Main British Car:
1955 Healey 100-4 v8 chevy 350
Front and rear Wilwood disc brakes on a 100-4 bn1
Posted by: 55BN1Chris
Date: October 09, 2019 02:27PM
12.88” Wilwood discs 1.1” thick both front and back
6 pot front calipers and 4 pot rear
Using the original BN1 spindles.
This is what worked for me so far......
1955-57 Chevy Hat mounted hubs have the same A2 outer bearing (0.75" outer bearing inner diameter) and A6 inner bearing (1.25" Inner bearing inner diameter).
These are the correct bearings to fit the BN1 spindle however the spacing for the bearings on the Chevy hub is 3.02" and that would put the outer bearing partially on the castle nut thread. (Wilwood doesn't have a narrower hub). This was unsatisfactory to me, and so....
I had a local high-end CNC shop remove the inner bearing race, and hone the bearing seat an extra 0.18" deeper on the inside bearing seat. Then re-seat the bearing raise and now it fits beautifully (took 1 day to get them back), rolls smooth as butter and they are super light compared to the hard to find steel lug mount hubs others are having to resort to fabricating. These clear the spindle cleanly. I avoided seating the outer bearing 0.18" deeper because the inside of the hub shape design. Seating it deeper would likely remove too much of the metal behind the bearing raise and weaken the hub, while seating the inside bearing deeper only increase the amount of metal directly contacting the bearing race.
Overall project parts identification:
The hub is Wilwood part #270-7631 and they are $135 a piece (x2) and the machine shop work was another $100.
The hats are WIL-170-8132 (0.41" offset) $158 a piece (x2); although I am still not sure if I should have gone with 170-8919 (0.29" offset). The 0.41" offset brings the disc as close inboard as I felt comfortable in relationship to the steering arm and the suspension arms, the 0.29" would put the disc even further outboard and further from the steering/suspension components, but put both the rotor and the caliper closer to the wheel. The only benefit of the lower offset would be decreased spacers on the caliper mount to caliper bracket (will discuss later).
The hat bolts are WIL-230-4572 $60 a pack (x2)
The rotors are WIL-160-13543-BK $225 a piece (x2)
The calipers are WIL-120-12003-RD (Left) and WIL-120-12002-RD (Right) $325 a piece (x2)
The front caliper brackets.
I have the BN1 original 3.25" spaced caliper mount brackets that come with the BN1 stub axle. However 3.25” is a rare spacing for most vehicles.
I also happen to have a set of Dennis Welch's BJ8 Caliper Bracket Kit alternative for P16 BJ8 calipers (part # CBRK152BL $180). These mount perfectly on BN1 stub axles and can be faced in either direction and give a 3.5" caliper mount spacing that is more common to cars..... mounting them arched outward.
Used a radial mount wilwood bracket to give me the spacing I need to get the caliper at the right radial location from the spindle center line for the brake calipers to sit flush with the edge of the rotors (I need a caliper mount height of 2.0875" from the BJ8 caliper bracket mount center line to the wildwood caliper mount surface (This include the use of the included shims and spacer to clear the caliper in addition to the bracket height; the shims are suggested for flexibility in alignment). WIL-250-6309
The rear was a kit for the ford 9” axle I have in the car, so it was buy and install.
I have a tilton pedal kit with independent front and rear master cylinders and the balance bar.