Caster Adjustment mk4 gti

[joe-nathan09]

Alright so I need some help with the front caster on a mk4 gti. I just replaced the lca bushings on both sides with the Audi tt bushings and got 4 brand new tires. When I went to get it aligned they told me my caster was off on both wheels by about a degree and they didn't adjust caster. This is causing my car to drift to the right a bit.

Now I know it has to do with the small adjustment where the ball joint meets the lca and I was wondering if anyone knew of a measuring method for getting the caster in check. Much appreciated!

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[rex_racer]

It helps to know where the caster value is at now. You can also shift the subframe side to side to adjust the caster and even it out. Did you replace the front most bushing on the control arm as well? Those wear out too.

[joe-nathan09]

Ya I changed both bushings on each control arm. I believe my caster was off about a degree. I still have the sheet I could post a pic of it later. The caster was below SPEC, I think it was 6.5 something and SPEC is 7-8

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[joe-nathan09]

Here are the numbers

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[meboice]

a little less caster should be bothersome, but unequal caster is. The toe might be more responsible for the pulling you wrote about...it doesn't take a lot of toe change on one side to cause some pulling. How this really manifests depends upon how much stiffer the bushings and tires are. One tire appears to be slightly negative and the other a bit more positive. Neg toe literally drags the tire away from the car's centerline. While drive, due to bushing and tire deflection, neg toe can grow, especially off throttle and through a turn.

I think most folks are much more sensitive to toe changes...

[joe-nathan09]

Well they got the toe back in check if you look at the "Actual" column. Is there any way for me to get that caster back in to SPEC? I finally went and tried adjusting the ball joint/lca connecting joint and it was such a pain since I had no real way to measure it. So I would move the bracket a little one way, Bolt it up, test Drive it to ser where it would pull, then repeated the process

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[greyhare]

The out of spec cross camber is the cause of the right drift.

I would not be over concerned about the caster. You could try to shift the sub-frame forward.

The camber is what you were messing with at the ball joints. Move the left one in and the right one out then get the alignment checked again.

[joe-nathan09]

Ok I will try that and see what happens. Weird how caster would be out of alignment if I never touched subframe or been in an accident

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[greyhare]

Worn suspension bushings can cause things to move as can big potholes.

[joe-nathan09]

Ok well let's say my subframe moved a bit and Im going to adjust it. Aren't all those bolts stretch bolts that mount the subframe? Wouldnt I have to replace them if I adjusted it?

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[rex_racer]

Ok well let's say my subframe moved a bit and Im going to adjust it. Aren't all those bolts stretch bolts that mount the subframe? Wouldnt I have to replace them if I adjusted it?

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They are stretch bolts but people reuse them all the time, just tighten them up a lil more. Most of the bolts on the car are stretch bolts including many on the suspension, but I'm sure you probably reused a bunch of those too.