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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Tue Sep 04, 2018 6:16 pm Post subject: Lost brakes while driving. |
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I was driving and went to slow down to turn. Felt a small pop and the pedal went to the floor. I pulled over and nothing was leaking so we limped home with the e-brake. This was my third drive with the car since rebuilding it. I replaced the soft brake lines, wheel cylinders, master cylinder, shoes springs and all that stuff. I vacuum bled the system and had good brakes for the first couple drives.
When I tried the brakes a few times after they failed, we heard a type of clink sound or scrapping sound (we can't agree on what to call the sound but there was definitely a sound) coming from what we thought was the fwd left wheel. So, we finally made it home and took the drums off the front and everything up there looks normal. The Reservoir has fluid in it. We suspect the master cylinder. But it's new German from WW.
Like I said, there's no leaks that I can find. What kind of experience has anyone had with similar situations. It's a 66 12v 4 wheel drums, all new parts. |
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mukluk Samba Member
Joined: October 18, 2012 Posts: 7028 Location: Clyde, TX
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Posted: Tue Sep 04, 2018 6:30 pm Post subject: Re: Lost brakes while driving. |
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To me a pop suggests that something broke, came apart, or it was hanging up previously and finally seated fully into position.
I'd recommend pulling the rear drums to finish inspecting all the brakes for any obvious issues. Barring finding anything, reassemble the brakes and rebleed them, paying close attention to any shoe that takes noticeably more adjustment to get it into contact with the drum than the others. _________________ 1960 Ragtop w/Semaphores "Inga" |
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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Tue Sep 04, 2018 6:35 pm Post subject: Re: Lost brakes while driving. |
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mukluk wrote: |
To me a pop suggests that something broke, came apart, or it was hanging up previously and finally seated fully into position.
I'd recommend pulling the rear drums to finish inspecting all the brakes for any obvious issues. Barring finding anything, reassemble the brakes and rebleed them, paying close attention to any shoe that takes noticeably more adjustment to get it into contact with the drum than the others. |
Definitely gonna be my next step.
But if something was hanging up previous and finally seated, I would be able to build brake pressure again by stepping on the pedal repeatedly, correct? |
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mukluk Samba Member
Joined: October 18, 2012 Posts: 7028 Location: Clyde, TX
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Posted: Tue Sep 04, 2018 6:51 pm Post subject: Re: Lost brakes while driving. |
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Possibly, but if it was a brake shoe not fully seated in the adjuster previously then you may not have enough pedal travel to get the shoe close enough to the drum to start building pressure, even by pumping the pedal. _________________ 1960 Ragtop w/Semaphores "Inga" |
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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Tue Sep 04, 2018 7:00 pm Post subject: Re: Lost brakes while driving. |
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mukluk wrote: |
Possibly, but if it was a brake shoe not fully seated in the adjuster previously then you may not have enough pedal travel to get the shoe close enough to the drum to start building pressure, even by pumping the pedal. |
I gotcha man, good advice. Thanks. |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31373 Location: Hot Arizona
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Posted: Tue Sep 04, 2018 7:22 pm Post subject: Re: Lost brakes while driving. |
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seethesvt wrote: |
We suspect the master cylinder. But it's new German from WW.
Like I said, there's no leaks that I can find. What kind of experience has anyone had with similar situations. It's a 66 12v 4 wheel drums, all new parts. |
Sometimes the master cylinder can leak into the pan or firewall or into the driver compartment through its rear seal.
But check all of the above suggestions. _________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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KTPhil Samba Member
Joined: April 06, 2006 Posts: 34009 Location: Conejo Valley, CA
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Posted: Tue Sep 04, 2018 7:29 pm Post subject: Re: Lost brakes while driving. |
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Also check your pedal linkage/rod, and also the little sheet metal tab that holds the pivot pin in place. |
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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Tue Sep 04, 2018 7:36 pm Post subject: Re: Lost brakes while driving. |
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Cusser wrote: |
seethesvt wrote: |
We suspect the master cylinder. But it's new German from WW.
Like I said, there's no leaks that I can find. What kind of experience has anyone had with similar situations. It's a 66 12v 4 wheel drums, all new parts. |
Sometimes the master cylinder can leak into the pan or firewall or into the driver compartment through its rear seal.
But check all of the above suggestions. |
I checked the pan from front to back and the seal. Dry. |
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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Tue Sep 04, 2018 7:37 pm Post subject: Re: Lost brakes while driving. |
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KTPhil wrote: |
Also check your pedal linkage/rod, and also the little sheet metal tab that holds the pivot pin in place. |
That's the first thing I checked. |
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herbie1200 Samba Member
Joined: April 27, 2006 Posts: 833 Location: Rome - Italy
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Posted: Tue Sep 04, 2018 11:30 pm Post subject: Re: Lost brakes while driving. |
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mukluk wrote: |
Possibly, but if it was a brake shoe not fully seated in the adjuster previously then you may not have enough pedal travel to get the shoe close enough to the drum to start building pressure, even by pumping the pedal. |
But the handbrake did work, so we should assume that in the rear all is OK
Start with checking the front. |
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TDCTDI Samba Advocatus Diaboli
Joined: August 31, 2013 Posts: 12854 Location: North Carolina
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Posted: Wed Sep 05, 2018 3:19 am Post subject: Re: Lost brakes while driving. |
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The metal brake line will rust due to moisture retained by the carpet. Check the length of the brake line, especially in the area between the seat & pedal assembly. If this is the case, now is a good time to upgrade to a dual circuit master cylinder. _________________ Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Wed Sep 05, 2018 5:46 am Post subject: Re: Lost brakes while driving. |
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herbie1200 wrote: |
mukluk wrote: |
Possibly, but if it was a brake shoe not fully seated in the adjuster previously then you may not have enough pedal travel to get the shoe close enough to the drum to start building pressure, even by pumping the pedal. |
But the handbrake did work, so we should assume that in the rear all is OK
Start with checking the front. |
Well, the right side worked for sure. When I pulled the handle it pulled right. So, it could be something with the left. |
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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Wed Sep 05, 2018 5:48 am Post subject: Re: Lost brakes while driving. |
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TDCTDI wrote: |
The metal brake line will rust due to moisture retained by the carpet. Check the length of the brake line, especially in the area between the seat & pedal assembly. If this is the case, now is a good time to upgrade to a dual circuit master cylinder. |
Question about that because that's what I'm planning to do.
So, a 68+ Dual circuit MC just bolts right up? What about the Reservoir? And reservoir lines? |
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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Wed Sep 05, 2018 7:00 am Post subject: Re: Lost brakes while driving. |
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I pulled the left rear wheel and found one pad shattered and the other one not connected to the shoe. There's my problem?
I've never had an old car before and this was my first time adjusting drums brakes. The ride i took was my longest ride yet, about 20miles when It failed. I reckon I had the shoe improperly adjusted, causing it to over heat and fail. Leason learned. I don't have time to fix it today, but will tomorrow. I'll update the situation incase that wasn't my problem, but just a coincidence. |
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mukluk Samba Member
Joined: October 18, 2012 Posts: 7028 Location: Clyde, TX
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Posted: Wed Sep 05, 2018 8:28 am Post subject: Re: Lost brakes while driving. |
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The shattered shoe does explain your brake problem, replacing it and readjusting your brakes should return everything back to normal. I would advise replacing all four shoes on both sides of the rear since there is a possibility the failure was due to a defective part. It's unlikely in my opinion that a dragging shoe would lead to such a failure, but if it was then you should see evidence of discolouration or burning on the metal portion of the shoe and drum from being overheated.
With a closed hydraulic single system like our brakes, you can't start building pressure in the system until all eight brake shoes have come in contact with the drums -- all pedal travel is dedicated to physically moving the shoes up to that point via the wheel cylinders. This is the reason proper adjustment of the shoes is so important since no braking action can occur without pressure being exerted upon the shoes in contact with the drums. Dual system brakes provide a safety margin in cases such as this or when a hydraulic leak/rupture occurs in that each circuit only operates two brakes/four shoes, ensuring that you should still have at least half of your normal service brakes operating.
A search will bring up quite a few posts on the subject of converting to dual circuit, but a couple quick answers are yes, a dual master will bolt straight in; the metal lines will need to be rebent some to line up with the ports but should screw right in; you'll need a dual circuit reservoir and associated correct brake hoses or a reservoir that attaches directly to the master; you can also continue to use a single brake light switch, although a second will be needed to plug the additional switch port in the master, or you could consider installing a pair of three post switches and wire them up with a warning light similar to what was used on 68+ Bugs if you wish. _________________ 1960 Ragtop w/Semaphores "Inga" |
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seethesvt Samba Member
Joined: February 03, 2018 Posts: 58 Location: Atlanta GA
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Posted: Wed Sep 05, 2018 9:13 am Post subject: Re: Lost brakes while driving. |
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mukluk wrote: |
The shattered shoe does explain your brake problem, replacing it and readjusting your brakes should return everything back to normal. I would advise replacing all four shoes on both sides of the rear since there is a possibility the failure was due to a defective part. It's unlikely in my opinion that a dragging shoe would lead to such a failure, but if it was then you should see evidence of discolouration or burning on the metal portion of the shoe and drum from being overheated.
With a closed hydraulic single system like our brakes, you can't start building pressure in the system until all eight brake shoes have come in contact with the drums -- all pedal travel is dedicated to physically moving the shoes up to that point via the wheel cylinders. This is the reason proper adjustment of the shoes is so important since no braking action can occur without pressure being exerted upon the shoes in contact with the drums. Dual system brakes provide a safety margin in cases such as this or when a hydraulic leak/rupture occurs in that each circuit only operates two brakes/four shoes, ensuring that you should still have at least half of your normal service brakes operating.
A search will bring up quite a few posts on the subject of converting to dual circuit, but a couple quick answers are yes, a dual master will bolt straight in; the metal lines will need to be rebent some to line up with the ports but should screw right in; you'll need a dual circuit reservoir and associated correct brake hoses or a reservoir that attaches directly to the master; you can also continue to use a single brake light switch, although a second will be needed to plug the additional switch port in the master, or you could consider installing a pair of three post switches and wire them up with a warning light similar to what was used on 68+ Bugs if you wish. |
There is no discoloration. I'm definitely replacing all 8 shoes. A search on this forum should tell me which are the best. I definitely don't want a repeat of this situation. I will get in contact with the manufacturer of the shoes to make them aware of my situation. Thanks for the info. |
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mukluk Samba Member
Joined: October 18, 2012 Posts: 7028 Location: Clyde, TX
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Posted: Mon Sep 17, 2018 11:16 am Post subject: Re: Lost brakes while driving. |
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Could you update with any response you got from the manufacturer of shoes and who that would be? Another recent post had a situation where their shoes came apart while driving and I'm rather curious if both situations are due to the same brand.
https://www.thesamba.com/vw/forum/viewtopic.php?p=8884380&highlight=#8884380 _________________ 1960 Ragtop w/Semaphores "Inga" |
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KTPhil Samba Member
Joined: April 06, 2006 Posts: 34009 Location: Conejo Valley, CA
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Posted: Mon Sep 17, 2018 11:23 am Post subject: Re: Lost brakes while driving. |
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Were the drums turned when the shoes were replaced? If there was a lip where the old shoes wore the drum, perhaps the shoe "caught an edge" and that precipitated the breakup.
Any new skier understands the concept...
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mukluk Samba Member
Joined: October 18, 2012 Posts: 7028 Location: Clyde, TX
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Posted: Mon Sep 17, 2018 12:09 pm Post subject: Re: Lost brakes while driving. |
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KTPhil wrote: |
Were the drums turned when the shoes were replaced? If there was a lip where the old shoes wore the drum, perhaps the shoe "caught an edge" and that precipitated the breakup. |
Can one even find anybody that offers drum turning service these days?
_________________ 1960 Ragtop w/Semaphores "Inga" |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31373 Location: Hot Arizona
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Posted: Mon Sep 17, 2018 1:30 pm Post subject: Re: Lost brakes while driving. |
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mukluk wrote: |
Can one even find anybody that offers drum turning service these days?
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Yes, but better look for a VW machine shop. Retailers like Autozone and O'Reilly turn drums, but do not have the adapter for our VW drums for their newer equipment. _________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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