Parking brake adjustment
03-09-2010, 08:10 AM
#21
Drifting
I am stealing this from Gerry72 but it is one of the best write ups I have seen on adjusting these. Hardly anyone mentions that you can't adjust these right with the halfshafts drooping while the car is jacked up. Anyway, here it is....
Courtesy of Gerry72:
C3 parking brakes are difficult for shadetrees to correctly adjust due to some design issues that aren't well addressed and just experience shortfalls.
If you try to adjust the shoes by turning the star wheel until you feel a drag on the rotor/drum you'll confront the design issues. They have to do with the halfshafts going into a bind when the rear suspension is in full droop and the limited slip driving the opposite wheel which will also be in a bind as well as contributing to drag and shoe friction. There is a very specific adjustment method that must be followed, otherwise you'll not have full shoe contact and may also destroy the shoes.
The meat of the issue is that you have to loosen the adjuster cable to the point where there is no tension on the cable. The cable moves the top of the shoe out in an arch. The bottom part of the shoes only pivot. So, for the most part, what you are adjusting with the star wheel is the bottom part of the shoe. Once you have the bottom part of the shoes adjusted on both wheels, you can put tension on the cable so that when the handle is pulled, the shoes come into equal contact with the drum.
The tricky part, again, is knowing when you have the bottom part of the shoes in proper contact. If you are off, you'll have contact difficiencies in either the top or bottom of the shoes on the drum. With improper adjustment, the brake mechanism will perform poorly or you'll destroy the brake lining...or both.
So, how does the shadetree deal with this? Not easily. The best way is to disconnect the halfshafts at the spindle flange (not the differential stub axle) so that both rear wheels are not connected to the differential and are free to rotate without any halfshaft binding, opposite wheel drag, or drivetrain drag. Doing it this way will allow you to have a very good tactile sense of when the bottom part of the shoe is contacting the drum. You want light contact so that you can hear the shoe contact throughout the full revolution of the wheel. Once you have the bottom shoes adjusted on both sides, you can tighten up the cable. With the handle fully retracted, you start adjusting the cable until you hear and feel the full shoe lightly contact the drum. It should be an equal feel and sound on both sides. The drag from the contact friction should be very, very light. Once you think you have the right cable adjustment, pull up on the handle. You should get around three clicks and then strong resistance. If all seems well, button it up and give it a test.
You can do it without disconnecting the halfshafts but, again, for a shadetree, you'll be fighting the ills and your experience level. You'd at least have to jack up both sides of the spindles to put the halfshafts at ride height so you can keep them from binding. Of course, in adjusting the star wheel, you are essentially doing the adjustment based upon your experience in doing it this way. For the most part, you're working from hearing only since you have drivetrain drag contributing to the brake friction.
It does take longer to do it by disconnecting the halfshafts but the outcome is usually better for the shadetree. And it's not like you'll be doing this every couple of months. If you have a good parking brake assembly, you should have to do this only once. So your time is sort of like an investment in the outcome.
Courtesy of Gerry72:
C3 parking brakes are difficult for shadetrees to correctly adjust due to some design issues that aren't well addressed and just experience shortfalls.
If you try to adjust the shoes by turning the star wheel until you feel a drag on the rotor/drum you'll confront the design issues. They have to do with the halfshafts going into a bind when the rear suspension is in full droop and the limited slip driving the opposite wheel which will also be in a bind as well as contributing to drag and shoe friction. There is a very specific adjustment method that must be followed, otherwise you'll not have full shoe contact and may also destroy the shoes.
The meat of the issue is that you have to loosen the adjuster cable to the point where there is no tension on the cable. The cable moves the top of the shoe out in an arch. The bottom part of the shoes only pivot. So, for the most part, what you are adjusting with the star wheel is the bottom part of the shoe. Once you have the bottom part of the shoes adjusted on both wheels, you can put tension on the cable so that when the handle is pulled, the shoes come into equal contact with the drum.
The tricky part, again, is knowing when you have the bottom part of the shoes in proper contact. If you are off, you'll have contact difficiencies in either the top or bottom of the shoes on the drum. With improper adjustment, the brake mechanism will perform poorly or you'll destroy the brake lining...or both.
So, how does the shadetree deal with this? Not easily. The best way is to disconnect the halfshafts at the spindle flange (not the differential stub axle) so that both rear wheels are not connected to the differential and are free to rotate without any halfshaft binding, opposite wheel drag, or drivetrain drag. Doing it this way will allow you to have a very good tactile sense of when the bottom part of the shoe is contacting the drum. You want light contact so that you can hear the shoe contact throughout the full revolution of the wheel. Once you have the bottom shoes adjusted on both sides, you can tighten up the cable. With the handle fully retracted, you start adjusting the cable until you hear and feel the full shoe lightly contact the drum. It should be an equal feel and sound on both sides. The drag from the contact friction should be very, very light. Once you think you have the right cable adjustment, pull up on the handle. You should get around three clicks and then strong resistance. If all seems well, button it up and give it a test.
You can do it without disconnecting the halfshafts but, again, for a shadetree, you'll be fighting the ills and your experience level. You'd at least have to jack up both sides of the spindles to put the halfshafts at ride height so you can keep them from binding. Of course, in adjusting the star wheel, you are essentially doing the adjustment based upon your experience in doing it this way. For the most part, you're working from hearing only since you have drivetrain drag contributing to the brake friction.
It does take longer to do it by disconnecting the halfshafts but the outcome is usually better for the shadetree. And it's not like you'll be doing this every couple of months. If you have a good parking brake assembly, you should have to do this only once. So your time is sort of like an investment in the outcome.
The following users liked this post:
marshal135 (06-14-2020)
03-09-2010, 10:16 AM
#22
Burning Brakes
Thread Starter
thanks all. i've got the back end up on jack stands, car in neutral, parking brake released, and the rear wheels off. looking through the holes in the rotor i can't seem to find the adjusters. i read in another thread that i need to spin the disc to 6 o'clock position. is this correct? don't see the adjuster. harder to spin the disc than i thought it would be
03-09-2010, 01:54 PM
#24
Burning Brakes
Member Since: Sep 2008
Location: Naperville Illinois
Posts: 805
Likes: 0
Received 5 Likes
on
4 Posts
The star wheel (adjuster) is at the six o clock position.
Because the shop said that they thought the shoes might be new, I assume that the rotor rivets have been drilled out. Why not take the rotor off and have a look? Two bolts will release the caliper from the trailing arm, and the flexible brake hose is held in place by a clip; you don't have to un-do the brake lines. You will have to suspend the caliper from something with wire to keep it out of your way. This way you can examine the system and see if anything else is wrong.
Mark your rotors as to side before you remove them so they don't get mixed up. Once the rotor has been removed, it must be re-installed in the exact same position relative to the spindle, or the adjustment holes won't line up and you may end up with unacceptable disc run-out--and a whole new set of problems.
Because the shop said that they thought the shoes might be new, I assume that the rotor rivets have been drilled out. Why not take the rotor off and have a look? Two bolts will release the caliper from the trailing arm, and the flexible brake hose is held in place by a clip; you don't have to un-do the brake lines. You will have to suspend the caliper from something with wire to keep it out of your way. This way you can examine the system and see if anything else is wrong.
Mark your rotors as to side before you remove them so they don't get mixed up. Once the rotor has been removed, it must be re-installed in the exact same position relative to the spindle, or the adjustment holes won't line up and you may end up with unacceptable disc run-out--and a whole new set of problems.
03-09-2010, 03:36 PM
#25
Burning Brakes
Thread Starter
ok - found the adjuster. i loosened the parking brake cable, then i tightened the adjuster as much as possible on both wheels. after tightening all the way, i loosened the adjuster about 8 ticks. last, i tightened the cable, put the wheels back on and gave it a test. the car still rolls away like the brake isn't even on. i don't even feel any drag at all.
the shop did say he thought the shoes may need to be worn in, so i assumed he thought they were relatively new. i'm wondering though if maybe they are no good. i think i may have to take off the calipers and rotors and have a look. not sure what exactly to look for when they are off.
the shop did say he thought the shoes may need to be worn in, so i assumed he thought they were relatively new. i'm wondering though if maybe they are no good. i think i may have to take off the calipers and rotors and have a look. not sure what exactly to look for when they are off.
03-10-2010, 04:10 AM
#26
Le Mans Master
Member Since: Aug 2006
Location: mount holly NC
Posts: 6,989
Received 1,246 Likes
on
966 Posts
C3 of Year Finalist (appearance mods) 2019
You are getting close to getting the parking brakes to work 100%. At this point do as others have suggested, mark the position of the rotors and pull them off and look at the condition of the parking brake shoes. They only have a little pad on them but if there not cracked or glazed they should still be OK. Most times the parking brakes don't work because the parts are rusted in place or the pads wore out from someone leaving the brake on and driving for a long time.
After getting the rotors tight backing off 7 to 9 clicks should be correct.
The next step is to tighten the cross cable, did you still have more threads to go, if not the cable may be stretched and although the mechanic said he replaced it does it look new?
At this point you should be able to pull the parking brake lever inside the car 14 clicks and have the brake hold 100%.
After getting the rotors tight backing off 7 to 9 clicks should be correct.
The next step is to tighten the cross cable, did you still have more threads to go, if not the cable may be stretched and although the mechanic said he replaced it does it look new?
At this point you should be able to pull the parking brake lever inside the car 14 clicks and have the brake hold 100%.
03-10-2010, 05:19 AM
#27
Burning Brakes
ok - found the adjuster. i loosened the parking brake cable, then i tightened the adjuster as much as possible on both wheels. after tightening all the way, i loosened the adjuster about 8 ticks. last, i tightened the cable, put the wheels back on and gave it a test. the car still rolls away like the brake isn't even on. i don't even feel any drag at all.
the shop did say he thought the shoes may need to be worn in, so i assumed he thought they were relatively new. i'm wondering though if maybe they are no good. i think i may have to take off the calipers and rotors and have a look. not sure what exactly to look for when they are off.
the shop did say he thought the shoes may need to be worn in, so i assumed he thought they were relatively new. i'm wondering though if maybe they are no good. i think i may have to take off the calipers and rotors and have a look. not sure what exactly to look for when they are off.
As said, it sounds like taking off the rotor may be your next move. Take care to release the clip holding the brake hose so that you cane move the solid brake line enough to move the caliper out of the way, you don't want to bend the pipe if you can aviod it! You'll need to adjust the shoes so that they are fully off to ease removing the rotor.
While you are there and have the calipers off, have a good look at how the cable is connected to the parking brake mechanism at the wheel to ensure that it has been done correctly. And ensure that it runs through the outer casing atached to the trailing arm freely, ie, is actually releasing when the lever is down. Personally, I've never had issues with the "half shaft thing", so I'd delay disconnecting it!
And as I say, if it come to having to remove and replace the shoes, you'll need a LOT of patience!
03-10-2010, 05:20 AM
#28
Burning Brakes
Thread Starter
yes, the cable looks new and the cable is not tightened all the way. i did tighten it a bit more from how the shop had it. next thing i'm going to do as a test is tighten the shoes all the way and verify that this locks the wheels. i'm not convinced that will be the case. if so, i may try backing off fewer than the 7-10 clicks and see how that works. if not, off come the rotors. i wanted to avoid that in fear of screwing something up, but the article posted earlier in this thread makes it look doable.
by the way. after making all the adjustments to the star wheel and cable i did try burnishing by driving 50mph with brake on for 50 seconds. i barely felt any drag...maybe just a little.
by the way. after making all the adjustments to the star wheel and cable i did try burnishing by driving 50mph with brake on for 50 seconds. i barely felt any drag...maybe just a little.
Last edited by pwsusi; 03-10-2010 at 06:18 AM.
05-23-2010, 06:36 PM
#29
Melting Slicks
I am in the same boat here, i am turning the adjuster, but there is no clicking? It goes to a point then stops i am not sure which way to go with it? The trailing arms and brakes are all brand new, did they screw something up when they put it together?
05-23-2010, 11:32 PM
#31
Le Mans Master
Member Since: Aug 2006
Location: mount holly NC
Posts: 6,989
Received 1,246 Likes
on
966 Posts
C3 of Year Finalist (appearance mods) 2019
If the adjusters are installed correctly, inserting a screwdriver in the hole in the rotor and pulling the handle UP will spread the adjuster out. The spring just above the adjuster holds the shoes against the lower pivot. You may have to pull the rotor off to see if everything is installed correctly.
05-24-2010, 01:16 AM
#33
Burning Brakes
Level the Halfshafts
Crash80 nailed the procedure for the home mechanic! I also couldn't get the PB to work right until I did the adjustment with both halfshafts at the level position.It made all the difference in getting the right feel on the star adjustments and then adjust the cable.Took a good 1/2 day to get it all right.Now I have a decent PB that will hold the car on a hill. Good Luck ! Alohas
05-24-2010, 01:25 AM
#34
Melting Slicks
What holds the adjuster wheel in place that keeps the adjustment? anybody have an exploded view of the parts? I didnt pay attention when i put the rotors on.
05-24-2010, 01:30 AM
#35
Melting Slicks
Crash80 nailed the procedure for the home mechanic! I also couldn't get the PB to work right until I did the adjustment with both halfshafts at the level position.It made all the difference in getting the right feel on the star adjustments and then adjust the cable.Took a good 1/2 day to get it all right.Now I have a decent PB that will hold the car on a hill. Good Luck ! Alohas
Not sure if i will be able to get the half shafts at level? I tried to jack the trailing arm up to attach the rear sway bar, but it lifted the car off the jack stands. I have half a tank of fuel in the car too, i can see the car looking like a 4x4? May end up having to make 15" or longer bolts to get the ride height to where it needs to be, or put the old multi leaf spring back in and sell the mono leaf.
05-24-2010, 09:08 AM
#36
Team Owner
I just finished rebuilding the e-brake on my '70, and I did it years ago on the '69 I sold. Lots of stuff makes this job sound scary, but it really is a relatively easy job to do. Disconnecting the half shaft will definitely make the job of intial adjustment a lot easier, but I didn't do it either time and I got a fine adjustment. YOU CAN DEFINITELY REPLACE THE ENTIRE E-BRAKE SYSTEM WITH THE TRAILING ARM INTACT! I did it twice just to prove the first time wasn't a fluke
Both times, the hardest part of this job was loosening the bolts that hold the caliper to the trailing arm. They seem to always be stuck from the heat of the brake and are a bastard to get off much more often than not. If they've been off recently, the most important things you will need to do the whole job is patience and a good pair of needle nose pliers. A second pair of hands is helpful when putting the upper return springs on.
05-24-2010, 09:14 AM
#37
Team Owner
05-24-2010, 11:00 AM
#38
Melting Slicks
No. If you unclip the brake line where the solid line meets the flexible line, then take out the two bolts holding the caliper to the trailing arm, you will be able to lift the caliper out of the way without having to disconnect the brake line.
I just finished rebuilding the e-brake on my '70, and I did it years ago on the '69 I sold. Lots of stuff makes this job sound scary, but it really is a relatively easy job to do. Disconnecting the half shaft will definitely make the job of intial adjustment a lot easier, but I didn't do it either time and I got a fine adjustment. YOU CAN DEFINITELY REPLACE THE ENTIRE E-BRAKE SYSTEM WITH THE TRAILING ARM INTACT! I did it twice just to prove the first time wasn't a fluke Both times, the hardest part of this job was loosening the bolts that hold the caliper to the trailing arm. They seem to always be stuck from the heat of the brake and are a bastard to get off much more often than not. If they've been off recently, the most important things you will need to do the whole job is patience and a good pair of needle nose pliers. A second pair of hands is helpful when putting the upper return springs on.
I just finished rebuilding the e-brake on my '70, and I did it years ago on the '69 I sold. Lots of stuff makes this job sound scary, but it really is a relatively easy job to do. Disconnecting the half shaft will definitely make the job of intial adjustment a lot easier, but I didn't do it either time and I got a fine adjustment. YOU CAN DEFINITELY REPLACE THE ENTIRE E-BRAKE SYSTEM WITH THE TRAILING ARM INTACT! I did it twice just to prove the first time wasn't a fluke
Both times, the hardest part of this job was loosening the bolts that hold the caliper to the trailing arm. They seem to always be stuck from the heat of the brake and are a bastard to get off much more often than not. If they've been off recently, the most important things you will need to do the whole job is patience and a good pair of needle nose pliers. A second pair of hands is helpful when putting the upper return springs on.Ok will look at it again? At first glance it didnt appear that the calliper would come off with the lines intact. Everything is new so rust is not an issue. Sill pisses me off that the so called rebuild experts i sent the trailing arms too didnt do this correctly.
05-19-2014, 12:50 PM
#39
Intermediate
Member Since: Mar 2014
Posts: 40
Likes: 0
Received 0 Likes
on
0 Posts
Thanks
I am stealing this from Gerry72 but it is one of the best write ups I have seen on adjusting these. Hardly anyone mentions that you can't adjust these right with the halfshafts drooping while the car is jacked up. Anyway, here it is....
Courtesy of Gerry72:
C3 parking brakes are difficult for shadetrees to correctly adjust due to some design issues that aren't well addressed and just experience shortfalls.
If you try to adjust the shoes by turning the star wheel until you feel a drag on the rotor/drum you'll confront the design issues. They have to do with the halfshafts going into a bind when the rear suspension is in full droop and the limited slip driving the opposite wheel which will also be in a bind as well as contributing to drag and shoe friction. There is a very specific adjustment method that must be followed, otherwise you'll not have full shoe contact and may also destroy the shoes.
The meat of the issue is that you have to loosen the adjuster cable to the point where there is no tension on the cable. The cable moves the top of the shoe out in an arch. The bottom part of the shoes only pivot. So, for the most part, what you are adjusting with the star wheel is the bottom part of the shoe. Once you have the bottom part of the shoes adjusted on both wheels, you can put tension on the cable so that when the handle is pulled, the shoes come into equal contact with the drum.
The tricky part, again, is knowing when you have the bottom part of the shoes in proper contact. If you are off, you'll have contact difficiencies in either the top or bottom of the shoes on the drum. With improper adjustment, the brake mechanism will perform poorly or you'll destroy the brake lining...or both.
So, how does the shadetree deal with this? Not easily. The best way is to disconnect the halfshafts at the spindle flange (not the differential stub axle) so that both rear wheels are not connected to the differential and are free to rotate without any halfshaft binding, opposite wheel drag, or drivetrain drag. Doing it this way will allow you to have a very good tactile sense of when the bottom part of the shoe is contacting the drum. You want light contact so that you can hear the shoe contact throughout the full revolution of the wheel. Once you have the bottom shoes adjusted on both sides, you can tighten up the cable. With the handle fully retracted, you start adjusting the cable until you hear and feel the full shoe lightly contact the drum. It should be an equal feel and sound on both sides. The drag from the contact friction should be very, very light. Once you think you have the right cable adjustment, pull up on the handle. You should get around three clicks and then strong resistance. If all seems well, button it up and give it a test.
You can do it without disconnecting the halfshafts but, again, for a shadetree, you'll be fighting the ills and your experience level. You'd at least have to jack up both sides of the spindles to put the halfshafts at ride height so you can keep them from binding. Of course, in adjusting the star wheel, you are essentially doing the adjustment based upon your experience in doing it this way. For the most part, you're working from hearing only since you have drivetrain drag contributing to the brake friction.
It does take longer to do it by disconnecting the halfshafts but the outcome is usually better for the shadetree. And it's not like you'll be doing this every couple of months. If you have a good parking brake assembly, you should have to do this only once. So your time is sort of like an investment in the outcome.
Courtesy of Gerry72:
C3 parking brakes are difficult for shadetrees to correctly adjust due to some design issues that aren't well addressed and just experience shortfalls.
If you try to adjust the shoes by turning the star wheel until you feel a drag on the rotor/drum you'll confront the design issues. They have to do with the halfshafts going into a bind when the rear suspension is in full droop and the limited slip driving the opposite wheel which will also be in a bind as well as contributing to drag and shoe friction. There is a very specific adjustment method that must be followed, otherwise you'll not have full shoe contact and may also destroy the shoes.
The meat of the issue is that you have to loosen the adjuster cable to the point where there is no tension on the cable. The cable moves the top of the shoe out in an arch. The bottom part of the shoes only pivot. So, for the most part, what you are adjusting with the star wheel is the bottom part of the shoe. Once you have the bottom part of the shoes adjusted on both wheels, you can put tension on the cable so that when the handle is pulled, the shoes come into equal contact with the drum.
The tricky part, again, is knowing when you have the bottom part of the shoes in proper contact. If you are off, you'll have contact difficiencies in either the top or bottom of the shoes on the drum. With improper adjustment, the brake mechanism will perform poorly or you'll destroy the brake lining...or both.
So, how does the shadetree deal with this? Not easily. The best way is to disconnect the halfshafts at the spindle flange (not the differential stub axle) so that both rear wheels are not connected to the differential and are free to rotate without any halfshaft binding, opposite wheel drag, or drivetrain drag. Doing it this way will allow you to have a very good tactile sense of when the bottom part of the shoe is contacting the drum. You want light contact so that you can hear the shoe contact throughout the full revolution of the wheel. Once you have the bottom shoes adjusted on both sides, you can tighten up the cable. With the handle fully retracted, you start adjusting the cable until you hear and feel the full shoe lightly contact the drum. It should be an equal feel and sound on both sides. The drag from the contact friction should be very, very light. Once you think you have the right cable adjustment, pull up on the handle. You should get around three clicks and then strong resistance. If all seems well, button it up and give it a test.
You can do it without disconnecting the halfshafts but, again, for a shadetree, you'll be fighting the ills and your experience level. You'd at least have to jack up both sides of the spindles to put the halfshafts at ride height so you can keep them from binding. Of course, in adjusting the star wheel, you are essentially doing the adjustment based upon your experience in doing it this way. For the most part, you're working from hearing only since you have drivetrain drag contributing to the brake friction.
It does take longer to do it by disconnecting the halfshafts but the outcome is usually better for the shadetree. And it's not like you'll be doing this every couple of months. If you have a good parking brake assembly, you should have to do this only once. So your time is sort of like an investment in the outcome.
05-19-2014, 01:39 PM
#40
Pro
Tried this myself on my 81 recently... When I had my trailing arms and bearings replaced I noticed they replaced the two top springs for the shoes... So, after install of the rear T/A's I tried to get my e-brake working...
With the tires off, found the star wheel through the inspection hole from the outside of the rotor(about 5 o'clock if looking at it as a clock face) then started adjusting them with a flat head screwdriver... To tighten the star wheel you need to lift the outside grip of the screwdriver upwards towards the roof of the car.
Tightened them til I thought I had good drag, then went after the adjuster under the center of the car.. Which was roughly adjusted about 60% of its adjustment, but loose... I lifted the e-brake handle to 13 clicks , then tightened it almost to 100% of its adjustment! Mine had one nut above and below the T... And in all the instructions I found they all showed both nuts below the T.. So I pulled it all apart and reset it that way...
Needless to say, all said and done... It didn't give me an e-brake... And very little 'drag' felt when applying it fully... I was very cautious and stopped periodically to put my hand on the drum of the rotor to make sure I wasn't causing heat... Which I wasn't... So perhaps I need to go do some more fine tuning/adjustments, but being at or close to 100% adjustment at the T... I worried that something else was wrong, and I haven't had the time to look into it further ... More info to continue next time I play with the system...
***Oooh ooooh! Took too long writing this and EVERYONE else pointed out some great advice! I will be pulling off the half shafts and doing this over! ;-)***
With the tires off, found the star wheel through the inspection hole from the outside of the rotor(about 5 o'clock if looking at it as a clock face) then started adjusting them with a flat head screwdriver... To tighten the star wheel you need to lift the outside grip of the screwdriver upwards towards the roof of the car.
Tightened them til I thought I had good drag, then went after the adjuster under the center of the car.. Which was roughly adjusted about 60% of its adjustment, but loose... I lifted the e-brake handle to 13 clicks , then tightened it almost to 100% of its adjustment! Mine had one nut above and below the T... And in all the instructions I found they all showed both nuts below the T.. So I pulled it all apart and reset it that way...
Needless to say, all said and done... It didn't give me an e-brake... And very little 'drag' felt when applying it fully... I was very cautious and stopped periodically to put my hand on the drum of the rotor to make sure I wasn't causing heat... Which I wasn't... So perhaps I need to go do some more fine tuning/adjustments, but being at or close to 100% adjustment at the T... I worried that something else was wrong, and I haven't had the time to look into it further ... More info to continue next time I play with the system...
***Oooh ooooh! Took too long writing this and EVERYONE else pointed out some great advice! I will be pulling off the half shafts and doing this over! ;-)***
Last edited by FireballXL5; 05-19-2014 at 01:45 PM.