Changing rear springs at track

Changing rear springs at track

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Discussion

Clarkgti

Original Poster:

51 posts

39 months

Friday 7th July 2023
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Running a devorced spring/damper setup on the car. It sits on the lower arm that is used to adjust toe. To change the rear spring I simple just undo the hub side of this lower arm, let it drop down and swap in the new one. I'm wondering is this going to throw out my rear alignment? Not a fan of doing my own alignments, takes time unless you have to expensive equipment and Ive made in accurate readings previously.

It's a 2008 golf, a pretty common indepent suspension with devorced spring setup like you see on many hatchbacks with independent rear suspension.

thebraketester

14,705 posts

145 months

Friday 7th July 2023
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If you undo the outer bolt (rather than the inner eccentric bolts) to lower the arm, it shouldn’t throw it out by much. Not ideal though.

Clarkgti

Original Poster:

51 posts

39 months

Friday 7th July 2023
quotequote all
Ah thats not ideal as if I want to test balance with rear springs changing the rear tracking could give false results.

In my head... If the arm used to adjust camber stays connected and just the toe arm is lowered on the side that simply connects to the hub then when you re-connect it, the eccentric toe bolt has not moved so should match up exactly as it was and the alignment should be exactly the same providing the ride height has not changed.

Dave.

7,515 posts

260 months

Friday 7th July 2023
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If you unbolt the top of the rear shock, would that let everything droop enough to get the spring out?

Clarkgti

Original Poster:

51 posts

39 months

Friday 7th July 2023
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As you can see the damper is totally separated so undoing the damper makes no difference

LactoseJoe

93 posts

168 months

Saturday 8th July 2023
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Yes, it will change your alignment. The new spring rate will create a different amount of sag and will change the behaviour through the suspension’s travel.

To what degree the alignment changes will depend on the difference in spring rates. I always seem to notice minor changes in suspension geometry.

Clarkgti

Original Poster:

51 posts

39 months

Saturday 8th July 2023
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LactoseJoe said:
Yes, it will change your alignment. The new spring rate will create a different amount of sag and will change the behaviour through the suspension’s travel.

To what degree the alignment changes will depend on the difference in spring rates. I always seem to notice minor changes in suspension geometry.
Yes you're right, but if measure the length of the damper on the old spring with all wheels on the ground, put in the new spring, measure the damper again and adjust ride height so it's exactly the same then won't it stay the same? As we've compensated for the amount of sag and ensuring ride height is exactly the same?

LactoseJoe

93 posts

168 months

Saturday 8th July 2023
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Maybe you’ll be alright. But I know I wouldn’t be able to get it perfect with the measurements, especially when accounting for differentiation in the ground level and load on the bushes after jacking the car up. It all might be quite minute and have zero impact on how the car tracks but it’ll be very difficult gauge. I wouldn’t bother but it’s just me; some of my friends are so anal about it they get alignments when they swap their tyres, others will happily fudge a new tie rod onto the car, eyeball it and get back on track.

Xcore

1,372 posts

97 months

Saturday 8th July 2023
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One bolt and drop it out, be careful starting the bolt on refitting as it’s Easy to cross thread as it’s not perpendicular to the side of the car