Sheet metal flexing at master cylinder

[wht968]

I am just starting to replace a master & slave clutch cylinders & hoses on 968 --- they appear original ( the main hose burst) - and I noticed the sheet metal the master clutch cylinder is bolted to flex's when the clutch pedal is depressed.

Is there a quick easy fix for this?

[kdjones2000]

Not really. The typical fix is to add an extra layer of sheet metal to reinforce the area, which means tearing everything out and lots of custom fabrication. Some have even welded a support to the shock tower for extra strength.

Is this a tracked car? Mostly this happens with the heavy pedal forces associated with track conditions.

Good luck, Keith

[John_AZ]

Firewall reinforcement plate:
944 firewall reinforcement plate - Rennlist Discussion Forums

DIY
http://kevingosselin.blogspot.com/2009/02/firewall-gooooo-and-pack-those-bearings.html
John

[flash968]

wht - you have a PM

[John_AZ]

Originally Posted by John_AZ

Firewall reinforcement plate:
944 firewall reinforcement plate - Rennlist Discussion Forums

DIY
Kevin Gosselin: Firewall Gooooo! and pack those bearings...
John

Plate shown is just an example of reinforcement used. 968 slightly modified?

[rmcdonnell]

I had a 924 with this problem.
I'm ashamed to say I fixed it with a shortish length of 1.5inch square wood, can't remember how I mounted it. Lasted more than 10 years too and was very quick, easy and cheap. The point is anything stiff and non-flameable can be used to safely reinforce it... the choice of material is yours. (Don't use wood!).

cheers
Russell

[wht968]

As far as I know it was never a track car. A florida car yes. Not taken care of by previous owners yes. I've probably put 1200 miles on it. Thanks for all the inputs. I'll have a look into them. Thanks to all for the suggestions.

[flash968]

there are a number of reasons the 968 has firewall failure.

east coast cars are more prone to it due to the increased corrosion as a result of the salted roads

a worn clutch fork or clutch fork bearing will create increased load and stress the firewall. these are very often ignored, and wear gradually so you don't notice until it's too late.

a heavier than stock pressure plate will do the same thing. many of the cheap internet suppliers are sending the wrong pressure plate, and the change creates this problem.

if worn, the pivot shaft in the clutch pedal will too. this one often leads to breaking the pedal, as it is plastic.

a real repair involves removal of the items in the way, and then welding in reinforcing material to repair the tear. bracing it in the wrong spot will actually create a larger problem than you started out with too. of course the first thing to determine is why it tore, and then correct that problem.

[wht968]

again thanks for all the inputs. I assume corrosion due to many years of breathing salty air.... a on the coast car. As the car has zero performance mods. As I am pulled many other directions in my life this will be a very low priority for me. Guess I start removal of wires and such. Nice.
Again, thanks for all guidance.

[Arthropraxis]

I have this issue with my car and fixed it a similar way that is in the DIY link above. I used an inch or so wide piece of angle iron in place of his longer bent pieces. The angle iron is formed and has more strength. This made my pedal much lighter and more predictable. Now there is minimal movement of the MC.

[flash968]

don't assume it's just corrosion. if the previous owner changed the clutch, and got one of the internet pressure plates, it could easily be wrong. the fork bearings and shaft are wear items, and almost always neglected. about 9 out of 10 cars are missing the inspection plug, which leads to moisture and contamination getting in there. once that happens, it's downhill.

the salt and corrosion just set the sheet metal up for failure. they are not the cause.

[FRporsche]

A reinforcement plate welded directly to the firewall is the best solution, but there are other quicker and easier ways. Here's a thread with some pics of various other solutions. The first pic is the way I went (mine wasn't cracked, I just wanted to stop the flex).

Cracked Firewall Repair? - Rennlist Discussion Forums