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Discussion Starter · #1 ·
Hello everyone, I just replaced my master cylinder, along with all the brake shoes and springs inside the drums. I bled the brakes so there's no air in the lines but for some reason there's little to no pressure when pressing the brakes and the car has little to no response. When replacing the shoes I did set the adjustment screws so that the shoes are just barely gliding on the drums. I'm not sure what's wrong but I do know the e-brake at least works as intended. So I guess my question is even with the brakes being bled could I still have a faulty master cylinder?
 

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If you didn’t bench bleed the master before installing it is hard getting all the air out. You usually see some brake fluid seeping out of leaky wheel cylinders but they could be worn out and losing pressure.
 

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Discussion Starter · #5 ·
If you didn’t bench bleed the master before installing it is hard getting all the air out. You usually see some brake fluid seeping out of leaky wheel cylinders but they could be worn out and losing pressure.
That could also be my issue as I didn't think to do that. Would it help to pull it off and do a bench bleed then re-install? I'm feeling really dumb forgetting to do that.
 

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It couldn't hurt. Then again it is easy for me to say when I'm not doing the job. You may be able to do it in place with line disconnected and a helper gently pumping pedal.
 

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Hello everyone, I just replaced my master cylinder, along with all the brake shoes and springs inside the drums. I bled the brakes so there's no air in the lines but for some reason there's little to no pressure when pressing the brakes and the car has little to no response. When replacing the shoes I did set the adjustment screws so that the shoes are just barely gliding on the drums. I'm not sure what's wrong but I do know the e-brake at least works as intended. So I guess my question is even with the brakes being bled could I still have a faulty master cylinder?
Hello everyone, I just replaced my master cylinder, along with all the brake shoes and springs inside the drums. I bled the brakes so there's no air in the lines but for some reason there's little to no pressure when pressing the brakes and the car has little to no response. When replacing the shoes I did set the adjustment screws so that the shoes are just barely gliding on the drums. I'm not sure what's wrong but I do know the e-brake at least works as intended. So I guess my question is even with the brakes being bled could I still have a faulty master cylinder?
If all four wheels are just barely touching, then most likely the master cylinder. if some wheels are working then it would be the cylinder the operate the shoes. The next question would be is how long has the car sat? If it has been years, replace all cylinders just to be safe.
 

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Hello everyone, I just replaced my master cylinder, along with all the brake shoes and springs inside the drums. I bled the brakes so there's no air in the lines but for some reason there's little to no pressure when pressing the brakes and the car has little to no response. When replacing the shoes I did set the adjustment screws so that the shoes are just barely gliding on the drums. I'm not sure what's wrong but I do know the e-brake at least works as intended. So I guess my question is even with the brakes being bled could I still have a faulty master cylinder?
You can always check the experts at
Bench Bleeding the Master Cylinder and Brakes. Rob and Dave are the best!

Whether you bench bled or not, on a vintage bug I start by loosening the brake lines and switches at the master cylinder first. Make sure you always have clean fluid in the reservoir. Let those bleed until both the front and rear circuits run as well as each switch. Tighten those up, then open the drum bleeders and have a beverage or two. Let those lines purge until new clean fluid comes out. Close all of the drum bleeders and run through the bleeding exercise. Bleed the drum from the furthest away from the peddle to the closest (passenger rear, driver rear, passenger front, driver front). Never fails if the system is good.
 

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You can always check the experts at
Bench Bleeding the Master Cylinder and Brakes. Rob and Dave are the best!

Whether you bench bled or not, on a vintage bug I start by loosening the brake lines and switches at the master cylinder first. Make sure you always have clean fluid in the reservoir. Let those bleed until both the front and rear circuits run as well as each switch. Tighten those up, then open the drum bleeders and have a beverage or two. Let those lines purge until new clean fluid comes out. Close all of the drum bleeders and run through the bleeding exercise. Bleed the drum from the furthest away from the peddle to the closest (passenger rear, driver rear, passenger front, driver front). Never fails if the system is good.
Oh yea, if a drum bleeder does not flow, there is a good chance that line is clogged or leaking before the bleeder. The bleeding exercise should clear out any debris. If that's the case, keep bleeding that line until new fluid appears. Clean it out good. If not, check for dripping down the tires (bad wheel cylinder or line/connection), under the body (bad line or junction/connection), wet carpet (bad line or junction/connection), under the front hood.

The next step is to replace everything. It's not that hard to replace the lines and wheel cylinders. Just more beverages :).
 

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67 Bug. 2275cc, 10.1:1, 48IDA,Eagle2242Cam,2300Lb clutch, 3.85 diff. Lowered,roll bar, 5pt, swaybars
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R_moore,
Can we back up a minute. Why did you replace your master cylinder? What problems were you having with the brake system in the first place?
Did you look at the old master cylinder to see if it was rusted inside the piston bores? Brake fluid is hydroscopic and so can gather water from the atmosphere over long periods of time. Many reasons/causes but we will leave that for another day. The moisture in the fluid tends to spread evenly through the fluid so if the master cylinder is rusty, the wheel cylinders probably are too. Rusty wheel cylinders eventually leak or seize up.
Did you bleed the brakes by yourself or with a partner? Unless you have a pressure or vacuum bleeder setup it takes two people to bleed brakes correctly, along with the proper technique. It is easy to reintroduce air if done improperly. I have no idea what your skill level is but having taught many mechanics how to service brakes, I have probably seen most of the non-obvious errors.
Assuming you get all the air out of the lines and cylinders, the other common problems might be the brake pedal pushrod not adjusted to correct length, the brake shoes are not adjusted correctly, the wheel cylinders have seized or the rubber hoses at the wheels are flexing (probably not). Some basic background on the original problem would be helpful.
 

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Discussion Starter · #11 ·
I replaced the master cylinder because the boot the pushrod goes in was destroyed and it was leaking brake fluid into the car. When bleeding the brakes I had my friend inside the car pumping the brakes and holding as I loosened the bleeder screws tightened them before it stopped flowing. I did one brake at a time starting with the rear passenger, then the rear driver, then front passenger, and finally front driver. Before bleeding I tightened/loosened both adjusting screws on each drum brake until the drum was just barely touching the shoes. I didn't want to adjust the pushrod because it was at the factory setting and the restoration manual I use advised not to mess with it. I hope this answers all your questions.
 

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One thing we always did, and I have no idea if it helps. When adjusting new shoes we spun the wheel and had helper slam on brakes a few times. Theory was it centered the shoes. Maybe just one of those "because we always dud it that way" things If losing pressure it has to be hydraulic
 

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R_moore, You only have so many choices. Take it to a shop or keep at it.


As 67_bug pointed out, if the peddle is not even pushing the plunger in the master cylinder, then none of this would work. Make sure the peddle is pushing the rod that is pushing the plunger.

If you are getting pressurized flow of fluid out of each bleeder when bleeding, then the peddle is pushing the rod that is pushing the plunger and the new master cylinder is most likely good, and the lines are ok. If not, the line(s) could be clogged, broken or bent or the new master cylinder could be bad (unlikely but possible).

If you are getting pressure and flow out of the bleeders and you have a good peddle feel but the brakes are not working, then the only thing left is inside the drums. Wheel cylinders or bound shoes.

This being a new master cylinder situation, bleeding the brakes a couple times is not unreasonable.

General bleeding procedure

I'm writing the following bleeding details because I know this works. I also don't know the experience others have. If you never have bled brakes or just want to see how someone else does it, read on. It has worked for me on cars, trucks, tractors, backhoes etc... for 50 years.

  1. You typically start with bench bleeding the master cylinder. If you don't do that, you are starting off knowing you are clever enough to do that in the mounted position, or lucky enough to skip it. Bench bleed!
  2. Make sure the brake fluid reservoir is always full. Preferably purge it from old brake fluid first and fill it with new fluid. This probably happened when the master cylinder was replaced. Make sure the hoses/lines are good and not leaking. If there is a problem here, this can suck air into the system at the very beginning. With old beetles this can be where the hose changes over from hose to metal. Clamps and fittings may be leaking.
  3. Start at the master cylinder letting all ports bleed (switches and lines). Disconnect the switches and lines completely. Don't just loosen them. Make sure clean fluid comes out of each port. Have some patience, let it sit until all ports are flowing. If stubborn, you can let it sit over night as long as you keep fluid in the reservoir. If this doesn't work, you will have to remove the master cylinder and bench bleed it, or figure out how to bench bleed it in place. If you have bench bleed and you are not getting flow out of the master cylinder overnight, replace the master cylinder. Tighten the switches and lines back up.
  4. Crack all of the bleeders and allow them to flow, tighten them up.
  5. You can skip ' 4) crack all of the bleeders and allow them to flow' if you want as it is unconventional, but for me, this exercise in patience (sometimes it takes 15 minutes or better) can identify a line that is not flowing under gravity. Unless someone has added a valve or something in the lines, gravity should move the fluid. A benefit the old beetles have is that the entire brake system is much lower than the reservoir. Air goes up, fluid goes down. Up to you. This also helps purges the lines of air so the number of cycles you have to bleed the brakes can be reduced.
  6. Bleed the brakes one by one in the order you mentioned (PR, DR, PF, DF). Repeat this cycle until you get good peddle feel. This can take 2-5 times on an empty system.

If you have a line not flowing, it may have a clog in it or it is bent or broken and leaking before it gets to the end. If not leaking, the bleeding step hopefully will push any blockage out. If slow flow, the line could be clogged a little or bent. Note that this line could be on its way out or you could have picked up something when you took the line loose and put it back together. Safety first!

Bleeding Methods
As far as methods go for the actual bleed, you can do it as a team old school or use a vacuum or a pump.

Whichever method you use remember brake fluid is not good for anything other than brakes. Clean up as you go and at the end of the job.

Detailed old school. 'Pumping', 'holding', 'loosening', 'hit the floor', 'tighten up 'OK pump it up' do it again...

If you are not shy about getting dirty or letting cardboard under the car absorb the fluid, hold a finger over the bleeder as it is loosened. Put a thin glove on (like a nitrile glove) and loosen the bleeder using a box end wrench so you can feel the hole at top of the bleeder.

You should be able to feel a good clean flow. Always keep you finger on the hole of the bleeder screw when the bleeder is open to seal out the air.

There is pressure in the system when pumped up. Loosen the bleeder slowly at first until you get confident that the pressure isn't going to take your finger off (which it won't). Once you do this a couple times, you will get a good feel of what a good flow feels like.


Otherwise, you can put a tube (preferably clear) snuggly over the bleeder screw into a bottle with some brake fluid in it. Keeping the bottom of the tube under the brake fluid in the bottle will only allow air and fluid out. Not in. This allows you to see the fluid, keep things clean, and if clogs pop out, see what it is.

In the following you are either using your finger or keeping the tube in the bottle.

Here’s how it typically goes:
  1. ‘Pumping’ - 1st person (the wife) pumps the peddle 4 or 5 times and holds it down on the last stroke.
  2. ‘Holding’ – 1st person lets the second person know they are holding the peddle down.
  3. 'Loosening' - The 2nd person (us) loosens the bleeder keeping your finger on top of it feeling for pressure, hear and feel air (if any), feel for a clog that lets go and get a feel for a good complete push of fluid out of the bleeder.
  4. 'Hit the floor' – 1st person, the peddle should sink to the floor when the bleeder is opened up.
  5. Tighten up the bleeder screw - 2nd person, tightens the bleeder and lets the 1st person know, 'OK, pump it up'.
  6. Repeat this 4-5 times each wheel. Once clean fluid comes out with nice strong flow you know the system is working all the way up to the wheel cylinder. If you finger or the tube slips off, put your finger back on or hook up the tube and just do it a couple more times again. No big deal. If air gets into the bleeder it’s not going to race up to the master cylinder. It will be right there. Just push it out gain.
  7. Every time you go around the drums, the peddle should feel better. Sometimes you get it the first time (like a simple brake repair on one wheel), but often you will have to go through the bleeding cycle 2 or more times.
  8. If after 5 times you’re not getting anywhere. Your probably thinking, I should have bench bled the master cylinder.
  9. Use plenty of brake cleaner to clean off any fluid from your tires and wheels. Clean and wax any painted surfaces that may have gotten brake fluid on them.
I suspect brake bleeding is elsewhere in this forum. Hopefully all of the comments of this thread will provide R_moore some encouragement to give it another try(s). Don't skimp on the steps and it may take a couple bleeding cycles.

Let us know how you did. Regards!
 

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Discussion Starter · #14 ·
@Bug Fever Thank you for that detailed message. Yes I have fluid going to the brakes and they bleed fine. I did forget to bench bleed and did take it off and do that. For the most part the brakes work, just not great. I think some new wheel cylinders will help. Allthough I'm not going to do anything else for the front brakes as I'm planning on switching them to discs here soon anyway. I may end up doing a few more bleeds here as well. And no I don't mind getting my hands dirty, I expected to when I bought the car.
 

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67 Bug. 2275cc, 10.1:1, 48IDA,Eagle2242Cam,2300Lb clutch, 3.85 diff. Lowered,roll bar, 5pt, swaybars
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Thanks Bug Fever, lots of detail there.
Just a couple of comments and amplifications. Step 1 above. Pump the pedal slowly, probably not more than twice. You don't want to create foam if air is present in the master cylinder. Step 2, holding, don't need much pressure on the pedal, it is just to allow the pedal to be pushed to the floor when the bleeder valve is open. Step 5, when the pedal gets to the floor, don't take pressure off the pedal until after the bleeder is closed or it tends to draw air back in. You want the master cylinder to draw fluid from the reservoir as you take your foot off the pedal, not pull air in from the bleeder valve.
As Bug Fever pointed out, don't let the reservoir get low during the bleeding process. There is a tendency to keep working on the bleeding process to get it done but you must keep an eye on the level or it will pump air in and you will have to rebleed the master cylinder again and start over.

Also, Keep in mind that the more modern bugs have a dual circuit brake system. They operate separately. One circuit may have some air and the other circuit may not. For example, you might find the rear brakes work better than the front if the front circuit still has some air in it.

You might raise the rear wheels off the ground and adjust the brake shoes to get a slight rubbing of the shoes on the brake drums. Have someone push on the brake pedal. Try to turn each of the rear wheels with a flex bar on either the axle nut or one of the lug nuts. If the slave cylinder works and the shoes are free to move, the wheel should lock up. Upon release of the pedal, the wheel should return to free spin and slight rubbing of the shoes. Try this on the front wheels with the rear on the ground. This is a check that all the shoes are adjusted properly and the wheel cylinders are working.

One other test for the rear is to try stopping, somewhere safe, by pulling on the emergency brake (while holding the release button in the released position). Try this a about 20mph. This tests how well the rear brakes can stop the car. If the car hardly stops, you have a problem with the mechanical parts in the brake drum and not the fluid based brake system. If you can lock up the rear wheels with the ebrake but not with the brake pedal, you still have air in the brake lines.

If the car pulls to one side when hard braking, one the front wheels is not adjusted correctly or the wheel cylinder is frozen up.
 

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67 Bug. 2275cc, 10.1:1, 48IDA,Eagle2242Cam,2300Lb clutch, 3.85 diff. Lowered,roll bar, 5pt, swaybars
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R_moore,

It is easy to over do it on upgrades to the braking system. You only need just enough brake performance to allow you to just lightly lock up the four wheels for a panic stop at highway speeds. Unless you do a lot of mountainous rally driving where the brake drums/rotors get almost red hot, you should not have to worry a lot about brake fade. Don't overspend on the brakes, put your money on better handling.

You could switch to a set of Karmann Ghia front disk brakes (just bolt on). As light as a bug is, this will provide more than enough stopping power for the car. If you are worried about brake fade from lots of down hill mountain driving, switch to semi-metallic brake pads/shoes. Keep in mind while you may get a little more stopping power and fade resistance with semi-metallic pads/shoes, they tend to ware out the rotors and drums faster.

I used to race and rally my 67 and choose KG front brakes and squareback axles and drums (wider drums and brake shoes). Due to a lot of sustained high speed driving in the mountains, I switched to a high copper content semi-metallic pads/shoes.

No matter how fast or how hot I got the brakes, they never faded or failed to stop the car. Under worst conditions they will stop the car from 90 in the same distance as a good stock car from 60. Down side is that the pads/shoes tended to quickly ware out the rotors/drums.

The point of this is I have seen a lot of people spend way too much money on fancy four piston disks with rear disk brake setups that are capable of stopping a 4000lb F150 pickup. When you decide to upgrade, consider how much upgrade is really enough. I would suggest looking at a simple KG type setup and stop there.
 

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Discussion Starter · #17 ·
I'm only converting the front to disc brakes and nothing high performance. I found a simple bolt on conversation kit on jbugs.com that I like. I agree that I have no need for a 4 disc brake system in this car. I have aftermarket 5 lug rims that came pre-installed on the car. They are wider and slightly bigger than the stock wheels.
 

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Discussion Starter · #18 ·
So over the weekend I bought a manual self pump vacuum bleeder for my brakes and I noticed when trying to bleed the furthest brake line (PR) I'm getting 90% air pretty much and barely any brake fluid. I ended up taking off the metal brake line from the wheel cylinder and connect the vacuum bleeder to that to see if the wheel cylinder was the issue but nope still almost all air is what I'm getting. But if I move to the other side (DR) and do the same thing I get some air bubbles but mostly brake fluid. Now I'm really confused, do I need to do another bench bleed?
 

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Discussion Starter · #20 ·
That's my plan when I get home today, my confusion as to why one side is fine and the other not is because from my understanding the two rear lines are connected together at some point in the line before connecting at the master cylinder.
 
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