Servo issues?

Rebuilt front callipers with new pistons. Bled through the whole system.
Car pulled to the right on heavy braking, but was sure there was no air as put loads of fluid through.

yesterday I had 3te trailer on and noticed my braking effort was massive to get the car to slow- trailer brakes work well, so couldn’t understand.

unhooked the trailer and the issue continues- really heavy with my foot to get braking action. Strangely the pulling to the side issue has now gone.

put through more fluid last night, still no air found.
Engine off, the pedal has a bit of travel before it’s hard (expected amount). It’s not spongy, in fact it’s quite solid. I don’t find pumping the pedal increases pressure though.
With foot on pedal, turn the engine on and there is no movement in the pedal thanks to the servo.
Took hose off servo and there is good suction.

so I don’t know where to look now.
No air
Pulling to side has stopped
Servo packed in overnight?! It’s only 6 months old and a decent branded one!

Pulling is most likely the whole lot bedding in/sorting itself out.
Engine off, pump pedal until hard, hold foot on pedal and start the engine, pedal should drop as you keep pressing it.

New does not mean good!

Yeh i assumed as much for pulling to the side, so hopefully resolved its self.
pedal doesnt seem to build pressure, but it is hard. Engine on there is no change.

Servo worked fine since new but stopped working overnight which is strange.

Any thoughts how i can confirm whats going on?

As said above, the accepted method of testing the servo is to press the brake pedal several times with the engine off to clear any residual vacuum.
Once you have done this press the brake pedal and KEEP IT DEPRESSED while you start the engine, if your servo is working you should feel the brake pedal dip as the engine starts.

Rougharse Racing said:

As said above, the accepted method of testing the servo is to press the brake pedal several times with the engine off to clear any residual vacuum.
Once you have done this press the brake pedal and KEEP IT DEPRESSED while you start the engine, if your servo is working you should feel the brake pedal dip as the engine starts.

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I understand that - i noted that in my OP too. So with foot on pedal, starting the engine, the pedal doesnt move anymore. Is that a case of "servo replace" or could there be somethign else?

Rorie said:

I understand that - i noted that in my OP too. So with foot on pedal, starting the engine, the pedal doesnt move anymore. Is that a case of "servo replace" or could there be somethign else?

Click to expand...

that would be servo vac pump or a leak between the 2

Does seem to be a servo problem. If you put your thumb over the end of the vac pump pipe [ engine running ] does it stick ? If so good. There is a one way valve where the pipe fits on the servo, may be faulty. Can be hard above engine noise but try listening at the servo for hissing air leek.

I’ve pulled the hose off the servo and there is definitely a vacuum.
Looks like the servo then ‍