break peddles peddle question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

forestb · 03-13-2018, 04:30 PM

I know that the brake peddles on this trucks are vary high but mine does not seem to even enguage the brakes until the peddle is about half way down.
I have front cpp discs and rear drums with a captonfab booster bracket. they stop the truck fine but it is a little bit of a pain. I have the correct proportioning valve for a disk drum setup. Will shortening the rod and lowering the peddle help? Or will I just be stepping around the problem?

TheBrewery · 03-13-2018, 06:08 PM

I'm chasing down brake problems too

If you shorten the pedal won't that just put the effective area out of reach? Have you checked the clearance between the booster and the master? It should be 0.25 - 0.75 mm of clearance, but if there is more it will cause what you are talking about. There also could be air in the setup that is compressing before the fluid moves. Have you tried rebleeding?

forestb · 03-13-2018, 06:28 PM

Do you mean clearance from the push rod or between the surfaces that come together when it is bolted together. No I have not tried rebleeding but when I took it to the mechanic to check them out he said they were fine. Maybe it is low on fluid.

I wonder if there is a way test to see when I start to get brake pressure maybe the rod is to short.

Quote:

Originally Posted by TheBrewery

I'm chasing down brake problems too

If you shorten the pedal won't that just put the effective area out of reach? Have you checked the clearance between the booster and the master? It should be 0.25 - 0.75 mm of clearance, but if there is more it will cause what you are talking about. There also could be air in the setup that is compressing before the fluid moves. Have you tried rebleeding?

TheBrewery · 03-13-2018, 09:06 PM

Quote:

Originally Posted by forestb

Do you mean clearance from the push rod or between the surfaces that come together when it is bolted together. No I have not tried rebleeding but when I took it to the mechanic to check them out he said they were fine. Maybe it is low on fluid.

I wonder if there is a way test to see when I start to get brake pressure maybe the rod is to short.

So check out this video, https://youtu.be/rYYzPIGoxfY?t=1915, It shows you how to measure the booster pin and MC piston to ensure they are "set" correctly.

**jayoldschool** · 03-13-2018, 09:27 PM

Quote:

Originally Posted by forestb

I know that the brake peddles on this trucks are vary high but mine does not seem to even enguage the brakes until the peddle is about half way down.
I have front cpp discs and rear drums with a captonfab booster bracket. they stop the truck fine but it is a little bit of a pain. I have the correct proportioning valve for a disk drum setup. Will shortening the rod and lowering the peddle help? Or will I just be stepping around the problem?

Do you have the correct DISC drum master as well?

forestb · 03-13-2018, 09:54 PM

here is the best photo I have of it.

TheBrewery · 03-13-2018, 11:16 PM

That looks like the corvette style dual pot, it is equal but you have a proportioning valve so you should be fine there.

**Captainfab** · 03-14-2018, 12:25 AM

Is your booster pushrod in the original hole in the pedal or did you drill a new hole 1" lower?

chevy_mike · 03-14-2018, 10:38 AM

Quote:

Originally Posted by Captainfab

Is your booster pushrod in the original hole in the pedal or did you drill a new hole 1" lower?

Yes, what he said. This is one of the most common mistakes people make. The pedal ratio is different between manual and power brakes. Power needs to be 1" lower than where a manual pedal would hook too. If not, your pedal will engage way too low and the brakes tend to be touchy.

Buddy did his truck conversion and didn't believe me. Had the same problem of low pedal engagement and being touchy. Finally drilled a hole 1" lower and the brakes were perfect.

forestb · 03-13-2018, 09:45 PM

I believe so. It is a dual cylinder.

forestb · 03-14-2018, 11:29 AM

I have heard of that but never done it. I should give it a try.

**The Rocknrod** · 03-14-2018, 03:36 PM

Brake pedal ratio - https://techtalk.mpbrakes.com/how-to...ng-pedal-ratio

forestb · 03-14-2018, 03:49 PM

Thanks. This is always something I have thought about doing but never got around to.

forestb · 04-02-2018, 04:27 PM

So i lowered the hole but have not gotten a chance to drive it yet. But what I was wondering while I was laying on my seat pushing the break peddle down with my hand I heard what sounded like air coming out of where the rod comes out of the booster. But it might just be air being pushed out of the rubber cup that covers where the rod goes into the booster. Is this normal?

**The Rocknrod** · 04-02-2018, 05:24 PM

While the truck is running? or off?

forestb · 04-02-2018, 05:37 PM

while running

03-13-2018, 04:30 PM	#1
forestb Registered User Join Date: Jan 2009 Location: Burbank, CA Posts: 3,619	break peddles peddle question I know that the brake peddles on this trucks are vary high but mine does not seem to even enguage the brakes until the peddle is about half way down. I have front cpp discs and rear drums with a captonfab booster bracket. they stop the truck fine but it is a little bit of a pain. I have the correct proportioning valve for a disk drum setup. Will shortening the rod and lowering the peddle help? Or will I just be stepping around the problem?

03-13-2018, 06:08 PM	#2
TheBrewery Registered User Join Date: Aug 2017 Location: Memphis, TN Posts: 79	Re: break peddles peddle question I'm chasing down brake problems too If you shorten the pedal won't that just put the effective area out of reach? Have you checked the clearance between the booster and the master? It should be 0.25 - 0.75 mm of clearance, but if there is more it will cause what you are talking about. There also could be air in the setup that is compressing before the fluid moves. Have you tried rebleeding? __________________ Mike 1960 C10 Short Step 235 w/ 3 on the tree 1999 Mazda Miata <- Track Car 2016 Chevrolet Colorado z71 2016 Chevrolet Traverse - Wifes Car 2014 Honda CBR500R <- Also A Dust Collector 2009 Suzuki GSXR600 <- Stolen

03-13-2018, 09:54 PM	#6
forestb Registered User Join Date: Jan 2009 Location: Burbank, CA Posts: 3,619	Re: break peddles peddle question here is the best photo I have of it. Attached Images

03-13-2018, 11:16 PM	#7
TheBrewery Registered User Join Date: Aug 2017 Location: Memphis, TN Posts: 79	Re: break peddles peddle question That looks like the corvette style dual pot, it is equal but you have a proportioning valve so you should be fine there. __________________ Mike 1960 C10 Short Step 235 w/ 3 on the tree 1999 Mazda Miata <- Track Car 2016 Chevrolet Colorado z71 2016 Chevrolet Traverse - Wifes Car 2014 Honda CBR500R <- Also A Dust Collector 2009 Suzuki GSXR600 <- Stolen

03-14-2018, 12:25 AM	#8
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: break peddles peddle question Is your booster pushrod in the original hole in the pedal or did you drill a new hole 1" lower? __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

03-13-2018, 09:45 PM	#10
forestb Registered User Join Date: Jan 2009 Location: Burbank, CA Posts: 3,619	Re: break peddles peddle question I believe so. It is a dual cylinder.

03-14-2018, 11:29 AM	#11
forestb Registered User Join Date: Jan 2009 Location: Burbank, CA Posts: 3,619	Re: break peddles peddle question I have heard of that but never done it. I should give it a try.

03-14-2018, 03:36 PM	#12
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: break peddles peddle question Brake pedal ratio - https://techtalk.mpbrakes.com/how-to...ng-pedal-ratio __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

03-14-2018, 03:49 PM	#13
forestb Registered User Join Date: Jan 2009 Location: Burbank, CA Posts: 3,619	Re: break peddles peddle question Thanks. This is always something I have thought about doing but never got around to.

04-02-2018, 04:27 PM	#14
forestb Registered User Join Date: Jan 2009 Location: Burbank, CA Posts: 3,619	Re: break peddles peddle question So i lowered the hole but have not gotten a chance to drive it yet. But what I was wondering while I was laying on my seat pushing the break peddle down with my hand I heard what sounded like air coming out of where the rod comes out of the booster. But it might just be air being pushed out of the rubber cup that covers where the rod goes into the booster. Is this normal?

04-02-2018, 05:24 PM	#15
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: break peddles peddle question While the truck is running? or off? __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

04-02-2018, 05:37 PM	#16
forestb Registered User Join Date: Jan 2009 Location: Burbank, CA Posts: 3,619	Re: break peddles peddle question while running

Thread Tools
Show Printable Version Email this Page
Display Modes
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.