Rear Disc Conversion - 19/01/2011

[danhock]

You'll have to be careful when doing this mod..

you gotta remember that the brakes are setup for drums so putting discs at the back will completely throw the braking balance between front and rear.. (usually biased to 80%+ on front).

I had a mate who did this on his track car and used a manual brake adjustment setup up in the cockpit (dial which restricted brake fluid going to the rear).

The only real reason for doing this mod is for looks and as it actually compromises safety may not be worth doing.....

[golfvr6]

Does the mk1 not already have a rear compensator?

[SoundillusioN]

Not sure if this is what you mean but, On the Mk1 there's a Brake pressure regulator located just in front of the rear axel (drivers side).  Its connected to the axel via a spring.  Its meant to adjust the brake pressure at the rear according to how much the car is laiden.  I'm not sure how serious, but I believe the rear brakes on the car can be a bit over powering if the car is slammed because the reg thinks the cars got a tonne of bricks in the back due to the height (or lack of it).  I'm sure this regulator can still be used and will still work with a rear disc conv since its only part of the brake lines.  

[golfvr6]

Yeah thats what i meant.
If the rear lock up then adjust the valve so there is less tension in the spring.

[old_boy]

This is something which gets overlooked when people put disc's on a MK 1, as I did  
My wake up call was on a slight downhill bend, as I was giving it large and I hit my brakes, the rears locked up and spun me 180, so I was facing the cars that were following me.
The way to adjust the compensator valve is this......
With your cars wheels stood on the ground, IE, no jacks or ramps, you need to get under the N/S and locate the valve, find the spring attached to the lever and you will see a 13mm nut and bolt.
So armed with a 13mm socket and spanner (and WD40-because all MK!'s are rusty) JOKE, loosen the nut and bolt on the spring until the spring is just starting to take up the tension on the lever and then tighten-HEY-PRESTO-properly balanced braking, with no brown trouser moments!
Whilst under you car, its a good idea to check that the lever on the valve moves freely and the pipes are in good nick.
Another important thing to remember is that if you subsequently lower your car, you will need to do the above again or you may wish you were wearing bycycle clips.
Dont forget-the car must be supporting its own weight.

[richandhazel]

Nice one.........something I would have overlooked too. Glad I made this sticky, some good points and tips being raised

[SoundillusioN]

So has anybody had a go yet?  

[richandhazel]

I plan to. I ripped the brake calipers, carriers, discs and stub axles off that mk2 I just scrapped with a view to fitting them to the cabrio. The calipers aren't in very good condition so I need to delve into my shed and dig out another set I kept from a previous mk2 that I broke. Once I've got all my bits and pieces together I'll give it a go. I'll take lots of photo's with a view to creating a step by step guide.

[SoundillusioN]

Can't wait because if it?s successful I'd be tempted to do the same as part of my GTI's resto.  

[mk1]

I also have the calipers etc (a morning at the scrappers well spent ).
Have to o/haul the calipers and clean up the parts.
Will keep you all posted.
Steve.