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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Brakes and Braking Systems => Topic started by: gwcrim on December 20, 2016, 06:34:02 AM

Title: making stock brakes great again
Post by: gwcrim on December 20, 2016, 06:34:02 AM
In this thread:  http://forum.73-87chevytrucks.com/smforum/index.php?topic=27999 the idea is put forth that the stock brakes, if "up to snuff" are pretty darn good.  I want to believe that and I want to achieve that.

My 1980 C10 needs help.  It rolled out of the factory with non-power disk/drums.  I've recently replaced the master cylinder, disks, calipers, hoses, pads and had the drums turned.  The pedal is not firm and the rear brakes lock up early.  I did the front, I had a mechanic do the rear. I took it to a shop and had them bled.  In my opinion, they suck.

In October the poor truck ended up on a guard rail because the rear end locked up.  This needs fixed.

What specifically can I do to make my stock brakes great again?
Title: Re: making stock brakes great again
Post by: zieg85 on December 20, 2016, 07:32:45 AM
First off if the pedal isn't firm there is air in it somewhere.  Did you bench bleed the master before you put it on?
Title: Re: making stock brakes great again
Post by: gwcrim on December 20, 2016, 07:46:20 AM
No, it was not.
Title: Re: making stock brakes great again
Post by: gwcrim on December 20, 2016, 07:58:13 AM
It was bled after installation. I've done it this way in the past on my `70 Challenger and it worked fine.
Title: Re: making stock brakes great again
Post by: zieg85 on December 20, 2016, 04:35:27 PM
Some work fine while others don't.  You need to bench bleed it.  You don't need to take it off the truck but take the lines off and return it back into the reservoir to get all the bubbles out.
Title: Re: making stock brakes great again
Post by: VileZambonie on December 20, 2016, 05:31:14 PM
You need to bench bleed the MC or air will be trapped in the system. Nevertheless if your truck is equipped without power brakes, they will never perform well. At the very least I would recommend upgrading to power brakes.

Title: Re: making stock brakes great again
Post by: zieg85 on December 20, 2016, 05:44:30 PM
You need to bench bleed the MC or air will be trapped in the system. Nevertheless if your truck is equipped without power brakes, they will never perform well. At the very least I would recommend upgrading to power brakes.

I'd put my manual against any power brakes.  Yes it requires more foot/leg pressure but mine stops as good as any...
Title: Re: making stock brakes great again
Post by: VileZambonie on December 20, 2016, 06:28:17 PM
You need to bench bleed the MC or air will be trapped in the system. Nevertheless if your truck is equipped without power brakes, they will never perform well. At the very least I would recommend upgrading to power brakes.

I'd put my manual against any power brakes.  Yes it requires more foot/leg pressure but mine stops as good as any...

lol okay let's race....or stop I mean
Title: Re: making stock brakes great again
Post by: bd on December 20, 2016, 06:29:39 PM
Race to a stop....  What a novel idea!  lol
Title: Re: making stock brakes great again
Post by: VileZambonie on December 20, 2016, 06:39:02 PM
I remember back when we had DMV inspections and part of the inspection was the stopping pad. So we had a guy with a C10 6 cyl, 3 on the tree, manual steering, manual brakes long bed. The DMV guy kept failing him even though the brakes were as true as they could be. I finally got the inspector to allow me to perform the stop after the 3rd fail because truly he couldn't operate it correctly. All I know is there was nothing enjoyable about driving or stopping that truck!
Title: Re: making stock brakes great again
Post by: hatzie on December 20, 2016, 07:48:03 PM
Don't just upgrade the Master and booster.  It's a system. 
You will need the proper pushrod and pedal.   
You'll need to do some research to make sure the non power calipers, drum components, and combination valve are the same as the power setup.
Title: Re: making stock brakes great again
Post by: gwcrim on December 20, 2016, 07:59:12 PM
My Challenger was pretty stout for a street car.  It had 11" manual DRUMS on all 4 corners.  Fred Flintstone had a better set up.  It shook like a dog passing a peach pit.

I drove this truck home the day my dad bought it brand new.  The brakes were good enough new.  Something isn't right now.  Even though I bled the MC several times with a helper, I suppose that could be the problem.  During my online research today, someone somewhere mentioned that the pedal and rod won't push all the air out.

Not looking forward to this.  Brake fluid everywhere.  Climbing under the dash.  Blah!
Title: Re: making stock brakes great again
Post by: bd on December 20, 2016, 08:13:05 PM
In general, it sounds like a tripped combination valve, because of air trapped in the front half of the system.  Does the park brake warning lamp illuminate with ignition on?
Title: Re: making stock brakes great again
Post by: gwcrim on December 20, 2016, 08:15:56 PM
In general, it sounds like a tripped combination valve, because of air trapped in the front half of the system.  Does the park brake warning lamp illuminate with ignition on?

I thought about that but the light doesn't come on.  It sure is in a hard to get to location.
Title: Re: making stock brakes great again
Post by: bd on December 20, 2016, 08:27:47 PM
As in, never illuminates under any circumstances - even when the park brake is set?  Is the tan wire connected to the switch on the combination valve?  Does the dash telltale illuminate if you ground the tan wire at the combination valve?  Generally, the valve can be recentered w/o removal.
Title: Re: making stock brakes great again
Post by: zieg85 on December 20, 2016, 10:42:34 PM
All I know is there was nothing enjoyable about driving or stopping that truck!

Back in the day some were a handful to stop but something must have been off.  Even on the oval track my car was manual steering and manual brakes.  I would even take the guts out of the right rear so there were 3 wheel braking, still stopped better than most. 
Title: Re: making stock brakes great again
Post by: gwcrim on June 26, 2019, 12:25:59 PM
Thought I'd update this.  I got a new master cylinder and bench bled it.  The brakes work MUCH better now.  Still too much rear bias but not near as bad as before.

Not sure what I'll do next for further improvement.  A proportioning valve?  Might have to.
Title: Re: making stock brakes great again
Post by: JohnnyPopper on June 26, 2019, 05:53:03 PM
Wow it took 3 years to bleed?  ::)

Does anyone make an aftermarket anti-lock system? I would consider it, the rear locks up on my K10 especially after a car wash.
Title: Re: making stock brakes great again
Post by: VileZambonie on June 27, 2019, 06:10:18 AM
RWAL came on these trucks. I think they are garbage systems but they are out there if one was so inclined.

If your brake system is 100% perfect and still locking up replace the combination valve but something sounds off if it is impacted by a car wash.
Title: Re: making stock brakes great again
Post by: JohnnyPopper on June 27, 2019, 05:33:53 PM
You're probably right, might need to crack one open.

Just thought the high water pressure is finding it's way inside the drum and causing it to seize.
Title: Re: making stock brakes great again
Post by: roundhouse on July 04, 2019, 09:36:35 AM
Some times the rear brakes will lockup it they axle seals are leaking and oil gets onto the shoes and drums

I know it doesn’t make sense that oil would make them lock up
But it does

It that does not cure it you may need to install an adjustable prop valve on the rear

And there are lots of kits to convert the rear to discs
Title: Re: making stock brakes great again
Post by: gwcrim on September 29, 2019, 03:12:03 PM
I have a suspicion that a brake drum is out of round.  Have to find someone to turn them.  That sure would cause the same rear tire to skid.
Title: Re: making stock brakes great again
Post by: gwcrim on December 02, 2019, 05:03:50 PM
Latest update.  I have the bed off so I decided to closely examine the rear brakes.  Seems as though the drums had probably never, ever been turned.  They appeared to be round but somewhat worn @ 70K miles.  I ordered new drums.  No one locally likes to turn them any more.

I'm hoping that the new drums fix the squishy pedal feel as well as stop the lock up.  If not, I'll have to try disks.
Title: Re: making stock brakes great again
Post by: MIKE S on December 02, 2019, 09:32:21 PM
Something else you may want to think about is that your rear brakes are locking up because your front brakes are not working good enough. In other words you are pressing on your brakes so hard that your back brakes are locking before your front brakes do. This can be caused by not having matched grades of braking material front and rear. If you have a metallic type pad on the front you have to get them hot for them to grab and they typically have a harder pedal. The rotors may not have a good non directional pattern on them. I’ve seen a lot of offshore rotors without a good finish. If you didn’t “burnish” in the front brakes when you put them on they could be glazed and that could cause some problem.
Title: Re: making stock brakes great again
Post by: gwcrim on December 03, 2019, 05:12:45 PM
This can be caused by not having matched grades of braking material front and rear.

I've thought about that. There aren't many selections of rear brake pad materials.  I have ceramic pads on front.  Cleaner for the mag wheels, ya know?
Title: Re: making stock brakes great again
Post by: MIKE S on December 03, 2019, 09:28:54 PM
I had problems on my 87 when I changed rear shoes. I tried O’Reillys and had a heck of a time. You could tell the friction material was very inferior. The forward or short shoe was not right. The friction material was attached to low on the shoe and I just could not get them to work right after a couple of sets. I finally found a set of AC/DELCO shoes that were far superior. Fit perfect and was able to adjust those for a good pedal with no lock up. Another thing to look at is the wheel cylinder. A larger bore would give you a softer pedal but more apply pressure to the shoes. You could have been given the wrong cylinders when you replaced them. They are different bores between 11 inch and 11 5/32 shoes.
Title: Re: making stock brakes great again
Post by: gwcrim on March 01, 2020, 09:03:12 AM
Update.  I replaced the rear drums.  Though I've only put about 50 miles on it since then, there seems to be a remarkable improvement in pedal feel.  I haven't tried a panic stop yet to see how quickly the rear tires skid, if at all but  I'm optimistic.