MK2 Subframe and control arm questions

[zracer22]

I just removed the suspension and subframe from my 88 GTI racer. Can anyone tell me why the bolt holes in the subframe are so much larger than the bolts that attach it to the car? Also, Why are the bodies of the control arm bolts thinner than the threaded section? It seems to me that this allows for a ton of play in the front end. I'm replacing the control arm bushings with Prothane poly bushings, where can I get bolts that fit snuggly in the bushing inserts?

I'm considering the idea of welding the subframe in place, but I'm still not sure what to do about the control arm bolts?

[wclark]

The bolts in mine are not the undersized shafts you describe and they fit the bushings fairly closely. Yours may have had different bolts installed at some point and for some reason. I suspect the slightly large holes in the subframe to mount it are intended to permit some chassis alignment error and still accmodate the subframe.

I would not weld the subframe to the frame. Removing the engine/tranny is a lot esier if you drop the engine/tranny/subframe out the bottom (or lift thecar off of it). You cant do that if it is welded.

I torque my subframe bolts to 120 pounds. I found I needed that much to keep the Shine spherical bearing in the rear locations tight. At 90 pounds the subframe didnt squeeze the bearing assembly inserts enough and they shifted around audibly when thev ehicle was driven.

[JoshS]

Wow, I learn something new every day. You can weld the subframe into the car legally? What allows that?

[Knestis]

Mark runs NASA GTS rather than IT, so he can pretty much do anything he wants..

The MkII's had those awful little crush sleeves that fit over the bolt, in the subframe. That might account for the slop you are seeing, Mark.

K

[RSTPerformance]

Wow, I learn something new every day. You can weld the subframe into the car legally? What allows that?
[/b]


I think that he runs a different class... Just asking for help from the "Racing experts" that frequent the site a lot and offer advice :)

Raymond

[zracer22]

The bolts in mine are not the undersized shafts you describe and they fit the bushings fairly closely. Yours may have had different bolts installed at some point and for some reason.[/b]

I just purchased 4 new bolts from VW, and they also have the smaller shaft.




Wow, I learn something new every day. You can weld the subframe into the car legally? What allows that?
[/b]

Legally???? That never stopped IT racers before! B)

[wclark]

After your reply I checked mine again. It looks like the OEM bolts in the rear bushing/subframe and the front subframe were those with a slightly reduced shaft size. I looked at where mine came from and now realize I had replaced them with 10.9 bolts I got from BelMetric about 3 years ago. BelMetric Fine pitch bolts (http://www.belmetric.com/html/catalog8.htm) I also went a bit longer and ran a tap up in the captive "nuts" to get more bite and account for the flat washers I added.