I was thinking about doing a cheap and cheerful alignment check using a magnetic camber/caster gauge. They resemble giant thermometers and have a magnetic disc at one end (perpendicular to bubble scale) which fixes to the rotor.

Obviously wheel has to be off, so car would be on stands. Would this affect measurement of either camber or caster? If so how do you arrange things so you can take readings reflecting the true set-up of the car?

I know geometry can be checked with string and geometry, but these gauges looked handy.

 

You cannot lift the car and then get a true reading......you need steel wheels

 

Car has to have suspension laoded and settled to see useable results. Sorry!

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On my old LeGrand mini sports racer, I made a set of aluminum disk "alignment wheels". Everything in the suspension moved on spherical rod ends or hard metal bushings so there was no friction and therefore no 'settling". I could do the whole alignment front and rear with a tape measure in less than 10 minutes, sitting on the trailer.

 

Thanks - thought as much. Can't remove wheel centre either as dust cap means no flat surface.

Have seen other gauges which snug up against the tyre rim (they look like two arms joined at right angles, but one arm makes base of triangle). Will keep an eye out on ebay for one.

 

The DFW group has one. I made a steel disc that replaces the center cap. It does require you to hold it against the flat section of the wheel were the center cap goes but it has proven to still be very accurate. Unfortunatly I don't have any pictures.

 

Hey that's a very smart idea Jim. Would even be possible to have a version of centre cap made with flat disc as you describe, but same design as existing cap so this could be held in the wheel leaving hands free for measurements?

 

Captain Earl has a nice write up here on a home alignment setup. I believe he has refined it further since.

http://members.rennlist.com/captearlg/928aligndiy.html

He did an alignment for me when I first purchased my S4 and ever since I've been considering putting together a setup like his.

 

At the N'Ring Euro 928 meet organised by Kurt Rottner, the Porsche Dealer in Aachen (I think) demonstrated a 928 wheel alignment on their new laser alignment machine - I think Beissbarth.

Instead of using clamp on wheel sensors the sensors were attached to the wheel using an "expanding bolt" type fitting into the centre hole of the wheel - imagine a 60mm dia very short Rawlbolt.

I'm thinking something like this would be fairly simple to make using a short length of appropriately sized exhaust pipe with a couple of cuts in it and another smaller diameter piece inside to act as an expander drawn outwards using a bolt threaded into a plate welded inside.

 

There's some history on alignment in this forum. Do a search on "DIY ALIGNMENT" and "DIY TOE-IN" and find some of it.

My alignment fixtures are configured to fit against the outside of the rim, held on with bungee cords. For toe, the lasers mounted on the fixtures make it a snap to adjust toe, using a tape measure. Read the DIY threads above for the methods and (simplified) math. For adjusting camber, I use a separate level on the same fixture, and a drill-bit shim similar to Earl Gillstrom's description. For caster, a digital level (from Sears) on each side goes the camber at three rotation spots on the turn plates, a calculator does the math. Method is described in Earl's bible, referenced in the DIY thread, but I can read the camber degrees directly from the digital level.

There are several inexpensive bubble level camber devices around that attach to the wheel center. I'm not so sure you need to reinvent them unless you want to use a different level. The level I use is a bit too massive to attach to that little wheel center patch, so I stick with the metal frames I made for the toe checks.