Written by: Ed Lofton
I have a 1965 Catalina 2DHT that had power drum brakes. I purchased a set of 1970 Bonneville disc brakes to install on my ‘65. Either the ‘69 or ‘70 fullsize discs will work, but the ‘70 is a one piece rotor and the ‘69 rotor is a two piece unit, so the 70 is more desirable in my opinion.
You will need all the items associated with the front discs including, discs, backing plates, splash shields, calipers, rotors, booster, master cylinder, 2-piece proportioning valve, distribution block, flex hose to frame “L” brackets, brake pedal and all lines and hoses,
The spindles are a direct bolt-on item and attach to the upper and lower ball joints with no problems. The ’70 steering knuckle arm will not work with the ’65 outer tie rod ends. They bolt up OK, but the ’70 steering knuckle arm is longer than the ’65 and there is not enough adjustment for the proper toe-in. I re-used the knuckle arm from my ’65, but the ’70 bolts that hold them on are 1/2” diameter and the ’65 used one size smaller. I used a drill press to enlarge the holes to 1/2” and used the ’65 units. Note: You may be able to use the outer tie rod ends from a ’70 and bypass this part, but I had already purchased the tie rods for the ’65.
You will need the ’70 master cylinder and power booster. I purchased these as a set from AutoZone (part # 50-1004) that is listed for a ‘70 Bonneville w/disc brakes for around $100. They required a core return. You should use the ’70 power booster because it is larger than the one from the ’65. If you have a good unit off the ’70, you should be able to re-use it, but mine was in need of repair.
Next are the front brake distribution lines. You will need all the lines that go to and from the master cylinder and distribution block. I ordered a complete new set from InLine Tube (810-294-4093) for a 69-70 Bonneville. It is part #PBB7002 and was $65 in 2000. It fit perfectly and included all the lines to and from the master cylinder and proportioning valve and the one that crosses under the engine to the right brake. You will have to find a spot on the top of the frame to mount the ’70 distribution valve. The lines pretty well dictate where it will go and you just have to drill one small hole for the attachment bolt. The old line going to the rear brakes will be a little to long, so I took a tubing bender and put a couple small “S” curves in it to take up some length. Also, you will have to purchase an adapter so this line will connect to the distribution block. (the old line fitting is too small). I purchased a 9/16” fitting from Advanced Auto (part # PA 9075593) for a couple bucks that converted the smaller line to the larger block.
You will have to use the flex lines from the ’70, as well as the frame attachment “L” brackets. The ’65 “L” brackets will NOT work.
The brake pedal from the ’65 will not work properly because the attachment rod from the master cylinder is different. In ’65 they used a clevis type and in ’70, it is a rod and pin arrangement. Also, the ’70 pedal is offset at the attachment point. The only thing that will require some fabricating with the ’70 pedal will be the brake light switch. You will need to fabricate a small “L” bracket and attach it to the brake pedal so the switch contacts the pedal.
All the brake pads, calipers, seals and hoses are available at the local auto parts store. You will want to be sure you get a good set of rotors as they could be hard to find junk yard ones and new replacements run $225 each!!
I hope this helps. It is not hard and I hope my experiences save you some time and money.
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