4 wheel disc brakes

Robbie Welch · 08-05-2013, 04:03 PM

I've been doing needed updates to the old Fairlane. We built new headers 1 3/4 stepped to 1 7/8 there at Nitroplate getting coated. So while that's being done I thought I'd replace the 4 wheel (stock) drum brakes with strange 4 wheel disc. My question is what size bore master cylinder should I use? I asked the techs at strange and a friend that's done lots of dirt car brakes but got different answers from both of them. I also took the master cylinder off the car and measured the bore it was 1" and worked great with the drum brakes. Any help would be greatly appreciated

Lee Valentine · 08-05-2013, 06:11 PM

Ask Tom Goldman,nobody better.

Richard Grant · 08-05-2013, 06:44 PM

I would try the 1" before changing it. You can get a generic suggestion from the brake people but my experience is it takes trial and error to find what works best for you. There are a lot of ifs ands and buts, such as brake petal ratio, car weight, perfered petal feel, etc.

Robbie Welch · 08-06-2013, 06:58 AM

Thanks for the response's, yea I'll probably try the 1" MC. I had to pull it a part to check the bore size I suffer from CRS. I just don't want a peddle so hard I can't stop the car. Thanks Robbie

Tom Goldman · 08-06-2013, 08:22 AM

1" Might be a little small . It might work if the pedal ratio is low ,like 4-5 to1.like many power units use.
Robbie , I suspect your car was also manual brakes ,so the ratio is probably at least 6-7 to1.
Since you will be using 4 piston calipers ,I'd use at least a 1 1/16", or even a 1 3/32" bore cylinder.
You should be able to stop with normal pedal pressure. ...The smaller bore will give higher pressure with less effort, but it also makes it easier to lock the brakes when stabbing the pedal .

astikhossw · 08-06-2013, 12:04 PM

I have a 1984 t-bird that is 2500 lbs with driver and i have strange disc brakes on all 4 with a stock ford master cylinder and i can stab it once or twice at 129 slows down great nothing scary.I use 2 pistons front and 4 piston rear.

Tom Goldman · 08-06-2013, 04:25 PM

Your T-bird master cyl is 21mm or about 13/16".
It will work with 2 piston calipers, but would probably be undersized for a 4 piston front caliper. It also will work better with a low pedal , ratio like 4-1.
If you're using the stock pedal and it had power brakes ,thats about what most of them are.
Getting good brakes is all about balancing pressure with the correct volume ,while getting a comfortable feel for the pedal pressure required.

Robbie Welch · 08-06-2013, 07:42 PM

Tom thanks for the reply, Do you think it will stop ok with the 1" MC. I'm sure its a manual brake set up on the car from the factor.

Tom Goldman · 08-06-2013, 10:51 PM

Robbie, it should stop ok as long as you don't run out of pedal travel .

Robbie Welch · 08-07-2013, 06:50 AM

Thanks Tom, see you at Cecil.

08-05-2013, 04:03 PM	#1
Robbie Welch Live Reporter Join Date: Sep 2005 Location: Golden Beach Maryland Posts: 1,232 Likes: 52 Liked 262 Times in 124 Posts	4 wheel disc brakes I've been doing needed updates to the old Fairlane. We built new headers 1 3/4 stepped to 1 7/8 there at Nitroplate getting coated. So while that's being done I thought I'd replace the 4 wheel (stock) drum brakes with strange 4 wheel disc. My question is what size bore master cylinder should I use? I asked the techs at strange and a friend that's done lots of dirt car brakes but got different answers from both of them. I also took the master cylinder off the car and measured the bore it was 1" and worked great with the drum brakes. Any help would be greatly appreciated

08-05-2013, 06:11 PM	#2
Lee Valentine Senior Member Join Date: May 2004 Location: Brookfield, CT Posts: 708 Likes: 13 Liked 322 Times in 68 Posts	Re: 4 wheel disc brakes Ask Tom Goldman,nobody better. __________________ Lee Valentine 1661 STK

08-05-2013, 06:44 PM	#3
Richard Grant Member Join Date: Jan 2002 Location: West Monroe, La. Posts: 301 Likes: 9 Liked 13 Times in 7 Posts	Re: 4 wheel disc brakes I would try the 1" before changing it. You can get a generic suggestion from the brake people but my experience is it takes trial and error to find what works best for you. There are a lot of ifs ands and buts, such as brake petal ratio, car weight, perfered petal feel, etc. __________________ Richard Grant 4988 STK

08-06-2013, 06:58 AM	#4
Robbie Welch Live Reporter Join Date: Sep 2005 Location: Golden Beach Maryland Posts: 1,232 Likes: 52 Liked 262 Times in 124 Posts	Re: 4 wheel disc brakes Thanks for the response's, yea I'll probably try the 1" MC. I had to pull it a part to check the bore size I suffer from CRS. I just don't want a peddle so hard I can't stop the car. Thanks Robbie

08-06-2013, 08:22 AM	#5
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,436 Likes: 776 Liked 700 Times in 204 Posts	Re: 4 wheel disc brakes 1" Might be a little small . It might work if the pedal ratio is low ,like 4-5 to1.like many power units use. Robbie , I suspect your car was also manual brakes ,so the ratio is probably at least 6-7 to1. Since you will be using 4 piston calipers ,I'd use at least a 1 1/16", or even a 1 3/32" bore cylinder. You should be able to stop with normal pedal pressure. ...The smaller bore will give higher pressure with less effort, but it also makes it easier to lock the brakes when stabbing the pedal . __________________ Tom Goldman 1500 SG , 1506 STK Last edited by Tom Goldman; 08-06-2013 at 08:26 AM.

08-06-2013, 12:04 PM	#6
astikhossw Member Join Date: Jul 2008 Location: moreno valley Ca Posts: 263 Likes: 2 Liked 10 Times in 7 Posts	Re: 4 wheel disc brakes I have a 1984 t-bird that is 2500 lbs with driver and i have strange disc brakes on all 4 with a stock ford master cylinder and i can stab it once or twice at 129 slows down great nothing scary.I use 2 pistons front and 4 piston rear.

08-06-2013, 04:25 PM	#7
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,436 Likes: 776 Liked 700 Times in 204 Posts	Re: 4 wheel disc brakes Your T-bird master cyl is 21mm or about 13/16". It will work with 2 piston calipers, but would probably be undersized for a 4 piston front caliper. It also will work better with a low pedal , ratio like 4-1. If you're using the stock pedal and it had power brakes ,thats about what most of them are. Getting good brakes is all about balancing pressure with the correct volume ,while getting a comfortable feel for the pedal pressure required. __________________ Tom Goldman 1500 SG , 1506 STK

08-06-2013, 07:42 PM	#8
Robbie Welch Live Reporter Join Date: Sep 2005 Location: Golden Beach Maryland Posts: 1,232 Likes: 52 Liked 262 Times in 124 Posts	Re: 4 wheel disc brakes Tom thanks for the reply, Do you think it will stop ok with the 1" MC. I'm sure its a manual brake set up on the car from the factor.

08-06-2013, 10:51 PM	#9
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,436 Likes: 776 Liked 700 Times in 204 Posts	Re: 4 wheel disc brakes Robbie, it should stop ok as long as you don't run out of pedal travel . __________________ Tom Goldman 1500 SG , 1506 STK

08-07-2013, 06:50 AM	#10
Robbie Welch Live Reporter Join Date: Sep 2005 Location: Golden Beach Maryland Posts: 1,232 Likes: 52 Liked 262 Times in 124 Posts	Re: 4 wheel disc brakes Thanks Tom, see you at Cecil.