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View Full Version : 1989, 1990, 1992 Front Brakes and Spindle FAQ



Mike8675309
02-11-2003, 11:15 PM
1989, 1990, 1992 Front Brakes and Spindle FAQ

What Brake Mods are available with STOCK front Spindles(1989-1992)?

None. The spindle design on the first years of the SC were changed in 1993. The 1993+ spindles are very similar to the Ford Mustang. And since a ton more Ford Mustangs were built, that's where the brake mods can be find. So if you want those trick dual piston front calipers, or those bigger Mark VIII brakes, or even bigger KVR brakes. You need to change out the front spindles to those from a 1993+ Thunderbird or Mercury. An SC part is not necessary.

Do I need to swap the front Hubs If I swap the Spindles?

No, the 89-92 hubs will bolt onto the 1993+ spindles. But there are some issues to consider:

The 89-90 hub does not have a machined lip to support the center of the brake rotor. The 91+ hubs have a machined lip to help center the rotor that fits a larger opening on the brake rotor. That means a 89-90 rotor won't fit on a 91+ hub, but a 91+ rotor will fit a 89-90 hub but won't gain the support of that machined lip.

A replacement 89-90 Hub is around $200. A replacement 91+ hub is about $75.

So the story here is you can retain your 89-90 hub if it's in good shape. But when it's time to replace it, move to the 91+ and get some new rotors. And if you're getting new rotors now, get the 91+ rotors. (Any of the upgraded brake rotors should be for a 93+ already)

What is the biggest brake I can fit with STOCK wheels?

The largest brake rotor size is from a Mark VIII car at 11.57". The downside to that choice is that it's only available with the Mark VIII caliper which is single piston. The increased surface area of the rotor will help dissipate heat quickly, but you won't gain the increased clamping force of a dual piston setup. Not a must, but certainly handy if you want to do any type of road racing.

Stock rotor diameter is 10.9"

What is the issue with the 1989-1992 Spindles?
Below is a picture of the 1993+ spindle on the left, and the 1989-1992 spindle on the right. Notice the tabs sticking out on the 89-92 that are used to retain the brake shoes. In 1993 it was changed out to a bracket that bolts on. These are the major items that prevent a larger rotor, and dual piston calipers from fitting on them. Yes you could cut them off, but notice the reduced material around the bolt holes for the caliper brackets. Remember, you're messing with your brakes here.

http://www.frontiernet.net/~miketoni/images/tbird/spindlecomp.jpg

Thanks to George Davenport (gldiii) for the pictures and information and Rich Thompson from www.MN12Performance.com for his information and heads up on a deal on PBR dual piston calipers and Ed Nicholson(fast Ed N) for his detailed information.

(edit: fix spelling, Clarify text)

ss_scuba
09-11-2004, 04:42 AM
There are some upgrades available for the early style brakes, just not calipers. KVR offers direct bolt in cross drilled or slotted rotors and Carbon Fiber pads. I agree with the 93+ style being better, but if you're on a budget and want better brakes...then you can always just go with a drop in replacement.

Mike8675309
09-11-2004, 08:29 PM
"None" may have been a bit harsh but I felt it fit pretty close.

The key issue with the front brakes is their mass. The only way, on the early models, to increase the brake mass requires replacement of the front spindles to a late model style.

Without an increase in mass of steel to absorb the heat generated in braking, the stock "size" brake rotor becomes quickly heat soaked reducing the friction level available. Carbon Fiber Pads will help as they're tendancy is to increase friction with heat, but the caliper is also less than substantial and will quickly transfer the heat into the brake fluid, leading to fade.

Certainly, if you can't do the front spindle swap, then upgraded rotors and pads will help. But I personally don't feel that they would be worth the cost. I'd go with the Mark brake upgrade rather than upgraded stock rotor and pads.

With that you are getting a larger mass in the rotor and a larger caliper.

SonySC
02-08-2005, 11:53 PM
If you want to do it all in one shot you can use the Mark 8 spindles,hubs, rotors, and calipers. Just replace the whole shooting match without disassembly if you can find a MK8 in a junkyard.

I used the MK8 spindles and swaybar links and kept my stock 92 hubs and rotors and bolted on PBR calipers from a 00 Mustang. One note of warning, you must use the PBR hollow hose brass bolt and washer and either modify your hoses or use aftermarket SS hoses like I did. Works great!
George Clarke