Brakes again but this isnt simple...

[paulob1]

brand new mc, think that is the next play, but going to strip the calipers first...then its take pumaspeed and swap out parts...cos its driving me nuts...

 

[paulob1]

pumaspeed is my other standardish puma

 

[mix2000]

Re-Asking the question? Are the flexi-hoses from the donor brakes a larger bore and did you fit them with the calipers?
Did you pinch the existing hose to stop fluid?

 

[DOH]

I have had a similar problem to this on a Citroen when I changed callipers. Things to try:

1) Not sure of the exact set up of the Mondeo calliper but it probably has the 2 alen key bolts that holds the caliper on(like the standard Puma)? If so , Remove your brake pads , now check to ensure that you can move freely by hand move the calliper in towards disc and out again. You are checking to see if everything is running freely on the alen key sliders. If not remove alen key bolts clean them up and then apply copper slip grease to help them move more freely.

2 From your previous description, it appears that the piston gets pressed out but won't return unless you release the bleed nipple?
One thing to check here is can you push the piston back with only slight pressure with a screwdriver against the back of the brake pad?

After pistons have been cleaned up when refurbing callipers I get them so that I can push the pistons back by hand (with the bleed nipple open)

3) The final thing to try , which I don't think has been mentioned yet by anybody?
I had this on a Citroen after swapping callipers and they too were sticking on .
I discovered that a tiny bit of dirt had moved from the master cylinder reservoir into the brake line. I know you've changed the master cylinder , but the dirt may have got into the line before you changed it.( Also that black sludge build up inside the master cylinder Reservoir)
So what you need to do, is disconnect the brake lines that go to each calliper and then at the other end and blow them back from the calliper end with an airline. It may even be a tiny fragment of rubber hose, that's enough to do it.

Remember the dirt is being forced forward under master cylinder & servo pressure , but when you release the brake pedal, there is nothing to dislodge the dirt jammed in the line, hence causing the piston to jam on.

 

[crispy1980]

right, are you sure there isnt an inline valve on the brake lines? bloke at work was talking about this yesterday on his car, ok it wasnt a puma. but he had exactly the same symptoms and he changed everything to no avail. there is a valve that only allows a certain amount of fluid back to mc in order to maintain pressure in the braking system. on his this had failed and wasnt allowing hardly any fluid back which in turn builds up pressure until the brakes lock on. as an extra coincedence he had also just fitted new calipers and lines when this valve failed.

 

[ScubaSteve]

if there is, it will be on the mastercylinder, theres nothing on the lines themselves.

 

[paulob1]

calipers off this week, wont get chance for a couple of days but i will...its made the car completely unuseable...

 

[paulob1]

sorted it...it was the master cylinder, the actuator on the block was longer than needed so once the brake was activated it stayed on and would not release, different master cylinder fitted works a treat. the ST200 front calipers and disks are very powerful...very good indeed. am very happy now...

 

[ScubaSteve]

should have listened to me 3 weeks ago

 

[lb81]

should have listened to me 3 weeks ago

:lol:

Your going to be saying the same thing to me in 6 months when I start moaning about rust coming through my Hammerite :roll:

 

[ScubaSteve]

haha you may be lucky