Flange on ACE pipe going to valve block

In short, yes! - if I've correctly identified what you're calling a flange.

If you've dismantled it you'll have seen that it is not a 'flange' which is part of the pipe(s) but a retaining plate that holds several pieces down the hole. Without it they'll be forced out by the hydraulic pressure. As those parts seal the pipes into the valve block you'll have a leak probably bigger than the one that you are trying to repair.

I'd suggest that copper is not a good idea as it readily work hardens and subsequently breaks. The ACE system has high frequency pressure spikes in the hydraulics and would be particularly prone to problems.

Cost avoidance, Ben - seriously think about ditching the ACE.

Thanks for your reply,

The flange I was referring to is part of the pipe, its like a ridge in the actual pipe before it reaches the seal. The pipe had cracked around this.

Having looked at the problem further I'm going to investigate removing the ACE system, does seem by far the least hassle.

Do you know if this counts as a modification needed to inform my insurance co of?

Cheers

Ben.

Fixed the leak by removing the seals and taping the block to accept a 1/4bsp pipe connector.

In answer to the question below: My insurance co state that as this is a downgrade to 'stock' then there is no need to inform them, if going the other way then it is a modification.