Caddy Disc Brake Conversion - Upgrades (non engine related ) - VWDiesel.net The IDI, TDI, and mTDI source.

• Caddy Disc Brake Conversion by ORCoaster on 19 Jan, 2025 20:19
• So how many of you have thought or tried or pulled off the removal of the drum brakes and installed the disc brakes from one of the many choices of Rabbit or Scirroco?
  
  I was able to find a set of rotors and calipers on line from a guy in CA and he sent them to me.  They were in really nice shape and with a bit of cleaning and checking I proceeded to remove the drums and put on the discs.  What I bought contained the needed hubs, rotors and calipers along with the little flex hoses on the calipers.  What didn't come with that stuff was the ebrake cables.  That was a rub!  But places sell those, Right.
  
    This was the beginning of a couple of week project for me.  I do not have a garage, I live on the coast of Oregon, and it was raining cats, dogs and slugs for most of the month of Dec.  I barely got this far without getting soaked.
  
  I did my homework and knew that I would need different ebrake cables and I went to Parts Place Inc and specifically told them what I was doing and that I would need their longer cables that they mention on their site when you read the disc brake conversion kit stuff they sell.  Well long story short, the cables they swear will work are only 71 inches in total length.  That leaves you about two inches short of getting the ball of the cable on the ebrake engagement lever on the caliper.  It also leaves you about the same amount of outer cable short of getting the cable to the caliper at all.
  
  
  
  So back to the Utube videos I went to see if there was a solution there.  I happened across a guy from the UK talking about doing a disc conversion on a Rabbit or Cabriolet.  He mentioned a source of where he got some of the parts he was using so I decided to go to them and see if they had longer cables that would do the job.
  
  Well it turns out that according to them there are none.  But don't dismay.  They made an adapter that allows you to use your existing pickup ebrake cables on the new disc calipers. 
  
  I figured out that you could do that with a short piece of flexible copper pipe, the 1/2 inch size stuff.  That goes just perfect over the end of your cable on the one end and allows the spring covered cable and swaged end to slide inside the pipe.  So noting the look of that adapter I decided to make my own from local parts.
  
  This is what they sell.
  
  
  I found that by using the 1/2 inch flexible pipe I could put on a 1/2 inch shaft collar with just a bit of file work to enlarge the hole on the collar.  It has a set screw on it and that allows it to stay snug to the pipe. That takes up the slack on the inner cable and allows you to connect the cable to the engagement lever and still have the push back of the spring to keep the lever and the ebrake lever in place once all is released. 
  
  This is my final product.  I extended the pipe well passed the bracket as I didn't want it coming out once it was released.  I set my first pipe a bit short like the product the UK folks can use but I noticed the pipe would drop out of the bracket once I pulled up on the brake lever and released it.  I just had to undo that collar set screw and move it a little and all was good.
  
  
  
  
  So for all of those driving around with no ebrake on their converted discs you now can fix that.  Get the standard ebrake cable, yes the one you took off the drums, the one in the parts stash box and install it.  Ii won't take you weeks to do this and you will not have to keep that brick in the passenger floorboard for when you park on a steep hill.  That is what I was thinking I would be doing until I figured out the outer cable extension.
  
  Finding the little adapter for sale made it all the simpler for me to change what I had going and make a proper fit for the cable to lever match.
  
  Hope this helps some of you, I didn't find many how-tos on the net and most were lacking the brake final part.  They either threw up their hands and said they would drive without an emergency brake or figured it out later and never posted what they did. 
  
  
• #1 by RustyCaddy on 20 Jan, 2025 18:00
• Thank you for posting this very informative thread.  Nice work sussing out the solution!  Pickups seem to be a tough fit for disk brakes, not including the difficulties of a functioning emergency brake cable.
  
  Sort of a tangent here but are you going to/did you modify or otherwise upgrade the brake master cylinder? Have read that a MK3 booster and master cylinder really firm things up when adding rear disks or larger front disks.  There is also a place in Canada that sells 22mm brake master cylinders modeled on the MK1 stock 21mm with VAG part number ending in 025A or something like that (probably going to see a 25% increase in prices pretty soon).
• #2 by ORCoaster on 20 Jan, 2025 21:28
• I didn't have plans to do anything to the MC but after my road test today I noticed that the pedal goes down quite a bit and then will sloowlly sink to the floor.  So I tested a spare MC I have and it seems to hold pressure. So my first work will be to just swap out what I have on hand.
  
  If that doesn't do any good then I will be looking for those other parts.  So thanks for the information there. 
  
  I just thought everyone swapped the discs off other cars to the axle and was done.  Oh Silly me! 
  
  On other Rabbits yes, not so on the Pick me up.  There is always something different there.
  
• #3 by ORCoaster on 26 Jan, 2025 17:48
• Rusty,
  It appears that a larger MC and booster are in my future.  I still have a pedal that goes way far down to the floor. But at least it holds against my foot pressure now. 
  
  I think with the larger capacity rear disc calipers I need to have more fluid being pushed per stroke of the pedal.  Makes sense to me anyway.  I mean those little drum brake cylinders were what 3/4 of an inch in diameter where the disc ones are closer to 1.25 maybe?
  
  I could do the math for the area of a circle and figure out the increased amount of fluid with the other MC compared to what I have but logic, what? Do you use logic?  says I need the increased capacity,
  
  What say you?
  
  
• #4 by RustyCaddy on 29 Jan, 2025 09:47
• It seems like the MC is where folks run into problems with rear disk conversions from what i have read.
  
  Short of going with the MK3 setup of booster and MC, a bigger diameter MC with a MK1 booster also seems a way to go.
  
  i got one of these along with a upgraded proportioning valve, mostly because the 1980 Caddy has a one off for that year proportioning valve and it seems to be getting sketchy.  Haven't installed it yet.
  
  https://tech-53.com/product/vw-mk1-22mm-master-cylinder-bendix-style-booster/
  
  The seller is in Canada so that price might be going up 20% on Saturday.
  
  BTW what are your rear disc brake off of originally?  Please share.
• #5 by ORCoaster on 29 Jan, 2025 19:29
• Thanks for the information Rusty, and the link. 
  
  I found that I could use a discount I had coming from Rock Auto and pick up both the booster and the MC for about 180 bucks.  35 of that is core charge so looking at 150 or so for both parts.  I am suspect of the booster on my truck so using it and putting on that MC from Canada might leave me without good boost.  Since I need to pull off the MC and bleed the brakes and stuff I just went for all new components off a 1994 Corrado.
  
  BTW what are your rear disc brakes off of originally?  Please share.  You asked this, and I have to admit that I would have to joke with you and say they came off the UPS truck. 
  
  Honestly, I don't remember, but I should find out. I do know that they are the 226 mm ones, and I have 280 mm up front, so that is good to keep the rear end under control. I am using the original proportional valve, and it seems to do the job. I rebuilt it about a year ago with new seals. It is the one on the driver's fender, not the one in the rear of the truck. In 1981, they switched it over. 
  
  Found the ad on Marketplace.  This is what I bought.  I got the rotors, calipers, and hoses and all were in excellent shape.  A little fine sanding on the rotors knocked the oxidation right off and gave me shiny bright metal.  No deep pitting at all. 
  
  Vw Mk1 Mk2 Mk3 Corrado/Passat Rear Disc Brake Conversion Kit
  This is 4 lug conversion with Lucas calipers
  I’m asking $265
  
• #6 by ORCoaster on 01 Feb, 2025 19:18
• So to continue the saga I ordered a new booster and MC from Rock Auto and the MC came today.  I expect the booster on Tues.
  
  Once all the parts are here, I will hope for a sunny day and install them. That will either involve making new lines for the front and down to the proportional valve or maybe doing a bit less and going with a fitting for the front lines that will take that 45-degree fitting off the MC, run it at a 90-degree angle, and use the front lines as they are. 
  
  I have a tubing bender, tube, and fittings, so maybe I will run new lines off the MC to the proportional valve.
  
  I ended up buying a 1994 Corrado booster and MC for those interested.  I think that is what the four-disc calipers need to have to fill then on one stroke of the MC.
• #7 by RustyCaddy on 02 Feb, 2025 09:26
• Smart way to go about this, as usual
• #8 by ORCoaster on 02 Feb, 2025 16:30
• I had to try what I had just in case it worked.  As you knew well it would not.  Thanks for prompting me to go the extra mile and do it completely from booster to calipers. 
  
  I will have to get out the tubing bender and tube to make a couple of little pieces to get from the proportional valve to the 45-degree outlet on the MC.  The two front lines have enough length to just add some bend and they should work.  I say should but we all know how that can go.
  
  I looked online for a 45-degree fitting, 10mm 1.0 pitch and I guess it is just easier to do a tube bend.  90 degrees yes but no to a 45.  I have plenty of 3/16th inch tubing left and a double flare tool so I might as well use it. 
• #9 by ORCoaster on 09 Feb, 2025 18:54
• The sun, the temperature and my time lined up long enough for me to fit the new booster and MC on and proceed to connect the push rod to the brake pedal. 
  
  Major stop!
  
  New pushrod is just a tad too short to get the pedal more than 1/2 inch off the floor.  I compared the two set ups side by side and see where the nose of the old MK1 Caddy booster is a bit longer than the Corrorado one.  So I think I need to get a short piece or rod and a connector to lengthen that rod and it will work out.
  
  Is the brake pedal that much different in the Corrorado?  Anyone have experience with this particular peculiarity?
  
  Looking for advice here. Not a bunch of that, should not have done that.
  
  
   
• #10 by ORCoaster on 14 Feb, 2025 18:16
• I found enough time today to stop by the hardware store and buy a 10mm bolt and a castle nut that I will use to extend the current rod and see how that works.  Supposed to be sunny or at least no rain tomorrow. 
• #11 by ORCoaster on 15 Feb, 2025 18:07
• I finished it!   
  
  
  That is to say the conversion is done and they work way better than those drums ever did.  The new booster and MC took a bit of tweaking to make the rod to the brake pedal somewhat longer. Now I need to adjust it back so that when I take my foot off the go pedal I don't have to lift it up to get to the brake pedal. 
  
  I wasn't sure what kind of position it would end up at when installing it so I just took a shot.  Missed the bullseye but I at least hit one of the inner rings.  Adjusting it will be a pain as setting it up was a pain.  In more ways than one.  I finally had to pull the seat out to get enough room to work under the dash properly.  But with the cold, my damaged hands, my age, and poor lighting I found getting that rod into the bracket and then getting the pedals on that rod, well let's just say I was not mumbling good words.
  
  I also had to go source those nylon bushings that go between the pedals and the rod that holds them in.  NAPA finally bailed me out.  The guy found two bushing kits in his inventory.  One set of two fit great but he only had one card of those. I needed four.  So he opens the package of the mixed set and digs out two more and charges me for two sets.  He said he would order a couple of the replacements and then put back the two in the multiple sets.  Very nice of him to do that and not force me to buy an additional four bushings that would never work for me.  He wanted to see me get the project done.
  
  So now I have the conversion complete and I can go about doing other things to the truck.  Like prep for painting.  I have some rusty spots that need to be sanded down, an application of rust stop put on and then repaint with some primer surfacer. 
  
  I did not need the addition of spacers on the rear wheels like I did on the front.  Must be the smaller diameter discs and calipers.  The emergency brakes hold like a brick in front of the wheel.  Since I live and park on a steep hill that was a gotta-have thing for me.  Hence the solving of the emergency brake cables I got from Parts Place.  I did get my money back for them but the cost of shipping them both ways was about the total purchase price. 
  
  I am holding on to the master cylinder and booster I took off.  I think MK1 boosters are a needed item every so often here so I will pile it in the shed with all the other parts.