disc brake conversion question?
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Senior User
Joined: Mar 2007
Posts: 482
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From: orange county ca.
disc brake conversion question?
ok so i found some disc brakes off of a 73 and i am going to switch out my drums but i had a questions. i know that i have to put a new master cyl. on the truck but do i have to change the brake booster? right now i have power drum brakes.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
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From: Creedmoor, North Carolina
The disc system uses a line to each wheel and a shared to the rear. Different systems use different pressures and have different bores in the master cylinders.
Would you defend your position on one system fits all, please. We need to make sure someone doesn't read this in the future, do it and get killed.
John
Would you defend your position on one system fits all, please. We need to make sure someone doesn't read this in the future, do it and get killed.
John
Laughing Gas
Joined: Nov 2000
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From: tulsa
If he has factory power drum brakes then he is already set up with the right master cyl and brake boster. the propoting valve takes care of the pressure issues. since his parts are from a 73 the master cyl should have the same size bore. Every truck i have worked on in this year range has had seperate brake lines to the front wheels. The two conversions I have done have worked well and both trucks stop better than my 03 ranger.
Senior User
Joined: Feb 2008
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If that is accurate, then the part numbers should be the same- double check and let us know. I haven't ever converted a Ford from drum to disc, but I have done Mopar and AMC. I used the entire set-up off of a '76 Dart (lines, prop valve, suspension, M/C) for my '69 Valiant 2-dr sedan, then the entire braking set-up off a '78 Matador (including booster) to fit a '68 Rebell SST. Ford trucks might be different, but I would error on the side of caution and past experience if I was having to do this to my truck.
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Elder User
Joined: Jul 2006
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From: East Helena MT
I looked in my Ford parts catalog and cannot come up with a part number for the master cylinder used on 67-72 F-100’s as it skips over those in my book. The brake booster diameter used on 68-72 F-100 is 8.84 inches where as the one used on a 73 with disk brakes is 11.46.
I am with John on this one and would install the parts called out for the year of pickup your parts came off of. There is no need to save a few bucks and use parts that are not designed for each other when it comes to brakes. As always that is JMHO.
Jeff
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Fleet Owner
Joined: Jun 1999
Posts: 24,552
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From: Creedmoor, North Carolina
The thing that concerns me is the guy that comes here and reads this later and says oh yeah I read on FTE that you can swap anything into your truck and it is fine. This site is the size it is today, because you can come here and get good honest info that you can take to the bank, not BS.
John
John
Posting Guru
Joined: Jun 2007
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From: Butler, IN
Yes, change the booster also. The MC & booster were designed to work together with disc brakes. You didn't mention what year your truck is, but I wouldn't trust an older brake booster to stop my truck. You will be changing out MC's anyway, change the booster while it is apart. Better in the long run.
Posting Guru
Joined: Feb 2007
Posts: 1,996
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From: Pittsburgh,Pa.
I just finished the disc swap on my 72 F100 that came with power brakes.The doner truck was a 76.I used a new master cylinder for a 76 with power brakes on my 72 booster.It bolted right up with no problems.The difference between disc and drum master cylinders is disc units have a larger reservoir for the front brakes.This is because discs require more fluid.As the pads wear the caliper pistons move further out of their bore and the fluid level drops.The pads can wear out and not run the master out of fluid.
If your booster is leaking or it's original then swapping it out would be good idea.I kept mine because the original owner had installed a reman unit about a month before I bought the truck last summer.Hope this helps.
If your booster is leaking or it's original then swapping it out would be good idea.I kept mine because the original owner had installed a reman unit about a month before I bought the truck last summer.Hope this helps.
Freshman User
Joined: Apr 2007
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i can see what every one is thinking on the keep it all the same when your doing an easy swap like that but what about the guys (like myself) that are doing the CV front end swap into my 65 what do you do for the power breaks on that i was planing on taking the master cyl off a late 70s truck and fitting it on mine and using an adjustable proporting valve
Posting Guru
Joined: Feb 2007
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From: Pittsburgh,Pa.
None that I've found.You can swap them with no mods from 68 thru mid 77.A 67 booster is a 1 year item and the linkage and pedal were changed in mid 77.The only problems I've heard of is when a large diameter booster is used with a 429 or 460 the booster hits the left valve cover.
Posting Guru
Joined: Jun 2007
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From: Butler, IN
None that I've found.You can swap them with no mods from 68 thru mid 77.A 67 booster is a 1 year item and the linkage and pedal were changed in mid 77.The only problems I've heard of is when a large diameter booster is used with a 429 or 460 the booster hits the left valve cover.
