Powertune remote brake servo

[AGR 441 B]

Fitted the LE 72696 unit a few years ago but its started to hang on after braking. Brakes work well but hang on and only release after a few seconds when you want to pull away.

 

What is the problem? Can anyone who has taken the unit apart tell how easy they are to service or where the internal details can be found.

 

Thanks for your attention.

 

[graeme]

Are you using SBF? This has been blamed before.

 

Are you sure its the Servo? Failing flexible hoses can cause brakes to hang.

 

Graeme

Edited September 21, 2014 by graeme

[AGR 441 B]

Thanks for the reply Graeme, like the TRs, nice to see them out of the workshop.

 

Still on DoT 4 fluid, replaced the four flexis with Goodridge and put on new Master Cylinder. Someone said there was a toggle switch type arrangement inside that may be sticking. Wondered if it was serviceable?

[ctc77965o]

I don't know this Servo in particular, but in general on a remote servo this hanging-on is caused because the air valve doesnt close properly. This can happen because the air valve seat is damaged or contaminated (it's usually a rubber ring or disc), or because the little hydraulic piston that operates it is sticking/not returning. If everything looks OK and it still hangs, then you could try a slightly stronger return spring on the air valve.