MOT Failed need help with 2 issues please

[johhny5]

Took van for MOt today and was all going well then :
1-At the end of the brake test , saw some vapour comming from under the van, pedal went soft, then found metal brake pipe from front to the rear brake 'T' piece split and leaking fluid .Question is can i get a replacement pipe or will it be easier if i get a mechanic mate to make a length of pipe and sort the ends??
2- if failed on the exhaust output at 6.25 % CO and max is 4.5 %. Thing is the guys at the garage said when i bring it back we can put it on the machine and reduce the CO to a level that it will pass on before the re test.What am i looking for as a percentage and at what tick over revs. I have heard if you run it too lean its bad for the engine.

Its a 2,0 cu Aircooled engine in a 1981 westy.
Cheers

[Hacksawbob]

it is usual practice for a garage to cut the pipe to the length, add the screw ends and flare it, not difficult shouldn't cost more than £10 for the pipe itself, removing old can be a different story.

[kevtherev]

High CO could be an airleak on the inlet side
check your vac hoses and gaskets for splits.

[johhny5]

Thanks for the reply,
Recently i have changed the gaskets under the carbs,checked the inlet manifolds and replaced the vac pipe conections between the inlet manifolds , so im pretty sure that i have no air leaks.
I recently had the carbs balanced and timing checked by a guy @ van west but ever since i have had the van it seems to be drinking fuel and the exhaust pipe is sooty.
SO i will reduce the CO to what ever will pass the test ???
I am going to remove the old metal brake hose on Monday so one of my mechanic mates can make a new one up and then fit it and bleed the brakes with the Mrs help.