Rear camber adjuster

[pegasus]

Hi there,after some steering work to my old banger S2 i have booked a jim bean 3d alignment on thirsday. when freeing off all the relevant bolts etc I am confused as to how the rear camber eccentic achieves the adjustment. I changes the position of the aluminium trailing arm relevant to the spring strut,is this not the same as altering the ride height slightly or am I missing somethig. Any help here would be great many thanks in advance John.

 

[robwright]

Are you referring to the two nuts on the trailing arm to the rear of the torsion bar? AFAIK these will only addjust the ride height of the rear of the car. One is a locking nut and the other is an eccentric nut to adjust the height. I think the camber should be adjusted by an eccentric nut at the bottom of the McPheerson strut. Someboddy please come along and correct me soon if I am wrong.

 

[pegasus]

Hi Rob,no the macpherson struts are at the front,I an talking about the camber eccentrics at the rear,there are three bolts that hold the torsion bar stuts to the trailing arm, the forrad one of the three is the rear camber adjuster.

 

[robwright]

Sorry mate I shouldn't have siad McPheerson too many Chardonays!!! Have you tried Clarks's site? There maybe some adive on there. Are you ex forces by any chance with a name like Pegasus???

 

[pegasus]

Hi Rob,Its no big deal really I just wanted to get it clear in my mind before I let someone loose on my old banger. I thought that one of the racing types might get back as they all have to adjust their suspension more than road types, Pegasus comes from pegase, a glider I used to fly, It belonged to the navy but I didn't,all the best John.

 

[zcacogp]

Good Q. I have never understood the rear adjustments - I know that there are three bolts, and I think that one is toe in/out and another is camber, but I have never understood how they work. (I also know that they are often seized solid and can be a pain to move.)


Oli.

 

[pegasus]

Hi Oli, yes they don'tend to be moved very often, the adjustment has to do with altering the ali radius are relative to the steel sprung arm(porsche calls this the strut,confusing but probably not if you speak german) but I can't quite grasp how this works. It is all simple with adjustable radius arms and the like,the porsche adjustment must be quite limited hence the use of what they call perch mounts on serious racers with big negative cambers ( I don'know what a perch mount is and where they fit). I am sure that one of the racers on the forum will get back to us and explain all this, all the best John.

 

[Mike_Pollock]

Dont know turbo / S2 rear but on my '83 car I cant find any camber adjustments. All I cam find are thebolts on the spring plates which will adjust ride height and toe in.
Would love to know more!
Mike

 

[pegasus]

Sorry I should have explained that the toe in is altered by moving the ali control arm forward or back relative to the steel strut making that side if the triangle shorter or longer hence giving you toe in when shorter and to out when longer,its just the camber that need explained.

 

[Big Dave]

If your after adjusting the REAR geo, then i think the top bolt of the 3 is the camber bolt + you will need a Porsche tool to do the adjusting correctly, The tool is only about £15 ish from Porsche...
If you adjust the spring plate for + aft it adjusts the toe aswell...
If you look on Rick Cannels site , im sure itl all be docoumented there,,, somewhere...

 

[pegasus]

Hi Dave,the camber eccentric is the forward of the the three bolts and is built in,the only adjustment that needs a tool is the toe, the toe tool fits in the emty hole just aft of the camber eccentric.(it is common to the 911 range as well) What I really want explained is how when thw camber eccentric is moved,which alters the angle of the radius arm to the steel torsion strut,acctually adjusts the camber. The actual range of adjustment is quite limited and the castor eccentric idea is not the best hence the manufacture of after marked mods to increase the range.It would be nice to have one of the racing types explain the ins and outs of the rear suspension,all the best John

 

[Big Dave]

OK, Its been a while since i did mine...[8|]

 

[pegasus]

Hi lads,went to camborne this morning to get my jim bean 3d alignment set up. when I arrived I was told that they could not contact me to say that the guy that does the 3d was ill because the girl that booked me in did not ask for a contact number. The owner was very helpful and got a chap from another business to pop along and do my alignment.When he arrived I asked him if he was familiar with this machine(very simple to use,they are designed so anyone can use them) to which he replied that it was more hi-teck than he had used. OK I said I have put the car details in and the machine now knows what to look for lets put the targets on and see what we have got. The machine came up with reading that were just in tolerance all except the front toe due to me fitting new track rods(n/s inner balljoint worn,replaced both + steering shaft). By this time the garage whizz kid had come over to advise and started poking around under my car. I told him I wanted the rear set up to mid tolerance and the front set to 3 degrees castor. Turns out niether of them lnew how to adjust the rear, I showed them how and asked for the tool to adjust the rear toe. I was then told they did not have the tool (cost about £15 should have been ordered with their £3000 jim bean gear) and the car would have to go to Porsche to be done, when I pointed out that the tool costs pennies and the car should not have been booked in if they could not do the job I just got blank looks. Turns out that normally they do no touch the rear just take readings and say the rear is OK. I then decided that enough was enough and went down the road and had my tracking done (it was done OK as I checked it myself) by a chap that did not know the difference between minutes and degrees but the equipment lets anyone do the job. What happened to british engineering? I despair,all the best John.

 

[bertelli_1]

Nice. So you know there are 3 adjustments possible on the rear, camber, toe and height. The height is adjusted at the forward eccentric bolt. To do this slacken the 2 outer 24mm nuts, one has a 24mm nut, the other a 30mm nut, this one is the eccentric. Camber is adjusted using the bolt shared with the roll bar link & has a 27mm head, also eccentric. Toe uses the special tool inserted in the hole adjacent to the camber bolt. Camber and toe adjustments are done with the 3 19mm bolts loose, camber moves the arm up & down, toe moves it forwards and backwards (relative to the steel torsion bar arm). As already mentioned the alloy arm is commonly corroded to the steel torsion bar arm although brute force will often free them off.

hth.

 

[pegasus]

I know exactly how the adjustments are made,I made a point of removing all the adjusting and eccentrics bolts cleaning and replacing before going to get the suspension dialed in,I have most equipment in my garage but draw the line at forking out fot a 3d laser alignment set.These people advertise that they can do the job but when it comes down to it it is all bullshit.Snap on make this gear user friendly, it is a big outlay but the trick is it is so quick to do an initial assessment you can give the customer a printout and he can than decide to have the alignment made.It is not rocket science when I had to do it years ago we relied on spirit levels and protractor based devices anyone who can clamp a target on a wheel can do it, the trouble is they can't.The essence of this thread was that I wanted the rear camber adjustment explained,I know that when I turn the eccentric the camber changes I just wanted someone to explain why. As it is I am just disgusted with the standard of people working the the auto trade,I know they are not all like this but it is an unfortunate fact that a lot are useless and I worry about the people who put complete trust in these so called experts and even comment on what a good job they do,like I say I despair for britains engineering prowess,rant finished John.

 

[Indi9xx]

We tend to completely seperate the springplate from the hub, clean up the two mating faces and use an aluminium grease as an anti seize when performing an alignment on a 924/944/968, without doing this you spend a long time fighting against the car and an adjuster which will not adjust.

I did have a Jim Bean setup and a couple of car's had me distrusting the accuracy of the Jim Bean kit and going to extensive lengths (such as the rear beam disassemble thing) to make sure we could be precise.

I thought long and hard (about a year) before taking the plunge with replacing my 4 wheel alignment equipment, ended up buying probably the most expensive and most accurate available simply because the more demo's I had and the more I researched, the more that I became even more obsessive about precision/error margins. Ended up importing a "Bear" alignment system from the USA about 6 months ago.

Since then I became even more obsessive... I am now obsessive about calibration.. Not being happy with six monthly calibrations from an engineer who might not care about it being accurate to a 60th of a degree, I just spent a couple of months twisting BearUSA's arm to sell me a calibration jig, diagnostic equipment and calibration software so we can calibrate ours on a super regular basis and run diagnostics on it whenever paranoia takes me!

With the paranoia, comes a great understanding of alignment.. Not many people (including those doing alignments) realise how many factors play a part in 4 wheel alignment.. Tyre pressures, tyre wear all play a part in getting alignment right.. But when you get it right.. WOW

Its also worth being picky about wear in the steering and suspension.. After a lot of experiments, it is absolutely amazing how much a slightly worn steering column UJ can effect a Porsche into tramlining, bump steering or even following the camber of the road too much.

Another thing is "runout adjustment".. One thing you rarely see done by people performing and alignment, and some kit does not even support, is a rolling runout adjustment. When performing an accurate 4 wheel alignment, you should really attach the 4 wheel sensors/heads, put the software into "runout adjustment" and roll the car backwards and forwards (on following software prompts) to allow the machine to measure and automatically compensate for any runout on the 4 wheels.. Even a slight buckle on a wheel or some corrosion behind a brake disk, mismatched hub machining can really effect your readings when your measuring angles accurate to a 60th of a degree! Yet very few people bother with this.

Interestingly (another possibly boring fact) is that this is exactly why Porsche specify mounting the wheel in the same orientation to the hub (red marked wheel stud and wheel hole relative to the tyre valve) so that when the car was setup from the factory (Bear CCD originally at the factory) or at a main dealer, they could rely on the runout in the hub/disk/wheel to remain relative... not a lot of people know that... the other reason for this was due to zero balancing the wheel to the hub... but thats something else I obsess about so you really do not want to ask me about balancing!

With the rear adjusters on a 944, you can adjust camber, toe and height.. the front can be adjusted by toe, camber, caster and height (with shims or via threaded strut variants). Caster does not come into it on the rear of a 944 as such (although to be picky, there is an element of something similar to caster but its a long story)

If somewhere does not have the tools to adjust your suspension.. avoid them.. if they confess they never adjust the rear.. well thats really bad news!.. confessing they "say its ok".. thats just beyond belief!!

Not wanting to blow just my trumpet here for a moment. I respect the work done by CentreGravity.. I have been asked to second guess their alignments a couple of times and can't really fault it in the real world, although I am a bit obsessive and could even find reason to re-tweak an alignment I performed even once I have put the tools down!

My advice... find someone obsessive... easy way to spot them is to talk to them.. if they waffle on and on way beyond the point you get a glazed expression on your face and they seem really enthusiastic about alignments, they are probably going to do an amazing job!

 

[pegasus]

Thanks for that John, I have just fitted two new track rods and a steering shaft,new front wheel bearings,dial gauged all wheels for runout no perceptable play in the rear bearings and suspension/radius arms etc, just wanted the suspension dialed in but that is asking too much I think. I have always worked on fact that if somone knows what they are doing they can explain it to you and you will understand it,if you ask a question and they say you don't have to know that,or even worse thay say you wouldn't understand that, I can assure you don't know and you should just walk away. The trouble with living three miles from lands end is that you are so restricted for services,and it is just not cost effective to travel any distance just to get your suspension dialed in.all the best John.

 

[Indi9xx]

pegasus,

Well done for clocking your wheels with a dial gauge.. good work! That shows a professional approach sadly not seen often even with professionals.

Lands end... hmmm.. your stuffed!! lol

Having said that.. it might be worth talking to the chaps with the jim bean gear and asking them if you turn up with your own tools, will they let you do the alignment,,

 

[pegasus]

My wife suggested that I hire the ramp and alignment rig for a couple of hours but after the performance with the chuckle brothers and the fact that I waited five days for the alignment booking and the twenty mile drive I did not leave the so called tyre specialists on the best of terms, I cannot help it I do not suffer fools (you can say that when you get older), as for the dial gauge thing when you align £200,000 of marine diesel it all boils down to clock readings from two £50 gauges,but they don't come with user friendly software,you even have to make your own brackets for holding them,all the best John.

 

[zcacogp]

I know that good alignment places are in short supply (I have used one which I thought was pretty good, but he never changed the rear alignment either ... ), but if you are happy to use someone else's kit then it may be worth asking around for other places which have an alignment jig and a helpful owner. You could book an alignment session as normal, turn up with your own tools, and 'help' the guy doing the work.

Have you tried asking on Pistonheads? There are quite a lot of track boys on there from around the country, and someone may well know a suitable place.


Oli.

ETA: Can't believe there is an alignment jig brand called 'Jim Bean' ...