Brakes again but this isnt simple...

[ScubaSteve]

bias is self adjusted in the master cylinder no external adjustment

 

[Voa]

Sure your brake lines are ok and you don't have any small holes or damage in the brake lines running to the backup of the car.

 

[paulob1]

well the brakes worked fine on the st we took them off, just days prior to fitting, we have changed all of the hoses except the ones to the master cylinder, it has a new master cylinder and new rear brake shoes, wheel cylinders and handbrake adjusters...its all now getting crazy, can only believe its the abs controller, do they fail?

 

[yippeekiay]

Sure I read on the TIS the other day about some adjuster near the rear end :?

Can't find the bloody thing now as it's not exactly a well oiled (excuse the pun) bit of software to navigate.

 

[mix2000]

bias is self adjusted in the master cylinder no external adjustment

How is lowering catered for with no external adjustment?

 

[yippeekiay]

You've lost me mix (it is late/early mind), how would lowering effect the brakes or require brake adjustment?

I'm going to sleep, too much thinking for one night, my head is hurting :?

 

[mix2000]

Brake bias is factory setup and when the car is lowered , the change in centre of gravity and suspension inertia changes. In some sense give the car the dynamics of an overloaded vehicle of the same dimensions. When the this dynamic changes the factory brake bias is no longer accurate.

 

[Voa]

There has to be some automatic bias compensation built in, because the ride height of the car changes as the car gets older and also as the car compresses on it's suspension under different road conditions ie hard braking. How does the centre of gravity of the car come into the mix ? Are you saying the weight distribution if the puma is 50/50?

Sorry you lost me as well ?

 

[ScubaSteve]

il just repeat what i said in my earlier post then, the rear bias IS controlled in the master cylinder

Vehicles fitted with the standard braking system have pressure conscious reducing valves (PCRVs) fitted in the master cylinder outlet ports. The PCRVs control the hydraulic pressure applied to the rear brakes reducing the risk of rear wheel lock-up under braking.

..from tis

 

[mix2000]

The lower the car the lower the change in weight transfer in the car during braking, just wondering if an electronic means would pick this up if said car was radically lowered.

 

[ScubaSteve]

if you lower it technically the bias will be out, and you cant adjust it, the car bias is setup for standard ride height etc.

wether youd notice enough to cause problems is another thing

 

[mix2000]

Probably at limit in bad conditions. (shouldn't be there anyhow :lol: )

 

[paulob1]

hmm okay abs bled up, all seems okay but still front brkaes coming on and staying on, more movemtn than before but still basically staying on...its got me totally baffled.

we have bled the system exactly how ford recomend. think its time for the calipers to come off again...thing is when we bleed the caliper it releases instantly, so it isnt a sticking caliper..and its on both front wheels, it doesnt seem to affect the back brakes....

 

[mix2000]

Possibly sounds like a flexible hose bore problem if all else is exhausted?
Is the flexi-pipes from the donor brakes a larger bore or that both flexi hoses were somehow pinched during installation leading to restriction during brake release.

 

[paulob1]

still no luck, not sure what else I can change now...

 

[mix2000]

The only other thing else I can think of is gravity bleeding all four at once and top up regularly while doing it.

 

[ScubaSteve]

got to be MC imo, if you are ruling out caliper strip down

 

[Voa]

Tend to agree with Steve .You said you changed the MC was this for a new one or a second hand one ?

 

[ScubaSteve]

thing is is that you come on with this problem baffled, saying youve bled the brakes and are out of ideas, so we suggest some things to try, then you come back and say youve bled the brakes again and are still baffled :lol:

 

[yippeekiay]

If it was me I'd try another MC of one of your other cars that is working then you can eliminate that part once and for all.