Brake Servo Failure?

[johnnyboy666 195 1 Cars]

One of my cars,that has been stood for a while, has developed wooden brakes!

When driving it feels exactly like it would when you try to apply the brake with the engine off, wooden and hard to stop, as if there is no servo assistance.

Does this indicate that the servo is dead? That was my initial assumption, but thought its worth getting a second opinion, as I haven't heard of many dead servos during my time as a 205 owner.

 

If it is the servo, are all 205 servos the same? The car in question is a 1.4, and I have a servo from a 1litre that I could swap out with minimum effort.

 

If it isn't the servo, any pointers? Already changed the servo vacuum hose, and tried bypassing the sunroof vacuum feed within that hose just in case that was leaking, with no difference.

 

Cheers!

[steve@cornwall 100]

Hold foot hard on the brake pedal before starting the car. If when you start it your foot goes down noticeably the servos dead.

[jackherer 543]

Hold foot hard on the brake pedal before starting the car. If when you start it your foot goes down noticeably the servos dead.

 

Isn't that normal, correct behaviour?

 

The Haynes manual has this procedure for testing the servo:

 

Testing

1 With the engine switched off, depress the brake pedal several times. The distance by which the pedal moves should now alter over all applications.

2 Depress the brake pedal fully and hold it down then start the engine. The pedal should be felt to move downward slightly.

3 Hold the pedal depressed with the engine running, switch off the ignition and continue to hold the pedal depressed for 30 seconds during which period the pedal should neither rise nor drop.

4 Start the engine whilst the brake pedal is released, run it for a minute and switch off. Give several applications of the brake pedal. The pedal travel should decrease with each application.

5 Failure of the brake pedal to act in the way described will indicate a fault in the servo unit.

[steve@cornwall 100]

Oops......should have been if it DOESN'T give noticeably.

[Slo 283 1 Cars]

just remove the two nuts on the master cylinder and manipulate it out of the way while you press the pedal if it goes down its the cylinder and if not you got your answer

[johnnyboy666 195 1 Cars]

Well. I decided that before taking the servo off, I would run a hose from my XRADs vacuum pump to the 1.4s servo. When I did that, it seemed to work perfectly, passing all the above tests, then when I disconnected it and plumbed back in the the 1.4 engine, it didn't work again, so my problem is with the amount of vacuum rather than the servo itself.

 

This seems to tally up with my next discovery of the day..... the head gasket has failed, so presumably low compression and therefore low vacuum. Booooo.

[Slo 283 1 Cars]

Oh no you love it long time and no sucky sucky