

http://i26.photobucket.com/albums/c1...rear/rear2.jpg

http://i26.photobucket.com/albums/c1...rear/rear1.jpg

Now on to reassembly...

Put on the rubber donut bushings (inner and outer) then fully seat the outer end of the torsion spring back into the spring retainer cup...

http://i26.photobucket.com/albums/c1...ear/rear29.jpg

Then slide this assembly into the rear torsion tube. You will want to 'place' the inner teeth onto the correct notches at this point, dependent on how low you are going...

http://i26.photobucket.com/albums/c1...ear/rear28.jpg

If you replaced the rubber donuts like me, you'll find they won't just pop back into place...

http://i26.photobucket.com/albums/c1...ear/rear27.jpg

I used a couple of threaded clamps to pull everything together, and a couple screwdrivers to hold everything into alignment, then get the bolts started.

http://i26.photobucket.com/albums/c1...ear/rear26.jpg

Tighten it all up. The spring retainer plate should cinch down all the way flush... no gaps.

http://i26.photobucket.com/albums/c1...ear/rear25.jpg

...and a shot of my 'drop' settings. I left about 1/2" under the spring plate... now this doesn't look like much but after the tranny, motor, body and all the trimmings are back in the car, it will sink a good 3 inches.

http://i26.photobucket.com/albums/c1...ear/rear24.jpg

Once you have the spring plates where you want them. slap the trailing arms back on and yer done!

http://i26.photobucket.com/albums/c1...ear/rear23.jpg

http://i26.photobucket.com/albums/c1...ear/rear22.jpg

Notice there is PLENTY of room for lowering this down to the ground, and it will have a dead vertical or very very close to vertical rear wheel.

...and reference shot of stock...

http://i26.photobucket.com/albums/c1...ear/rear21.jpg

Hope this shed some light on how to lower the rear end and retain a nice vertical wheel.

And just like the man said... be sure to read, understand and follow the instructions and safety rules for your tools! and don't forget the most important safety item of all, safety glasses.

good luck!

Tbone16 March 7th, 2006 02:06 PM

Awsome article man, REALY in depth. Good shit man, very apreciative.

38Chevy454 March 7th, 2006 02:19 PM

Once again, great tech and photos of how to do the process.

Driveway Jewelry March 7th, 2006 03:22 PM

Fonzy, I know you live somewhere near me. We met at ennis last fall. I have a BJ beam at the house wanna narrow it a few inches for me?

FONZY March 7th, 2006 07:13 PM

Sent you a PM GD... we can prolly hookup at ennis.

Hebster52 March 7th, 2006 10:21 PM

How much lowering do you expect this trailingarm flip will give you?
I have concidered to do it too. Would be nice to know how low you need to go to get the Chamber correct.

Awesome How-to pictures! [img]style_emoticons/<#EMO_DIR#>/bowdown.gif[/img]

FONZY March 8th, 2006 04:55 AM

<div class='quotetop'>QUOTE(Hebster52 @ Mar 8 2006, 01:21 AM) Quoted post</div><div class='quotemain'>
How much lowering do you expect this trailingarm flip will give you?
I have concidered to do it too. Would be nice to know how low you need to go to get the Chamber correct.

Awesome How-to pictures! [img]style_emoticons/<#EMO_DIR#>/bowdown.gif[/img]
[/b][/quote]

well, the flipped trailing arms doesn't really lower the car any more than you could do just by moving it like lormal... the flip keeps the rear wheels vertical...

Unfortunately I won't know until I get the motor tranny and body back on the frame to load it up... which will be a while :( But just as a guess as it sits right now it's going to need to be lowered al least one more inner notch to sit correctly.. or rather, to pull the wheels 'in' to vertical. I can look at the drums right now (unloaded) and they sit outward at the top at about 3.5 degrees.

so basically long story short, gonna have to wait till I get it put back together some more to really see exactly how much, but I know with all the mods I made to the bumpstops, springplates and whatnot, I can go ALOT lower and still have a good amount of suspension travel, AND vertical rear wheels.

HeidelbergJohn4.0 March 8th, 2006 06:55 PM

Good write up.

We inadvertently did that with a set or rear tariling arms we boxed for a Baja. Unfortunately, we wanted to go higher, not lower, so we did all that work and then let out the huge F bomb and had to flip them back.

FONZY March 8th, 2006 11:42 PM

OK guys I fucked up a little on this...

ran into a problem.

when I load up the rear suspension, the spring plates hit the leading retainer bolt head on the inside edge...
the car basically bottoms out on these bolt heads instead of the rubber stops... the red arrow shows where...

http://i26.photobucket.com/albums/c1...earnewhole.jpg

what I am going to do is drill a new hole all the way through the spring plate and trailing arm bracket where the yellow 'X' is...

what I SHOULD have done is NOT swap the spring plates from side to side but rather drilled a new hole in the trailing arm bracket only (if I hadn't swapped em side to side. the spring plates would have retained the stock 'elongated' holes for this bolt for adjustment / alignment of the rear wheels... toe in and whatnot)

since I have already cut mine in the wrong place and I don't really give a shit about adjustability since I have the back end all aligned anyways, I can't really change it back now....

no worries just thaught I would give a heads up to anyone planning on doing this:)

later on when I have my motor tranny and body back on the frame I will re shoot some photos and then edit the main post above to reflect these discoveries, and show a nice slam shot of the rear WITH the full weight of the car ... and a bit of adjustment tech for setting up the back-end alignment...

Texasbuggys March 9th, 2006 09:14 AM

Hey Fonz, I am working on a similar setup. Cool write up. One thing you can do to see what you will start running into problems is to pull the torsion bars out and re-assemeble everything then run the arms through thier cycle to see where you start having that oh crap the top of the tire is heading out syndrome. Just a thought since you have it down this far it will give you a real idea of just how low or up for that sakes the arm will travel before the dreaded ti toe look occurs. Good pictures and write up. You guys going to Ennis?

Ian March 9th, 2006 10:48 AM

Back-end alignment adjustment tech would be schweettttt.

FONZY March 9th, 2006 11:41 AM

<div class='quotetop'>QUOTE(Texasbuggys @ Mar 9 2006, 12:14 PM) Quoted post</div><div class='quotemain'>
Hey Fonz, I am working on a similar setup. Cool write up. One thing you can do to see what you will start running into problems is to pull the torsion bars out and re-assemeble everything then run the arms through thier cycle to see where you start having that oh crap the top of the tire is heading out syndrome. Just a thought since you have it down this far it will give you a real idea of just how low or up for that sakes the arm will travel before the dreaded ti toe look occurs. Good pictures and write up. You guys going to Ennis?
[/b][/quote]

definitely going.. Ill have swap meet spot again... Im pretty sure dirtyfokker , kittywhiskey and ghiadesigns will be there too...


catch ya there!

kittywhiskey March 18th, 2006 11:18 AM

<div class='quotetop'>QUOTE(FONZY @ Mar 9 2006, 02:41 PM) Quoted post</div><div class='quotemain'>
<div class='quotetop'>QUOTE(Texasbuggys @ Mar 9 2006, 12:14 PM) Quoted post</div><div class='quotemain'>
Hey Fonz, I am working on a similar setup. Cool write up. One thing you can do to see what you will start running into problems is to pull the torsion bars out and re-assemeble everything then run the arms through thier cycle to see where you start having that oh crap the top of the tire is heading out syndrome. Just a thought since you have it down this far it will give you a real idea of just how low or up for that sakes the arm will travel before the dreaded ti toe look occurs. Good pictures and write up. You guys going to Ennis?
[/b][/quote]

definitely going.. Ill have swap meet spot again... Im pretty sure dirtyfokker , kittywhiskey and ghiadesigns will be there too...


catch ya there!
[/b][/quote]

I was planning to unload the brick off my trailer today so I can get loaded up by next weekend. Didn't plan on the damn rain though. Dirtyfokker may have his new ride by the show too!

swoodard23 March 18th, 2006 11:32 AM

Fonzy,
I ran into the same problem with the bolt but solved it by using a carriage bolt. I used an angle grinder to clear the metal so that it fit the hole correctly and put it in from the back side. It locks it in there so you can attach the nut on the outside. Works pretty good.
Scott

FONZY March 18th, 2006 01:55 PM

[img]style_emoticons/<#EMO_DIR#>/Idunno.gif[/img] yeah scott good idear.. I was pondering the same thing. It will solve the clearance issue nicely and avaoid having to drill another hole through that thick ass metal AND keeps me from losing the 'toe-in' adjustability, cuz I can't really reproduce the slotted hole like the factory makes to allow for adjustability.

only probem is I cannot seem to find a source for something grade 8 or better.. I think off the shelf carraige bolts from homer's are not quite strong enough... I'm pretty sure if I put a good load on it it will snap... but not sure. haven't gotten to that particular issue yet:)

thanks for the input though! It will probobly be the solution I use... or just get some new spring plates and redo it...

roofchop March 30th, 2006 08:42 AM

Just started this last night, and ran into a problem when I didn't have a hex key to remove the trailing arm. I couldn't find the size in my books, does anybody know what size it is? I will have to buy one this weekend.

roofchop

Griznant March 30th, 2006 08:51 AM

<div class='quotetop'>QUOTE(roofchop @ Mar 30 2006, 09:42 AM) Quoted post</div><div class='quotemain'>
Just started this last night, and ran into a problem when I didn't have a hex key to remove the trailing arm. I couldn't find the size in my books, does anybody know what size it is? I will have to buy one this weekend.

roofchop
[/b][/quote]


17mm. Sears carries them.

HotRodMatt March 30th, 2006 04:06 PM

Thanks for sharing this.

Only comment I would make is that when notching springplates, it is a good idea to radius the corners, retains a lot more strength. The abrubt corners give the metal a failure point if the experience an extreme load.

Flipper_1938 July 9th, 2006 05:07 PM

Re: Learn how to Flip IRS trailing arms for an ultra low stance
 
Any updates yet? ....like pictures of the assembled car?


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