brakes?

[Factory Guy]

I just watch this interesting video about how Matt upgraded his brakes from a later model Tahoe to his older Tahoe from "yard" parts. This got me to thinking I wonder if we can do this with our Square bodies? Anybody done this without buying expensive aftermarket parts?

FYI mine is a 8 bolt 3/4 ton.

I know you can add hydro boost and the like. But I am looking at the simplicity of his deal swapping rotors and calipers AND GETTING BIGGER BETTER brakes.

Here is the video I watched.

https://youtu.be/E11z7hLzpxw

[Dead Parrot]

I know on the 1/2 ton C10 trucks, there are two or three levels of brakes depending on the designed carrying capacity of the truck. Light duty vs heavy duty. Get an option list for the year/weight of your truck. If there are multiple brake options then check your SPID to see which your truck was built with. Then you have to check if a PO already did an upgrade.

There are some threads on swapping to the heavy brakes if the original truck came with the lighter duty version.

[kipps]

What's the year and gvwr of your 3/4-ton?

If you have one of the 1980's c20 or k20 trucks with the 7200-gvwr, then you should be able to easily upgrade brakes to the 8600-gvwr version.

The 8600-gvwr 3/4-ton trucks have a "c6p" RPO code on the SPID sticker, and they come with JB7 brakes. The 7200-gvwr 3/4-ton trucks don't have that "c6p" code, and they come with JB6 brakes.

[cadillac_al]

I never noticed any shortcomings with my 76 K10 brakes while hauling 6000 lbs and making several hard stops. Maybe with a bigger load I could notice some deficiencies. How much are you hauling?

[Factory Guy]

Truck is a 1973 3/4 ton Camper Special (8200 GVWR).

Really not pulling (hauling) anything with it anymore and yes it does have largest brakes (back in 1973) on it.

It stops well.

However if there are bolt on parts from a newer unit that gives better stopping ability I am interested.

[SCOTI]

Never heard of anything from later models that worked on the earlier generation trucks.

The 'heaviest duty' braking package on Squares used the same caliper & rotor size but had hydraulic boost vs. vacuum. When I changed the front brakes on my dually ('89/Square), I just swapped to vacuum but left the remaining parts in place. The pedal pivot rod placement is different if you do the swap from vacuum to HB brakes.

[Factory Guy]

Looks like I have found my answer. It involves a new Master Cylinder, from a later model SUV, as they displace more Brake fluid when the pedal is depressed. Apparently the Disc's on these Trucks are pretty darn good its the Master that is the weak link.

More details to come.

[LT7A]

Originally Posted by Factory Guy

Looks like I have found my answer. It involves a new Master Cylinder, from a later model SUV, as they displace more Brake fluid when the pedal is depressed. Apparently the Disc's on these Trucks are pretty darn good its the Master that is the weak link.

More details to come.

Cool! Keep us posted.

[Willowrun]

Originally Posted by Factory Guy

Looks like I have found my answer. It involves a new Master Cylinder, from a later model SUV, as they displace more Brake fluid when the pedal is depressed. Apparently the Disc's on these Trucks are pretty darn good its the Master that is the weak link.

More details to come.

I would agree with this in theory at least. I had a '99 2500 Suburban 4x4 for several years that I towed with that I felt was severely under braked at the time. Brakes only lasting 30-40,000 miles, soft pedal, pulsating, etc. After owning several newer generation truck with my newest now a '17 2500 the brakes are leaps and bounds better than my '99.

So with that, unless the upgrade is coming from something much newer, I don't think there was much improvement in braking from the square bodies through '99.

[kwmech]

If everything is put together and adjusted correctly you should have no issues stopping the truck. I'm still running 4 wheel drum on my 68 3/4 ton haul and tow occasionally without any issues. The hauling includes a complete pallet of block now and then. Then back for about 20-30 sacks of concrete or cement. The square bodies had even better brakes with the 13'' drums and disc brakes.

[SCOTI]

Originally Posted by Factory Guy

Looks like I have found my answer. It involves a new Master Cylinder, from a later model SUV, as they displace more Brake fluid when the pedal is depressed. Apparently the Disc's on these Trucks are pretty darn good its the Master that is the weak link.

More details to come.

Originally Posted by kwmech

If everything is put together and adjusted correctly you should have no issues stopping the truck. I'm still running 4 wheel drum on my 68 3/4 ton haul and tow occasionally without any issues. The hauling includes a complete pallet of block now and then. Then back for about 20-30 sacks of concrete or cement. The square bodies had even better brakes with the 13'' drums and disc brakes.

Having "no problems stopping the truck" & 'improving' the brakes are two different things. Improvement is also subjective w/o testing & validation.

If the brakes stop the truck w/o issue, technically they work & we call that a win. But what distance did it take to perform the task? The ability to complete the same task better in this case would likely be a shorter distance. Stopping the the same vehicle/weight in a shorter distance would be an improvement if it's repeatable.

I can see increased hydraulic pressure helping to some degree but there is going to be a limit as the existing surface area of the brakes will become the point of diminishing returns.
Increasing hydraulic pressure along w/the contact surface area that pressure is applied to? I can see THIS making a bigger difference.

What Matt did in that linked video was increase the surface contact area by changing over easily swapped parts. He did not change or improve/increase the hydraulic pressure.

In his case w/his Tahoe, the rotor size was increased. A larger rotor has more contact area for friction. It's possible the caliper piston size also increased since he swapped the matched calipers for the slightly larger rotor. It's also possible the piston area is not larger; we'd have to research that. On a similar GM format (Camaro vs Corvette brakes), the parts can similarly be easily swapped over & the same caliper can be used on the 12" LS1 rotor as well as the base C5/6 12.9" rotor or you can increase the piston area of the caliper w/a different caliper.

Like I mentioned initially, I have not seen any later model parts that can easily be swapped over to these earlier chassis trucks. That being said, I'm always open to listen to the ideas of others.

You could probably increase the hydraulic pressure applied on a vacuum brake set-up by simply swapping to a manual brake master cylinder of the same era as they have smaller bore sizing which would yield higher line pressure w/everything else being unchanged. That's also a common swap on the car platforms when dialing in brake performance changes.

[Honest Bob]

With JB7 brakes you are at the end of the line as far as an easy/cheap brake upgrade.

1/2 tons and blazers with jb5 I think can upgrade to jb6 pretty easily and probably even to jb7 as well I think if going from 6 lug to 8 lug isnt a big deal.

The 1 ton JB8 hydroboost brakes are super nice however...

A hydroboost swap requires quite a bit of planning and parts but can be done.

The front would require a different caliper mounting bracket which I dont think will fit on anything but a dana 60 front axle on a 4x4. I'm not sure about the front on a 2wd but I would assume its also more than just a caliper/bracket/rotor (different hub?).

The rear 3.5" rear drums I believe would be a bolt on affair if starting from a 3/4 ton with a FF 14bolt with the 2.5" drums, just replace the whole backing plate/drum assembly. You would need to find a used set of those brakes from a single rear wheel 1 ton preferably of the same ebrake style that you already have. The backing plates use different parking brake apparatus depending on if you have the a 73-80 or 81-91. Last I looked the one ton 3.5" 14 bolt ff backing plates are NOT available new. Trying to drive away with the parking break engaged on properly adjusted 3.5" drums feels like the truck is chained to a house.

[Factory Guy]

According to Scotty Baccus, he indicates that if you replace the Master Cylinder on a Squarebody to a Master Cylinder from a 2001Tahoe, you will dramatically improve the stopping performance. According to him, GM "upped" the brake fluid volume and lowered the Brake fluid pressure, thus giving a better pedal feel and eliminating the spongy feeling many complained about. Nothing needs to be done to the Disc brake pads/rotors.

But with this change, you will also need to change the reservoir for the Master Cylinder, as the Tahoe one will not fit under the hood of a Square.

He also indicates older Squares (like mine) probably could use a 81-87 Vacuum Booster, for peak performance, as these were improved as well, in the later years of the Squares.

[SCOTI]

Originally Posted by Factory Guy

According to Scotty Baccus, he indicates that if you replace the Master Cylinder on a Squarebody to a Master Cylinder from a 2001Tahoe, you will dramatically improve the stopping performance. According to him, GM "upped" the brake fluid volume and lowered the Brake fluid pressure, thus giving a better pedal feel and eliminating the spongy feeling many complained about. Nothing needs to be done to the Disc brake pads/rotors.

But with this change, you will also need to change the reservoir for the Master Cylinder, as the Tahoe one will not fit under the hood of a Square.

He also indicates older Squares (like mine) probably could use a 81-87 Vacuum Booster, for peak performance, as these were improved as well, in the later years of the Squares.

Interesting.

[Factory Guy]

I will be trying out, Scotty's suggestions on mine probably come fall...

AS I ALWAYS improve the brakes before I add horsepower to a vehicle!!!

[Shugalou]

Before going down the road with all the parts swapover have you considered stainless brake lines? I have them on my truck and the pedal feel is pretty good.

I've also read that endless yellow brake pads are a nice upgrade...I have a set of stop tech pads and cross drilled and slotted rotors waiting to go my truck and I'm hoping to notice an improvement.

Good luck.

[Factory Guy]

Originally Posted by Shugalou

Before going down the road with all the parts swapover have you considered stainless brake lines? I have them on my truck and the pedal feel is pretty good.

I've also read that endless yellow brake pads are a nice upgrade...I have a set of stop tech pads and cross drilled and slotted rotors waiting to go my truck and I'm hoping to notice an improvement.

Good luck.

Thanks. I know I put a set of the red pads on my Chevelle and noticed a big improvement with my braking. Didn't notice much (on Chevelle) with the change to stainless brake lines.

[LT7A]

I think I've heard of EBC having different color pads. Is endless another manufacturer? And speaking of stainless, are we talking brake lines or brake hoses? I don't imagine a difference in pedal feel with SS brake lines, but the good SS hoses are supposed to not expand as much and give a better pedal feel.

[SCOTI]

Originally Posted by LT7A

I think I've heard of EBC having different color pads. Is endless another manufacturer? And speaking of stainless, are we talking brake lines or brake hoses? I don't imagine a difference in pedal feel with SS brake lines, but the good SS hoses are supposed to not expand as much and give a better pedal feel.

This....

[Shugalou]

Yeah the brake pads are EBC Yellow my mistake - they are supposed to have a good bite to them and perform like race pads but are made for the street...I haven't had any experience with them but in Jim Pickering's book how to modify 1973-1987 chevy trucks he references this as a good upgrade before going to a big brake kit.

And yes stainless drop lines - I put Russell lines on my truck.

[LT7A]

Originally Posted by Shugalou

Yeah the brake pads are EBC Yellow my mistake - they are supposed to have a good bite to them and perform like race pads but are made for the street...I haven't had any experience with them but in Jim Pickering's book how to modify 1973-1987 chevy trucks he references this as a good upgrade before going to a big brake kit.

And yes stainless drop lines - I put Russell lines on my truck.

Thanks, good info. I'm not familiar with Jim Pickering's book, I will have to check it out.

[Factory Guy]

Its Works!

I just did Scotty Baccus's, brake up grade and it works great! The pedal feels much more like a modern car. Basically his up grade is a new 2001 Tahoe Master Cylinder. I kept my old Brake booster. (You can change it, but I saw no need) You need a S10 reservoir to allow the Square hood to close. The back of the new Master must be trimmed down to fit inside the old Brake booster. More brake testing to follow after we get a little nicer weather.

I changed really nothing else.

Long term I plan to get some new stock rotors and EBC RED brake pads (I really like my RED EBC brake pads on my Chevelle.
For the rest of the brake components being stock this works Amazing!

The parts list for the Brake swap is below in the photo's.

[Factory Guy]

Originally Posted by LT7A

I think I've heard of EBC having different color pads. Is endless another manufacturer? And speaking of stainless, are we talking brake lines or brake hoses? I don't imagine a difference in pedal feel with SS brake lines, but the good SS hoses are supposed to not expand as much and give a better pedal feel.

EBC has all kinds of different colors a lot of racing stuff... The ones I know of are Red, yellow, green, blue black, Gray, and the list goes on. Most of these are racing related.

I know my Chevelle got the red ones and it was night and day difference between the old pads (local parts store) and the red pads!