The broken part completely disables the clutch, and is not readily available. The plastic mounting flange between the firewall and clutch master cylinder, is flimsy, and subject to high stress from clutch pedal, thru clutch linkage to m.c.Linkage pushes the m.c. away from firewall, and plastic mount eventually breaks.When broken,the m.c.moves away from the firewall, instead of actuating the m.c.pushrod. My repair person is having great difficulty trying to find a replacement part. Some of those who also experienced this, have ordered a metal replacement that they found is not interchangable,and cannot return it because it had to be a special order. The only way at this point,is possibly to have to fabricate something.I thought G.M.C.would be more durable.

Update from Aug 28, 2016: repair person had to order the complete clutch pedal assembly at $70.00,to obtain the broken piece that failed.It works fairley well now,but when depressing the clutch pedal,the master cylinder flexes up,which will eventually break the new plastic part.I will try to figure something to eliminate the movement of the master cylinder before it fails again.