I am considering buying a 1965 Oldsmobile Jetstar 88 and using it as a summer daily driver. Due to safety, I would want to update the vehicle to a dual circuit brake system and disc brakes in the front. From the research I have done (and info from Scarebird Brakes), the Jetstar 88 has an intermediate (A-body) brake system and unique front spindles, which is why I have not been able to find a bolt-on disc brake system for this car.

Questions I am throwing out to the forum:

1. Has anyone on the forum updated their Jetstar to front disc brakes? How did you do it?
2. Could I swap on front spindles from a '65/'66 Delta 88 or Chevy Impala and then put a kit made for those cars on this Jetstar? I seems logical to me, but I have not compared the parts side by side to make sure the geometry is the same between the Chevy and Olds. I'm sure the Delta parts would go on without a problem.

Any information is appreciated. Thanks!

 

Not sure if the Jetstar has the same spindles as a "65" Cutlass (perhaps one of the experts will chime in) but if it is try www.paddockparts.com. They claim to have true bolt on kits for a "65" Cutlass. If you find out they are the same and do it, let me know how it turns out as I'd like to do my car (Cutlass) in a few months.

 

The J88 used unique B-body spindles with A-body brakes and 4.75" bolt pattern. All other Olds B and C-body cars used a 5" bolt circle. Disks were optional on the 67-70 B-body cars but with the 5" bolt circle. Note that these larger rotors ARE NOT AVAILABLE anywhere.

The A-body spindles are different and will not work on a J88. The caliper brackets may be able to be adapted. The J88 uses the same wheel bearings as the A-body, so Cutlass rotors should bolt right onto your spindles. Use the 69-72 single piston caliper and a same year master cylinder and proportioning valve and it might work.

The one problem with adapting the caliper brackets will be the need to machine the spindles. The drum brake backing plate attaches with three bolts, a large one on top and two smaller through bolts on the bottom. These bottom bolts also attach the steering arms. The caliper brackets attach to the top bolt and one of the two bottom bolts. The boss that the top bolt threads into needs to be machined down to allow the caliper bracket to fit properly. A machine shop can do this if you pull the spindles off. I don't know if the A-body caliper brackets have the same bolt spacing as the J88 spindles, but I suspect they do. If not, it's a simple cut and paste with an arc welder to get them to fit.

By the way, EVERYBODY and their mothers sell repro A-body brakes. The caliper brackets regularly sell on ebay for around $40 a pair. The A-body rotors, wheel bearings, grease seals, and calipers are all available at any auto parts store.

 

Thanks for the info! It really clears up the confusion about the Jetstar and what brake system it has. It is definitely different, and explains why everyone says Jetstar brake parts are hard to come by and no disc kit exists for it! I did not realize the bolt circle (4.75") was smaller than a traditional B-Body (5") - I'm sure I would have realized it when I started working on it!

I'll keep you guys posted if I buy the car. I'll use Joe's plan of attack - buy '69-'72 Cutlass parts and adapt brackets to fit.

One last question - using the '69-'72 parts, is it safe to assume a 14" Olds Rallye (SSII) wheel will work OK? This car already has early 1970s vintage 14" rallyes on it it. Just wondering, as I am making a budget for this project (while I try to whittle down the price) and want to make sure I know what I am getting myself into.

 

Assuming the caliper brackets don't require mods that push the caliper outboard, then 14" SSII/SSIII rims will fit. SSI rims come in disc and non-disc versions. The former will fit, the latter won't.

By the way, whatever your budget comes out to be, double it and you might be close...

 

I have two 66 starfire's and i think the setup of the j88 is the same as the starfire. can someone just make me a list of what to look for to convert my drums to discs? thank you, i was reading but i just got lost, im new to this conversion cause this is my fist olds school car, i love them though