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REAR SWAY BAR (The Rest of the World Edition)

6K views 19 replies 10 participants last post by  markmitch 
#1 ·
REAR SWAY BAR for ASTRO - SAFARI. (The Rest of the World Edition)

In the USA they sell Astro REAR SWAY BAR kits for around $260.
For UK owners that price increases to nearly $450 !!! ( = approx £335 British pounds).
Nice,, if you can afford it !!!

I have found another option if you have a few simple skills and some common sense available.
Total cost was less than $30.
It works beautifully on my Gen1 88 shorty with stock suspension, but I'm not saying it'll fit every Astro, it's up to you to discover if it'll suit your particular Astro !!
I have an LPG tank fitted behind the rear axle, so I needed a bar that fitted forward of the rear axle.
I've done a thousand+ miles, so far, on winding Welsh roads without any problems and corning is a breeze.

I'm not going to walk you thru' a long article of 'how to'.
If you need that, it's probably beyond your capabilities and you shouldn't do it.
The 'difficulty level' is about 3 out of 10. with some measuring, drilling, sawing, bending,
flattening and a few inches of welding. plus a bit of spanner work, etc.

Caution, once fitted, your vans handling characteristics + Understeer (tight) & oversteer (loose) can be affected. Drive safely and well within your own ability.

Parts needed are,, the suitable* sway bar with rubber mountings & housings along with two ball joint end links. (EbayUK JY £14.50 including shipping).

4x 70mm exhaust Ubolt clamps (cut as saddles).
2" angle iron, for link anchors, adjustable.
2" wide flat 1/8" steel, for axle strap clamps.
Some strong Nuts & Bolts for fixings.
(I added 2x small ex clamps to prevent the sway bar migration to either left or right).

Take a look at the photos,
see how the bar is positioned so there is clearance everywhere to allow the Sway bar to pivot without contacting,, axle tubes, diff cover, exhaust, dampers, leaf springs & chassis rails.
Note the angle of the clamps around the axle tubes.
See the end links are cut & welded short, so the leaf springs can flex upwards without any contact.

Check and adjust route of brake pipes and parking brake cable as necessary for clearance. Then go around checking everything again !!

Which Sway Bar is pictured ???
It is from a BMW E53 X5 4.4L '01 FRONT ANTI ROLL SWAY BAR (28mm or 1.10inch Dia).
(I believe many BMW E53 X5 were produced in Spartanburg, South Carolina)

Happy Cornering
 

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#3 ·
I've been scouring ebay looking at all kinds of sway bars to retrofit. That front is probably a little large for a rear bar, but I get why it's on there. Congrats!
 
#5 ·
Yes Ken2.7, I 'welded' a couple of angle iron brackets onto the frame.
I drilled three holes in each, just to give a method of adjustment,, just in case.
At first I bolted them thru', but they shifted in the holes resulting in knocking noises.
I'm no Welder, but hopefully I did it well enough .
The bar is a chunky lump, so does a very good job of flattening body roll on corners,especially quick left-right-left maneuvers negotiating 'roundabouts' (which we have lots of here in the UK)
The bar passes diagonally between the frame and leaf spring, deciding the clearances needed is important to prevent the bar from contacting either, during excessive moments of travel.
Thankfully, because this area is close to the ball jointed link, the bar doesn't travel very far.
 

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#11 ·
I need to bookmark this for future ref.

Is there any detriment to a Bar that is "Oversize for it's Duties"?
An extra 5-10 lbs cannot make that big a difference.
We are not heading for Indy-turn 4, just the the Roundabout from Au5 to FR423 - geez...
 
#13 ·
petema said:
An oversize bar mounted close to the center of the rear axle, may have the unwanted effect of making the axle itself flex. In my opinion. The closer to the wheels the force is applied, the better. P
Wow, sounds like "Track Info". Got any "Empirical Evidence" to go with helping us "Good Ole Boys" make it around the 'Cutthroat/Deadmans/Cut in the Hill' next time ??

Really??? a Flexed axle - gosh...
 
#14 ·
petema said:
An oversize bar mounted close to the center of the rear axle, may have the unwanted effect of making the axle itself flex. In my opinion. The closer to the wheels the force is applied, the better. P
Maybe. But then again.. it works for BMW
 
#17 ·
Cant help feeling a slight hint of disagreement with my comment here. My rear axle is BENT, it has a 3-5 mm sag, probably due to high loads, hard driving, and using adjustable air shocks over a longer periode of time (prev. owners). It doesn't have to be a problem, but reminds me about the need to be aware of certain factors concerning applying loads. Standup comedian? Nope. Top poster of the day? Maybe some other day. P
 
#18 ·
petema said:
My rear axle is BENT, it has a 3-5 mm sag, probably due to high loads, hard driving, and using adjustable air shocks over a longer periode of time..
Air shocks? Not likely.

But I will go with possible high-loads and hard driving. It is my belief that the weight of the center-carrier being slammed on a hard impact (from both wheels) while being suspended mid-way may be enough to sag or bend the axle tubes where they are fitted to the center carrier. I don't believe the tubes themselves are bent, but there may be issues where they are attached. I'm sure this info is available.. I've seen rough-use 4x4 differential brace solutions for this very issue.

Every rear-end I've ever had (on any van) always seems to have a little inward camber on the rear wheels.
 
#19 ·
Interesting, Petema, I understand & respect your thinking.
But lets delve in a little deeper,,,,,
Any 'flex or bending' would obviously have to occur on cornering,, as the Bar does nothing much in a straight line. Possibly with the exception of hitting a sink hole or high kerb on one side.
The Bar is clamped to the axle and is held by two large rubber bushes. They would have to be compressed to between the 'event horizon & singularity' before any excessive load was exerted on any metal parts.
The first metal to flex would be the Bar. Both torsionally (centre part) and almost simultaneously compression + expansion (of the two long link arms).
Taken together, the actions above have the effect of 'cushioning' any severe blow to any axle components.
To go a little further,,,, The bar resists the torsion through its stiffness.
The stiffness of an anti-roll bar is proportional to the stiffness of the material, the fourth power of its radius, and the inverse of the length of the lever arms i.e., the shorter the lever arm, the stiffer the bar (The BMW bar has LONG lever arms, therefore SOFTER).
Stiffness is also related to the geometry of the mounting points and the rigidity of the bar's mounting points.
The stiffer the bar, the more force required to move the left and right wheels relative to each other. This increases the amount of force required to make the body roll.
The total lateral load transfer is determined by the CG height and track width.

That said, I respect your views, opinions & warning advice. Thank you.

I will monitor the situation and also 'tone down' my Bullit & Dukes of Hazzard driving style by a notch or two,

Yes, Mmusicman "Every rear-end I've ever had (on any van) always seems to have a little inward camber on the rear wheels". I believe you could be correct.
 

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