Losing vacuum on brakes

[gumby6371]

As I've said before my brakes are good when first applied then pretty poor if used soon after.

I've recently fixed a vac leak on the swirl actuator which has fixed the EML/limp mode, this improved the brakes a little but there still not where I'd like. All the EGR and air dozer piping is now in the boot so I know there is no leak there new acuator and associated EV fitted.

Brake pedal is hard with the engine off and softens up to normal position on start up so I presume it's just a small leak somewhere on the vac circuit.

Here's my question, if I blank everything except the servo I'll get dash lights but will I do any damage?
Logic says I'll have maximum braking assistance in this configuration so if I still lose braking efficiency it has to be pump, vac pipe or servo??
If brakes are good I can add things one at a time until the fault is located...I think
If brakes are poor with only servo connected what sort of vac pressure should the pump be outputting?

[jonsowman]

Here's my question, if I blank everything except the servo I'll get dash lights but will I do any damage?

The only thing that might cause damage is the turbo permanently being on full boost. People have driven cars with vac faults causing this for ages so it can't be too big a problem, but I'd keep testing time to minimal and not rag it too hard whilst it's on full boost.

Logic says I'll have maximum braking assistance in this configuration so if I still lose braking efficiency it has to be pump, vac pipe or servo??

Agreed, try and use some brand new vac hose if you have any available to ensure that isn't the problem.

If brakes are good I can add things one at a time until the fault is located...I think
If brakes are poor with only servo connected what sort of vac pressure should the pump be outputting?

You should be seeing at least 850mb vacuum at the pump (i.e. 850mb below ambient). I'd start to worry at less than 800mb.

[gumby6371]

Thanks Jon,

I'll pick some new hose up on my way home from work, shouldn't take long to change it all as there isn't much left any more