Front Calipers
Click through the pictures to view the calipers during disassembly, sandblasting, and powder coating.
- Picture 1: Taped for glass bead blasting
- Picture 2: Before and after blasting
- Picture 3: Before and after wire wheel
- Picture 4: Masked for powder
- Picture 5: Finished
I used flat clear and really liked the way they looked. Too bad they rusted.
I have read that you are not supposed to hone stainless steel cylinder sleeves. However, these had a wear ring, so I figured it couldn't make them worse. I set the honer tension so the stones were snug against the cylinder sleeves, but not tight. Using cutting oil, I honed for 30 second intervals until the wear ring around the cylinder was gone. I cleaned the cylinders with brake cleaner afterwards and lightly coated them with brake fluid. I hope I won't be replacing my calipers.
I cleaned the piston and springs with brake cleaner and inspected them. I found some minor pitting in non-critical areas and smoothed them with some sandpaper. As you can see, there is some wear, but they are serviceable.
When I installed the lip seal, I noticed it wasn't completely seated in the groove. I used a small flat tip to press against the base of the seal to seat it properly in the piston. Compare the lip angles in each picture and you can see what I mean.
Inserting a piston into a cylinder takes a little patience because the spring wants to push the piston out. I pressed on the piston until the seal contacted the cylinder rim. Then I maintained light pressure with my left hand while tucking the lip seal into the cylinder using a small flat tip screw driver (second picture). Once the lip seal is properly tucked into the cylinder, it should look like picture three. To facilitate photo taking and explanation, I didn't have the spring inserted in the first four photos. Ensure the dust seal metal ring is seated evenly (fourth picture, otherwise it will deform when pressed in and could be ruined.
Caliper assembly is straight forward. The half containing the o-ring seats also contains the bolt threads, so it's easier to put it on the bottom and set the other on top. Before assembly, I chased the threads so the torques would be accurate. The torque on these babies is 135 ft-lbs.
I went with the stainless steel, one man bleeder screws. I don't know how well they work, but I really got them because I get tired of having to use vise-grips to get bleeder nuts cracked loose. These came with a rubber cover and hopefully between that and the stainless material, I won't have to worry about grinding flats in bleeder nuts again.
SUMMARY: That completes this portion of the brake project. I'd rate this job as a 4. Take your time installing the lip seals and lining up the dust seal lock ring and you won't have any problems.
I won't be posting a walk through for the rear calipers, as they are nearly identical. The only differences are an extra bleeder screw and the bolts are torqued to 85 ft-lbs because the calipers are smaller.
This project will be open a while. I rebuilt the front calipers while doing the front suspension, and I'll rebuild the rear calipers along with the rear suspension. The master cylinder will get done with the firewall, and the lines get installed prior to mating body and frame. So you see that this project intertwines with several others. Before tackling the brakes, I needed to make some decisions.
BRAKE PADS: I'm still researching, but Hawk brand gets good reviews. They have a variety of compounds, and I'm interested in their HP pad for auto cross applications. This compound allegedly alleviates brake fade and could nicely compliment the blank rotors I'm using.
BRAKE PAD SHIMS: Many Stingray owners, including myself, can testify to the annoying squeak coming from the calipers during slow cruising. This is caused by the pads rubbing against the pistons as they rock back and forth on the retaining pin, and corrected using shims that fit on the ends of the pads to stop movement. I'm definitely installing those.
BRAKE ROTORS: There wasn't much to research here. I intended to use the existing rotors because I installed new trailing arms from Ikerds in 2011. These have the factory blank rotors riveted on, and about 15,000 miles on them, if that. Once I discovered new front rotors were required, I felt I had to go with blanks. I'm not sure you can run different types of rotors in front and back. I've never heard of it, and didn't research it. This was unplanned cost I wanted to minimize.
O-RING SEAL KIT: These kits convert the old lip seal design to an o-ring design. The o-ring set up has two advantages: it maintains integrity over longer periods of inactivity, and is more tolerant of rotor run-out. The disadvantage is the conversion requires new caliper pistons and costs a little over $40 per caliper, where lip seal kits can be had for about $13 per caliper. O-rings are a great option for seldom driven cars, but they do not improve braking. And while the o-ring kits are tolerant of run-out, run-out by itself can cause significant pedal and steering wheel vibration. As discussed in the Spindle and Rotor walk through, my new rotors had significant run-out when mated with the hub, and pedal / steering vibration was a real concern. Since that needed correction, I saw no reason to spend the extra money on the o-ring conversion.
HYDRO-BOOST: For those that don't know, hydro-boost uses power steering hydraulic pressure instead of manifold vacuum to assist with braking. A new, bolt-in hydro-boost system is slightly north of $1,000. It's also possible to put one together from components out of a 3/4 ton GM pick-up (and probably other vehicles as well), though a firewall mount plate must be fabricated. Hydro-boost is mainly useful for folks with long duration camshafts (and hence low manifold vacuum), or those who don't like the vacuum system's feel. Hydro-boost assisted brakes require less effort to engage, but braking power remains the same. Because they require less effort, it may be argued that hydro-boost decreases stopping distance by engaging the brakes earlier, but I suspect the difference is insignificant at cruising speeds. To me, it's a lot of or effort for little gain to my application. I'm staying with the vacuum assisted stock system, but will be replacing the vacuum booster with a new one because they fatigue with use.
BRAKE LINES: Just a short word here, but I plan to upgrade to stainless lines. They are harder to seat but help prevent brake fluid contamination due by eliminating rust in the lines. UPDATE: I replaced all my brake lines a couple years before and decided to reuse them since they were in very good shape.
CALIPER PAINT: I decided to use powder coat on the calipers because of its superior durability. I wanted a stock look so I went with flat clear. UPDATE: It has been almost a year since I finished rebuilding the calipers and I'm sorry to report that surface rust has started to appear on them. I admit to being a novice at powder coating, so I likely did something wrong. I suspect that the porous nature of the cast iron requires a second coat and/or longer preheat than I did. I'll change these on the rear calipers and post an update if it makes a difference.
Modifications: None
Upgrades: Three
- Brake pad vibration dampers
- Hawk HP auto-cross semi-metallic pads
- Stainless steel brake lines (DID NOT INSTALL THIS UPGRADE)
Brakes