Front subframe change

[s2driveruk]

Just finally put on the freshly painted front subframe along with new solid mounts and wondered if there is any specific alignment steps i need to go through? I've basically unbolted the wishbones from the subframe so settings would be against the old frame which is not going to be much help.

If there is a set procedure or any advice, would be welcome, fully intending to get a proper alignment dont but want to be sure that the subframe is sat square on.

Cheers
david

[S2central.net]

You really need a bodywork jig to do this accurately, but with care, some stiff string and a tape measure you should be pretty accurate... Use the head bolt points on the existing subframe (Fitted) to measure distance to other fixed reference points under the car... Then just get as close to those dimensions when you fit zee new subframe.

I might have some OFRM on this one - at worst a Bentley book... I did once have the bodywork chapters from Erwin, but the damn license expired before I could print it... Then the prices went outrageous

[Keeper of The Kitten]

The best reference points are the other suspension hard points on the rear. If you get diagonal measurements that match, that's good.

[stiglet]

When i did mine i really didn't have a whole lot of adjustment room. You using the ally mounts? They were a VERY snug fit! And getting all 4 bolts to line up was a challenge.

If you get a 4 wheel alignment you will know if anything is whack out.

[Error404]

I agree with Al, alignment should show up any major problems
There was no room for manoeuvre when i fitted my refurbed subby, it was a PITA to refit as it was.

[s2driveruk]

yep alloy mounts and as such it 'settled' in as i did up the bolts. I'll basically bolt it all back up and let them know i changed the subframe so they know to be aware if measurements are all over the shop which they will be i'm sure.

[S2central.net]

Its better when the alignment boys get the car with everything out of whack... Forces them to back to 1st principles and get it right... Versus turning up and its 'close enough' that only a small effort is made to correct things within tolerance - when maybe that is masking some other misalignment.


Paul

[Error404]

good point Paul, I always put mine out when I free up all the adjusters, just to make sure they have to adjust everything back to stock not just tweak the worst bits

[Acidburn]

Does anyone know if there is much room for error with the rear subframe as this is one part that I have to do and I want to make sure its right this time as a couple of us think that my rear subframe either has something wrong or is not on properly, hence my bmw tendancies.

[Rusty]

Isn't one of the 4 bolts fixed and the other 3 floating? I've never bothered aligning my SFs as I've not had the time, method or skill. Be nice if there was a proper method. I remember that this was discussed for the rear subframe and nothing much was decided...

[Error404]

i'll let you know in a couple of weeks when i swap mine mate
I don't undertand why Audi would make their lives difficult and have floating moutning points, it doesnn't make any sense to me.
Also the tightening torque isn't enough to maintain alignment if there was movement there.

[s2driveruk]

i think there wasn't any ovalled or floating bolt arrangement as far as I could see/feel

[Rusty]

Aren't they square/rectangular plates captive in the chassis? You'd need some sort of clearance somewhere for some tolerances, there are no dowels so there is no positive location, only the fit of the bolts on the bushes...

[Error404]

IIRC people have had problems before with the nuts shearing off inside the chassis rails, i'm convinced they are solid... i'll investigate in a couple of weeks when my rear one comes off

[s2driveruk]

ok, finished mesing about with the frame and it looks like the drivers side front bolt is a floater...

Looks great now underneath.....though it is amazing just how many new parts i put on last summer have a lovely coat of surface rust already

Anyway, hopefully with proper round bolt holes on the frame for all the wishbone bush bolts to locate on, I should be able to properly align it
David