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Rear suspension bump traverse

Posted: Sat Apr 04, 2015 12:10 pm
by Paulus
Hey Guys,

So I've changed out my na horrific rusty uk rear subframe for a nice Aussie nb subframe.

I swapped everything.

On the good side the car is much less rough over bumps as my old bushes were perished.

BUT over bumps the whole rear jumps sideways and it feels like a small drift.

I've torqued everything except the sways as I assumed they were torqued. Obviously I should check the sways but..

Question is this: is there an order I should torque the bolts etc? Should I undo the sways and redo them? They could be preloaded?

Same question goes for the nb bracing on the rear.. Something's not right.

I've had a hunter alignment btw

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 12:30 pm
by NitroDann
I'd bet its out of alignment.

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 12:32 pm
by Magpie
^^^^ what he said.

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 3:18 pm
by Paulus
It got aligned on a hunter in the Bridgestone shop as above.

Go back?

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 4:09 pm
by NitroDann
Nah you agreed to swap money for an alignment. You have no idea if it was aligned, and if it was you have no idea if it still is.

Dann

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 4:23 pm
by Muzdaman
Did you give them alignment specs?

Did they give you a before /after printout?

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 4:39 pm
by NitroDann
Before and after doesn't work. Its easily cheated.

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 5:47 pm
by Magpie
I sit in the car when they do an alignment.

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 8:56 pm
by Locutus
Did you load up the suspension on each corner with the weight of the car before you tightened the control arm bolts? The arms are supposed to be in their static positions before those bolts are torqued up - as if the car was sitting on level ground.

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 9:51 pm
by NitroDann
He didn't do anything but give a tyre shop 80 bucks. I'm being blunt but that's how it is.

Re: Rear suspension bump traverse

Posted: Sat Apr 04, 2015 11:33 pm
by Paulus
I gave them the lanny alignment specs. We had a good chat about the bushes on the front and the nb subframe being 5mm wider. But.. I paid $80. So maybe it wasn't quite right?

I didn't preload, no. I could fix that easily.

Re: Rear suspension bump traverse

Posted: Tue May 19, 2015 11:10 pm
by Paulus
After torquing when preloading it's much better.

However the wheels not following bumps has led me down the 'wheels are too heavy' path. I'm apparently around 18lbs per wheel! Amazing what you learn.. Lighter has many benefits and I hadn't appreciated how sh*t my wheels are.

Re: Rear suspension bump traverse

Posted: Wed May 20, 2015 3:25 am
by chrons_rotary
Paulus wrote:After torquing when preloading it's much better.

However the wheels not following bumps has led me down the 'wheels are too heavy' path. I'm apparently around 18lbs per wheel! Amazing what you learn.. Lighter has many benefits and I hadn't appreciated how sh*t my wheels are.


I'm assuming that its 18lbs (we live in Australia, use KGs :P) without tyres on.
Even with heavy wheels, it should not be jumping sideways when going over bumps.
I'm going to side with Dann, alignment is out.

Try checking the rear toe with some stringline, or a tape measure, checking distance between the rear wheels at front and back of the tyre.
If you are not sure, just google it, it is dead easy to check.

Most tyre shops have untrained tyre fitters using those accurate and expensive alignment equipment, and as a result are usually way out as they find ways to dodgy the figures.

Re: Rear suspension bump traverse

Posted: Thu May 21, 2015 6:13 pm
by project.r.racing
My bet is alignment is shite. My car had perfect alignment. I recently hit a huge pothole and my car did the same as what yours is doing. Back to the tyre shop to have an alignment done. No more problem. Wheel weights wont be the issue.