No Brakes !

[Mr Cerbera]

Sorry, copied some posts in order to start this very unsettling thread

1) During my recent delve into the bowls of my motah, I found a very frayed pipe which was hoseclipped onto a toothed Dowel (?) on the inside odd bank of the block. (Indicated ‘A’ in the pic). Does anyone know what this feeds/fed by ?
I thought it may be part of the Heating System as the pipe disappears into the Bulkhead.

Mr Confused

CerbWill said:

A is the brake booster vacuum hose. .....

Hi William

Have put everything back together. Went out for a test drive and had No Brakes

Do I have to wait until some sort of negative pressure is built up after altering this pipe ?
If so, how on earth does that negative pressure stay constant when the car has been stopped for a while (i.e. between 2 mins and 2 months) ?

Ta !

PJ

[ukkid35]

Did you tidy up the end of the vacuum pipe and put it back on the intake manifold vacuum connector (A) securing with a working hose clip?

If not then you now have massive vacuum leak so presumably no idle, and manual brakes with no power assistance.

You could make the car slightly more difficult to drive by disconnecting the Power Steering pump coupling as well.

[ukkid35]

The vacuum line will have a check valve in it somewhere, but as long as the engine is running you will be generating vacuum anyway.

That is why you get one or two goes at the brakes when the engine is off, before you lose all power assistance.

[TwinKam]

When you say you had no brakes. presumably you didn't mean that the pedal went to the floor (hydraulic failure) but that the pedal was rock hard but the car didn't slow as much for the usual leg effort (no servo assistance)?
Assuming the latter as more likely, (as that's the only part of the braking system you've recently touched) and that you reconnected it correctly at the inlet manifold, then it's possible that the hose has failed elsewhere or that the servo itself has. Vacuum (and therefore servo assistance) is available immediately the engine starts, the 'reservoir' of vacuum will be used up in three or four presses of the pedal once the engine has stopped, but otherwise can decay in anything from a few minutes to many hours.
Try this (also in another car to get the idea):
Engine off, fully depress the brake pedal half a dozen times (using up all vacuum). It should now be rock hard.
Now start the car with your foot hard on the brake, you should feel it move down.
Switch off and depress the pedal fully a few times and you'll feel the assistance decrease until it's rock hard again.
If yours isn't doing that then the servo or hose are goosed/blocked.

Edit: You beat me to it, Paul!
Must learn to type faster, must learn to type faster, must learn...

[TwinKam]

Did you have a struggle getting the old hose back on to the brass tail? I wonder if you've 'shaved' a bit off the inside of the pipe and that's causing a blockage?

[ukkid35]

TwinKam said:

Edit: You beat me to it, Paul!
Must learn to type faster, must learn to type faster, must learn...

Yes but you beat me in the useful facts vs pointless sarcasm stakes

[CerbWill]

I had this once after reconnecting the hose with a brand new jubilee clip. On inspection it turned out I'd been so paranoid about ensuring a good seal so the brakes would work that I'd overtightened the hose clip and it'd cut through the hose = no vacuum.

[FarmyardPants]

ukkid35 said:

You could make the car slightly more difficult to drive by disconnecting the Power Steering pump coupling as well.

[Byker28i]

FarmyardPants said:

ukkid35 said:

You could make the car slightly more difficult to drive by disconnecting the Power Steering pump coupling as well.

6 psi in the tyres if you want to do this properly

[Mr Cerbera]

Byker28i said:

FarmyardPants said:

ukkid35 said:

You could make the car slightly more difficult to drive by disconnecting the Power Steering pump coupling as well.

6 psi in the tyres if you want to do this properly

You have, in fact, defined my first few miles back on the road.

No Oil in the Power Steering Oil Reservoir and 1.2 Kg in all tyres.

Brakes returned after a coupla miles (Thank goodness )

SPA, here I come

(Actually, I would like to know what does the sucking on the protruding tube ?)

Edited by Mr Cerbera on Friday 12th May 08:20

[Byker28i]

A few test drives, check all oil, water, brake, clutch fluid levels, tyre pressures.
Take oil, tyre pump etc

[FarmyardPants]

Mr Cerbera said:

(Actually, I would like to know what does the sucking on the protruding tube ?)

On the intake stroke as the piston moves down it tries to draw in air/fuel into the combustion chamber. If the throttles are closed, this creates a partial vacuum in the inlet manifold. This is what is sucking the air out of your brake servo. There's a one-way valve in the tube which prevents the air going back in again.