The never ending brake saga !!

[fuzzedup]

Hi all, well if you see my previous posts I've been battling with the brakes on my mk5 campervan. At the moment I've got great brakes on the rear (changed shoes, cylinders and adjusted with the auto adjuster) but my front brakes are pants !! I've swapped both calipers, both front hoses and bleed the living day lights of them. There's not a drop of air in them !!
The mystery is when I clamp the front hoses the brake pedal goes solid and the rear brakes are great, but when I undo the clamps the pedal goes soft and to get any bite I need to pump them and even then the pedal needs to be right on the floor for the front to lock up. The only explanation I can see is the master cylinder is not holding pressure on the front side, is this possible or could I really have two duff calipers.. Any help would be great as at the moment I'm stumped ???
Cheers all
Paul (a totally p!ssed off tranie owner)

[ABA]

if it goes solid when you have clamps on the front flexi pipes its not the master cylinder has it got a b s

[cherniy_chack]

if it goes solid when you have clamps on the front flexi pipes its not the master cylinder has it got a b s

Yes.
I had a similar problem with my MK3.
The solution to the problem was to minimize the gaps between the rear brake drums and the pads.

[fuzzedup]

if it goes solid when you have clamps on the front flexi pipes its not the master cylinder has it got a b s

Yes.
I had a similar problem with my MK3.
The solution to the problem was to minimize the gaps between the rear brake drums and the pads.

Would this effect the front brakes ?? I've clamped the rear hose and it made no difference to the front, wouldn't this point to the front side of the brakes ?? As for abs, no it's the old standard type

[dumper]

In your last post you’d fitted new pads have you run it up road and beaded them in by driving with your foot on the breake till pads warm up and you can smell them then let them cool down and do it again till they are beded in you will have more travel on break pedal

[fuzzedup]

In your last post you’d fitted new pads have you run it up road and beaded them in by driving with your foot on the breake till pads warm up and you can smell them then let them cool down and do it again till they are beded in you will have more travel on break pedal

No, I've only fitted new shoes on the rear drums. The front discs and pads are pretty new so didn't swap them. Is it possible for the seams to go on only a section of a master cylinder ??

[dumper]

I think if the only old part on the system is the master cylinder then you need to re seal or replace it in the past I have knackered a master cylinder when chargeing front pads pushing the cylinders back

[Chug]

If clamping the front makes it solid but clamping the rear makes no difference, I would suspect the seal for the rear section of the master cylinder.

[fuzzedup]

If clamping the front makes it solid but clamping the rear makes no difference, I would suspect the seal for the rear section of the master cylinder.

Cheers chuggy, I thought this might be the case. Just needed someone with more knowledge to confirm it.
Ille get a new one and get back with the outcome

[grumpygramps-2007]

i was advised when you push the pads back to open the bleed nipple abit to let the pressure off.saves the mastercylinder some how. gramps.

[dumper]

i was advised when you push the pads back to open the bleed nipple abit to let the pressure off.saves the mastercylinder some how. gramps.

You’re probably right but in th last 45 years I’ve pushed the pads back hundreds of times and only knackered one master cylinder luckily was a company van and not my own

[vanfox]

I just changed front pads on Friday, pushed the pistons back fitted the pads and built up the brake, two or three pushes and all is well, brakes working both sides. Have you tried clamping just one front hose at a time?

[fuzzedup]

I just changed front pads on Friday, pushed the pistons back fitted the pads and built up the brake, two or three pushes and all is well, brakes working both sides. Have you tried clamping just one front hose at a time?

Yes, when I clamp one hose at a time the pedal does start (not loads) to firm up but it's the same firmness if I clamp either side. If I put clamps on both front hoses the brakes like stamping on a brick. I've ordered a new master cylinder today and a drivers side replacement caliper as even though it's a reconditioned caliper I think I could see fluid weeping from the boot.

[cherniy_chack]

If there is no air in the brake system, the large free travel of the brake pedal is associated only with large gaps in the working brakes.
In the front brake mechanisms, the gaps between the pads and discs are determined only by the elastic deformation of the rubber sealing rings of the front brake cylinders and, by definition, can not be large.
https://www.google.com/url?sa=i&rct=j&q ... 1247204253
https://www.youtube.com/watch?time_cont ... 4fAPpj3p48
In the rear drum brakes, the gap between the pads and drums is determined by the compression springs and various additional mechanisms to minimize the gap.
At the Transit MK3 ... MK5 this additional mechanism is often defective.
Therefore, in the absence of air in the system, the brake pedal has a large free stroke.
fuzzedup,lift the parking brake lever, make sure that the rear wheels are locked by the parking brake and depress the brake pedal two times.
For the first time the free stroke can be large, the second one must be normal.
If so, then a large clearance in the rear brakes.
I wish you success!

[fuzzedup]

If there is no air in the brake system, the large free travel of the brake pedal is associated only with large gaps in the working brakes.
In the front brake mechanisms, the gaps between the pads and discs are determined only by the elastic deformation of the rubber sealing rings of the front brake cylinders and, by definition, can not be large.
https://www.google.com/url?sa=i&rct=j&q ... 1247204253
https://www.youtube.com/watch?time_cont ... 4fAPpj3p48
In the rear drum brakes, the gap between the pads and drums is determined by the compression springs and various additional mechanisms to minimize the gap.
At the Transit MK3 ... MK5 this additional mechanism is often defective.
Therefore, in the absence of air in the system, the brake pedal has a large free stroke.
fuzzedup,lift the parking brake lever, make sure that the rear wheels are locked by the parking brake and depress the brake pedal two times.
For the first time the free stroke can be large, the second one must be normal.
If so, then a large clearance in the rear brakes.
I wish you success!

Thank you for your detailed response. Do I need to have engine running when doing the test you've mentioned ?? Also I've tried clamping off the rear brakes and still get the problem, wouldn't this rule out the rear brakes being not adjusted enough ??