MK1 Disc Brakes?

[monomer]

Has anyone done this on here?


I'd like to run a hydraulic ebrake and adjustable prop vales. I just dont know where to start...

[rallydiesel]

Hydraulic ebrake? Would this be a fully custom set-up?

[8v-of-fury]

Why hydraulic e brakes???

[monomer]

Autocross. I suppose you lose normal cable sneaked with disc in back...

[8v-of-fury]

Oh if its not a daily, then I do suppose it is ok. lol I just wouldn't trust a hydraulic system to hold my car on a hill is all lol.

[monomer]

Oh if its not a daily, then I do suppose it is ok. lol I just wouldn't trust a hydraulic system to hold my car on a hill is all lol.

Isn't that what 1st gear is for?

[8v-of-fury]

I wouldn't trust that alone either. LOL 1st and e-brake for me. I went a year with no e-brake.. all it took was a bump to get the engine past the first compression, and it would roll away.

[bajacalal]

Hydraulics are not DOT approved as an emergency brake, they must be mechanical. Now, that isn't really something I would be concerned about personally, but I think DOT has a good point, the e-brake should be reliable. If you park on a steep enough hill with no e-brake, your car will make it's way down the hill.

I would run rear disc brakes from a VW that had them and I would retain the stock e-brake, it should all fit as long as you have the right cables.

If you want to run a hydraulic e-brake or line-lock as an additional device to lock the rear tires, I would install that separately. I just don't think there's a reason to delete the stock e-brake though. A lot of people run rear discs with the stock proportioning valves, so I would try that first before buying adjustable valves. If you aren't satisfied with the way the rear brakes operate, then try adjustable valves.

The way the VW brakes work is different from most cars too. Most (modern) cars have dual chamber master cylinders, where one chamber controls the front wheels and one chamber controls the rear. Volkswagen for a long time has used an "X" system where the front chamber of the master cylinder controls a front tire and a rear tire, and the rear chamber of the master cylinder controls the opposite front tire and the opposite rear tire, and 2 proportioning valves are used, with 2 separate brake lines routed to the rear (and a separate line for each front wheel), all the way from the master... The idea is that if you lose pressure on one part of the system, you still have one front and rear wheel with good brakes, instead of just having front or rear.

This means you would have to use 2 proportioning valves and 2 line locks/hydraulic brakes or somehow reroute the stock configuration so that the fronts are on one chamber and the rears on another, eliminating one of the lines to the rear, plugging the extra hole, and using a "T" to each side of the rear after the second hydraulic cylinder/line lock. Every universal hydraulic e-brake I've seen is only one in, one out, which makes it incompatible with the stock VW setup that uses 2 separate circuits to the rear. I don't know if anyone has come up with a hydraulic e-brake compatible with Volkswagens (and other cars that do this, I think Volvo does too).

[monomer]

Good information to know. I live in the flattest part of the state, but I'll retain the factory manual handbrake.


Next question: What pieces are needed for just the conversion? From what I gather it's all the same rear end in mk 1-3 cars, so swiping brakes from a fancy GTI would be an non-issue?

[R.O.R-2.0]

Good information to know. I live in the flattest part of the state, but I'll retain the factory manual handbrake.


Next question: What pieces are needed for just the conversion? From what I gather it's all the same rear end in mk 1-3 cars, so swiping brakes from a fancy GTI would be an non-issue?

the rear ends are specific to a mk1.

you cant go and drop a mk2/3 rear beam in a mk1 car..

but you can put a mk1 GTI axle in a rabbit NO PROBLEM..

there are only 4 bolts holding the beam to the car.. 2 for the mounts, and 2 for the shocks..

then the brake lines, and e-brake cables.. after all thats disconnected, it all drops out..

on my 86 Golf, i swapped the stock drums out for a disk rear beam.. had a 92 Jetta GLI rear beam laying around with e brake cables still..

well, the 92 cables didnt fit the 86 hardware/e brake lever, so i pulled the cables out of my 85 GTI, that came stock with disks.

installed the beam in the car, and hooked up all the cables.. but, beware, the GTIs have a longer wheel base by like 1.5" and the difference is in the beam. so, if your tires look FARTHER BACK in the fenders when you get the swap done, its because they ARE farther back now..

i left the drum brake prop valves in the car.. i didnt feel like adding a load sensing valve to the system with all the proper lines, especially when its no secret that the load sensing prop valves like to fail at the most inconvenient times. another good thing about that was the fact that i really like the way the brakes work, even with the drum prop valves still in the system..

[danster]

If you can find a disc braked rear axle on a mk2 platform vehicle (there are various other VW and Seat group cars that can be used as a donor for parts) then you can unbolt the caliper, carrier, disc, and the stub axle. Then bolt these components back on to your mk1 axle once you have stripped off the original drum brake setup.

There is slight grinding of the mk1 axle required to allow clearance for one of the caliper carrier bolts, and for the stub axle to seat perfectly flat on the axle face.

Handbrake cables can be used from a 16 Scirocco or an early mk2 Golf.

Regarding the hydraulic side of things, you can strip out all the existing brake lines and re-plumb the car with a single line from one of the circuits of the master cylinder leading to an adjustable proportional valve, and then on to a hydraulic handbrake cylinder setup. This line will then split and supply both rear calipers.
The fronts can be plumbed in to the other circuit of the master cylinder.
I have used this setup before in my mk2 rally car and my Scirocco track car. It is not a perfect hydraulic circuit solution and does require care to ensure the brake balance of the proportional valve is not left adjusted with too much bias to the rear. Because if the car is used in wet conditions the rears could lock and result in a spin.
Also consider any construction and use regulations if the car is used on the road. Liabilities and all that.




Also, did the USA not get 16v Sciroccos with a disc braked rear end? That complete axle would be compatible with a mk1 vehicle too.

[bajacalal]

If I were you I would just run the entire GTI axle beam because it has a big sway bar thing built into it while the normal axles do not.

[mystery3]

Also, did the USA not get 16v Sciroccos with a disc braked rear end? That complete axle would be compatible with a mk1 vehicle too.

We did, although they're not terribly common the are probably the easiest to swap. The front setup is also a bolt-on upgrade if I'm not mistaken. There are a lot of parts bin/junkyard solutions to the rear disc conversion. I know nothing of hydraulic handbrakes.

[Henk]

you have 4 bolt stub axles in your MK1's right? All you'd need then is the stubs, callipers, carriers and discs off either a mk2 or mk3, shouldn't put you back for if it's scrapyard stuff

not great but that's my rear setup on a custom caddy axle (we have 6 bolt stubs so no disc setup is a straight fit  )
correct me if things are different for you guys over the pond, but i'd imagine they're easier that for us anyway! 

[R.O.R-2.0]

whats the want for a hydro hand break?