brake pedal goes to the floor

[S2 Giles]

Hi Folks

Just woken up the S for the summer and she's not been run since November, the only problem I can find is the fact I have NO BRAKES

The pedal is going right to the floor

After a run out I still only have rear brakes, the fronts are non existant.

Now the only other bit of info is that I had a new slave cylinder last summer.

I am guessing there is air in the system, what do you think ?

[clarenceboddiger]

It could well be that, also have you checked that you actually have fluid in the reservoir.

[S2 Giles]

yeah the fluid is fine, reservoir is full & level is the same as it was last year.

[ketvrin]

S2 Giles said:

Hi Folks

Just woken up the S for the summer and she's not been run since November, the only problem I can find is the fact I have NO BRAKES

The pedal is going right to the floor

After a run out I still only have rear brakes, the fronts are non existant.

Now the only other bit of info is that I had a new slave cylinder last summer.

I am guessing there is air in the system, what do you think ?

I'm not sure what you mean about "a new slave cylinder" here Giles ? are you saying you fitted new slave cyliders (two) to the rear brakes or are you describing the calipers and pistons of the front brakes ?
If your reservoir is full but your foot goes to the floor, either there is air in the system or the "new slave cylinder" is too big and is not getting moved by the amount of fluid being pushed through the system ?

my guess is its air, but I'm intrigued by this new slave cyl...?

cheapest first option is to completely bleed the whole system again and take it from there...

K

[greymrj]

Certainly sounds like air in the system. Sounds like you have hydraulic pressure at the rear but not at the front. This is a tandem system (effectively two separate master cylinders in line) with an inclined master cylinder and the front chamber is the one which operates the front brakes. It is also probably the highest part in your system and the place any air in the front brake system might go to in a long lie up of the car. On your car it should be possible to bleed the front brakes only to get rid of the problem. BUT, as the air may well be a long way from the bleed valve on each caliper, it may take a couple of refills of the reservoir before the air comes through. You may also need to bleed near side first (longest run), then offside, then repeat to ensure no air remains in the master cylinder. One small trick that might help; with the reservoir full just unscrew the top front brake pipe connection to the master cylinder very slightly until fluid starts to come out then re-tighten, it can reduce a pocket of trapped air and 'prime' the front chamber. Carefully wash off any spilt fluid.

Of course there is then a bigger issue; how and where did the air get in? Somewhere there is likely to be a problem that is likely to get worse.

[S2 Giles]

Thanks very much for the advice

I had the master cylinder (sorry - not slave) replaced and I was never astounded by the improvement in braking, it never felt great but worked fine. I have only driven maybe 500-1000 miles since then so i think the air may of got in from the change of cylinder at the specialists.

I may bleed the brakes in the next couple days as that is less hassle than taking the car back to the specialist. If that doesnt solve it then i'll take it back to them.

There are certainly no leaks or puddles that i can see

Thanks again

[ketvrin]

I take it the Master Cylinder was a direct replacement ? (Ford or SAAB)

K

[S2 Giles]

It was replaced by Dulford / TVR Car Parts, so we must assume its the right part

[S2 Giles]

.....Update................

I have solved the problem ! turns out we were right, two months without use was enough to let air gather in the master cylinder. I have bled the brakes and hey-presto I have all my braking power back.

Thanks very much for the advice