1969 C10 rear brake adjuster - The 1947 - Present Chevrolet & GMC Truck Message Board Network

REDROCKER652002 · 10-30-2021, 03:20 PM

My son had torn into the rear brakes, due to a leak in the cylinder. He bought new shoes and all the springs and all. He has everything on correctly that I can tell, but the adjuster star on the passenger side seems to be spinning to wrong way for the shoes to adjust. So, my question, simple and stupid as it may be, what direction should the star spin for the shoes to adjust outward towards the drum? It has has been way too long for me and I be damned if I can remember He is really stressed, so I am asking in the hopes I can kinda push him in the right direction. RR

cj847 · 10-30-2021, 03:50 PM

If I recall correctly, one side is left hand thread. I always
-clean the threads on the adjuster thoroughly and lube it
-adjust the shoes til I can just get the drum back on, that way there is not a lot of turning involved.
-I think 69 had self adjusting, so you can complete the adjustment with repeated application of the E brake. (assuming everything is in place and working)

**dmjlambert** · 10-30-2021, 05:50 PM

"what direction should the star spin for the shoes to adjust outward towards the drum?" Down.

When the lever that engages the star wheel teeth and pushes down, the adjuster should increase in length and tighten the brake shoes up against the drum.

REDROCKER652002 · 10-30-2021, 06:06 PM

Thanks guys, he bought the one that would work for the drivers side, not the passenger side. He jacked up the one on the passenger side so bad I cannot get it loose. I tried heating it up and no luck. Tried some penetrating oil, but to be honest, the teeth on it are pretty bad. He is going to try again and see if he can get the right one. If not, classic parts had it for 8 bucks. He will just have to wait for the shipping. All good, he is learning and that is what it is all about. RR

Accelo · 10-30-2021, 08:22 PM

Do not use the white lithium grease on them. New they were dry. Used you can use never-seize on them. White lithium (like installed in the window tracks will seize like lock-tight. I found out the hard way.

On some vehicles the self adjusting lever is above the center-line of the adjuster screw and pushes down on the screw to lengthen it. If you were adjusting the screw manually through the backing plate you'd push the tool down to tighten the brakes. If the self adjuster lever is below the center-line of the screw it lifts up to adjust the brakes tighter. If you were adjusting the brake manually through the backing plate you'd move the tool up to tighten the brakes. If you're adjusting the brakes through a cutout in the drum it's the opposite.

REDROCKER652002 · 10-31-2021, 11:41 AM

OK, now I am stumped. He put the rear brakes back together. He has a few issues that I think we cleaned up. Little back history, when he pushed the brake pedal it would slowly go all the way to the floor, like a leak in the system. I had him pull back the boot on the rear cylinders and there was some fluid, so I figured the brake cylinders were bad. Easy fix, right? LOL. Ok, now fast forward to yesterday. He put everything back, got the correct adjusting star for the right rear and has everything buttoned up. All good, time for bleeding. When I step on the pedal to put pressure on the line the pedal slowly goes down to the floor. We go thru the bleeding process anyway on both the rear wheels since he changed them. I put a C clamp on the proportioning valve to keep the valve closed, I think that is what I remember having to do. Same thing on both sides. He did get some air out of each, but I am guessing that was the brake cylinder filling with fluid. He gets fluid flow thru the bleeder so i know the lines seem to be working. I crawl underneath this morning and do a quick visual and no leaks are apparent at any of the junctions on the lines. According to him, when this all started he was not losing any fluid out of the master cylinder which I found to be very strange. Also, he started the truck just to keep the battery charged and I noticed the brake light was lit on the dash board, not sure if that has anything to do with it or not. Any suggestions on where I should go from here? There is a plastic valve in the brake booster that leads to the carb, i am guessing some sort of vacuum line, he checked that hose and no cracks. But could that plastic piece be bad? I blow into it and it seems to seal, but not sure how it works. Another suggestion I got was to take the master cylinder out and redo the seals. He put his fingers in each side of the master and there was a bit of gunk that was at the bottom, but not enough in my opinion to cause any issues. I have no idea where these parts that are on the truck came from as they were on it when we bought it. This problem just started about 2 weeks ago, and he has been working so much he hasn't had any time to deal with it, so i am trying to help. Any suggestions would be most appreciated. RR

Accelo · 10-31-2021, 12:07 PM

An internet search came up with this;

One of the signs that your brake system is not properly functioning is the brake pedal being soft or spongy, which means the pedal goes down to the floor when pushed. If you notice your brake pedal is soft, you may wonder what part of the brake system causes this issue. Brake pedals can go down to the floor for various reasons. Learn about four of these reasons.
1. You Have Air in the Brake Lines

One of the main reasons why your brake pedal may become soft is because you have air in your brake lines. Air can make its way into your brake lines when repairs are done, when fluid is added, or as your car operates.

Brake fluid is responsible for traveling through your brake lines and providing the force needed to make your brakes stop. Air does not provide any force that helps your brakes stop. As such, when air is in your brake lines, your brake pedal can be pushed all the way down to the ground due to the lack of force.

If you have air in your brake lines, you will need to have the brake lines bled to remove the air.
2. You Have a Brake Fluid Leak

Another common reason why your brake pedal may go down to the floor is because you are running low on brake fluid. The most common reason this happens is because you have a leak in one of your lines.

When you are ready to leave for work after your car has sat for a prolonged period of time, check the ground underneath your car for puddles. Brake fluid can range from light yellow to dark brown, depending on its age. It will also feel slick and oily, much like vegetable or canola oil does.

If you have a brake fluid leak, an auto repair shop will have to determine which line is leaking and replace the line.
3. Your Brake Booster Is Failing or Is Bad

The third reason why your brake pedal may go down to the floor is because your brake booster is failing or is bad. This commonly occurs due to age and wear. Those who slam on their brakes often or drive in stop-andgo traffic may experience this problem faster than someone who doesn't stop as often.

Your brake booster provides power to the braking system, helping to engage your brakes when you push on the pedal. When the system is failing, your brakes may not engage when you push the pedal, causing either a soft pedal or a pedal that doesn't seem to operate.

A mechanic can diagnose your brake problems and determine if the brake booster is causing the spongy pedal. If the booster is the issue, replacing it is the only option.
4. Your Master Cylinder Is Going Bad

The final reason why your brake pedal may be soft is because your master cylinder is failing. A master cylinder may fail due to age and wear.

The master cylinder is the main valve that pumps brake fluid into your brake lines. When the cylinder is failing, your lines do not get the brake fluid needed. In turn, there is no pressure, which allows your brake to go down to the floor.

If your master cylinder is going bad, a mechanic may be able to repair the master cylinder or a replacement may be needed, depending on the age and condition of the cylinder.

REDROCKER652002 · 10-31-2021, 12:22 PM

Thanks. I am pretty confident that there are no leaks, at least none that I can see doing a quick check. Bleeding was done to the rear wheels only cause that is the only part of the system he changed. The front discs were done by my mechanic and I am pretty confident they are ok. So, my thinking is starting with the cheapest first. The little plastic thing is called a brake check valve. It is 10 bucks at Oreillys so I am going to steer him that way to start with. He already bought the booster from Jegs, as he thought that was the issue to start with, and I am going to feel really stupid if it was, but what the heck, he learned about drum brakes LOL. Thanks for the input, I appreciate that. We are still learning about the history of the truck and what parts were put on it.

geezer#99 · 10-31-2021, 12:43 PM

Is the master new?
The slowly dropping pedal can be internal leakage between the front and back reservoir.

**pjmoreland** · 10-31-2021, 01:05 PM

Your brake warning light is on because the shuttle valve in your combination valve assembly has moved due to unequal pressure in the front brakes vs. the rear brakes. I struggled with this issue multiple times in the past until I got one of these tools that holds the shuttle valve centered while bleeding the brakes. It screws in in place of the warning light switch.

https://www.amazon.com/gp/aw/d/B07BY...b_b_asin_image

Once the shuttle valve has moved, it will block flow to the rear brakes. This makes it nearly impossible to bleed the rear brakes. You will need to get the shuttle valve centered again. I have read that stomping on the brake pedal can center the valve, but I have never tried this. Bleeding one of the front brakes might allow the shuttle valve to center.

In my experience, the rear brakes are much more difficult to bleed than the front brakes. You know you are done when you get a powerful flow of fluid out of each rear brake when the pedal is being pushed and you crack open the bleeder. There should also be zero air in the fluid that comes out. If the fluid flow is lethargic, then you aren't done.

REDROCKER652002 · 10-31-2021, 01:51 PM

Quote:

Originally Posted by geezer#99

Is the master new?
The slowly dropping pedal can be internal leakage between the front and back reservoir.

Not yet, but it might be soon. LOL. I am leaning towards changing the master and the power booster just to say they are new.

REDROCKER652002 · 10-31-2021, 01:55 PM

Quote:

Originally Posted by pjmoreland

Your brake warning light is on because the shuttle valve in your combination valve assembly has moved due to unequal pressure in the front brakes vs. the rear brakes. I struggled with this issue multiple times in the past until I got one of these tools that holds the shuttle valve centered while bleeding the brakes. It screws in in place of the warning light switch.

https://www.amazon.com/gp/aw/d/B07BY...b_b_asin_image

Once the shuttle valve has moved, it will block flow to the rear brakes. This makes it nearly impossible to bleed the rear brakes. You will need to get the shuttle valve centered again. I have read that stomping on the brake pedal can center the valve, but I have never tried this. Bleeding one of the front brakes might allow the shuttle valve to center.

In my experience, the rear brakes are much more difficult to bleed than the front brakes. You know you are done when you get a powerful flow of fluid out of each rear brake when the pedal is being pushed and you crack open the bleeder. There should also be zero air in the fluid that comes out. If the fluid flow is lethargic, then you aren't done.

Good info, thanks. From what my son said, the fluid was coming out with no air, so, to me, that should say the rears are bled. Now, with the brake light on, I am wondering if the unequal pressure was due to an internal leak in the master cylinder? That certainly could make sense to me. I just don't understand why, if he has a leak somewhere, there is no fluid on the driveway or on the frame where the line runs. Like I said, I am trying to let him do it, but I cannot help but be somewhat involved. LOL.

**dmjlambert** · 10-31-2021, 05:30 PM

Too much brake pedal travel on mine was because the brakes needed adjustment. Press the brake pedal gently and slowly when bleeding them, and check that you can get fluid flowing well out of all 4 brakes. Top of your brake fluid. Then when you're all done with that bleeding turn the star wheel adjuster until you can't turn the drum any more by hand on both back brakes. Press and release the brake pedal again, then go adjust the star wheel adjuster again until you can't turn the drum any more by hand. When the star wheel adjusters are fully tight, then you can back them off a little until you can turn the drum by hand. Then see how your pedal travel is.

10-30-2021, 03:20 PM	#1
REDROCKER652002 Registered User Join Date: Nov 2018 Location: South San Francisco CA, Posts: 435	1969 C10 rear brake adjuster My son had torn into the rear brakes, due to a leak in the cylinder. He bought new shoes and all the springs and all. He has everything on correctly that I can tell, but the adjuster star on the passenger side seems to be spinning to wrong way for the shoes to adjust. So, my question, simple and stupid as it may be, what direction should the star spin for the shoes to adjust outward towards the drum? It has has been way too long for me and I be damned if I can remember He is really stressed, so I am asking in the hopes I can kinda push him in the right direction. RR

10-30-2021, 03:50 PM	#2
cj847 Registered User Join Date: Sep 2016 Location: Ft Smith, AR Posts: 543	Re: 1969 C10 rear brake adjuster If I recall correctly, one side is left hand thread. I always -clean the threads on the adjuster thoroughly and lube it -adjust the shoes til I can just get the drum back on, that way there is not a lot of turning involved. -I think 69 had self adjusting, so you can complete the adjustment with repeated application of the E brake. (assuming everything is in place and working)

10-30-2021, 05:50 PM	#3
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,565	Re: 1969 C10 rear brake adjuster "what direction should the star spin for the shoes to adjust outward towards the drum?" Down. When the lever that engages the star wheel teeth and pushes down, the adjuster should increase in length and tighten the brake shoes up against the drum.

10-30-2021, 06:06 PM	#4
REDROCKER652002 Registered User Join Date: Nov 2018 Location: South San Francisco CA, Posts: 435	Re: 1969 C10 rear brake adjuster Thanks guys, he bought the one that would work for the drivers side, not the passenger side. He jacked up the one on the passenger side so bad I cannot get it loose. I tried heating it up and no luck. Tried some penetrating oil, but to be honest, the teeth on it are pretty bad. He is going to try again and see if he can get the right one. If not, classic parts had it for 8 bucks. He will just have to wait for the shipping. All good, he is learning and that is what it is all about. RR

10-30-2021, 08:22 PM	#5
Accelo Registered User Join Date: Mar 2015 Location: washington Posts: 2,161	Re: 1969 C10 rear brake adjuster Do not use the white lithium grease on them. New they were dry. Used you can use never-seize on them. White lithium (like installed in the window tracks will seize like lock-tight. I found out the hard way. On some vehicles the self adjusting lever is above the center-line of the adjuster screw and pushes down on the screw to lengthen it. If you were adjusting the screw manually through the backing plate you'd push the tool down to tighten the brakes. If the self adjuster lever is below the center-line of the screw it lifts up to adjust the brakes tighter. If you were adjusting the brake manually through the backing plate you'd move the tool up to tighten the brakes. If you're adjusting the brakes through a cutout in the drum it's the opposite.

10-31-2021, 11:41 AM	#6
REDROCKER652002 Registered User Join Date: Nov 2018 Location: South San Francisco CA, Posts: 435	Re: 1969 C10 rear brake adjuster OK, now I am stumped. He put the rear brakes back together. He has a few issues that I think we cleaned up. Little back history, when he pushed the brake pedal it would slowly go all the way to the floor, like a leak in the system. I had him pull back the boot on the rear cylinders and there was some fluid, so I figured the brake cylinders were bad. Easy fix, right? LOL. Ok, now fast forward to yesterday. He put everything back, got the correct adjusting star for the right rear and has everything buttoned up. All good, time for bleeding. When I step on the pedal to put pressure on the line the pedal slowly goes down to the floor. We go thru the bleeding process anyway on both the rear wheels since he changed them. I put a C clamp on the proportioning valve to keep the valve closed, I think that is what I remember having to do. Same thing on both sides. He did get some air out of each, but I am guessing that was the brake cylinder filling with fluid. He gets fluid flow thru the bleeder so i know the lines seem to be working. I crawl underneath this morning and do a quick visual and no leaks are apparent at any of the junctions on the lines. According to him, when this all started he was not losing any fluid out of the master cylinder which I found to be very strange. Also, he started the truck just to keep the battery charged and I noticed the brake light was lit on the dash board, not sure if that has anything to do with it or not. Any suggestions on where I should go from here? There is a plastic valve in the brake booster that leads to the carb, i am guessing some sort of vacuum line, he checked that hose and no cracks. But could that plastic piece be bad? I blow into it and it seems to seal, but not sure how it works. Another suggestion I got was to take the master cylinder out and redo the seals. He put his fingers in each side of the master and there was a bit of gunk that was at the bottom, but not enough in my opinion to cause any issues. I have no idea where these parts that are on the truck came from as they were on it when we bought it. This problem just started about 2 weeks ago, and he has been working so much he hasn't had any time to deal with it, so i am trying to help. Any suggestions would be most appreciated. RR

10-31-2021, 12:07 PM	#7
Accelo Registered User Join Date: Mar 2015 Location: washington Posts: 2,161	Re: 1969 C10 rear brake adjuster An internet search came up with this; One of the signs that your brake system is not properly functioning is the brake pedal being soft or spongy, which means the pedal goes down to the floor when pushed. If you notice your brake pedal is soft, you may wonder what part of the brake system causes this issue. Brake pedals can go down to the floor for various reasons. Learn about four of these reasons. 1. You Have Air in the Brake Lines One of the main reasons why your brake pedal may become soft is because you have air in your brake lines. Air can make its way into your brake lines when repairs are done, when fluid is added, or as your car operates. Brake fluid is responsible for traveling through your brake lines and providing the force needed to make your brakes stop. Air does not provide any force that helps your brakes stop. As such, when air is in your brake lines, your brake pedal can be pushed all the way down to the ground due to the lack of force. If you have air in your brake lines, you will need to have the brake lines bled to remove the air. 2. You Have a Brake Fluid Leak Another common reason why your brake pedal may go down to the floor is because you are running low on brake fluid. The most common reason this happens is because you have a leak in one of your lines. When you are ready to leave for work after your car has sat for a prolonged period of time, check the ground underneath your car for puddles. Brake fluid can range from light yellow to dark brown, depending on its age. It will also feel slick and oily, much like vegetable or canola oil does. If you have a brake fluid leak, an auto repair shop will have to determine which line is leaking and replace the line. 3. Your Brake Booster Is Failing or Is Bad The third reason why your brake pedal may go down to the floor is because your brake booster is failing or is bad. This commonly occurs due to age and wear. Those who slam on their brakes often or drive in stop-andgo traffic may experience this problem faster than someone who doesn't stop as often. Your brake booster provides power to the braking system, helping to engage your brakes when you push on the pedal. When the system is failing, your brakes may not engage when you push the pedal, causing either a soft pedal or a pedal that doesn't seem to operate. A mechanic can diagnose your brake problems and determine if the brake booster is causing the spongy pedal. If the booster is the issue, replacing it is the only option. 4. Your Master Cylinder Is Going Bad The final reason why your brake pedal may be soft is because your master cylinder is failing. A master cylinder may fail due to age and wear. The master cylinder is the main valve that pumps brake fluid into your brake lines. When the cylinder is failing, your lines do not get the brake fluid needed. In turn, there is no pressure, which allows your brake to go down to the floor. If your master cylinder is going bad, a mechanic may be able to repair the master cylinder or a replacement may be needed, depending on the age and condition of the cylinder.

10-31-2021, 12:22 PM	#8
REDROCKER652002 Registered User Join Date: Nov 2018 Location: South San Francisco CA, Posts: 435	Re: 1969 C10 rear brake adjuster Thanks. I am pretty confident that there are no leaks, at least none that I can see doing a quick check. Bleeding was done to the rear wheels only cause that is the only part of the system he changed. The front discs were done by my mechanic and I am pretty confident they are ok. So, my thinking is starting with the cheapest first. The little plastic thing is called a brake check valve. It is 10 bucks at Oreillys so I am going to steer him that way to start with. He already bought the booster from Jegs, as he thought that was the issue to start with, and I am going to feel really stupid if it was, but what the heck, he learned about drum brakes LOL. Thanks for the input, I appreciate that. We are still learning about the history of the truck and what parts were put on it.

10-31-2021, 12:43 PM	#9
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,515	Re: 1969 C10 rear brake adjuster Is the master new? The slowly dropping pedal can be internal leakage between the front and back reservoir.

10-31-2021, 01:05 PM	#10
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,329	Re: 1969 C10 rear brake adjuster Your brake warning light is on because the shuttle valve in your combination valve assembly has moved due to unequal pressure in the front brakes vs. the rear brakes. I struggled with this issue multiple times in the past until I got one of these tools that holds the shuttle valve centered while bleeding the brakes. It screws in in place of the warning light switch. https://www.amazon.com/gp/aw/d/B07BY...b_b_asin_image Once the shuttle valve has moved, it will block flow to the rear brakes. This makes it nearly impossible to bleed the rear brakes. You will need to get the shuttle valve centered again. I have read that stomping on the brake pedal can center the valve, but I have never tried this. Bleeding one of the front brakes might allow the shuttle valve to center. In my experience, the rear brakes are much more difficult to bleed than the front brakes. You know you are done when you get a powerful flow of fluid out of each rear brake when the pedal is being pushed and you crack open the bleeder. There should also be zero air in the fluid that comes out. If the fluid flow is lethargic, then you aren't done.

10-31-2021, 05:30 PM	#13
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,565	Re: 1969 C10 rear brake adjuster Too much brake pedal travel on mine was because the brakes needed adjustment. Press the brake pedal gently and slowly when bleeding them, and check that you can get fluid flowing well out of all 4 brakes. Top of your brake fluid. Then when you're all done with that bleeding turn the star wheel adjuster until you can't turn the drum any more by hand on both back brakes. Press and release the brake pedal again, then go adjust the star wheel adjuster again until you can't turn the drum any more by hand. When the star wheel adjusters are fully tight, then you can back them off a little until you can turn the drum by hand. Then see how your pedal travel is.



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