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DocErickson Samba Member
Joined: June 08, 2010 Posts: 3 Location: Virginia
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Posted: Tue Jun 08, 2010 6:36 pm Post subject: Leaking brake light switch on 1970 VW Bug master cylinder |
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So, I just installed a new master cylinder (Brazilian, not German) and did all the things you are supposed to do (bench bled, adjusted brakes, remove drums to check slave cylinders...etc.) and the front brake light switch is leaking. I cranked down on it as hard as I could and it's still leaking. I tried replacing it with the old one and it still leaks. That leads me to one of two conclusions. The MC is trash or the I misadjusted the push rod and it's going down too far, but I'm pretty sure I adjusted it right. Should I replace the master cylinder again or is it the push rod adjustment that I messed up?
Thanks for your help. |
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dakdak Samba Member
Joined: March 09, 2009 Posts: 579 Location: Sydney, Australia
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Posted: Tue Jun 08, 2010 6:43 pm Post subject: Re: Leaking brake light switch on 1970 VW Bug master cylinde |
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DocErickson wrote: |
So, I just installed a new master cylinder (Brazilian, not German) and did all the things you are supposed to do (bench bled, adjusted brakes, remove drums to check slave cylinders...etc.) and the front brake light switch is leaking. I cranked down on it as hard as I could and it's still leaking. I tried replacing it with the old one and it still leaks. That leads me to one of two conclusions. The MC is trash or the I misadjusted the push rod and it's going down too far, but I'm pretty sure I adjusted it right. Should I replace the master cylinder again or is it the push rod adjustment that I messed up?
Thanks for your help. |
When you say you "cranked down" as hard as you could, it is possible you may have craked the master cylinder at the threads. Check the master cylinder around the brake light switch threads for any cracking. If you're satisfied it's not cracked, you may try using the white teflon thread tape on the switch threads and see if it still leaks. This may draw some criticism, but if it works, it works. _________________ The great enemy of the truth is very often not the lie - deliberate, contrived and dishonest, but the myth - persistent, persuasive and unrealistic.
JFK |
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DocErickson Samba Member
Joined: June 08, 2010 Posts: 3 Location: Virginia
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Posted: Tue Jun 08, 2010 6:47 pm Post subject: |
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I had it pretty snug to begin with, saw that it was leaking when my assistant was pushing on the brakes, so I gave it another quarter turn, and I'm no Hercules, so I'm pretty sure I didn't crank it too hard. I'll try the dope tape method. |
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69 Jim Samba Member
Joined: September 27, 2004 Posts: 6264 Location: Chickengeorge's Neighbor
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Posted: Tue Jun 08, 2010 7:44 pm Post subject: |
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Not a good idea to trust your life on a garbage Brazil made master. |
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DocErickson Samba Member
Joined: June 08, 2010 Posts: 3 Location: Virginia
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Posted: Wed Jun 09, 2010 5:17 pm Post subject: |
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After all was said and done, I replaced the brake light switch with genuine German switches with high temp thread sealer, and it's holding up as of right now. Now I have to wait for my assistant to help me bleed my brakes. |
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johneliot Samba Member
Joined: August 29, 2005 Posts: 2189 Location: Chico, CA
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Posted: Wed Jun 09, 2010 11:30 pm Post subject: |
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I had exactly the same problem with my 69. I decided to go cheaper with the MC (i was a Varga I believe). No amount to tightening would stop th leak. I decided to eat the $25 and buy a German one and it never leaked again. You should not have to use any type of sealer on the switches. Brake fluid eats paint in no time, I can't imagine what it would do to teflon tape. _________________ John
There is no distinctly American criminal class - except Congress.
Mark Twain
69 bug - "The Grey Ghost" |
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69 Jim Samba Member
Joined: September 27, 2004 Posts: 6264 Location: Chickengeorge's Neighbor
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Posted: Thu Jun 10, 2010 12:06 am Post subject: |
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My switches came with brown loctite on them. |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31378 Location: Hot Arizona
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Posted: Thu Jun 10, 2010 6:28 am Post subject: |
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johneliot wrote: |
You should not have to use any type of sealer on the switches. |
Agree.
johneliot wrote: |
Brake fluid eats paint in no time, I can't imagine what it would do to teflon tape. |
Teflon (polytetrafluoroethane or PTFE) won't dissolve in brake fluid, or most anything. _________________ 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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bogrady Samba Member
Joined: November 08, 2009 Posts: 7 Location: Colorado
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Posted: Mon Dec 13, 2010 10:30 am Post subject: |
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Where did you purchase your part from? I am having the same problem and need to know the best/cheapest place to get it.
Thanks! |
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JonF Samba Member
Joined: December 16, 2005 Posts: 2030 Location: Oklahoma
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Posted: Mon Dec 13, 2010 11:35 am Post subject: |
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i had a prob over the summer with brake light switches also! there was a bad batch of switches made and i had to replace the switches 3 times before i got 2 good switches.
_________________ 68 bug 1600sp 30/31
68 baja 1600sp 010 32ndix |
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marcodelat Samba Member
Joined: December 10, 2007 Posts: 107 Location: Key Largo, Florida
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Posted: Mon Dec 13, 2010 12:44 pm Post subject: |
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DocErickson wrote: |
... Now I have to wait for my assistant to help me bleed my brakes. |
While you are waiting... let gravity be "your assistant"... in other words try gravity bleeding - do a search here or on the net. |
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velvetguru Samba Member
Joined: December 11, 2010 Posts: 19 Location: Owasso, OK
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Posted: Thu Dec 16, 2010 10:12 pm Post subject: |
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Why not just rebuild your original German made master cylinder. A kit is inexpensive and easy to install, it's just a few rubber parts and a spring. You have the advantage of keeping the car original and you don't have to deal with all these new 'just as good as the original' junk parts being made today. Just my two cents.
Joe |
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rtaylor Samba Member
Joined: November 08, 2010 Posts: 364 Location: Camden, NC
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Posted: Thu Jan 06, 2011 4:18 pm Post subject: |
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if anyones still checking this post, it has been a while since it was posted, butt im having the same problem with my brake switches. ive gone through litterally 8. autozone has replaced them everything since they have a warranty. buttt im gettin tired of buying brake fluid and having to bleed my brakes. soo any idea of a better palce i can go? i just ordered some from napa.....but if they ont work i need a back up plan |
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