Mustang 5.0 Stocker brake pressure

Bobby Fazio · 03-10-2014, 11:34 AM

I got the UPR race products manual kit but can't hold the car on the line past 2000 rpms. I bought some good brake pads for the front and still use drums in the back. Not helping and this is a 5000+ stall converter. My old 3000 stall used to hold at 2200 no problem (with power booster). I bled the system and have a very good pedal. Auto, not a stick.

I plan to put a pressure gauge on this week, how many pounds should I be looking for? Could new master cylinder be the culprit?

Lee Valentine · 03-10-2014, 12:53 PM

Move the pivot up on the pedal where the master cylinder hooks 3/4" and it will hold. Same problem with mine

87gt50 · 03-10-2014, 05:30 PM

A bit off topic, but how was the UPR kit to install?

Bobby Fazio · 03-10-2014, 06:11 PM

Thanks Lee. The UPR kit was not too bad but definitely not 45 minutes for someone like me. The challenging part was figuring out a line lock schematic because the master cylinders were very different. One had two ports and the other had 3.

kdanner · 03-10-2014, 09:05 PM

How big is the master cylinder bore? If it's 1-1/8" like a lot of those kits, that's way too big for the factory brakes, something like 7/8"-15/16" normally works well.

Bobby Fazio · 03-10-2014, 10:58 PM

Yea I think it is larger.. Crapp

Fr8teamster · 03-10-2014, 11:12 PM

Measure your brake pedal. That will tell you your pedal ratio. Then go to any brak mfg website and check their master cylinder chart and it will tell you exactly what size MC to use. If your not sure how to measure it. I can walk you through it, it's not hard. Let me know.

Fr8teamster · 03-10-2014, 11:15 PM

I have a chart somewhere. I just can't remember where I put it. There's actually 2 charts one for a foot brake and one for a hand brake. Chassis shops can tell you. http://www.mpbrakes.com/techtalk/how...ng-pedal-ratio

Bobby Fazio · 03-11-2014, 03:46 PM

Quote:

Originally Posted by Fr8teamster

I have a chart somewhere. I just can't remember where I put it. There's actually 2 charts one for a foot brake and one for a hand brake. Chassis shops can tell you. http://www.mpbrakes.com/techtalk/how...ng-pedal-ratio

Thanks for your help. Ok according to the measurement I am at about 4:1 in the pedal ratio. Will adjusting this make up for too large of a master cylinder?

Fr8teamster · 03-11-2014, 08:40 PM

Yes moving it will change your brake line pressure. Usually a 5:1 pedal ratio equates to 1000lbs of pressure with a .750 MC

03-10-2014, 11:34 AM	#1
Bobby Fazio VIP Member Join Date: Nov 2009 Location: Egg Harbor Township, NJ Posts: 1,377 Likes: 1,145 Liked 3,494 Times in 426 Posts	Mustang 5.0 Stocker brake pressure I got the UPR race products manual kit but can't hold the car on the line past 2000 rpms. I bought some good brake pads for the front and still use drums in the back. Not helping and this is a 5000+ stall converter. My old 3000 stall used to hold at 2200 no problem (with power booster). I bled the system and have a very good pedal. Auto, not a stick. I plan to put a pressure gauge on this week, how many pounds should I be looking for? Could new master cylinder be the culprit? __________________ '65 Mustang SS/L & L/SA DriverInterviews.com \| App.DragInsights.com

03-10-2014, 12:53 PM	#2
Lee Valentine Senior Member Join Date: May 2004 Location: Brookfield, CT Posts: 708 Likes: 13 Liked 322 Times in 68 Posts	Re: Mustang 5.0 Stocker brake pressure Move the pivot up on the pedal where the master cylinder hooks 3/4" and it will hold. Same problem with mine __________________ Lee Valentine 1661 STK

03-10-2014, 05:30 PM	#3
87gt50 Junior Member Join Date: Feb 2003 Location: Malm?, Sweden Posts: 22 Likes: 0 Liked 0 Times in 0 Posts	Re: Mustang 5.0 Stocker brake pressure A bit off topic, but how was the UPR kit to install?

03-10-2014, 06:11 PM	#4
Bobby Fazio VIP Member Join Date: Nov 2009 Location: Egg Harbor Township, NJ Posts: 1,377 Likes: 1,145 Liked 3,494 Times in 426 Posts	Re: Mustang 5.0 Stocker brake pressure Thanks Lee. The UPR kit was not too bad but definitely not 45 minutes for someone like me. The challenging part was figuring out a line lock schematic because the master cylinders were very different. One had two ports and the other had 3. __________________ '65 Mustang SS/L & L/SA DriverInterviews.com \| App.DragInsights.com

03-10-2014, 09:05 PM	#5
kdanner Member Join Date: Nov 2003 Location: Austin, TX Posts: 219 Likes: 47 Liked 34 Times in 14 Posts	Re: Mustang 5.0 Stocker brake pressure How big is the master cylinder bore? If it's 1-1/8" like a lot of those kits, that's way too big for the factory brakes, something like 7/8"-15/16" normally works well.

03-10-2014, 10:58 PM	#6
Bobby Fazio VIP Member Join Date: Nov 2009 Location: Egg Harbor Township, NJ Posts: 1,377 Likes: 1,145 Liked 3,494 Times in 426 Posts	Re: Mustang 5.0 Stocker brake pressure Yea I think it is larger.. Crapp __________________ '65 Mustang SS/L & L/SA DriverInterviews.com \| App.DragInsights.com

03-10-2014, 11:12 PM	#7
Fr8teamster Junior Member Join Date: Feb 2014 Posts: 30 Likes: 0 Liked 0 Times in 0 Posts	Re: Mustang 5.0 Stocker brake pressure Measure your brake pedal. That will tell you your pedal ratio. Then go to any brak mfg website and check their master cylinder chart and it will tell you exactly what size MC to use. If your not sure how to measure it. I can walk you through it, it's not hard. Let me know.

03-10-2014, 11:15 PM	#8
Fr8teamster Junior Member Join Date: Feb 2014 Posts: 30 Likes: 0 Liked 0 Times in 0 Posts	Re: Mustang 5.0 Stocker brake pressure I have a chart somewhere. I just can't remember where I put it. There's actually 2 charts one for a foot brake and one for a hand brake. Chassis shops can tell you. http://www.mpbrakes.com/techtalk/how...ng-pedal-ratio Last edited by Fr8teamster; 03-10-2014 at 11:56 PM.

03-11-2014, 08:40 PM	#10
Fr8teamster Junior Member Join Date: Feb 2014 Posts: 30 Likes: 0 Liked 0 Times in 0 Posts	Re: Mustang 5.0 Stocker brake pressure Yes moving it will change your brake line pressure. Usually a 5:1 pedal ratio equates to 1000lbs of pressure with a .750 MC