BRAKE LINES WON'T BLEED

"I tried installing one-way valves on the brake lines."

What the heck are THOSE?  Never heard of one-way valves on a two-way circuit (juice in = juice out).

Regardless, can you point us to a website showing the anti-rattle clips naked and then installed?

Thanks.

 Oh, and usually, of you have brake squeal, you chamfer the leading edge of the caliper pad.  If you have rattle, you can use so-called anti-rattle clips (some work, some not so much) OR you can apply anti-squeal/anti-rattle gel ("Squeal-Stop" or something like that) to the backside of the pads, let it set up 30-60 minutes and then install them.  That usually cures it.

Gordon Nichols posted:

"I tried installing one-way valves on the brake lines."

What the heck are THOSE?  Never heard of one-way valves on a two-way circuit (juice in = juice out).

Regardless, can you point us to a website showing the anti-rattle clips naked and then installed?

Thanks.

 Oh, and usually, of you have brake squeal, you chamfer the leading edge of the caliper pad.  If you have rattle, you can use so-called anti-rattle clips (some work, some not so much) OR you can apply anti-squeal/anti-rattle gel ("Squeal-Stop" or something like that) to the backside of the pads, let it set up 30-60 minutes and then install them.  That usually cures it.

Here’s a photo of the clips along with the pads used in A C Industry’s “wide five” disc brake system. The other shot is of the clip in place on an unknown caliper.

"Brakes won't bleed" ............For a start : Air in lines, loose fitting-hose , cracked line - hose, caliper / bleeder upside down  (Yes it happened to me) Master cylinder push rod out of adjustment not allowing the piston to fully close .... pedal rod to cylinder should have a " click " of clearance. Check and try these items.

Nothing that you did should have affected the pedal feel, unless you opened a bleeder for some reason or one of your rubber brake hoses was slightly loose.  

Some systems can be a real pain, depending on components used or how they're mounted....Even how the metal brake lines are routed.  Some calipers need to be elevated, as suggested by the AC notes, others don't care.  See if you can find a pressure bleeder to borrow and try that.  Using a pressure bleeder has usually been the "fix of last resort" when I've had brake issues in the past.   Fill the tank, attach it to the reservoir, give it a few pumps and start bleeding, longest run to shortest.  Doing all four wheels takes under 30 minutes.

Did you try traditional bleeding with someone inside pumping and holding the brake pedal down while you open valve?  Short piece of clear hose in  jar with some fluid is all that needed.  You can see condition of fluid too.  If fluid is few years old use a quart of new and replace what you can. Not seen VW Rabbit calipers/pads used on bug.   Do calipers have a piston both sides?  Maybe one is frozen where it doesn't move in and out?  Were old pads worn evenly?  Pads don't appear to have pins thru them to hold - the pins can bind and there is special lubricant for them. I feel more comfortable when bleed valve is low on caliper (per DrClock) comment - nothing can do there as yours are in middle.

WOLFGANG posted:

Did you try traditional bleeding with someone inside pumping and holding the brake pedal down while you open valve?  Short piece of clear hose in  jar with some fluid is all that needed.  You can see condition of fluid too.  If fluid is few years old use a quart of new and replace what you can. Not seen VW Rabbit calipers/pads used on bug.   Do calipers have a piston both sides?  Maybe one is frozen where it doesn't move in and out?  Were old pads worn evenly?  Pads don't appear to have pins thru them to hold - the pins can bind and there is special lubricant for them. I feel more comfortable when bleed valve is low on caliper (per DrClock) comment - nothing can do there as yours are in middle.

Tried all the bleeding techniques you describe. Calipers are by AC Industries which uses Rabbit pads and has a single piston. Photo of caliper is of another car just to show the anti-rattle clips in position.  Sorry for the confusion.

I know installing a new master cylinder you need to pre-bleed the cylinder, usually off the car and before install, perhaps air is in the master cylinder?

Funny this should come up now.  Bleeding brakes has been a hot topic around here for a week or so.  Cory Drake (HooptyPilot, and total FaceBook weenie) and I set off to do that on the Hoopty a week ago, since he was having to pump his pedal twice before he could get good braking.  I have experienced same in years past w/ old P cars.  It's funny how muscle memory takes over after a while and you give it that double pump without hardly knowing you are doing it. Anyway, We set out to bleed, no biggie.  Discs in front, drums in back.  Did the deed more or less, plus adjustments on the drum shoes in back, which were a bit off. No real change when all finished.  Hmmm . . .  So  we figure the master cyl is only other part to consider (10+ years old and of ?? heritage).  The plan was to get a new MC (he did last week) and he and his sweet rt seater Jeni were supposed to R&R the MC and redo all the bleeding, etc. today.  So far no news on how that went.  We are ever hopeful.  We even loosened the disc calipers to be sure the bleeder was uppermost.

Theoretical question on brake fluid:  DOT 3 or DOT 4?  Why one and not the other?  Can you replace a DOT3 using DOT4?  I read where you ought not to mix them, and also ought not to mix the same DOT from different mfr.  What does anybody know about all of that??  We flushed what was most likely DOT 3 using DOT4.  Mistake??

I was going to explain but found this ......

DOT 3, DOT 4, and DOT 5.1 brake fluids are glycol-based compounds that are compatible with one another. On the other hand, DOT 5 brake fluid is silicone-based and should never be mixed with any other type of brake fluid. DOT 3, DOT 4, and DOT 5.1 brake fluids will damage painted surfaces. DOT 3 and DOT 4 fluids have lower boiling temperatures than DOT 5 and DOT 5.1. Furthermore, DOT 3, DOT 4, and DOT 5.1 fluids are hygroscopic--they absorb moisture from the air. This causes the fluid to turn dark, indicating that it is time for the brake fluid to be replaced. DOT 5 fluid will not damage paint, has a boiling temperature in excess of 500 degrees F, and is not hygroscopic.

Alan: right-o. I also googled this question, and came up w/ the same info more or less.  The do not mix instruction was found in an '09 Subaru owner's manual about the brake fluid.  Lots of conflicting opinions (everybody has one . . .) on the net by assholes who don't really know.  the legit sources seem to say what you have put up. It seems obvious that glycol based should not be mixed with silicone based.  Flushing a DOT3 system with DOT4 looks to be OK.  FWIW, I did this on the Mazda as well, and the car stops.  Moreover,, the DOT3 fluid in there was REALLY old, and pretty dark, but was working well.  New fluid carried some bubbles out when bleeding, but when all said and done, basic function unchanged.  Car stops exactly right, pedal good.

On to next . . .

While DOT 3 and 4 are generally interchangeable these days, keep in mind that older brake systems that were designed for DOT 3 may not necessarily be compatible with DOT 4/5.1. Due to the different fluid chemistry it may cause seal or hose failure. Of course some systems may list DOT 4 Only and you don't want to go swapping things there either. Signs that the fluid isn't compatible are that new fluid will turn dark quickly (within days) or you start seeing black particulates in the fluid. Unfortunately, if that happens, it's already too late and you'll be repairing your entire braking system. I've personally used either DOT 3 or 4 in VW systems without issue, but I've also trashed a hydraulic clutch on an old honda before by using the wrong fluid. Basically, if either the fluid reservoir/cap or the owner's manual specify a type of fluid, be safe and stick with that type.

Alan Merklin posted:

I was going to explain but found this ......

DOT 3, DOT 4, and DOT 5.1 brake fluids are glycol-based compounds that are compatible with one another. On the other hand, DOT 5 brake fluid is silicone-based and should never be mixed with any other type of brake fluid. DOT 3, DOT 4, and DOT 5.1 brake fluids will damage painted surfaces. DOT 3 and DOT 4 fluids have lower boiling temperatures than DOT 5 and DOT 5.1. Furthermore, DOT 3, DOT 4, and DOT 5.1 fluids are hygroscopic--they absorb moisture from the air. This causes the fluid to turn dark, indicating that it is time for the brake fluid to be replaced. DOT 5 fluid will not damage paint, has a boiling temperature in excess of 500 degrees F, and is not hygroscopic.

... and can't be used if the system has ever had any other brake fluid in it. Switching to DOT 5 (which I'd love to do) would mean new MC, all new calipers, and probably new lines unless I could guarantee I was pumping pure DOT 5 through them to flush them out.

The non-hygroscopic nature, the high boiling point, and most of all-- the paint-safe aspect of it are all super-desirable to me. It's on the list of stuff I'd do differently if I were doing it again...

I had read that DOT 5 silicon doesn't compress as readily s DOT 3 and 4 so you'd have to press pedal further.

DOT 5 is less compressible (often creating a slightly softer pedal). It is not recommended for racing application. 
It is hard to pour  without introducing bubbles and thus results in soft pedal feel, It is a good choice for Concours cars which are rarely driven and/or never driven hard.. Careful bleeding is required to get all of the air out of the system. It is hard to you without introducing bubbles and thus results in soft pedal feel. These small bubbles will form large bubbles over time. It may be necessary to do a series of bleeds.

It is about twice as expensive as DOT 4 fluid. 

Good skinny here.  All should take note.