Using 90 spindles and brakes, do I need to upgrage master cylinder and booster?

[NewToFord]

I have an 80 fairmont. It was a 6cyl. I am running 90 GT spindles and brakes all around. I plan on using the 90 steering rack and power steering pump. Do I have to change the brake booster, or master cylinder, or porpitioning valve? Thanks

[gmatt]

I also have an 80 Fairmont with the later spindles/brakes(11") and 8.8(drum brakes) out of a GT. I didn't change the brake booster, master cylinder or proportioning valve. Stops fine.

[Stymees'mont]

You should be fine unless you have rear disc brakes, then you will need to change both master cyl and proportioning valve.

[83gtstang]

I have an 80 Fairmont wagon. I am sure it will be fine, as stated above. I converted to four wheel discs on my 83 Mustang and actually kept the same master cylinder for a while, before I upgraded to the SVO/Lincoln master cylinder with bigger bore. Just be sure you have good vacuum for the booster, but it will stop, just need to apply more foot pressure.

[83gtstang]

Just remembered something...do you need to change the A-arms? I do not remember, possibly even the struts? Can anyone confirm that?

[roadkill]

I believe the A arms will work, but there's an issue with the struts needing shimmed where they bolt to the knuckles IIRC.

[gmatt]

My later spindles came with struts, but I needed to retain the 'onion-head' upper mount as there is a slight difference between the early-late mount's bolt pattern. I'm not sure what was changed, the size of the mounting studs or the spacing between them, but the 'onion head' mount will work with the later strut or just get caster camber plates. I replaced my A arms with the M-3075 kit, but I'm not sure that is necessary.

[JACook]

The original A-arms will work just fine, unless you use SVO spindles. But the SVO spindles can be used
with a tapered spacer. The biggest reason to use the later A-arms is they have a low-friction ball joint,
that makes a very noticeable improvement in road noise and impact harshness. Plus you don't have to
grease them.