Technical Master Cylinder conversion!

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Technical Master Cylinder conversion!

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Hey guys!

some of you know that a while back i had a Seat Marbella. it has outstanding brakes. it used a vacuum assisted master cylinder that had 4 pipes coming out of it.

now i have 2x panda 4x4s with rubbish brakes. they both use a vacuum assisted master cylinder with 3 pipes coming out of it.

im looking for help here as i have forgotten how the brake system on the Seat Marbella works. on the panda with 3 pipes, 2x of the pipes go to the front wheels and one goes to the rear though a valve thingy just under the master cylinder then to the rear brakes.

does the Marbella have the same valve, or do the pipes coming out of the master cylinder go directly to the wheels?

my plan is to convert a panda to use the marbellas 4 pipe master cylinder by running an extra pipe to the rear wheels.

i have tried everything i can think of to get rid of the super spongy brakes i have at the moment (the whole braking system on Fallout is brand new!) but sadly the brakes are still spongy.. on both 4x4s!

could anyone with a marbella post a picture of the servo assisted master cylinder? i need to make sure the bolt holes are in the correct place.

the best of it is, even if this does not work i would have only spent like £30 on parts! man i love pandas. though i keep saying it.. i really wish we never sold the marbella.

Thanks all, you're the best-ist! :D
 
Similar thoughts I am fitting. Ls 200 servo complete with master cylinder. Larger 250mm diaphragm 75mm larger also 25 mm master Instead of 19.5
Let the force be with you


BTW I have found that the pedal box bushes can be worn using up 1. 1/2 “ of travel without any function
If stronger front brakes are required an extra inline servo can be used too . ex MGB or ford consul
 
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:yeahthat:
Also looking at Grumbleweed I can see a lot of the "sponge" on that brake pedal is actually the bulkhead flexing slightly where the pedal box & master cylinder mount when pressure is applied. Different layout to the servo system I know but worth watching what happens when somebody really leans on the pedal through the linkage & mounting points.
 
First stage is to make up some blank ends for your master cylinder pipes and begin testing what the pedal feels like at the master alone and then only front, only back, and if necessary wheel by wheel.

Maybe you are dealing with low strength flexing back plates which a bit of welding could sort out?
 
the back plates are in fantastic condition though on both cars :/

they have always been really bad. ever since i have had the cars. after the 10th flush, the 2nd servo change.. it still is really spongy. the marbella on the other hand was awesome. i gave it a brake fluid change and the pedal was instantly great as soon as i bled the air out of the last line.
 
Clamp off each of the flexi's one at at time. Some use Molegrips others use a pipe clamp.

You'll get an instant 'feel' at the pedal and know which brake is the culprit.

But before you do anything rash.............. My Terra van has the SEAT 4 pipe master cylinder and the brakes have always been hideously spongy; bad enough that I drive with a couple of clicks of handbrake on between adjustments.
I spent 2 years trying to improve them. It is the rear brakes that are the problem.

I piped out the rear sensing valve
I fitted back plates and self adjusting brakes from Purple Ronnie
I fitted new discs and pads
I changed the calipers
I fitted a brand new master cylinder
I fitted a brand new servo.
The only original part of the braking circuit are the pipes from the master cylinder to the rear flexi's.
The brakes are good but spongy.

Remember that the Marbella servo doesn't have the brake pedal adjustment
that the Panda servo has.

Having said all that, my van has a diesel engine and may have a different (shorter) master cylinder as a Panda master cylinder and servo unit won't fit as it comes into contact with the engine.

I have a special plan in hand to improve the van brakes. Watch this space
 
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Brakes and hose. Panda Brian BFG
Although we have discs at the rear compared to standard brake system the layout an extra 1.3 Mtrs Of rubber hose is in our system the rear. This would for further pipe expansion and loss of pressure but always the losses appear at the font air trapped along the exit pipes from the cylinders and then around the balance valve. If you can make a pump from an old master cylinder
Then push fluid the wrong way through the system (get the idea !) it should then purge back to the reservoir
If it’s air. The bushes must be looked at though . Sj .
 
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hmm ok then, what i am tempted to do then is to undo the rear brake feed pipe then put a blocked off union or bolt in its place. take it for a slow test drive and see if the pedal gets more solid.

really though. the amount of pedal travel in both cars we are talking about here is all the way to the floor. you can actually feel the pedal hit rock bottom if you press it hard enough.

i am also sure that my hand brake binds too as that is adjusted as much as i can get it. one click and the hand brake is on almost :(
 
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hmm ok then, what i am tempted to do then is to undo the rear brake feed pipe then put a blocked off union or bolt in its place. take it for a slow test drive and see if the pedal gets more solid.

really though. the amount of pedal travel in both cars we are talking about here is all the way to the floor. you can actually feel the pedal hit rock bottom if you press it hard enough.

i am also sure that my hand brake binds too as that is adjusted as much as i can get it. one click and the hand brake is on almost :(


Today I have had real good look at the pedals and losses in movement it would be possible to drill through the boss welded to the brake pedal through the transfer shaft and then drive a 5mm roll pin in place this would remove slack at that point then the 2 end bosses need to be drilled and tapped m6 to allow fitting of a 6mm brass bolt at each end that would in turn tighten the worn steel shaft
 
Clamp off each of the flexi's one at at time. Some use Molegrips others use a pipe clamp.

You'll get an instant 'feel' at the pedal and know which brake is the culprit.

But before you do anything rash.............. My Terra van has the SEAT 4 pipe master cylinder and the brakes have always been hideously spongy; bad enough that I drive with a couple of clicks of handbrake on between adjustments.
I spent 2 years trying to improve them. It is the rear brakes that are the problem.

I piped out the rear sensing valve
I fitted back plates and self adjusting brakes from Purple Ronnie
I fitted new discs and pads
I changed the calipers
I fitted a brand new master cylinder
I fitted a brand new servo.
The only original part of the braking circuit are the pipes from the master cylinder to the rear flexi's.
The brakes are good but spongy.

Remember that the Marbella servo doesn't have the brake pedal adjustment
that the Panda servo has.

Having said all that, my van has a diesel engine and may have a different (shorter) master cylinder as a Panda master cylinder and servo unit won't fit as it comes into contact with the engine.

I have a special plan in hand to improve the van brakes. Watch this space

Ahh purple Ronnie we hardly knew ye
 
You can slip the bar from the brake pedal to the back of the servo (inside the car) off its splines; turn it back a tooth or two (compress the servo rod a little)and reconnect.



I always meant to do this but someone gave me a Ford Focus which I fixed and have been driving for a year.



It has very good brakes. Hmmm


Our 2wd has perfect brakes with the same system a touch and there on ,even with drums .
 
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