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[minifreek]

Hello folks, the brakes on the Miggy have developed a strange fault where when I first use it in the day, the brakes are shite and absolutely solid to the point where they kinda work but no-where near as good as they should be... now this is intermittent as it doesn't happen everyday just when it feels the need to try and shit me up I guess... but once it has scared me shitless for a couple of minutes it doesn't do it for the rest of the day.....?

Iv checked for vacuum leaks and as far as I can see/hear there are none...

Could it be the master cylinder is on its way out maybe, or is it a sticky caliper...?

I can do nothing tomorrow as I have to go to my Mums, but Thursday I'm adjusting the handbrake as the HB shoes need replaceing....

Anyone any thoughts on what it might be...?

Fanx folks

[05omegav6]

If you pump the pedal until it's solid with the engine off, then start it, the pedal should drop as the vacuum builds. If it doesn't, then the servo is toast.

Before you try that test, and again before starting the car, try and pull the big vacuum hose from the servo... if it comes out easily with no hiss, then the non return valve is faulty.

Cheap enough to replace the valve, but you will need to soak the pipe in hot water to separate the old valve from the pipe and fit the new one

[minifreek]

Thanks for that, I shall give them both a 'go' tomorrow when Im back from Mothers

[05omegav6]

Thanks for that, I shall give them both a 'go' tomorrow when Im back from Mothers

If you're having problems at the first drive of the day, then the vacuum pipe check will need to be done when the car has been stood overnight. This will then prove that the vacuum is leaking, (through the oneway valve if you can't hear it).

The brake pedal test can be done whenever, just be sure that the engine is off when you pump the pedal and hold it down whilst you start the engine. There's a maximum time that it should take for the pedal to sink once the engine starts... iirc around 3 seconds at idle a healthy servo will start to sink the pedal the instant the engine fires, a weak one will take a while...

[chrisgixer]

Only ever heard of one servo issue on here. But plenty if vac pipe faults. Usually where's it's rubbed though on the ac pipes by the scuttle drain. Almost impossible to spot unless you know to look there or you remove the pipe.

[minifreek]

Righto folks, just been outside and pumped the pedal until hard, started the engine and the pedal sank almost immediately, so presuming the servo is OK...

Where is the 1 way valve located... and whats it look like...?

Thanks

[RobG]

Righto folks, just been outside and pumped the pedal until hard, started the engine and the pedal sank almost immediately, so presuming the servo is OK...

Where is the 1 way valve located... and whats it look like...?
Thanks

Pipe from brake servo to plenum

[minifreek]

Aaaaaaah thanks for that, Im sure I have 1 of them in me spares bin....

Can these be tested....? maybe by sucking or blowing...?

I presume it will only work 1 way, as the name suggests....?

[Kevin Wood]

The other test to try is to stop the engine, and see how many pumps of the pedal you can get before the assistance disappears. You should get a good 4 or 5 pumps of the pedal. If this doesn't happen, the non return valve may have failed, and this could cause the assistance to disappear when engine vacuum is low.

[minifreek]

Thanks for that, I shall give it a try later

[plym ian]

Aaaaaaah thanks for that, Im sure I have 1 of them in me spares bin....

Can these be tested....? maybe by sucking or blowing...?

I presume it will only work 1 way, as the name suggests....?

Don't say that. He who shall not be named May be lurking

[minifreek]

Im trying to flush him out but I dont think he's biting tonight.... LOL