DIY: Installing Chase Bays Dual Piston 6:1 Brake Booster Delete

[xdewaynex]

This has been an on going thing in my head ever since I saw Chase Bays first brake booster delete and I had been wanting to clean things up. I done a Brembo 6 piston front and 4 piston rear setup on my car using Apikol front brackets and Voshmod kit in the rear, along with ABS delete, steel braided brake lines and adjustable proportioning valve. I had swapped my old 98 A4 single diaphragm brake booster to a dual diaphragm booster from a 00 A4/S4. I started having trouble with the rear brakes locking up in stop and go traffic and I figured what better time to try out the Chase Bays product. The kicker....Chase Bays doesnt offer a bolt up solution for our chassis but Im the guinea pig for that.

The Chase Bays booster has 4 threaded bosses on the back with studs that go through the firewall, this is common for the BMW E30 and mk2/3/4 VW's. I unscrewed 2 of the studs from the plate and they line up perfectly with the A4 brake booster, so this gave me some hope.





So this is where the fun begins....removing the pedal bracket inside the car...be prepared to use several cuss words, hands cut and an achy back. The pedal bracket is bolted up with 2 bolts into the firewall and 1 under the steering column. Before you can get to the bolts you have to get the rod that supports the clutch and brake pedal, which is held in with 2 spring clips that are a bit of pain to get off. I ended up destroying them and going back with a small R-clip to hold it in place.

Once the pedal bracket is out, there are 2 red caps that hold in threaded inserts that the brake booster bolts thread in to. Once you remove those, the booster delete studs slide in, but you will have to cut some of the bracket away to get a nut on the thread studs.









You can see where the studs come through, but here isnt any access to the threads because of the casting of the bracket. I will have to clearance these areas, as well as creating 2 more holes for the other studs to mount up. This also shows that the dual piston actually clears the opening, unlike a lot of other cars where you have to cut out a half moon shape for it to clear.







Not a finished picture but this how much room is left when the booster delete is flush at the firewall. This also comes with an adjustable proportioning valve for the rear brakes.



I will be updating this as I go, so stay tuned.

[xdewaynex]

Got a bit more done today. Made 2 more holes in the firewall for the mounting bolts to slide through and mount up to the pedal box.



Had to get a die grinder and deburr tool to help modify the pedal bracket, so I can access all 4 studs to secure it inside the car. Pictures shows the modified portions and the Chase Bays plate sitting flush with the pedal bracket.









Once in the car, I should have pretty good access to all 4 nuts and tighten it up. I still have to play around with the pedal to piston rod, may even have to get a longer bolt but we will see.

[xdewaynex]

Slowly chipping away at this, with what little free time I have between planning a wedding and getting a home garden started. I had to modify the brake pedal to get the clevis and push rod bolted up and clearance another area of the pedal bracket to clear.



I still need to clean up the inside of the pedal to make this look better.



A portion of the bracket where it steps in was interfering with the clevis attachment so I trimmed it out so the pedal has full movement.



Once I got everything cleared and the brake pedal into position in the bracket, the push rod is about 3/4" from hitting the master cylinder. This is where I stopped at since I have to figure out a way to get it in line.



Im thinking of getting a piece of solid square stock to move the bolt over, or possibly a piece of threaded rod and bend into sort of a Z shape to make it hit the master cylinder. Once I get this figured out, I can fully install the setup.

[A1 A2 German]

Good shizzle.....I have to figure out how to hook it up to the abs as there's two ports in....thinking the main cylinder would be one port and the proportioning valve (lower) would be the other abs port.

Or...maybe both lines from the top master into the 2 abs ports and it sorts it out for the rear itself.

[xdewaynex]

Good shizzle.....I have to figure out how to hook it up to the abs as there's two ports in....thinking the main cylinder would be one port and the proportioning valve (lower) would be the other abs port.

Or...maybe both lines from the top master into the 2 abs ports and it sorts it out for the rear itself.

The front port with the banjo fitting and Y adapter goes to the front brakes, the other output goes to their included proportioning valve for the rears.

I was emailing Chase Bays about the alignment of the pedal clevis rod to master cylinder and they suggested drilling a hole 1" above where the oe join is and placing a rod in center of the pedal to align with the master cylinder. This was something Ive been stuck on the last few days. I will likely drill 2 holes and run a bolt through the pedal and allows the clevis to pivot from the center of the pedal.

[xdewaynex]

Got back to it today. Drilled a hole through the brake pedal about 1" higher from where the oe pivot ball sits and ran a bolt through it with the clevis from Chase Bays. I through a nut on next to the clevis to keep it from moving back and forth on the nut. This helped center up the rod to the master cylinder. I also ended up having to piece together some 5/16-24 threaded rod and acorn nuts because the included bolt wasnt long enough to reach the master cylinder.











The delete kit is fully bolted up to the car. I just need to finish up the brake lines, install the clutch master reservoir and get everything bled.

[xdewaynex]

Clutch reservoir installed, system filled with fluid and brakes bled but unfortunately I cannot drive the car until I get new wheel studs in.....a few lugs decided to seize to the studs and not come off.

The wiper cowl and firewall cover are going to need some trimming to fit.

[A1 A2 German]

Nice! Hell yeah!

And of course something gets in the way of driving it!