16 replies to this topic

[jackready]

I have a problem with my brakes the pedal is really soft i have:

4pot calipers.
new wheel cylinders.
new master cylinder.
stainless braided hoses.

i have bleed them loads of time with and with out a eezi bleed
when i have the eezi bleed on the car the brake pedal s really good but when i take it off is goes soft again.

some one said to me about the brake pressure valve could this be the problem ??

Cheers jack

[minislapper]

Are the calipers etc newly fitted? Are they on the correct way so the nipples are pointing in the right direction, ie at the top?

Are the rears adjusted properly?

Try leaving the pedal jammed down overnight.

[jackready]

Are the calipers etc newly fitted? Are they on the correct way so the nipples are pointing in the right direction, ie at the top?

Are the rears adjusted properly?

Try leaving the pedal jammed down overnight.

yes there are but the brakes where like that before i fitted these ones

i have 3 nipples on each caliper one on each side and one on the top

yes i adjusted the rears up sunday becuase some one said that to me saturday



cheers jack

[cowboy]

what type of master cylinder do you have? and how did your back brakes bleed?

if you have the master cylinder with the two pipes, try bleeding the top pipe before you bleed the brakes. this was a problem i had with mine;

[TOMMO0302]

What 4 pot conversion hoses are you using? I had real trouble actually getting a seal on the old ones i had, despite everything being done up as tight as could be. Therefore, as you describe, no amount of bleeding will get rid of a soft pedal.

[Dan]

Does the pedal go soft the instant the Eezi-bleed is removed or does it take a few strokes of the pedal for this to happen?

[taffy1967]

some one said to me about the brake pressure valve could this be the problem ??

It's possible Jack and i've heard that part can be a right pain when it fails, but i've never experienced a problem with it myself.

[jackready]

what type of master cylinder do you have? and how did your back brakes bleed?

if you have the master cylinder with the two pipes, try bleeding the top pipe before you bleed the brakes. this was a problem i had with mine;

hi here is a picture of the master cylinder
[attachment=28685:img121.jpg]


I bleed there rear n/s,
Then the rear o/s,
Then front n/s
and front o/s

which pipe would i bleed ??
and would i just crack the pipe off to bleed it ??

cheers jack

[jackready]

What 4 pot conversion hoses are you using? I had real trouble actually getting a seal on the old ones i had, despite everything being done up as tight as could be. Therefore, as you describe, no amount of bleeding will get rid of a soft pedal.

hi here is a picture of my hoses on the car
[attachment=28686:img126.jpg]
they all look like they are sealing i mean there is know fluid leaking for them
but can air get in with out fluid getting out ??


cheers jack

[jackready]

Does the pedal go soft the instant the Eezi-bleed is removed or does it take a few strokes of the pedal for this to happen?

hi

i think it takes a few strokes cant really remember was the other weekend

cheers jack

[Dan]

You aren't talking about having a solid pedal with the engine off and a softer pedal with the engine running are you? You have a vacuum servo so it's meant to be like that.

[jackready]

You aren't talking about having a solid pedal with the engine off and a softer pedal with the engine running are you? You have a vacuum servo so it's meant to be like that.

know im not talking bout that
when the engine is off and the Eezi-bleed is on i have a really good pedal and when i take it off it goes soft

cheers jack

[jackready]

hi
i was talking to some one today and they said try taking the brake pressure valve out and putting in 2 t-piece or 2 stright link pipes wolud this be ok to do ????
would this affect brakes as in to much fluid goin to the rear ???


cheers jack

[Dan]

When talking to anyone about the FAM7821 valve you need to remember that nobody, anywhere actually knows what it does. Most people assume it is a pressure reducing valve for the rear brakes but it definitely is not. Some people call it a PDWA and it definitely isn't one of those either. The closest I have come to figuring out what it does is to realise that it seems to be a delay valve that makes the rear brakes engage more progressively but this is still just a guess. On this site we have sliced these valves up and dismantled them to try to find out what they are.

You can try to replace it if you like but personally I would only advise replacing it with a proper pressure reducing valve of the adjustable type or a brand new FAM7821 valve. They are very well known for failure but the effect they normally have when they fail is to make the car slew dramatically sideways under braking as the rear brakes engage too well. This is what WILL happen if you just replace the valve with straight pipes. DO NOT use a tee piece either. A second hand valve will usually turn out to be in the same condition as the one it is replacing and so I only fit new ones. If you fit an adjustable pressure reducing valve you must take the process of setting up the front to rear brake bias seriously and tell your insurance company you have done it, they probably won't like it. Also it must not be adjustable from the drivers seat.

It could be that this is the problem but it will be an expensive item to replace so you should have a thorough check of everything else first.

[jackready]

When talking to anyone about the FAM7821 valve you need to remember that nobody, anywhere actually knows what it does. Most people assume it is a pressure reducing valve for the rear brakes but it definitely is not. Some people call it a PDWA and it definitely isn't one of those either. The closest I have come to figuring out what it does is to realise that it seems to be a delay valve that makes the rear brakes engage more progressively but this is still just a guess. On this site we have sliced these valves up and dismantled them to try to find out what they are.

You can try to replace it if you like but personally I would only advise replacing it with a proper pressure reducing valve of the adjustable type or a brand new FAM7821 valve. They are very well known for failure but the effect they normally have when they fail is to make the car slew dramatically sideways under braking as the rear brakes engage too well. This is what WILL happen if you just replace the valve with straight pipes. DO NOT use a tee piece either. A second hand valve will usually turn out to be in the same condition as the one it is replacing and so I only fit new ones. If you fit an adjustable pressure reducing valve you must take the process of setting up the front to rear brake bias seriously and tell your insurance company you have done it, they probably won't like it. Also it must not be adjustable from the drivers seat.

It could be that this is the problem but it will be an expensive item to replace so you should have a thorough check of everything else first.

cheers i didnt think you could take it out because if you could then why would it have been in there in the first place.

would there be anything else is could be

i cant see what it can be

ive tryed every thing

is this the fam7821 ????

cheers for the help jack