Problem with Power Disc Conversion - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Low69CST · 01-19-2004, 03:30 PM

My truck came originally with non-power drums and i'm switching it to power discs. I got the bracket that bolts on the firewall with the pivots that hooks to the booster. The problem I have is the 2 levers that pin the booster rod and the pedel rod come all the way back and hit my freshly painted firewall. Its like the rod on the brake pedel isn't long enough. It doesn't even allow the brake pedel to rise all the way up to it's stop, the levers hit the firewall before the pedel returns all the way. I tried to adjust the pedel rod out, but ran out of threads. We had the same problem on my dad's 72 and he had a new and longer pedel rod made. Since this is the 2nd truck we did with this problem i figure we're doing somethin wrong.

71Chev · 01-19-2004, 04:59 PM

You have to get the power brake pedal rod also. The rod for power brakes is longer than the rod for non power brakes.

Low69CST · 01-19-2004, 05:14 PM

This should be a power brake rod, aren't non-power rods just have a rounded tip on the end, like on the inside of my brake booster and power rods have a eye in the end for the pin to go through on the pivot rods, right??

71Chev · 01-19-2004, 05:29 PM

Yes the power brake rod have an eye on each end. What year did the booster, rod, and firewall bracket come off of?

Low69CST · 01-19-2004, 05:33 PM

I'm not sure what year they came off of. We just have a collection of parts and I picked out the best lookin.

Low69CST · 01-20-2004, 08:06 PM

anybody else?

Primed67 · 01-20-2004, 08:15 PM

I would say that you have the wrong pedal rod in it. You said that you were not sure what year it came out of. When I converted mine I took the MC, the booster and the rod out of a 72. Mine worked like a charm.

Low69CST · 01-20-2004, 08:37 PM

I dunno, if someone has a rod they know came out of a 72, if they could measure it, i'd appreciate it

71Chev · 01-20-2004, 08:44 PM

A 67-72 power brake set up bolts right in if you get the rod, bracket, and booster from a 67-72. I'd say find a known 67-72 set up and get it.

SWEET7T · 03-22-2004, 02:02 AM

Don't worry. Mine doesn't hit the rubber bumpstop either. I did the conversion on my '70 2 weeks ago. I got the bracket off of a '70 that had the power brake option. I just used it as a good excuse to have my brake pedal closer to being even with my gas pedal, so that it is easier to get my foot on the brake pedal. I hated how high it was before power brakes. My pedal doesn't move much at all, so I'm not worried about hitting the floor.

I don't think your doing anything wrong. The only thing that I can think of, is to replace the pedal assembly from a pwr brake truck. I took the pedal assembly from the donor truck, but didn't care enough to swap, or even measure to see if there was a difference. I just don't worry about it.

Tx Firefighter · 03-22-2004, 08:40 AM

Here's a 72 setup from the back...

Low69CST · 03-22-2004, 10:40 AM

Sweet,
What stops your brake pedal from coming all the way up? On my truck, the 2 fingers in the picture above were coming back and hitting the firewall. That was being the true stop for brakes. I was thinking the booster should stop it or it should rest on the pedal stop? What does the actual stopping on your setup? PPG paint is expensive, i don't like having big pieces of steel smacking it

01-19-2004, 03:30 PM	#1
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	Problem with Power Disc Conversion My truck came originally with non-power drums and i'm switching it to power discs. I got the bracket that bolts on the firewall with the pivots that hooks to the booster. The problem I have is the 2 levers that pin the booster rod and the pedel rod come all the way back and hit my freshly painted firewall. Its like the rod on the brake pedel isn't long enough. It doesn't even allow the brake pedel to rise all the way up to it's stop, the levers hit the firewall before the pedel returns all the way. I tried to adjust the pedel rod out, but ran out of threads. We had the same problem on my dad's 72 and he had a new and longer pedel rod made. Since this is the 2nd truck we did with this problem i figure we're doing somethin wrong. __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

01-19-2004, 04:59 PM	#2
71Chev Senior Member Join Date: Dec 2000 Location: Indiana Posts: 3,074	You have to get the power brake pedal rod also. The rod for power brakes is longer than the rod for non power brakes. __________________ 71 Chevy CST Long Fleet 350/350/3.07 leaf rear.

01-19-2004, 05:14 PM	#3
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	This should be a power brake rod, aren't non-power rods just have a rounded tip on the end, like on the inside of my brake booster and power rods have a eye in the end for the pin to go through on the pivot rods, right?? __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

01-19-2004, 05:29 PM	#4
71Chev Senior Member Join Date: Dec 2000 Location: Indiana Posts: 3,074	Yes the power brake rod have an eye on each end. What year did the booster, rod, and firewall bracket come off of? __________________ 71 Chevy CST Long Fleet 350/350/3.07 leaf rear.

01-19-2004, 05:33 PM	#5
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	I'm not sure what year they came off of. We just have a collection of parts and I picked out the best lookin. __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

01-20-2004, 08:06 PM	#6
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	anybody else? __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

01-20-2004, 08:15 PM	#7
Primed67 Registered User Join Date: Sep 2003 Location: Tyler Posts: 575	I would say that you have the wrong pedal rod in it. You said that you were not sure what year it came out of. When I converted mine I took the MC, the booster and the rod out of a 72. Mine worked like a charm. __________________ 1969 Chevrolet SWB Stepside 1959 Chevrolet apache * Sold 1967 Prostreet Chevy SWB Fleetside *Sold 2014 1/2 ton Crew Cab Chevrolet 4x4

01-20-2004, 08:37 PM	#8
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	I dunno, if someone has a rod they know came out of a 72, if they could measure it, i'd appreciate it __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

01-20-2004, 08:44 PM	#9
71Chev Senior Member Join Date: Dec 2000 Location: Indiana Posts: 3,074	A 67-72 power brake set up bolts right in if you get the rod, bracket, and booster from a 67-72. I'd say find a known 67-72 set up and get it. __________________ 71 Chevy CST Long Fleet 350/350/3.07 leaf rear.

03-22-2004, 02:02 AM	#10
SWEET7T Try spinnin 4 rear tars Join Date: Sep 2003 Location: Salt Lake City, Utah Posts: 757	Don't worry. Mine doesn't hit the rubber bumpstop either. I did the conversion on my '70 2 weeks ago. I got the bracket off of a '70 that had the power brake option. I just used it as a good excuse to have my brake pedal closer to being even with my gas pedal, so that it is easier to get my foot on the brake pedal. I hated how high it was before power brakes. My pedal doesn't move much at all, so I'm not worried about hitting the floor. I don't think your doing anything wrong. The only thing that I can think of, is to replace the pedal assembly from a pwr brake truck. I took the pedal assembly from the donor truck, but didn't care enough to swap, or even measure to see if there was a difference. I just don't worry about it. __________________ SWEET7T 1970 C10, 2wd, LB, 307/TH350/3.08. PS, PB

03-22-2004, 08:40 AM	#11
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Here's a 72 setup from the back... __________________ I'm on the Instagram- @Gearhead_Kevin

03-22-2004, 10:40 AM	#12
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	Sweet, What stops your brake pedal from coming all the way up? On my truck, the 2 fingers in the picture above were coming back and hitting the firewall. That was being the true stop for brakes. I was thinking the booster should stop it or it should rest on the pedal stop? What does the actual stopping on your setup? PPG paint is expensive, i don't like having big pieces of steel smacking it __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks



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