Disc brakes

[thessler]

Hi
I'm looking at different front disc brake conversion kits and am a little confused.
Seems you put in the dual master, one site says replace rear wheel cylinders they are engineered to work with the front discs.
Another says the same but add a proportioning valve, so one of them isn't right. Just looking at them it seems if you run it through the existing power booster you only have power front brakes and manual rear.
One site has the whole package front and rear power but you need to relocate the battery. I'm trying to educate myself before making a purchase, wondering what you guys are using and how they are working out.
Thank you, Tom

[Joe Johnston]

I'm looking at different front disc brake conversion kits and am a little confused.
Seems you put in the dual master, one site says replace rear wheel cylinders they are engineered to work with the front discs.

I used the complete kit from CASCO and it was this way. I've had no problems over the years and was able to retain the 14" wheels on my 57'

Another says the same but add a proportioning valve, so one of them isn't right.

My understanding is this all depends upon the master cylinder used for the conversion. IF all is properly sized, the proportioning valve is not needed, but the "Combination Valve" should be considered to truly separate the front and rear. Not all proportioning valves do this or do all dual master cylinders truly isolate the front and rear chambers.

Just looking at them it seems if you run it through the existing power booster you only have power front brakes and manual rear.

That is correct.

One site has the whole package front and rear power but you need to relocate the battery.

Also correct. This conversion uses a physically larger more powerful power booster attached to the master cylinder, not fender mounted as the original. There is no room for this new booster unless the battery is relocated.

[thessler]

Joe
Thanks for the reply.
Question in your experience does the front only power disc stop significantly better then all four power drums?
Would you do anything different?
Thanks, Tom

[Joe Johnston]

Yes the front disks are an improvement. I did not rebuild the original booster for several years and ran manual front disk brakes and the system worked fine. Later I had the booster completely rebuilt by Whitepost Restorations and connected to the front and the pedal effort was noticeably improved. If you drive in heavy traffic or repeatedly on interstates at high speed I feel the disk conversion greatly reduces brake fade from high speed stops. All that said, IMO, the brakes are definitely better but not as good as a modern vehicle with antilock disk brakes because the modern rotors are bigger, pads bigger and the boosters more powerful. I would definitely do it again & also include the pedal mounted mechanical brake light switch instead of the pressure switch.

[MarkR]

Tom, Joe has given you great advice. There are also some in depth articles at the CTCI website, click on Gil’s Garage and scroll down to the Body/suspension section. Gil has posted Several articles there regarding disc brakes on our Thunderbirds.
Mark

[thessler]

Thanks guys