Bleeding brakes

Kbarnes · Post by **Kbarnes** » Thu Dec 28, 2006 11:23 pm

I just finished a voltage conversion, all new wheel bearings, brake shoes, and replaced a rear wheel cylinder. I am now having trouble bleeding the brakes. I last tried bleeding the master cylinder first and then went to the right rear wheel. I get the master cylinder bleed and have some pedal but after one or two bleeds on the rear wheel I loose all pedal. I tried removing the brake fluid tank and line and cleaned them out thinking maybe they were stopped up but did not help any. I did notice that the fluid drains real slow out of the tank. IE not a steady stream but rather by drops. I have never tried to bleed a system like this where the fluid is not placed directly into the master cylinder. Any suggestions?

Post by **jmartini** » Fri Dec 29, 2006 4:21 am

Hi Kbarnes: This is really best done as a two person job - You should start by bleeding the right rear brake as it is the furthest from the master cylinder. Loosen the bleeder bolt then snug it up again. Have a friend pump the brakes five or six times then quickly open and shut the bleeder bolt. If nothing comes out but clear fluid then tighten the bleeder bolt back up and move on to the next wheel. If it sputters, then repeat the procedure. You will probably need to keep adding brake fluid during this procedure. If that doesn't do it your master cylinder may need attention.

It's a little disturbing that the fluid doesn't run out of the tank but maybe thats normal with no pressure - I can't answer that part of the puzzle but someone else may be able to.

Good luck!

thatguy · Post by **thatguy** » Fri Dec 29, 2006 9:11 am

I was having a similar difficulty with my "out 'o the box" new master cylinder. I had to return it to the store and get a second one. Something in the back half of the cylinder was off; I seem to remember a bum valve somethingorother wouldn't let the fluid get through to the lines. Dropped in a new one, and away I went...until Thor's hammer struck the engine on the drivers side; now the motor is in the garage in bits and pieces...

*sob*

scruffy · Post by **scruffy** » Sat Dec 30, 2006 8:53 am

I replaced my master cylinder and had a simular problem,put in new kit and had brakes for about 3 miles and then all the wheels locked up.Problem; Rubber brake lines were old and colapsed, acted like a check valve.Just because master cylinder is new doesn't mean it's good. You may have to tear it down and take look see, maybe piston not coming all the way back.did you bench bleed the cylinder first? Bleeding procedure you describe is right on,I use a mityvac vacumn bleeder to bleed all mine,saved my marriage!

Bugs are a bear to bleed you may have to do it three or four times to get all the air out. so fill the fridge with pop invite a few freinds over and enjoy the evening!

Happy New Year

volksbugusa · Post by **volksbugusa** » Sun Dec 31, 2006 4:07 am

hello Kbarnes:
I hope you are using a jar filled with brake fluid and a rubber hose to the bleeder.you will see the air bubbles as you pump and hold the brake pedal.if you are not following this type of procedure all you are doing is putting air back into the lines.Make sure the shoes are adjusted first . Start with the pass rear .You are using dot 3 ? It will take a good 1 1/2 hours to bleed.If all fails ,it could be a bad master cylinder.It has happened.

You can also buy speed bleeders,from mid america
not sure which size you might need
6mm x 1.0 thread pitch
7mm x 1.0 thread pitch

Matthew D'Azzo
Volksbugusa

Kbarnes · Post by **Kbarnes** » Fri Feb 23, 2007 4:41 pm

I am sorry I have not got back before now but I solved my brake bleeding problem. Wanted to post what I found out for others. I discovered that the fluid would not run out of the tank until I took the cap off. For some reason the tank was vapor locking. The hole in the bottom of the tank is very small so I took a drill bit and made it slightly larger. When I bleed the brakes I left the cap off the tank and had no more problems.

rokemester · Post by **rokemester** » Thu Jul 02, 2009 8:06 pm

Scruffy would you mind going through your MityVac bleeding routine? I just picked one up because there is no way my better half is going to hang out with me in the garage to push a brake pedal up and down! In other forums they give the vacuum bleeding method a hard time, saying it won't work for air cooled VWs with drum brakes. THANKS!!

volksbugusa · Post by **volksbugusa** » Fri Jul 03, 2009 3:51 am

rokemester
happy 4th !!! yeah the vw brakes are so simple yet such a pita...
most of the time when bleeding is an issue it is because the brake master cylinder is not german....you can also use the drip method which works very well....i have used the vac tool its alright still like the good old fashion way...if you have brakes but not the best pedal...the best thing to do is go to a brake repair shop and they will get the air out 100% with a power vac system...not expensive.....is your master cylinder new? was it bench bleed first?
matt

scruffy · Post by **scruffy** » Fri Jul 03, 2009 5:20 am

with the mityvac,attach your hose to the cylinder,crack the bleeder open,pump your vac tell your fluid runs clear.tighten bleeder and move on to next. works on your master cylinder also. keep your bottle full and cap off as mentioned.i've used it on my MG hydraulic clutch also and it worked great,and the nice thing no big mess to clean up and ARE YOU DONE YET,MY LEG IS GETTING TIRED AND HOW COME YOU DON'T GET ONE OF YOUR BEER DRINKING BUDDIES TO HELP. Hope this help Scruffy

rokemester · Post by **rokemester** » Fri Jul 03, 2009 9:28 pm

You guys are very helpful! When I first tried the MityVac I put vaccum on the system with the bleeder valve closed...duh! I was purchasing some additional brake fluid this afternoon at a Federated Auto Parts store (the benefits of going to an auto parts store vs. a WalMart) and I happened to ask the counter guy about vacuum bleeding brakes. He told me as you have Scruffy that that you leave the bleeder valve open as you pump. I got small bubbles but I think those are from the the vacuum bleeder not from the system. How do I bleed the master cylinder while it is installed on the car?

Before I started bleeding I removed my front brake pads and cleaned up some rust residue on pads and drums (car was sitting for 6+ years). I also lubed the adjusters, one was sticking. When I put everything together, with the star adjusters turned all the way in, I had a tough time getting the drums over the pads. I finally succeeded but the pads are rubbing against the drum. Despite that, my lovely bride gave me a bone and sat in the bug and applied some brake pressure. Hey, all four brakes worked!!

Now I need to get Murray to run.

rokemester · Post by **rokemester** » Fri Jul 03, 2009 9:30 pm

Matt, I like the idea of having a shop evacuate every bit of air in my system. I think I got most with the MityVac, but you never know. What is the drip method?

Blue Baron · Post by **Blue Baron** » Thu Jul 09, 2009 4:10 pm

Kbarnes wrote:I am sorry I have not got back before now but I solved my brake bleeding problem. Wanted to post what I found out for others. I discovered that the fluid would not run out of the tank until I took the cap off. For some reason the tank was vapor locking.

For some reason? You need to find the problem and fix it. All VW reservoir caps have a small vent hole, and must be vented to the atmosphere or the brake fluid will stay in the reservoir. It sounds as if yours is plugged.

Take the cap off and pull out the rubber inner seal and examine it. Was it plugging off the hole in the center of the cap? The seal should have a small hole in it. If it's plugged, you need to open it up. If the center of the seal was stuck against hole in the top top, the easiest fix I've found is to simply reinstall the seal upside down, leaving an air pocket in the top.

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