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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 22
Location: Tulsa, OK
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 Posted: Sun Jun 29, 2025 7:09 pm Post subject: Drum brake problems |
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Something is going on with my brakes and I can’t figure it out.
I have a new master cylinder (bench bled) and all new shoes, springs, wheel cylinders, new flex lines at all 4 corners. Drums and backing plates are all that have been reused.
I have bled the brakes multiple times and can’t get any pedal pressure. I’ve heard not to adjust the piston attached the pedal, except as a last resort. This is my first drum brake car and I’m at a loss.
The only thing I can think to do is pull the drums to see if the shoes aren’t adjusted as much as I think they are or adjusting the brake pedal plunger. What would you all do? |
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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 22
Location: Tulsa, OK
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| Posted: Sun Jun 29, 2025 7:39 pm Post subject: Re: Drum brake problems |
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| Sorry forgot to mention this is on a 63. |
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viiking
Samba Member
Joined: May 10, 2013
Posts: 3126
Location: Sydney Australia
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| Posted: Sun Jun 29, 2025 8:05 pm Post subject: Re: Drum brake problems |
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Single or dual circuit master cylinder?
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3 |
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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 22
Location: Tulsa, OK
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| Posted: Sun Jun 29, 2025 8:30 pm Post subject: Re: Drum brake problems |
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| Single. Definitely should have went double. |
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VW_Jimbo 
Samba Member
Joined: May 22, 2016
Posts: 11077
Location: Huntington Beach, CA
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| Posted: Sun Jun 29, 2025 9:18 pm Post subject: Re: Drum brake problems |
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Did you adjust the brake shoes?
Did you fill up the reservoir first up, then not allowing it to go dry during the bleeding, and finally filing it up to the correct level?
_________________
Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
| TDCTDI wrote: |
| Basically, a whole bunch of fuckery to achieve a look. |
| 67rustavenger wrote: |
GFY's Xevin and VW_Jimbo!  |
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viiking
Samba Member
Joined: May 10, 2013
Posts: 3126
Location: Sydney Australia
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| Posted: Sun Jun 29, 2025 10:33 pm Post subject: Re: Drum brake problems |
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| JBradford84 wrote: |
| Single. Definitely should have went double. |
I asked because the bleeding sequence (in theory)is rears first for the single and fronts first for the dual.
VW_Jimbo is (as always) correct. First, you need to adjust ALL the shoes so they are tight against the drum making sure that the shoes are both in contact i.e. symmetrical. Then back off a hair. A slight drag is ok.
Then starting at the right rear, bleed the brakes. Not to insult you but this is how it should be done when you use two people. This is the VW method (and for every old car I ever worked with). Some people suggest gravity bleeding or pressure or vacuum bleeding, but the old method should work just as well.
1. Connect a tight fitting tube to the bleed nipple. It needs to be tight.
2. Immerse the other end of the tube into a clear container with brake fluid in it. You need to see the bubbles coming out of the end of the tube. Hence a clear container.
3. Open the bleed valve.
4. Your helper is to press the pedal down SLOWLY. Say 2 seconds. Doing it too fast or too violently will break the large air bubbles into small micro bubbles which are hard to remove. Big bubbles are easier to remove rather than the micro bubbles which end up producing a froth like medium.
5. Allow the pedal to also return SLOWLY. Again say 2 seconds.
6. Pump the pedal as many times as you need to remove the air from that part of the circuit. NEVER LET THE RESERVOIR GET LOW. Keep topping it up.
The right rear is expected to require at least 12 full pumps or 80ml of fluid from dry. All other wheels will require about 8 pumps or 70ml.
7. When no more bubbles are present, get the helper to SLOWLY start the final press down with the pedal as you close off the bleeder.
8. Do not press any more against the closed bleeder valve.
9. Continue on to the next wheel. Left Rear, Right Front and Left front.
10. Now you should have a pedal.
If you don't there is something else wrong.
Check all connections are tight, including any brake light and residual pressure valves. There are also some complications with how the brake cylinders attach to the brake shoes. There are some variations in brake shoes in the cutout area of the shoe where the brake cylinder piston lands. It is easy to get the wrong shoes. Compare them to the originals.
Have a look here
If you have a part pedal that comes up higher after a couple of pumps then your brake shoes are still too far away from the drum or the brake pushrod has been fiddled with and probably will need adjustment.
The pushrod needs to have a small amount of free play (about 1mm) at the pushrod to the MC piston. This is hard to measure directly. If you are sensitive enough sometimes you can feel it. This 1mm equates to about 5-7mm at the pedal (forward-backward travel). This clearance can be measured whether the brakes are bled or not.
This is to ensure that when the pedal is released, the master cylinder piston reaches the end of its travel and is not still slightly depressed. This can be best be felt by hand at the pedal.
On some rare occasions I have heard that some of the replacement MC's have a different type of recess at the end of the piston so that the previously working pushrod now does not fit into the depression. This means that the pushrod is now too long and can cause problems. It is unlikely for you, but always worth checking the new and old parts are visually identical in this area.
On the other hand if the pushrod is too short, then the appropriate compensating port in the MC will remain open and you will not be able to bleed the brakes properly. To adjust the freeplay you need to adjust the brake stop bracket FIRST. Only then if you cannot get the freeplay right should you consider adjusting the pushrod.
Put up a photo of the MC. We may be able to see something else that might be an issue.
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3 |
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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 22
Location: Tulsa, OK
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| Posted: Mon Jun 30, 2025 4:55 am Post subject: Re: Drum brake problems |
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| VW_Jimbo wrote: |
Did you adjust the brake shoes?
Did you fill up the reservoir first up, then not allowing it to go dry during the bleeding, and finally filing it up to the correct level? |
I have adjusted the shoes but I’m starting to think it’s not enough.
The reservoir has not been dry while bleeding. |
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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 22
Location: Tulsa, OK
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| Posted: Mon Jun 30, 2025 4:58 am Post subject: Re: Drum brake problems |
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| viiking wrote: |
| JBradford84 wrote: |
| Single. Definitely should have went double. |
I asked because the bleeding sequence (in theory)is rears first for the single and fronts first for the dual.
VW_Jimbo is (as always) correct. First, you need to adjust ALL the shoes so they are tight against the drum making sure that the shoes are both in contact i.e. symmetrical. Then back off a hair. A slight drag is ok.
Then starting at the right rear, bleed the brakes. Not to insult you but this is how it should be done when you use two people. This is the VW method (and for every old car I ever worked with). Some people suggest gravity bleeding or pressure or vacuum bleeding, but the old method should work just as well.
1. Connect a tight fitting tube to the bleed nipple. It needs to be tight.
2. Immerse the other end of the tube into a clear container with brake fluid in it. You need to see the bubbles coming out of the end of the tube. Hence a clear container.
3. Open the bleed valve.
4. Your helper is to press the pedal down SLOWLY. Say 2 seconds. Doing it too fast or too violently will break the large air bubbles into small micro bubbles which are hard to remove. Big bubbles are easier to remove rather than the micro bubbles which end up producing a froth like medium.
5. Allow the pedal to also return SLOWLY. Again say 2 seconds.
6. Pump the pedal as many times as you need to remove the air from that part of the circuit. NEVER LET THE RESERVOIR GET LOW. Keep topping it up.
The right rear is expected to require at least 12 full pumps or 80ml of fluid from dry. All other wheels will require about 8 pumps or 70ml.
7. When no more bubbles are present, get the helper to SLOWLY start the final press down with the pedal as you close off the bleeder.
8. Do not press any more against the closed bleeder valve.
9. Continue on to the next wheel. Left Rear, Right Front and Left front.
10. Now you should have a pedal.
If you don't there is something else wrong.
Check all connections are tight, including any brake light and residual pressure valves. There are also some complications with how the brake cylinders attach to the brake shoes. There are some variations in brake shoes in the cutout area of the shoe where the brake cylinder piston lands. It is easy to get the wrong shoes. Compare them to the originals.
Have a look here
If you have a part pedal that comes up higher after a couple of pumps then your brake shoes are still too far away from the drum or the brake pushrod has been fiddled with and probably will need adjustment.
The pushrod needs to have a small amount of free play (about 1mm) at the pushrod to the MC piston. This is hard to measure directly. If you are sensitive enough sometimes you can feel it. This 1mm equates to about 5-7mm at the pedal (forward-backward travel). This clearance can be measured whether the brakes are bled or not.
This is to ensure that when the pedal is released, the master cylinder piston reaches the end of its travel and is not still slightly depressed. This can be best be felt by hand at the pedal.
On some rare occasions I have heard that some of the replacement MC's have a different type of recess at the end of the piston so that the previously working pushrod now does not fit into the depression. This means that the pushrod is now too long and can cause problems. It is unlikely for you, but always worth checking the new and old parts are visually identical in this area.
On the other hand if the pushrod is too short, then the appropriate compensating port in the MC will remain open and you will not be able to bleed the brakes properly. To adjust the freeplay you need to adjust the brake stop bracket FIRST. Only then if you cannot get the freeplay right should you consider adjusting the pushrod.
Put up a photo of the MC. We may be able to see something else that might be an issue. |
Great info! As stated this is my first drum system so I take no offense and I should be considered a complete noob. I’m thinking the shoes aren’t adjusted right and I need to dig into that. Thanks. |
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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 22
Location: Tulsa, OK
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| Posted: Mon Jun 30, 2025 8:03 am Post subject: Re: Drum brake problems |
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Here is the requested picture of my new master cylinder. |
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rcooled
Samba Member
Joined: September 20, 2008
Posts: 2745
Location: Santa Cruz, CA
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| Posted: Mon Jun 30, 2025 11:33 am Post subject: Re: Drum brake problems |
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| JBradford84 wrote: |
| Definitely should have went double. |
Nothing wrong with a well-maintained single-circuit brake system...millions & millions of vehicles used them from the late-1920s all the way until the mid-1960s.
| JBradford84 wrote: |
| I’ve heard not to adjust the piston attached the pedal, except as a last resort. |
This is basically true, but you do need to insure that you have the proper clearance between the pedal's push rod and the master cylinder's piston. This is especially true when you swap out the MC for a new one. If there isn't enough clearance, you'll never get the brakes to bleed properly.
There should be roughly 1/8"-1/4" (manual says 5-7mm) of pedal movement, measured at the top of the rubber pad, before the push rod contacts the piston. You can easily feel this free play by pushing on the pedal with your fingers.
FWIW, I've been bleeding brakes for years using a slightly different method. Instead of opening & closing the bleeder valve between pumps, I connect a clear tube & catch jar to the valve, open it and keep it open, then have an assistant keep slowly pumping the pedal thru its full stroke until there are no more bubbles present in the outgoing fluid. When I stop seeing bubbles, I close the valve as the pedal starts a downward stroke, which is easy to tell by watching the fluid start to move in the clear tube.
For this method to work properly, that push rod clearance is critical and must be set to the factory spec. I've also found it helpful to make sure the car is level while bleeding brakes.
_________________
'63 Ragtop (current)
'65 Ghia coupe (totaled)
'67 Ghia convertible (current)
'69.5 Ghia convertible and
'62, '63, '65, '69 Bugs (all long gone) |
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jinx758
Samba Member
Joined: October 04, 2014
Posts: 1002
Location: half a bubble from plumb
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| Posted: Mon Jun 30, 2025 12:01 pm Post subject: Re: Drum brake problems |
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Good info from above great members ...
... with one caveat :
ALL eight shoes should be adjusted out/tight to drums so rim does not spin whatsoever before bleeding.
If not the brake pedal is not getting a full stroke.
Check fluid level often.
THEN adjust shoes for slight drag.
Also the E-brake can tell you when the shoes need periodic adjusting. When it clicks 4-5 times they need attention.
I use the hose in a bottle just make sure the hose is below the brake fluid in the bottom of bottle.
A cheap pressure bleeder can be made from an $8 pump up garden sprayer = one person bleeder w/ no pedal pumping needed.
None of my old cars have ever had discs & I have adopted the driving habits accordingly.
You got this ... stay safe
jinx
_________________
" It's not valuable unless you learn something from an experience. " Henry Ford
It's not unlike the same difference ...
My Craigslist rescued 100 footer :
1971 Standard Bug
1776cc dual port
034 distributor
38mm EGAS Carburetor |
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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 22
Location: Tulsa, OK
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| Posted: Mon Jun 30, 2025 12:23 pm Post subject: Re: Drum brake problems |
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Thanks to you all. My shoes are not adjusted correctly. All 4 of my wheels can freely spin. I have a path forward. If I have further issues I'll check back in.
Thanks again! |
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Cusser
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Joined: October 02, 2006
Posts: 32973
Location: Hot Arizona
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viiking
Samba Member
Joined: May 10, 2013
Posts: 3126
Location: Sydney Australia
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| Posted: Mon Jun 30, 2025 4:20 pm Post subject: Re: Drum brake problems |
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| rcooled wrote: |
FWIW, I've been bleeding brakes for years using a slightly different method. Instead of opening & closing the bleeder valve between pumps, I connect a clear tube & catch jar to the valve, open it and keep it open, then have an assistant keep slowly pumping the pedal thru its full stroke until there are no more bubbles present in the outgoing fluid. When I stop seeing bubbles, I close the valve as the pedal starts a downward stroke, which is easy to tell by watching the fluid start to move in the clear tube.
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I think that is what I said in 6 and 7.
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3 |
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rcooled
Samba Member
Joined: September 20, 2008
Posts: 2745
Location: Santa Cruz, CA
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| Posted: Mon Jun 30, 2025 4:40 pm Post subject: Re: Drum brake problems |
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| viiking wrote: |
| I think that is what I said in 6 and 7. |
Yes, you're right. I just quickly glanced at your post and wrongly assumed that it was the usual procedure that everyone quotes for brake bleeding: press & hold the pedal...crack the valve open...quickly close it...release the pedal. Repeat 'till no more bubbles.
Didn't mean to come off like a dumbass by repeating the sound advice you already offered 
_________________
'63 Ragtop (current)
'65 Ghia coupe (totaled)
'67 Ghia convertible (current)
'69.5 Ghia convertible and
'62, '63, '65, '69 Bugs (all long gone) |
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viiking
Samba Member
Joined: May 10, 2013
Posts: 3126
Location: Sydney Australia
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| Posted: Mon Jun 30, 2025 5:12 pm Post subject: Re: Drum brake problems |
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Not upset at all just noting it if other people are searching. We all mean well. 
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3 |
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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 22
Location: Tulsa, OK
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| Posted: Mon Jun 30, 2025 7:56 pm Post subject: Re: Drum brake problems |
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| Update for everyone involved. Adjusted the shoes, bled the system again and I had to adjust the plunger to get it closer to spec. Got brakes! Thanks for all the help. |
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aquifer
Samba Member
Joined: August 30, 2021
Posts: 313
Location: Nebraska
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| Posted: Tue Jul 01, 2025 2:36 pm Post subject: Re: Drum brake problems |
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I've always just adjusted the stopper on the floor to get the right amount of free travel in the pedal. What is the scenario where you'd NOT want to adjust the stopper, but adjust the rod instead? I know the rods are adjustable, so there must be a reason for it.
_________________
Parts needed:
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VW_Jimbo
Samba Member
Joined: May 22, 2016
Posts: 11077
Location: Huntington Beach, CA
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| Posted: Tue Jul 01, 2025 3:03 pm Post subject: Re: Drum brake problems |
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| aquifer wrote: |
| I've always just adjusted the stopper on the floor to get the right amount of free travel in the pedal. What is the scenario where you'd NOT want to adjust the stopper, but adjust the rod instead? I know the rods are adjustable, so there must be a reason for it. |
The distance to the bulkhead wall or the distance to the driver. Both need to be accounted for. I have repaired multiple cars with brake pedals that are to far from the accelerator pedal or that hit the bulkhead. Both scenarios create a hazardous situation for the driver who is put into a panic situation. Those few seconds to reach the pedal or not get the full potential out of the system, might be in for an impact!
Very important to get it all correct!
_________________
Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
| TDCTDI wrote: |
| Basically, a whole bunch of fuckery to achieve a look. |
| 67rustavenger wrote: |
| GFY's Xevin and VW_Jimbo! |
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mukluk
Samba Member
Joined: October 18, 2012
Posts: 7452
Location: Clyde, TX
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| Posted: Wed Jul 02, 2025 5:41 am Post subject: Re: Drum brake problems |
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| VW_Jimbo wrote: |
| aquifer wrote: |
| I've always just adjusted the stopper on the floor to get the right amount of free travel in the pedal. What is the scenario where you'd NOT want to adjust the stopper, but adjust the rod instead? I know the rods are adjustable, so there must be a reason for it. |
The distance to the bulkhead wall or the distance to the driver. Both need to be accounted for. I have repaired multiple cars with brake pedals that are to far from the accelerator pedal or that hit the bulkhead. Both scenarios create a hazardous situation for the driver who is put into a panic situation. Those few seconds to reach the pedal or not get the full potential out of the system, might be in for an impact!
Very important to get it all correct! |
Further explanation and specs from the FSM:
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