65dynamo

Hello guys,

I'm new to posting here but I've been helped an immense number of times by all of the experts and masters that frequent here. I wanted my first post to be a detailed step by step how-to with pictures for the disc break conversion kit I purchased from SSBC, but alas, I got stuck and now I need to ask for help. The kit was actually for a 1965 delta 88, not a dynamic 88 (i was assured there would be no difference) and the rotors don't fit onto the hubs as per included instruction sheet. My main question is what might be the difference between the delta and dynamic (convertible)? I'm hoping that I can just machine the hub to fit, as the bolt pattern is the same, but if there is major differences in the front end i might just cut my losses and sell the kit. So far everything has bolted right on And The hub is only around .125 big, so it would be a quick day on the lathe. I hope this all makes sense, this is my first real car build so I'm not the most knowledgable, especially on anything outside of motor work.

Another question I have is in regards to bolt pattern. Throughout researching this project I saw reference to the 5 x 5.00 bolt pattern, and I'm wondering how that is measured as mine seem to measure 4.75 centre-centre. Is this a legit bolt pattern or am I measuring wrong.

I appreciate any help you can offer and you can expect pics and how-to when it's all done.

Thanks
Ken

joe_padavano

The 5 x 5" bolt pattern refers to the diameter of a circle that passes through the centers of the wheel studs (also called a bolt circle). On a pattern with an even number of bolts, measuring across the two opposing studs is obviously the diameter of the circle. With an odd number of bolts, this is not possible.

Are you sure your car is a Dynamic and not a Jetstar 88? The 64-66 J88s used the smaller wheel bearings, brakes, and bolt pattern from the A-body cars (9.5" drums and 5 x 4.75" bolt pattern). If your car has 11" drums, it has the 5 x 5" bolt circle.

What exactly doesn't fit when you try to put the rotors on your spindles? If you are finding the bearings are binding when you try to slide them on, there is probably just a burr on the edge of the bearing mating surface on the spindle. Clean the surfaces thoroughly. I've had this happen frequently simply when replacing stock wheel bearings. Sometimes you have to use fine sandpaper or even a file to deburr the edge of the bearing surface on the spindle and the ID of the bearing.

65dynamo

Thanks for the answer Joe. The issue I'm having is fitting the rotor onto the outer part of the hub. I pressed the hubs out from the drums (which are 11", so I must have the 5x5 pattern) and replaced the studs. The instructions then say to Slide the rotor over the hub and install one lug nut to hold it place while the caliper brackets and caliper are installed. The rotor has kind of an inner race that the hub theoretically slides into, with the lugs poking through the lug holes. My calipers crapped out (stupid digital display) so just roughly measuring and estimating I would say the outer dia. Of the hub is 1/8" bigger than the inner dia. Of the rotor. I'm fine with machining it, I just wanted to tap into the expertise her to find out why this supposed bolt on kit doesn't bolt on and if maybe I made a mistake in assuming a kit for a delta would fit the dynamic.I've been told by a few local Oldsmobile enthusiast that the 65 dynamic is the same as a 65 delta in all but maybe some trim and options.

Oh and I'm sure it's a dynamic 88, not a jetstar 88. One other thing of note is, my car is a convertible. Not sure if that may change things.

Again thanks for the help,
Ken

joe_padavano

Ken,

All the Eighty Eights except for the Jetstar are mechanically the same, with only trim differences. The J88s used the smaller brakes from the A-body cars.

I have no experience with that aftermarket kit, so I can't explain why the parts don't fit, except that a lot could have been done to that car in the last five decades. It's possible (in fact, likely) that the front drums were replaced at one time, so while the kit may fit OEM hubs, the ones currently on the car may not be OEM. I think what you're saying is that the ID of the rotor doesn't fit over the machined surface on the hub. I'd have the rotor machined, not the hub.