With time, the fluid filled engine mounts are known to fail on 911s. This manifests itself as a bouncy rear end and difficulty in downshifting through the gearbox when braking hard. In the worst case a failed mount can transmit shocks through the engine carrier with the result that it can fracture and the engine fall out! So I thought with another trackday coming up I should examine mine as there is no record of them ever having been changed.
The left one was sagging a bit:
The right one was sagging a lot:
So I duly ordered new mounts which cost £133 + VAT for the left one and £141 for the right one. This included a discount of 15% from the OPC which I simply asked them for:
Fitting the new mounts involved taking the strain of the engine with a trolley jack, undoing a large nut underneath the mount to release if from the carrier and then undoing two small bolts that held the mount in place. Here's the left mount removed:
The new right mount from the top:
Compared to the old mounts the pictures below show there is only a small gap between the mounts and the frame. I also used some emery paper to clean away some of the unsightly rust on the rear heat shield (that you can see in the photos above) and applied some high temperature engine paint.
New left mount in place:
New right mount in place:
Here are the old mounts. They don't look too bad but when shaken I can hear hydraulic fluid sloshing around which indicates that they had leaked and were therefore were no longer capable of absorbing shocks transmitted from the engine and chassis:
Even on the first spirited test drive I could feel the difference. The mounts have really stiffened up the back end. It used to bob about on uneven road surfaces and crash over bumps. It's much, much more settled now. The gear changes are much slicker. Shifting down to 2nd under heavy braking used to be tricky and required patience. Now it just slots home. I'd heard before that duff mounts caused difficult shifting. It'll be interesting to see what it now performs like both on the road and on the track.