simon's learning what to do with the polo thread

[simon k]

well it did turn out to be a bit of a f*ckabout - they're just such a bastard of a thing to get in and out... I guess my main problem is that I try to do it without taking the balljoint out of the bottom arm and undoing the inner CV. I sweat and swear and finally give up and undo them and it's fine after that

I basically spent all day Saturday doing the drivers side, then realised on Sunday that I'd forgotten the top spring collar so took it half way apart again to put that in. Then when I was assembling the passenger side I realised I had put one bit in wrong so took the drivers side apart again to fix that. So by Sunday night I had the drivers side in and correct and the passenger side ready to install. I finished the passenger side on Monday night, then last night I put the wheels back on and evened up the camber by eye - the ride height was good with a thumb width of thread left at the bottom of the sleeve on both sides so did well there.

But! before I went to bed last night I made a camber measuring tool, I'd ebayed the little magnetic inclinometer a couple of weeks ago and it came in the mail today. So I can use this to measure and adjust the camber and caster.



check out my fully sick camber - and filthy bonnet & windscreen


I'm not very impressed with the KMac strut tops, the retainer/clamping plates are only ~6mm aluminium and way too soft for the job they're doing. There's a torque spec they're meant to be done up to, but being so thin they bend really easily. The bottom plate on both sides were quite badly out of shape. Obviously once they've bent once, they can be straightened but they're just going to bend again. One of the studs was stripped as well, but it's not surprising because they're really soft threads - definitely not high tensile. There are also little triangular washer plates to go under the nuts, they're soft aluminum too so doing up the nuts rips them to bits. I reckon I'll CAD up the retainer plates and re-make them in steel

I'm measuring/calculating caster and camber now...

[sambb]

Nice one Simon. Stoked you got them in. That camber looks like 3 deg. neg. to me. Was your take on the correct orientation of the top plates correct do you think? The good thing once you have coilovers is that getting the struts out again is easy. You just wind any preload out of the springs making knocking the bases out of the hubs straight forward. With my strut domes cut off, once that's done I only have to rattle off the damper shafts top nut and I can extract the whole strut without even moving the alignment of the top plates. Just something to consider if you feel like doing even more work with a grinder. Doubtful you do (believe me I've been there), but it does make things very straight forward later. Well done though. Keen to see how it feels for you once you get all the angles locked in.

[simon k]

Well my camber is even on both sides at .... 3.1° - you're a bit of a smartarse aren't you Sam! and yep, the texta markings on the plates were definitely wrong side

Caster is 4.9° on the drivers side and a little bit undecided on the passenger side. Caster and camber on the passenger side were a bit off on that side (2.3° and 3.7° respectively) so I had another look at the balljoint. There's a far bit of adjustment available down there so levering the rear out as far as it would go put the camber at my 3.1° without moving the top, I didn't remeasure the caster because it's an hour past my bedtime!

My measuring jigger is a champion though, the little ebay doover has an 'absolute' and 'relative' setting, so camber is absolute, and caster is relative from lock to lock (I just did 1 full turn of the wheel either way). Well worth a little bit of steel from my scrap bin and $15. I'll book in for a proper alignment on Friday - the rack isn't very well centered after I had both subframes out

[sambb]

Stoked for you man. Hadn't heard anything since you started and I was fearing the worst but it looks like you nailed it. You will loose the inside of those fronts pretty quickly with that much camber and a touch of toe out wont help either, but who cares it'll corner great when you lean on it. So you now have stiffer front springs, adjustable ride height, gobs of camber and caster etc. Time for a beer I'd say! I haven't used my gauge for caster measurements either. I think Gary said measure 20 degrees each side of straight ahead (40 degree total sweep) from memory. Keen to hear a report after it gets driven with spirit.

[simon k]

thanks Sam unless I need help or advice I tend to keep to myself till the job is done...

It's a lot better on my usual corners on the way to work, though I had a couple of cars in front of me on the sharp right hander... I did notice it being bumpier than it was, and the "fingers between the tyre and mudguard" test show the drivers side is a few mm lower than the passenger.

As an added bonus, it doesn't pull to the left anymore! it's been pulling to the left since I did the balljoints - my assumption was due to inconsistent camber or caster. I'd left it as is because I knew I was going to do this job - sorted!

edit 1:Question about removing the struts, do you undo the ball joint and driveshaft then bash on the carrier, or is there a cleverer way to do it?

edit 2: measuring caster, check this out... https://disco3.co.uk/gallery/albums/...ent%5B1%5D.pdf - as per page 7, the angle used is irrelevant as long as it is known and consistent... it also points out that the method I used to measure my caster wasn't checking caster at all, it was only checking the camber change. I just happened to get a number that sounded right-ish. If I plug in my 4.9° and assume one turn of the steering wheel is 20° then my caster is 7° - that'd be great, but assuming the angle of 1 turn of the wheel is obviously silly. I'll measure the angle tonight and calculate....

[Sydneykid]

For caster my process is relatively simple. The text book is plus and minus 20 degrees of wheel movement, but I don't really care about the text book number. I just want as much caster as I can get, I have never been able to physically get more caster than works (on a production based car). What I am really interested in is making sure that the camber change is the same side to side. So whatever test I apply it must be the same side to side. My usual process is half a turn one way, measure camber, then half a turn the other way, measure camber. Do the same on the other side and compare them. Then pick the side with the least amount, add some more adjustment and remeasure. Repeat until the readings are the same.

The only reason for the 20 degrees is that's the common amount of steering lock used by most aligners, so we can compare car A with car B (ie; mine has 6.5. degrees, what does yours have?). Personally I don't care, it only matters that it's the same side to side and I have as much caster as I can get.

If you do want to be able to compare them either do the 20 degree test yourself or take it to an alignment shop and get then to check the caster. Either way just count how many turns of the steering wheel = 20 degrees. Then you never have to go back or measure the 20 degrees ever again, well until you change the steering ratio anyway.

With race cars it's kinda useful as when competitors ask what caster we run I can honestly say that I don't know.

Cheers
Gary

[Sydneykid]

edit 2: measuring caster, check this out... https://disco3.co.uk/gallery/albums/...ent%5B1%5D.pdf

Thrust angle correction, yep that's relevant on a FWD car.

Cheers
Gary

[simon k]

What I am really interested in is making sure that the camber change is the same side to side. So whatever test I apply it must be the same side to side. My usual process is half a turn one way, measure camber, then half a turn the other way, measure camber. Do the same on the other side and compare them. Then pick the side with the least amount, add some more adjustment and remeasure. Repeat until the readings are the same.

yes - that's the right way to look at it, the actual number is irrelevant, it's the change that counts - like putting a car on a dyno, I want the number to get better, the number isn't relevant

With race cars it's kinda useful as when competitors ask what caster we run I can honestly say that I don't know.

lol, good call - "how much caster mate?", "...enough..."

[sambb]

I generally left the ball joint in the hub. I jack the hole front end and disconnect the FARB. Then I go nuts with WD/CRC etc and get it soaking while I do the next few things. On the difficult side I knock out the tie rod end so that the hub can swivel a bit more which helps with that last little bit at getting the strut base to pop out. Disconnect /clear all the brake lines etc. With struts I compress the springs - with coilovers I measure where the collars had been and drop them down to remove any spring preload. Spread the hub with a spreading tool (hex key ground into an elliptical shape). With my spreader I fluked its size/shape so that I turn it to spread the hub and at its maximum I take out the 1/2in drive and the key stays put holding the hub open. I then lump hammer the only real part of the hub side to side till it wont go any further and then start rocking the hub side to side and getting a tilt on it while hitting until the strut base pops out and hopefully doesn't mash a brake line in the process. The B8's were definitely harder than my MCA's. Wont help you now that you don't have a spring seat anymore but I had a special length rod that I used to fit under the spring seat and I'd get a little upwards force into the spring seat with a second jack, just enough to hold it up a tad for those last hits. The advantage of the MCA;s with their separate damper stroke and spring preload setup is that I can wind the damper stroke/strut base upwards to shorten the hole strut and it nearly lifts clean out after a couple of hits. The B8's were definitely harder to extract. Yeah there's no reason why you couldn't knock out the ball joint on that difficult side. I don't think you'd need to take the drive shaft out. That, with a tie rod end knocked out too would let you swing it away from the control arm/ball joint and then you could knock it out easier. I did it that way when I stripped my last Polo and I do remember thinking why the hell didn't I always do it like this.

[simon k]

had another sprint at the local track yesterday, I'm reasonably happy. I took 0.5 seconds off my best time which was in the 2nd session of the day, and most people said the track was a second and a half slower than usual, so I'll take that

I only did 1 lap of my first session, as I went to move into the lineup to enter the circuit my power steering stopped working. It had been working fine, I turned the ignition off and back on again but still no-worky. I went out anyway and did a lap but it was way to heavy for me. I had my laptop so checked the codes and it said no communications to the steering module - checked the fuse and sure enough, hairline crack through it - I'd let my tyres down right before I went to line up, I guess the extra caster plus low tyre pressures and maybe the fuse was old as well. It's one of the thin strip type fuses on top of the battery, one was broken when I first bought the car, I'd replaced a couple but not this one... I borrowed a socket and put a piece of wire across it.

It's a lot easier to drive fast through turns now, though the car still picks up its inside rear wheel, I can feel it and someone said 3-4" or so. I haven't seen any photos, but the front tyres weren't scrubbing the sidewalls like usual and I could feed it from one corner to the next. Braking from ~130kph at the end of the straight is fun, I reckon the backend is almost off the ground, it's like it lifts up and steps out to the right just a little bit. A load cell on each spring seat would be a fun engineering exercise...

It still won't give me any oversteer, any attempt results in tyre juddery understeer - I don't even get a squirm from the back. The nose is sitting a little lower than the rear - I recall some conversations b/w Sam and Gary about negative rake. The front is only low because I hadn't adjusted it from where I dropped it on the ground last weekend, I did lift it up a few mm but maybe it needs 1/2" or so.

I also had a problem with the inlet manifold hose popping off the 90° MAF pipe. I was using the standard spring clip and (rubber) hose, the hose was very soft and warm. I put a screw clamp on it this morning, will find one for the other end, and maybe buy a silicone hose (and yes Sam, hair spray...)