Hi all,

I've swapped my '68 notch from swing axle to IRS using the original "fork" and welding IRS brackets to it. I would like to know how much preload is needed for the torsion bars on the spring plates. (I am using wagon torsion bars in a sedan so thicker and stiffer than stock). Can I measure it easily? The front is lowered (ball joint) by about 40mm.
Also, is there a way to ensure that the inner / outer spline relationships are exactly the same on both sides? Obviously this is important for an equal spring rate on the left and right.
Any web links on reassembly etc or advice is greatly appreciated!
Cheers,
Toby :thumb

The difference between inner and outer splines give the minimum rotation adjustment amount. All you need is a good protractor from a combination set (eg. More and Wright). Set the sills level by jacking and packing and use the settings in the manual for your guide. Try rotating the spring plates upwards around 3-4 degrees for starters and see what it looks like. Both sides must be within the tolerance given in manual.

DH

Cheers DH,
I don't have a manual and therefore I don't know how much tension to preload the torsion bars with before bolting the spring plates up. The preload will affect the ride height won't it??
I have equal measurements now on both sides from the end of the spring plate to where the bump stops would meet their "cups" (measured with a ruler).

I was hoping that someone that has lowered a type 3 might have measurements or something that takes the hit and miss out of this awkward job.

Cheers,
Toby :thumb

Hi

Even setting the angles up with a protractor there is still a varaition because of the age sag in your torsion bars, so to get it exactly right you you may need to do it a few times over. There should be factory settings for the thicker bars in a workshop manual.

Steve

You really should invest in a good workshop manual.... The best are the factory ones, Gregories are ok.... Get the book and do it right.... But like Steve said.... Its trial and error unfortunately.... No way around it...

I never thought that the bars could lose their "spring" after time.
I know that a manual would help, but I've never had one - only the idiot's book and a bit of common sense. I won't have one before this job is done, so anyone that has some info etc about this job please don't hold out on me ;-)
The rear suspension is going to be reinstalled shortly, and so I'll just get them even and bolt it all up and see what happens.
It must also depend upon wheel and tyre size etc I'd imagine.

Oh, and also when I had it together before the left rear wheel was sticking out more than the right one - that is the left tyre protruded past the guard by a good 15mm, but the right one was fine. I think that the tyres are the same dimensions etc. What's up with this?
Cheers!
Toby

That's pretty helpful, thanks!
The wheels are from a beetle and are only temporary. They are Globe bathurst 14 x 6 I think.
The guards are stock and the body has been restored etc and I have had the car most of it's life with no accidents so I'm thinking that all is well there. It might just be the wheel and tyre combo hopefully!!!! There's a retread on one of them but the tyre sizes both read the same.

Anyhow, this job is proving to be a real b@#tard! What is the secret in reinstalling rear torsion bars, trailing arms etc and then getting the whole lot bolted up? Nothing wants to line up and I am an my wit's end! I don't remember it being that hard last time!
Cheers!
Toby

PS I just checked the rims - 6JJ x 14

PPS Does anyone know the correct reassembly sequence for the rear suspension?

[ Edited on 21-5-2006 by type3lover ]

These scans should help you get it back together....

As for setting the height.... your on your own....

Are the tyres the same brand? Even if they have the same sizes on the sidewall it doesn't mean that are exactly the same.... I have had many tyres in the past from different manufactures that were marked the same but were actually very different in width and hieght! Retreads will aslo make a difference.... Chuck'em out... Get a air of tyres thatare identical in every way.... the set you car up....

Don't forget the torsion bars are pre-stressed and have an arrow for the direction of rotation.

The angle of the spring plate unloaded is 22 deg +/- 50 minutes standard on the TL (Fastback) double joint setup. Haven't got the settings for the notch and square for double joint. The S/B swing axle have two payloads, the two settings are 21 deg 30 minutes and 18 deg 30 minutes for the lighter loaded one. Both +/- 50 minutes. You can work out with trig the close amount of rotation for lowering if you like. By the way. There isn't any "pre-load" on the bars. They are set with them rotating free.

DH

Thats good info Dallas.... I think thats in the factory manual I have here..... I should underline that....

I can't remember what manual I have now, maybe Gregory's or Scientific. Actually the old swing axle is easier with less things to do but both are the same with the setting sequence. If he wants to drive through the bush from Dural I'll lend him the book or copy the pages plus protractor! I'm only about 3/4 hour from him.

DH

Guys, you are legends!
The scans have given me the confidence to get back out there and have another crack at it. The first go I set it way too low (some would probably argue that there is no such thing!). I understand the protractor method now but I don't fancy a trip through the bush but I really appreciate the offer 1500S. If I simply cannot get it right I'll get in touch with you.
Anyhow I have done the left side and will have a look at the right when I can.
What sucks is that I still haven't replaced my broken ratchet and it takes forever to do all the unbolting and bolting up again without one!!

When I talked about "preload" before I meant the degree of rotation that the spring plate has to be jacked up so it clears the spring plate stop and can all be bolted up tight.

I'll post pics one of these days!
Thanks again for now and I'll let you know how it progresses,
Toby :thumb

Pleasure.... Now I just have to find the time to get my Notch on the road!

Humpty, I have the time...just need the $$$!!!

1st pic of front...too low because it scrapes on full lock

2nd pic of front

I need to rethink the whole job when I fit different wheels and tyres to the car don't I? Bugger...

Those rims have shocking offsets..... they are typical 70's style things... Very hard to get a car low with those things at the best of times, but with fat 70's style tyre too... just not gonna happen.... If you want to stick with those rims, go smaller in tyre size.... like a 195/50 or 55..... You could go with a more modern rim (FWD offset) or even some narrower rims wth a zero or negative offset, you'll be much better off and you can go loads lower..... Of course the lower you go the more likely you are to bind up the ball-joints.... A small price to pay for cool looks!... .... I like my cars very low!.... My Square runs 17x7.5's on the front with 205/45's without any problems.... but Im going lower with the Notch and Ill be running these same rims..... So to get it lower, Im fitting a TI LP beam with adjusters and drop spindles..... not for everyone sure, but if you want pan dragn low, you have to do it.... and if you want big rubber and low, you really have to do it!

Yeah these rims are just something I threw on so I could roll the car around (and burn around the block when the urge grabs me!) They are from my ex-gf's '76 convertible beetle and they looked great on tht car, but not on mine. I don't know what rims / tyres i am going to run yet but the ones on your square sound pretty cool. Got a pic?

I think I'll sell mine with the new centrecaps with Wolfsberg crest or swap with someone. I'll start another thread about rims...someone on here must have a set to part with!

Cheers for all the help!
Toby :thumb

[ Edited on 27-5-2006 by type3lover ]

I have some 16x7.5 with virtually new tyres on them.... But the PCD is 100! (stock TI/III is 130PCD).... Its the same as GOLF, BMW and most 4 bolt JAP stuff.... Thats what I have on the Square too..... Its a bit of work to do, but well worth it.... Plus I have big brakes on the car too!.... 300mm Supra rotor with RX7 4 piston calipers on the front and Magna discs and calipers on the back.... Can you say it stops!!!!

type3lover do you have any progress pix of the irs conversion? did you have to cut holes in the frame horns to weld the brackets in?

Unfortunately I didn't take progress pics of the job. I had the brackets welded in by Hellbug and I don't think there was a need to cut holes but I can't be sure. Sorry.
Cheers, Toby :thumb

All the conversions I have done-I have used the genuine brackets cut from donors-and you have to cut the horns to let in the bracket.I bought 2 sets of custom replacement brackets some years ago to try,and both sets were only good enough to go into a rubbish bin.

where are Hellbug now?

and does cutting into the horns and then welding weaken and stress them?

Jeffs up the central coast I think.... Somewhere up there.... Dumone knows for sure...Seek him out...As for the diagonal arm pivot point.... I have never converted a swinger TIII (Though I will be soon) rear subframe, but I have done a Bug (I have just put an IRS rear subframe in, in the past, but I want more transaxle mount strength back there with this car!)..... But the anwser to your question bus914, is no... If the mounting and welding is done correctly there are now strength issues... It will be the same as OEM IRS points on a IRS Bug....

Sadly, Hellbug closed a few years ago. That makes me realise what a long time it's been since my project had the IRS done. Nbturbo is right - the original brackets from a later model donor are the way to go.

There's another problem now with mine...one of the end caps has fallen out of the end of the torsion tube that becomes the spring plates. What's the safest way to get it back into place without risking damage from heat (welding). Surely it doesn't just tap back in?
Cheers, T

If you mean the welch plug looking thing that keeps the crud from the end of the torsion bar-tap it back in all the way and just peen the end of the tube to keep it in.Clean the recess out fully though B4 you start.Last one one of mine that fell out became lost-so I just used a brass welch plug-lightly skimmed the outer diameter on the grinder until it was a tight fit-tapped it all the way home around the edge,and then hit it in the gutz to lock it in-will never come out again.

Sweet! Thanks mate what a relief! I would go and do it now except that it's bloody freezing in Syd at the moment!!! BRRRR!!!!!!

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