S2 cab, rear suspension "weirdness!"

[simch1]

Strange one this, i have had my cab for 5 years, its had a fair old caning, and always drives seemingly very well indeed, tyre wear is very good no uneveneness at all, and despite being a little understeery for my liking, I have to say it handles rather well, not pulling on the gas or brakes, no tramlining, just tracks ture and straight.

I posted earlier today about some ET 30 8j cup 2 wheels, and opinion was they should fit the back of my beastie.
I took out a plumbline and a ruler to just satisfy myself where the new wheels would sit relative to the arch. Drivers side seems to have plenty of room, with the top fo the wheel rim sitting some 3.2cm in form the middle of the inside edge of the arch. I reckon they will sit about 23mill further out each side, so "jobs a goodun!"
Then went o the nearside and checked the same............WTF.......!! same measurement is only 1.9 cm........!..........! I reckon the drivers side is a bit lower than passenger, (next job to reset ride height) but even jacking it up a little on the drivers made only about 4 mill difference. So I am still out by about 1cm.....!
Strange thing is, when you look form the front of the car, the outside edge of the tyre and wheel seem to "cross" the rear arch panel in the same place, just about the leve of the stoneguard underseal paint on the bottom of the arch/wing.
But form the rear, the passenger sides seems to stick a little bit (very marginally) further out at the rear seeming "crossing" arch just above the rear underwing spoiler, wheras the drivers side seems to "cross" it just about at the top edge of this spoiler. I know these are not accurate as such, but it seems something is awry with the rear fo the suspension. I cannot make out if its camber, or rear toe etc, or most likely a combination fo both..


Any idea, is there rear toe alignment that is needed, I knwo the ride height is adjustable. Is camber adjustable, or could this be caused by some rear bush wear? Anyone had similar experience.
Car has done 96k miles, but again, tyre wear is very even, car seems to track and drive beautifully.

Could it be the rear spring plate bushes.......(like 911's?) Doe they do anything to locate the trailing arm in position/ Could it be the trailing arm bushes...or even a bent arm, or is it just a dodgy postioned rear arch...!??!

Are there any reference measurements I cna check by ruler etc, eg distance from refernce point on the floorplan to the hub/wheel/trailing arm?

Not usre how long this may have been like it as I only checked it with refernce to these potential new wheels?

Cheers for any input.
Although the allignment has not been done in some years, it was fine when these tyres were fitted 10k miles ago, according to the equipment at Michedever tyres in hants.

Could anyone measure theirs fomr the inside lip of the arch to the top edge of a stock rim, (using a plumb line) so I can even see which side is right on mine (if any!) and which is the wrong un!

cheers guys

 

[Diver944]

Don't worry TADTS (they all do that sir) []

The bodywork on teh rear arches is not symmetrical from side to side. These cars were designed before the age of cadcam and precision 'puters. The chassis is straight - it's just that the bodywork bolted on to it is not.

Scared the crap out of me when I did the same thing a few years ago. There's an old post of mine somewhere with pictures of the difference [8|]

 

[Fen]

Paul is absolutely right. It's always the passenger side that has the less clearance and I should have mentioned that in my post about your wheels. Also I assume your car (being a cab therefore quite late) has rolled arch lips? If it doesn't you will have problems. My '89 S2 coupe didn't, but my '90 Turbo does, as did my '91 (made) S2 cab, so it started at latest for MY90 I would guess. If you get a clearance problem it will be at the 10 o'clock position as you look at the passenger rear wheel. To fit the 18's to my Turbo after it was lowered quite a bit I had to flatten the rolled lip completely all the way round on both sides. It was fine with them when it was standard, though.

 

[simch1]

how weird is that!!

I was thinking that it may be the bodywork, but it is SO far out, its like the arches must have welded on by Helen Keller, whilst Ray Charles held them in place!

But then there is no other evidence of bad alignment on the body, ie the gaps look good, the plastic wing tops all fit in place perfectly......?!

Would be interested in seeing that previous post about it, Paul, for comparison, I tried a search but nothing came up.

My cab is a late '89 so no rolled arches for me! Looks like I will need the angle grinder in there!

 

[Fen]

Better to roll them (with heat) than grind them. Porsche Cars have an arch roller that your local OPC can borrow (Exeter did the passenger one on my S2 coupe with it) if you're stuck. All 944s are the same as far as I know, so the misalignment was presumably introduced either in the original (hand I guess) drawings or body jig. Cabs started out life as coupes and had the roof cut off so they suffer just the same.

 

[simch1]

It must be one of those covert things the germans do for us doing them over in 1966! (I can see them all wryly laughing as they engineer in an inch of bad arch clearance, knowing that some English fool will notice it and nearly have a heart attack 16 years later, nearly 40 years to the day of that awesome day!)

I have seen tohose arch rollers, they like clamp on the middle of the hub I think and have a big polythene wheel on the end and a massive handle! I think I may resort to a big hammer, like you say its only really the sort of 10 oclock to 2 oclock that needs dressing up.

 

[Diver944]

ORIGINAL: simch1


Would be interested in seeing that previous post about it, Paul, for comparison, I tried a search but nothing came up.

It took me a while to find it too. I remembered I had used the word 'ruler' and did a search on that in the end [8|] It's actually a post about tyre pressures and the arches are discussed in the last three posts:

http://www.porscheclubgbforum.com/tm.asp?m=87646&mpage=1&key=offside&#89124

 

[simch1]

My arch clearance difference is 2cm nearly, now I have had chance to better measure it with the et30 rears on.

Is there any adjustment on the hub location relative to the arch? I know on 911's you can have some via the spring plate bolts, and I was told its possible on the earlier 944's, but mine is an ABS equipped S2 model (1989).

I am woried that the clearance is so different, and I think the DRIVERS side (with the big clearance was rebuilt before I had the car. Just concerned that they may have put it back together out of adjustment.

 

[Hilux]

The bodywork on teh rear arches is not symmetrical from side to side. These cars were designed before the age of cadcam and precision 'puters. The chassis is straight - it's just that the bodywork bolted on to it is not.

You've got me worried now and for the wrong reason................................

Checked my wheelarches today (straight edge from the wheel rims) and mine are perfectly even. Checked again for accident damage but cant find any.......wierd [&:]