drum to disc conversion logistics

James Kanteraki

Registered User
:confused:
i was surfing another forum for another car but have some questions that only the guys with SCs are smart enough to answer.

when converting from drum to disc brakes, on the rears, what type of techincal problems might i run into?
Forget about brakets and fitment and that stuff.

what i want to know is this. when you change from drums to disc, will there be any fluid type problems. obviously the wheel cylinder has a much smaller surface area for the fluid to push on, versus the caliper piston. therefore when changing to disc, i would effectively be lowering the pressure to the rear brakes. however, the proportioning valve should compensate for that, (i think). is the proportioning valve not based on pressure regulation??? also what about a car with a power booster, would there be any kind of difference when changing brake systems??

thanks for the help
 
try it

You might want to just try it first. The fluid will be all the same. You might need the valve from the car you get the rear setup off. If you find that the rears are locking up on you then change it, if not leave it alone. I hope this is some help.....Rich
 
There was also an old Super Ford issue that described updating the rear MN12 drum brakes. They were able to use the car's original knuckles by drilling out the holes to mount the calipers and by grinding away a small part of the knuckle. This would save removing the knuckles!

If you are interested, email me and I'll try to get the article or at least which issue of the magazine it appeared in.
 
thanks

first i should mention that this will not be performed on an MN12 but i asked here because i knew i would get good info.

rich, thats what i was thinking, braking is braking.
but i think you thought wrong on one part. you said to try it with the old valve, and if the rears locked up then it should be changed. however, like i said, the area of the piston would be increased, therefore decreasing force, so then the rears would be less effective, how do i check that??? but, the original proportioning valve, should sense less pressure, and equalize, making everything fine.

Mark VIII, that article is excellent. we need to have an archive of stuff like that on this board. Questions. you say proportioning valve in some cases, could you explain why it may/ may not be needed. also, what kind of wheels are those, and what is on that center cap, and where did you get the center cap. i have some knock off cobras and they have that stupid snake in the middle, and the SVT caps don't fit the wheels just by a hair. last thing, on the N/A birds, what type of power brake system do they have, is it vacuum??

george, if you could get the info on that article that would be great.

thanks
jim
 
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