DIY pic Guide: proper re-alignment of rear axle

[Basil]

This is a little guide on how to change toe as well as camber setting on the fixed “non-adjustable” rear axle of the Fabia. The identical procedure applies to all VAG cars.

Basically it involves fitting universal TUV-certified plastic shims to change alignment (EZ shims made by speciality products in the USA). The amount of change needed in camber and/or toe is worked out from a 4wheel alignment printout and comparison to specs. Once you know the amount needed, you dial in the two corresponding numbers at the top of the shim.

Work involves removing the wheels, shifting the brake calipers, Hub bearings and disc as one assembly to one side and removing the stub axle. Shims are then fitted between the stub axle and the Twist axle beam. Depending on the arrangement of the two-piece shims you can obtain up to 1.5 degree positive or negative shifts in the toe as well as camber simultaneously.

So on to how to do it:

Jack up one rear side of the car on a level surface; leave it in gear, chocks under the front tyres. The handbrake should be OFF (otherwise you make life more difficult for yourself). Make sure that the car is secured with jack stands.

Remove the wheel.

Using a medium-sized screwdriver and a hammer tap away at the hub center cap until it pops off. Keep moving the screwdriver about so as not to deform it.



Using an 8mm Allen head bit remove the two bolts holding the rear brake calipers to the axle. View from under car looking outwards.




Using a 12-point 30mm socket remove the center axle nut – this has to be replaced as it will no longer be self-locking if put back on.



Unclip the brake lines at the two locations on the top of the axle beam.


Gently pull away the entire caliper/disc assembly from the hub and rotate around to the rear. Although I had a rubber mallet to hand, I found that all that way needed was a pull and very (!) gentle wiggle to get it off.


I found that a paint can made an ideal rest for it. There should be no stress on the brake lines. Try to get a finger around the assembly while removing to help the bearing shield stay together and to keep out debris.



Using a 15mm socket, undo the 4 bolts holding the dust-shield and remove the shield and rotate the hub around. Be careful not to damage the ABS sensor at the top of the hub. You can leave the ABS sensor connector undisturbed.






Use a wire-brush to clean the mating surfaces from any rust/debris.

Using the template provided for VW’s – hold the paper against the hub and using dirty fingers/screwdriver/pencil mark the paper where the bolts need to pass through.


The Fabia uses two of the regular holes that VW does (on the template’s right) but the other two are shifted, and you need to note this. The plastic “fingers” you remove are to allow the bolts to pass through. Here is a copy of the template that I used for the fabia. The bits you tear off are only to allow the bolts to pass through. As long as the numbers are at the top, the location of the torn-out bits varies to match different bolt patterns for different cars. As I've posted my results further down - it seems the EZ shims over-correct a bit when lined up this way- either going for less correction or perhaps lining the shim numbers up vertically and then poking holes in through the bolt holes from the inside of the hub with a drill or hot nail would be a better way of doing things. Since the shims are pretty cheap, may also be an idea to get an extra pair, and temporarily re-use the old axle hub nut to recheck alignment in case you need to change what you end up with. (thanks to Ric for this clever suggestion).





Using a screwdriver on the inside of the shims cut the perforations and tear through with a pair of needlenose pliers from the inside of the shims. Support the shim with your fingers an make sure that the numbers you want at the top of the shim are kept together at all times and do not shift.


Temporarily fit the shim directly to the beam axle with the bolts finger-tight. The numbers you want should be at the top.


Important: on Left side of the car you keep the numbers facing AWAY from you. Right side the numbers face TOWARDS you.
As you feel around the back, you’ll notice that the shim interferes with where the ABS sensor comes in. Using a rough file, and supporting the shim with your fingers, carefully file this part down to match the metal of the axle beam. A Dremel tool would probably make quick neat work of this. Then remove the bolts and shim.



All bolts put back on should ideally be renewed. I used loktite on all bolts and torques them to spec. I out in new center hub nuts as these HAVE to be changed.

Place two loktite-coated bolts through the dustshield and the hub’s upper holes. Shim should be positioned between this assembly and the axle beam - check that the numbers are facing the right way and are uppermost.Fit this onto the beam axle and finger tighten. Fit in the other two lower bolts. Torque to spec: 30Nm. I did mine in stages, always starting with the thinnest part of the shim.

Now before you put the rest on – coat the two brake caliper bolts with loktite, insert them through their holes and then and place two washers over the end – this is to compensate roughly for the shim’s thickness. Not doing this will cause rear disc brakes to bind. The EZ Shim manufacturers mention this for rear disc brakes and in fact sell a kit with different thickness plastic spacers for this purpose. The washers I used were Internal diameter 10.8mm, 1.2mm thick each and 20.5mm external diameter (bigger diameter would have been even better). 2 washers per bolt were used.
Not doing this before you put on the calipers and hub will mean that you have a rough time doing it afterwards. And the center axle nut once removed has to be changed.


Wipe off any debris on the stub axle and inside the hub bearings with tissue paper.

Refit the assembly sitting on the paint can and gently push it back on.
Halfway on check that the washers are still on the brake caliper bolts and engage the bolts into the calipers. Once you have checked this, push the hub back to its base.

If it gets stuck you can use the old center axle nut to help gently push it back on - then remove the old used nut…Tighten the two brake caliper bolts to 30Nm.

Once you are satisfied that all is well – and not before – fit the brand new 30mm center nut. Torque to 70Nm and then turn an additional 1/12 of a turn (30 °). Put a little smear of loktite around the edges of the cap and gently tap around the edges to get it seated back in. A deformed cap should be replaced – moisture in the bearings will cause premature wear.

Refit the wheel and get your alignment rechecked. I hope that this guide helps people to fix a common Fabia problem - namely rear axle being out of even the rather loose factory specs. Better performance, less tyre wear and better economy all can lead to even more enjoyment of the car. And in the case of a warped rear axle - at 12 quid a shim with postage, a lot cheaper than replacing the whole rear twist beam axle with the professional labour charges!
If you find this guide useful - please think about becoming a Freedom member if you're not already- it helps run this site and provide help and useful info to many people! PS. My 4WA before and after are posted below - Although not perfect - I'm more than happy with the way the car handles now!

Cheers, Bas

References:

1- shim instructions pdfhttp://www.lmfvauxhall.co.uk/store/s...-75200Blue.pdf
2- Shim fitting video: http://www.lmfvauxhall.co.uk/store/s...ZShimvideo.wmv
3- UK supplier approx 12 quid all in each! - you want the 75200 blue oneLMF Vauxhall - The Vauxhall Parts Specialist :: Car Exteriors :: Corsa C ('01 - '06) :: Suspension :: Eibach Rear Camber Adjustment Shims - Nova, Corsa C

[vRSLen]

Well done bas, nice to know that it can be done

[djswivel]

Great guide.

Now to follow it...

[Tom_vRS]

That is excellent stuff.

What toe in spec would you recommend to people, and what should it be from the factory??

[Basil]

Thanks for the kind comments mate. Please remember I'm not by any means any kind of trained mechanic, just an enthusiast! - see the thread http://www.briskoda.net/forums/ask-t...ice-plz/97260/ for some detailed stuff.
I 'aimed for' camber -1 deg 40-42 and toe-in 6-7'. As close to equal both sides as possible. Calculations showed aimed-for numbers to be within 2' of being equal. When you think that the max camber difference permitted by the manufacturer can be up to 30' difference, and the toe 10' - it kinda puts it into interesting perspective.....
What I ended up with exactly I don't know yet (!!) but I love it to bits! (Learnt that a performance setting is to use minimal toe-in and maximal camber - sometimes out of manufacturer's spec. I aimed for the non-vRS Fabia minimal allowable toe-in which is more aggressive than the vRS one!). No oversteer - or sensation of "push" now - really excellent change in the car's feel.... I seriously wonder if this is the real reason behind the 'nose-heavy' handling of the vRS - not just the heavy diesel lump!
Less toe in= less oversteer but too little - or toe-out settings = risk of understeer - more dangerous for regular drivers to control.
Factory Specs:
Toe-in: non-vRS Fabia 20' +/- 10'.
vRS 26' +/-10'
On some scoobs - especially if they go for twisty courses they use zero toe or even toe-out (!!!) Zero toe helps to reduce the rolling resistance for drag racing, but you lose the "self-centering' effect of some toe-in which would be annoying on long motorway journeys.

HTH mate

Bas

[mathepac]

Superb job, great guide, you're the man!

[faboka vrs]

Excellent.

Just looking over my last alignment.
Toe is:

Front total 10' Left 05' Right 05'
Rear total 22'. Left 09' Right 13'

Camber

Front Left -.52' Right -.42'
Rear Left -1.33' Right -1.26'

Castor

Left 4.41' Right 4.36'

[Basil]

So here are the printouts showing the alignment changes I ended up with. Seems the EZ shims over-correct a bit - perhaps lining the shim numbers up vertically and then poking holes in through the bolts with a drill or hot nail would be a better way of lining it up.

Still Changed from this:

to this (equal and zero toe in at the rear!!!):



Pleased with the results - car handles great now
will have to be alert to over-steer now!!