Break conversion help please.

Ok so I am getting closer to spending even more money on my brakes.

All rear beam parts ready to fire with new calliper kits, discs, bearing etc.

Now hydraulics. If I use the current set up then I need to do three basic jobs.

New mater cylinder and servo from a mk3. Plus pressure reducing valves on each feed line to the rear callipers. With a mix of new and second hand I am about 3-500 spent.

Or

I fit some new motorsport master cylinder set ups in the drivers side scuttle removing all the linkage issues. Don’t know what is involved in doing this or the costs but I am guessing about the same money.

Anyone have this done, doing or experience on this as I don’t want to trail eBay looking for parts I don’t need etc.

This is the type of thing I think I could use

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F191813589115




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As that unit replaces the servo, it will still use the brake linkage. I'd be worried that the pedal-effort required to stop the car would be quite high. If the unit removed the need for the linkage then I think it would be ok (as other folk seem to have done that).
I've fitted a 2nd hand MK3 servo, and T4 m/c - probably cost me £50 for both.
As for the pressurisation valves, you can get them for about £16 each. https://www.ebay.co.uk/itm/Brake-Residual-Pressure-Valve-Kit-Car-Rally-Drift-DRUM-Race-Performance-10-PSI/182187536192?_trksid=p2485497.m4902.l9144

I've read some info that suggests you don't need them if you are running discs at the rear, and then some that suggests you do, but 2 psi versions, not 10.

Interesting link.

So they keep the line pressurised so you have less pedal push to get the system up to pressure and then 'move the fluid' so to speak.

From my understanding, and of course I may be entirely wrong here, that's not the same as the reducing valves though as the reducing valves stop flow to the back to stop it locking up.

If you want rid of the transfer bar thingy then I believe a lupo or 6n polo MC/ Servo ca be used but it means chopping out bulk head and welding in the bit of bulkhead from the other small VW's.

Or just man and replace the whole thing with an MC from a Cupra R and have done. No valves, no servo. Just push with you right leg hard and pray  

Ian

Borednow - I think there are 2 different items in use on different models. The 'vales' on the Mk1 GTI are residual pressure valves (part no 113611191) that operate as you suggested. I believe that Scirocco's had pressure reducing valves as they didn't have the brake force regulator fitted.
At least that is what I have read on this forum….so it must be right  

Haha. I’m even more confused.

So my understanding is the standard drum set up is 70/30 bias (back/front).

When changing to discs then it needs to be 50/50.

Linkage introduces pedal travel before any breaking takes place hence would love to remove this but not keen on chopping big chunks and welding the scuttle so repositioning looks dead.  

So now we come to servo and master cylinder + pressure valves on the rear beam.

If I upgrade the servo to 9 inch and fit the bias controllable master cylinder arrangement then I guess I can balance the breaks and if desired chuck myself through the windscreen.

Also while on break balance I assume I want the fronts to but first or should they ideally all bite at the same time.

Once I have this thing stopping properly I can then look at making it go better.


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