spongy/low pressure Brakes

[Johnnybizzle]

Afternoon guys,

Bled my brakes a again last night to make them work better, still no joy, the pedal can be pushed al the way to the floor and when pumped a few couple of time the pressure builds up and locks the brakes but still a bit spongy, the m/c is new and allthe lines are new, calipers reconditoned. surely i should not be able to put my foot on the brake all the way to the floor and still shove the car forward.

may there be air in the system closer to the m/c??

Has anyone come across this before.

regards Jon

[Bonzo]

Hi Jon

Ash had a dreadfull time getting a decent feel to the brake pedal.

After hour's & hour's of bleeding the system, his new master cylinder tuned out to be the culprit

I would persist in bleeding the system for a while longer, if no joy, look for a likely cause elswhere

Golden rule of mechanics, even a new component can prove to be faulty

I hope you get it sorted

EDIT

Just to add

The symptoms you decribe are typical of trapped air in the system.

Have you been bleeding the system in a logical sequence ?
Rear brakes first, Furthest one from MC & then the next one.
Front's next, again furthest wheel from the MC first.

Then repeat if needed.

Sometimes it will help if you push the pedal down sharply & pause at the bottom for a couple of seconds to allow the MC time to refill.
Pressing the pedal sharply has been know to shift stubborn air pockets.

[Talonmotorsport]

Are you bleeding the brakes on your own using a one man bleed kit or doing the mate/wife/other on the pedal while you open/shut bleed nipple method? Are you using vac servo mc or a non servo unit?
I've just had a days worth of fun with my heinz 57 escort van trying to get the front to lock before the rear. Found out the light laden valve is not working and the rear drums are warped, great for left foot while power on hand brake type turns but scares the s**t out of oncoming traffic!

[Johnnybizzle]

Thanks for the quick response quys i will have to persist and keep bleedin at the weekend with the missus

[Neil P]

Check your brake pedal push rod height is level with the master cylinder.

I had a hell of a job getting a firm pedal on my brakes. Not sure if it's an amended spec now but the position of the hole in the brake pedal was incorrect in the original book. This means that the pushrod is pointing up at an angle so rather than applying direct pressure to the M/C it starts to fold towards the back of the pedal.

It gave symptoms of air in the system and I had low brake effort at SVA. I have no idea how much brake fluid I ran through it.

It was a real 'eureka' moment when I found it!

If you are working to modified dimensions, then the above will be of no use whatsoever.

Neil

[trickydicky0_16]

Hi
Are the calippers on the right way (i did this) changed them over apresto they work

[Johnnybizzle]

Well after taking advice, i have taken off the rear calipers turned them the right way up and re bled, They could now stop a steam train im well impressed.

[trickydicky0_16]

This kinda thing happens, like i say i did this in the front....... lol better chek the back now....