Author Topic: Tech: Disc-Brake Install  (Read 2335 times)

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Offline owdlvr

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Tech: Disc-Brake Install
« on: January 11, 2009, 07:18:39 PM »
Sorry, at the moment there are few Photos. When I repeat sections of the job on my '75, I will add more photos to this thread.

For this installation I'm using CIP's "ball-joint Disc Brake Kit", which I ordered with 2.5" drip spindles. The kit includes spindles, loaded-calipers, bearings, seals and hardware. You'll need to add a set of flex lines to your order, as they don't come with any. You may want to order additional bearings, the kit ships with "econo-bearings" (chinese origin) which some users may have an issue with. I installed them in my car, figuring I can always go in and replace them.



The hard part of the whole kit is pulling your drum-brake spindles off, and putting the disc-brake spindles on. VW has special tools for the spindle part, which you'll have to find solutions to.

a) Start by removing the drum, shoes and associated bits. I left the cylinders and hoses attached - Removing the rest lowers the weight of your assembly, which you'll appreciate later. Leaving the wheel cylinder and hose attached keeps it from leaking and makes the bleed easier. Remember, brake fluid is corrosive to paint...so I wait until I'm ready to do a quick hose swap.

b) Remove the tie-rod nut, and pop the tie-rod out of the spindle. I use an impact gun to pull the nut, which keeps the tie rod from spinning. If you don't have an impact, it's more of a challenge. I use a "ball-joint-press", but you can also use a ball-joint fork. The forks can tear the boots (meaning you get to replace the tie-rod) so I avoid them. If you're going to use a fork, apply a liberal coating of wheel-bearing grease to the fork and and boot, this usually keeps you from tearing the boot. Be sure to clean off the grease afterwords.

c) Remove the cotter pins and castle nuts from both ball joints.

d) Swapping spindles:

This is where the VW special tools come into play, and where you'll need to improvise.

VW has a unique ball-joint tool to remove the bottom ball joint from the spindle, and you'll need to do this ball joint first. I positioned my floor jack under the spindle assembly so that I could just catch the edge of the spindle (keeping the lower torsion arm and ball-joint free). Lift the jack until the suspension _just_ starts to compress. Pull out your big hammer, tap or hit the lower torsion arm which should pop the ball joint free. You won't pop it all the way out of the spindle, you're just looking to 'break the bond' between the spindle and the ball joint.

VW's second tool is a system that lifts the upper torsion arm, by spreading the space between the two arms. I positioned my jack near the assembly, grabbed a long piece of pipe and used it to leverage the upper torsion arm up. You'll need to lift the upper arm enough that that spindle clears the lower ball joint, and may need two people. One to use the lever, the other to catch the spindle.



To pop the new spindle in, first slide the upper ball-joint through the spindle and snug up the castle-nut finger tight. This hold the spindle to the upper torsion arm, and now you'll need to use your pipe-lever to raise the upper torsion arm. Again, you're lifting the upper arm enough to clear the lower ball joint. Lower the spindle onto the lower ball joint. Having two people makes this job a lot easier.

e) reinstall the two castle nuts, putting a cotter pin in the lower ball joint but not the upper ball joint. -> Your car will need an alignment, so I leave the cotter pin out for the drive to the shop. Be sure to tell the alignment guys to pop a cotter pin in for you.

f) reinstall the tie-rod end.

g) Install the Disc onto the spindle:

 If you've ever had to replace a drum, the job is the same for mounting the disc.

  • You'll need to install the bearing races into the drum. The 'proper' way to do this is using a press with the proper sized mandrel. I used my trusty hammer, a 30mm socket for the inner bearing race and a 20-something (22mm?) socket for the outer bearing race. If you're careful, you can set the bearing race in perfectly straight without doing any damage to it what-so-ever.
  • After packing the bearings, pop the inner bearing into the disc and set the seal. The seal takes a bit of work, again using the hammer (but go easy).
  • Slide the disc on, slide the outer bearing in...add the washer and nut, finish it off with the dust cap.


h) Swap the brake lines between your drum (which is probably hanging below the car) and your new disc caliper.

...Repeat everything for the opposite side of the car...

Bleed the passenger side of the car first, and follow that up with driver's side. While you're at it, this would be a good time to do a complete brake fluid flush of your entire system.

Put your wheels back on, and you're done. Make sure you bed-in the pad/rotor combo properly.

-Dave
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'71 Type 1 - Rally Car Project
'75 Type 1 - Heirloom
'95 F150 - Unfortunate daily driver...

Offline egspot

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Re: Tech: Disc-Brake Install
« Reply #1 on: January 11, 2009, 07:32:26 PM »
cool. ;D