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mbrobe Samba Member
Joined: July 06, 2005 Posts: 74 Location: Wisconsin
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Posted: Thu Aug 05, 2021 6:36 am Post subject: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Howdy People,
I am lowering the rear IRS on my 1972 bug. I have all the bolts removed and the trailing arm jacked up. I just need to break the sprig plate loose. Please see the pictures and is this something I should just give a good wack at it and try and get it off the housing?
I am following this video:
https://www.youtube.com/watch?v=0zkpQ-h57po&list=WL&index=10
Thanks in advance.
_________________ '72 Standard Bug |
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raydog Samba Member
Joined: February 09, 2006 Posts: 1157 Location: Cape Cod
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Posted: Thu Aug 05, 2021 6:43 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Pull the 4 bolt bushing cover back an inch or two, enough to get a prybar or large screwdriver behind the trailing arm at the splined bar. Try to work it out a little from there so you don't get it all jammed up. When it comes off the stop, it won't go too far. _________________ Come on, It's not rocket science. KISS |
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mbrobe Samba Member
Joined: July 06, 2005 Posts: 74 Location: Wisconsin
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Posted: Thu Aug 05, 2021 6:50 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Thank you that helps, I will give it a shot. _________________ '72 Standard Bug |
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air_cooled75 Samba Member
Joined: April 08, 2009 Posts: 376 Location: Lancaster, PA
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Posted: Thu Aug 05, 2021 7:13 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Been over a decade since Ive done it but I'm pretty sure you need to move the trailing arm down, not up. Then put a small floor or bottle jack under the spring arms to get them over the little lip thats holding them on the ledge. While its jacked up use a pry bar to get it out over the edge _________________ 1970 Bug
1975 Bug
1963 Ghia |
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air_cooled75 Samba Member
Joined: April 08, 2009 Posts: 376 Location: Lancaster, PA
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mbrobe Samba Member
Joined: July 06, 2005 Posts: 74 Location: Wisconsin
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Posted: Thu Aug 05, 2021 8:43 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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I got the cover off and that did make things much easier, thank you. After that was off hit the back with a rubber mallet a couple times and she came loose.
Now I need to figure out how to get the torsion bar out of the end cap, She a little stuck so a vice and some pulling will be in order.
_________________ '72 Standard Bug |
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W1K1 Samba Member
Joined: March 04, 2004 Posts: 4897 Location: Southern AB
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Posted: Thu Aug 05, 2021 11:49 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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they ususally come from the factory with a waxyoil type product on them to keep them from rusting, after a few decades, its more like a hard candle wax _________________ http://www.thesamba.com/vw/archives/manuals/jim_martin_engine_build.php
1973 super
1965 squareback 1500E
1971 bay window westy- subi swap |
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mbrobe Samba Member
Joined: July 06, 2005 Posts: 74 Location: Wisconsin
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Posted: Thu Aug 05, 2021 6:08 pm Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Thanks all for the help, I have it all back together. I sort of lost track of what splines moved to where with things being stuck, so I just eyeballed it and tried to measure it. I will have to wait for the body to get bolted on before I throw any wheels on and check it out.
Any guesses for ride height with the spring plate set in this picture?
_________________ '72 Standard Bug |
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slayer61 Samba Member
Joined: June 01, 2021 Posts: 999 Location: CA
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Posted: Fri Aug 06, 2021 7:40 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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I'm gonna guess a bunch lower. In the original pics, your spring plate was sitting on the perch. Now it's not even touching it. You have NO pre-load whatsoever.
Let us know how that turns out for you. |
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dirtkeeper Samba Member
Joined: February 19, 2008 Posts: 3200 Location: Left of everywhere
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Posted: Fri Aug 06, 2021 7:57 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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slayer61 wrote: |
I'm gonna guess a bunch lower. In the original pics, your spring plate was sitting on the perch. Now it's not even touching it. You have NO pre-load whatsoever.
Let us know how that turns out for you. |
Ya I am thinking when You get this back together it will sit up against the the top stop and the ride will be terrible. I would check the specs for standard preload and then adjust for slightly less, I guess if you want it to be lowered.
My guess is that even a ‘lowered car” with the minimum preload would have the spring plate sitting against the lower stop when the car has no body or drivetrain. |
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Chip Samba Member
Joined: July 19, 2008 Posts: 967 Location: Utah
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Posted: Fri Aug 06, 2021 8:14 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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dirtkeeper wrote: |
slayer61 wrote: |
I'm gonna guess a bunch lower. In the original pics, your spring plate was sitting on the perch. Now it's not even touching it. You have NO pre-load whatsoever.
Let us know how that turns out for you. |
Ya I am thinking when You get this back together it will sit up against the the top stop and the ride will be terrible. I would check the specs for standard preload and then adjust for slightly less, I guess if you want it to be lowered.
My guess is that even a ‘lowered car” with the minimum preload would have the spring plate sitting against the lower stop when the car has no body or drivetrain. |
Cars that are significantly lowered won't have preload. Heck cars that are lowered one outer spline won't have anywhere near the preload that a stock setup does. Preload is gone the second you start adjusting down and the only way to get it back is to cut and turn the torsion housing. Nobody does that. When we lower a car, we aknowledge that we'll be loosing the factory ride specs in order to get the car looking how we want them to look. Stock height rides don't "do it" for everyone, just like lowered ones.
That car is going to be dumped, but if it's too far, you know how to correct it now. Good luck with the build! |
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dunk Samba Member
Joined: April 02, 2006 Posts: 158
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Posted: Fri Aug 06, 2021 10:17 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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mbrobe wrote: |
Thanks all for the help, I have it all back together. I sort of lost track of what splines moved to where with things being stuck, so I just eyeballed it and tried to measure it. I will have to wait for the body to get bolted on before I throw any wheels on and check it out.
Any guesses for ride height with the spring plate set in this picture?
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I'll take me a stab at that
I've lowered more than "A few" aircooled vehicles in my time
With no body/engine weight on it...
That is 1.5 to 2 spline down....
Obviously depends on what look youre going for.... but.. She's low, she's not cal look... and you'll need to be careful with tyre choice especially with rims wider than say... 5.5 inches.... or weird offset wheels
now, is that inner or outer splines?! Or is it a mixture?!... very hard to say...
Did you free up BOTH ends and then just eyeball it back in?!
If so, its highly likely you're out of wack side to side... because theres a different amount of splines on the inner end to the outer end... more splines on the outer iirc...you wont be able to tell the difference between them, as they are currently, by eye..
You normally just lower it on the inners OR outers alone and use "mixing the two" if youre fixing a problem, very picky about ride height, or a glutton for punishment
you could check and/or correct this, by purchasing a cheap inclinometer or angle finder and rest it on the plate when there's no load on it... and see if they're the same side for side... very important there's no weight on it and its free to hang when this is done.. or use an angle finder app on your phone and rest the phone on the springplate! ...
Good luck sir! |
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mbrobe Samba Member
Joined: July 06, 2005 Posts: 74 Location: Wisconsin
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Posted: Fri Aug 06, 2021 10:21 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Yeah, this car will be far from a daily driver. It will be taken out for a cruise around town, run a quick errand and maybe an hour drive here and there. If it is bumpy as hell that is fine. As long as I am not bottomed out before even driving.
True, I will know how to raise it but easier before paint and with the body up.
Thank you all again for the help and comments. It helps me stay motivated _________________ '72 Standard Bug |
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mbrobe Samba Member
Joined: July 06, 2005 Posts: 74 Location: Wisconsin
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Posted: Fri Aug 06, 2021 10:25 am Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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dunk wrote: |
mbrobe wrote: |
Thanks all for the help, I have it all back together. I sort of lost track of what splines moved to where with things being stuck, so I just eyeballed it and tried to measure it. I will have to wait for the body to get bolted on before I throw any wheels on and check it out.
Any guesses for ride height with the spring plate set in this picture?
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I'll take me a stab at that
I've lowered more than "A few" aircooled vehicles in my time
With no body/engine weight on it...
That is 1.5 to 2 spline down....
Obviously depends on what look youre going for.... but.. She's low, she's not cal look... and you'll need to be careful with tyre choice especially with rims wider than say... 5.5 inches.... or weird offset wheels
now, is that inner or outer splines?! Or is it a mixture?!... very hard to say...
Did you free up BOTH ends and then just eyeball it back in?!
If so, its highly likely you're out of wack side to side... because theres a different amount of splines on the inner end to the outer end... more splines on the outer iirc...you wont be able to tell the difference between them, as they are currently, by eye..
You normally just lower it on the inners OR outers alone and use "mixing the two" if youre fixing a problem, very picky about ride height, or a glutton for punishment
you could check and/or correct this, by purchasing a cheap inclinometer or angle finder and rest it on the plate when there's no load on it... and see if they're the same side for side... very important there's no weight on it and its free to hang when this is done.. or use an angle finder app on your phone and rest the phone on the springplate! ...
Good luck sir! |
Super helpful, thank you!
I did have to eyeball due to torsion beams getting stuck and it coming all apart on me unexpected. Rookie mistake _________________ '72 Standard Bug |
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Busstom Samba Member
Joined: November 23, 2014 Posts: 3790 Location: San Jose, CA
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Posted: Fri Aug 06, 2021 1:47 pm Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Preload is irrelevant and inconsequential. The only time there is any "preload" on the rear torsion bars is when the car is in the air and the spring plates are resting on the perches. The moment you set the car on the ground - stock height or otherwise - the weight of the vehicle twists the torsion bars (compresses, if you wish) and the spring plates leave the perches and find a nominal point about the arc to call "home."
Therefore a lowered car has the same amount of suspension and "preload" as a stock height car does, because the only preload present is applied from the weight of the assembled vehicle itself.
I presume the reason the factory designed perches into the cast structure is so that when the vehicle is raised off the ground, the unloading of the torsion bars doesn't hyperextend the shock absorbers and axle tubes (exerting undue stress on the axle boots), and perhaps even the brake lines. |
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RickS Samba Member
Joined: May 05, 2005 Posts: 420 Location: Speonk, NY
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Posted: Fri Aug 06, 2021 3:31 pm Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Busstom wrote: |
Preload is irrelevant and inconsequential. The only time there is any "preload" on the rear torsion bars is when the car is in the air and the spring plates are resting on the perches. The moment you set the car on the ground - stock height or otherwise - the weight of the vehicle twists the torsion bars (compresses, if you wish) and the spring plates leave the perches and find a nominal point about the arc to call "home."
Therefore a lowered car has the same amount of suspension and "preload" as a stock height car does, because the only preload present is applied from the weight of the assembled vehicle itself.
I presume the reason the factory designed perches into the cast structure is so that when the vehicle is raised off the ground, the unloading of the torsion bars doesn't hyperextend the shock absorbers and axle tubes (exerting undue stress on the axle boots), and perhaps even the brake lines. |
I don’t agree with this. If you lower a car a significant amount, the spring plates are off the lower stop at rest. Therefore, you have less available suspension travel before you contact the rubber stops.
The reason for the lower stop is to stop the spring plate from going down too far and jacking up that side of the car. This would lead to a lot of positive camber, which is bad for handling. |
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johnnyvw164 Samba Member
Joined: July 27, 2020 Posts: 570 Location: South of Raleigh
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Posted: Fri Aug 06, 2021 3:49 pm Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Why not compare the angle of the spring plate to factory spec? Then you can get an idea of how far you've gone. |
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Busstom Samba Member
Joined: November 23, 2014 Posts: 3790 Location: San Jose, CA
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Posted: Fri Aug 06, 2021 4:27 pm Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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RickS wrote: |
If you lower a car a significant amount, the spring plates are off the lower stop at rest <snip> |
All of them are "off the lower stop" at rest, whether they are lowered or not, you recognize this, correct? If resting on the stop was the nominal position of the spring plates, you'd hear a massive "thunk" every time you traveled over road irregularities and came back to nominal. Thus, whether lowered or not, they all have the same "preload," which is merely the weight of the car itself. I believe what you're referring to is "available travel," but I wasn't really speaking to that. The only time the lower "hard stop" gives any benefit is if you jack the car up to work on it, or go over a jump and get airborne and fully unload the rear suspension. Other than that, the car is ALWAYS off the lower stops.
Edit: oh, to your point, I suppose if you're screaming around corners on two wheels, then yes, the inner wheels around the turn could tuck and reach the stops. But I suspect you'd be rolling over and seeing a new perspective out the windscreen by the time that occurred. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Fri Aug 06, 2021 4:49 pm Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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I put a Bus rear IRS in my 900 lb sand rail and even with torsions that stiff on a car that light the spring plates are 3/8" off the lower stops.
Don't do that by the way fellows, the ride is back breaking... literally! _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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RickS Samba Member
Joined: May 05, 2005 Posts: 420 Location: Speonk, NY
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Posted: Fri Aug 06, 2021 6:02 pm Post subject: Re: Lowering rear IRS 4"...trailing arm stuck on spring plate..help? |
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Busstom wrote: |
Therefore a lowered car has the same amount of suspension and "preload" as a stock height car does,
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Maybe I misconstrued this, but I read this as suspension travel?
Autocrossers used to weld up the lower stop to prevent jacking and tire tuck, and would contact it frequently. Not a great way to limit travel, but it worked. Limit straps are a better idea. |
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