Technical 100hp suspension knock

[Martinlfb]

Hi all.

Can anyone help with this?
My 100hp has an intermittent knock under braking which I can feel through the floor and pedals. The car has recent Bilstein B12 kit fitted along with MM wishbones, droplinks and SKF op mounts. I was thinking it could be an anti-roll bar bush? Any other ideas before I spanner check all the nuts and bolts?

Many thanks in advance
Martin

 

[koalar]

snapped sub frame bolt can be felt through the floor
as can the rear engine mount (likely) as does the lower arm (fail on fit part possible)

Both can sometimes be detected by pulling on the handbrake and slowly engage forwards and reverse. As you go rearward the back will go up and forwards sink down. You don't have to move the car just load the suspension in both directions in a rocking motion.

If I was a betting person I would put 1p on a bolt not tightened fully.

I have come across similar tightening down suspension parts in the past. Where the bolt torques down okay but for some reason it hasn't pulled the plates together properly. Refitting the part has always worked for me.

 

[DaveMcT]

Have you used the Bilsteins to lower the ride height ?

 

[Martinlfb]

snapped sub frame bolt can be felt through the floor
as can the rear engine mount (likely) as does the lower arm (fail on fit part possible)

Both can sometimes be detected by pulling on the handbrake and slowly engage forwards and reverse. As you go rearward the back will go up and forwards sink down. You don't have to move the car just load the suspension in both directions in a rocking motion.

If I was a betting person I would put 1p on a bolt not tightened fully.

I have come across similar tightening down suspension parts in the past. Where the bolt torques down okay but for some reason it hasn't pulled the plates together properly. Refitting the part has always worked for me.

Thanks. I'll check all of that

 

[Martinlfb]

Have you used the Bilsteins to lower the ride height ?

The B12 kit includes progressive rate Eibach springs which lower but 35mm IIRC. It doesn't look or feel a huge amount lower but has improved teh handling and ride quality enormously.

 

[DaveMcT]

The B12 kit includes progressive rate Eibach springs which lower but 35mm IIRC. It doesn't look or feel a huge amount lower but has improved teh handling and ride quality enormously.

BUT it might cause the track rods to foul the ARB or something else on full travel. It might be fine but needs to be checked out.

 

[Martinlfb]

BUT it might cause the track rods to foul the ARB or something else on full travel. It might be fine but needs to be checked out.

Thanks. I will check that as well.
I forgot to say that new track road ends were also fitted at the same time!

 

[DaveMcT]

If rod ends were knocking you'd know. !!!! Shortly before the steering fails. !!!
I'm not suggesting you'd leave broken parts on the car. I'm thinking the altered suspension angle might be allowing something to hit that normally would not get close.

 

[koalar]

The B12 kit includes progressive rate Eibach springs which lower but 35mm IIRC. It doesn't look or feel a huge amount lower but has improved teh handling and ride quality enormously.

35 or 30mm loads of people have used the Eibach -30 in the 100hp without any problems