Rusty Hope Discs, leak problems.

[Don Coatney]

It has been my experience that soft pedal on the first pump and firm on the second pump indicates air in the system. Suggest you bleed the system once again. Once all the air is out of the system you should have firm pedal on the first pump no matter how long the system has been sitting idle. Residual valves should have no effect on pedal firmness.

[Bmartin]

I bled the master and the system again and got no air.  Still no change in pedal. 

[TodFitch]

I bled the master and the system again and got no air.  Still no change in pedal. 

 

Last time I had my brake system open it took several tries at bleeding before I finally got all the air out. My guess is that there were some bubbles trapped at a high point and it needed some flow of fluid to get them to move on to the wheel cylinder to be removed. I do remember that they came out at the front right and that I had run a considerable amount of fluid through the lines before they finally showed up. Without the pressure bleeder I built, inspired by designs I'd seen on this site, I am not sure how long it would have taken me.

[P15-D24]

Start looking for a leak. Don's point in post #26 is spot on. I would suggest cleaning off every fitting with alcohol, pump up the system then inspect each one for a weep. Also check your rears for leaks. 

[Bmartin]

So to update this, I still have leaks.  It seems to take a couple times for me to find the leaks.  I keep pressurizing the system and letting it sit.  My pressure bleeder bleeds down after a couple minutes so I can't just pressurize and leave it, so its not the best scenario. 

 

Anyway, Looks like I currently have one good and one leaking.  The good one actually has an 8mm bleeder screw in it.  While the leaky one has the standard 10mm.  If I can't get it to stop, I may try to pick up a right one with the 8mm bleeder.  I also had to block off the rear brakes with a cap.  Looks like the original wheel cylinders have had enough bleeding and they are starting to seep around the threads too.  I've bled them a hundred times over the last year so that is not surprising.  I have some new ones waiting to go in. 

 

From the other post:

 

Please update your brake issue thread when you find out about the Wilwood calipers. Their website shows GM single piston calipers, which I think are what I used for my conversion......need to look further into it.

 

Sorry for the highjack.

 

 

 

I believe Charlie's kit uses GM Metric calipers (at least the two I've installed did), and those calipers are readily available brand new from a variety of aftermarket suppliers such as AFCO and CPP. You can even get them with non-standard bore sizes to tune your braking. Here's a quick vid: https://www.youtube.com/watch?v=iSYnQnYn_Dk

 

I'm planning to get some with oversized pistons for my '38 Chrysler as I have Crown Vic discs on the rear that have relatively large pistons.

 

 

I checked into AFCO, their site only shows up to a 2.75" bore.  I believe the ones we are using are 2 15/16" bore.  CPP's site was a little overwhelming.  I did not locate anything directly for a Caprice but there were a lot of kits for camaros and such.  But did not see any calipers separate.

 

I did locate what I think might work from Wilwood:

 

http://www.wilwood.com/BrakeKits/BrakeKitsProdFront.aspx?itemno=140-11291-R&year=1980&make=Chevrolet&model=Caprice&option=With+OE+11%22+Rotor+Spindles

 

But you need new brake lines since the banjo is a different size.  I'll need to give them a call if I go that route.

Edited September 18, 2014 by Bmartin

[plyroadking]

I am interested to hear about the wilwoods if you decide to go that route

[wayfarer]

Wilwood used to be top-notch stuff...haven't bought anything for several years so can't say about today.  Rock Auto is another good source for brake parts, yes, rebuilt stuff same as the local store but often less money.

 

One comment regarding trapped air. I have seen where some calipers can be mounted such that the bleeder screw is not at the top-most position and air gets trapped.  On a customers car many years ago we had to unbolt the caliper and pivot it to get the air out...

[Bmartin]

Question for those with disc front without residual a 2lb residual valve.  How long does it take for the fluid to flow back to the master so that you need to pump the brakes once or twice to get good pedal?  Trying to decide if my front residual is working properly. 

 

On the calipers, I've swapped both fronts to the ones with the smaller bleeder valve and they are not leaking yet.  Just got done swapping the rear wheel cylinders out.  Just observing for leaks right now. 

 

A weird thing is occurring.  If I open up the bleeders just a little, I get air bubbles.  If I open up a lot, then I just get more fluid flow, but not bubbles.  If I open and close the bleeders, I get air each time, leave open, just fluid.  Of course this is being determined visually, looking at the fluid in the plastic tube.  Perhaps the tube is leaking are around the bleeder.  Does the orientation of the bleeder screw hole in the caliper/cylinder have an effect on how much air is bled?  Strange.

[Niel Hoback]

You may be getting air in around the threads of the bleeder screw when its loose without pedal pressure. When its open and there is pressure, the fluid is pushing the air out from around the threads instead of allowing it back into the hose.

[Bmartin]

Yah, this is with the pressure bleeder on there.  I'm starting to think that once the fluid in the pressure bleeder gets below a certain point, its pushing the air through the system.  I would have thought the resevoir would need to be empty for this to happen, but its more like as soon as the feed tube can suck any air at all, its pushing it through.  Cause it just sits there and bubbles for minutes.  I'm going to keep a higher level in the bleeder and see if that solves it. 

 

 

What do you guys use to seal the threads on the pipe thread adapters on the rear cylinders?  I was told that brake fluid breaks down the Teflon tape and using loctite was suggested. 

Edited September 19, 2014 by Bmartin

[Jeff Balazs]

Question for those with disc front without residual a 2lb residual valve.  How long does it take for the fluid to flow back to the master so that you need to pump the brakes once or twice to get good pedal?  Trying to decide if my front residual is working properly. 

 

On the calipers, I've swapped both fronts to the ones with the smaller bleeder valve and they are not leaking yet.  Just got done swapping the rear wheel cylinders out.  Just observing for leaks right now. 

 

A weird thing is occurring.  If I open up the bleeders just a little, I get air bubbles.  If I open up a lot, then I just get more fluid flow, but not bubbles.  If I open and close the bleeders, I get air each time, leave open, just fluid.  Of course this is being determined visually, looking at the fluid in the plastic tube.  Perhaps the tube is leaking are around the bleeder.  Does the orientation of the bleeder screw hole in the caliper/cylinder have an effect on how much air is bled?  Strange.

I had residuals on my front discs when I revamped the brakes on my truck. They caused way too much drag. After discussing the situation with a couple of custom car builders I know they both suggested I remove the residuals. They told me they had quit using them altogether quite a while back as they caused lots of problems. Removing these took care of the problem I was having....and the pedal stays hard no matter how long the truck sets. This may or may not prove useful to you but I think it is worth a try.

 

I know a lot of folks use pressure bleeders. I personally don't think they are at all necessary. As long as the system is leak free,  the M/C is functioning properly and all the components are installed correctly it should be a pretty straight forward job to bleed the system. It took me and a helper less than 15 minutes to bleed my 4 wheel disc system the old fashioned way. If I had experienced the kind of problems you have had I would have to think that there is a serious flaw in one of components or the configuration of the system I built. The pedal should always feel the same no matter what amount of time the system has set. If it doesn't then there is a problem with what you have put together.

 

I hope this helps. Jeff

[deathbound]

I had residuals on my front discs when I revamped the brakes on my truck. They caused way too much drag. After discussing the situation with a couple of custom car builders I know they both suggested I remove the residuals. They told me they had quit using them altogether quite a while back as they caused lots of problems. Removing these took care of the problem I was having....and the pedal stays hard no matter how long the truck sets. This may or may not prove useful to you but I think it is worth a try.

 

I know a lot of folks use pressure bleeders. I personally don't think they are at all necessary. As long as the system is leak free,  the M/C is functioning properly and all the components are installed correctly it should be a pretty straight forward job to bleed the system. It took me and a helper less than 15 minutes to bleed my 4 wheel disc system the old fashioned way. If I had experienced the kind of problems you have had I would have to think that there is a serious flaw in one of components or the configuration of the system I built. The pedal should always feel the same no matter what amount of time the system has set. If it doesn't then there is a problem with what you have put together.

 

I hope this helps. Jeff

 

Is your M/C higher or lower than the calipers? I thought if the M/C is lower than the caliper, brake fluid would slowly drain back to the M/C.

[Niel Hoback]

   I don't believe that brake fluid can drain back to the MC from the wheel cylinders.  Air would have to enter the wheel cylinders to replace the fluid.

[Bmartin]

I'm taking an educated guess but I would think that the fluid flow back to the master would pull the piston back in, further from the disc.  Pumping it up, pushes the piston back out, but it takes two pumps to recontact the disc. Maybe?

[46 Pickup]

Neil is right you need a copper washer on each side of the fitting or they will never seal all the way. I work with this style of fittings all the time and they always require two washers.

[Niel Hoback]

I don't believe fluid, by its own weight could pull a piston with a good seal in a cylinder. Too much friction. 

[Jeff Balazs]

Is your M/C higher or lower than the calipers? I thought if the M/C is lower than the caliper, brake fluid would slowly drain back to the M/C.

If you have a closed system..... as it should be.......then the fluid should just be moving back and forth when the M/C is actuated. To me the only way fluid could be draining back if the system is leak free is if the M/C was allowing it to bypass. On the trucks the M/C is slightly higher than the calipers which may be why it is so easy to bleed. I used a Grand Cherokee M/C so perhaps the internals in it work differently than other possible choices? It works perfectly once the pedal adjustment is correctly set. The only real issue I had with this installation once I removed the residual valves was this pedal adjustment. It is particularly sensitive to the correct adjustment....with very little room for error. Other than that it works just as you would expect and without any external residual valves.

 

Jeff

[Niel Hoback]

  Think of the brake line as the straw in your Coke.  You push the straw down filling the straw with liquid.  Put you finger over the top of the straw and raise it out of the coke.  It stays full because nothing can get in the top to replace the Coke that is trying to drop from its own weight. The instant you break the seal at the top, the Coke drains out.  Fluid in a sealed line cannot move without force applied to it.

   If your wheel cylinders can leak air into the line, They will also leak fluid out of the seals. I would think you would notice fluid leaking out long before you notice air leaking in. 

[54Plymouth]

When I had my shop I ran into this quite a bit. I was in rural Southeast Alaska and Napa was the only game in town. I ran into a two part problem with calipers. First was the Chinese crap replacement banjo bolts are just a hair undersized! Example I found that what was a metric 10mm bolt head on a factory ball joint was always a 9mm bolt head on the Chinese stuff. So putting that together with the leaking caliper and a micrometer I found the threads just slightly undersized. The next problem was exactly the same thing with the crush washers. I bought a Napa master kit for banjo bolts and copper crush washers those at the time were USA made (may have changed been a little over a year now since I bought my last kit) I would switch out my leakers with ones from the kit when I came across them it was more frequent towards the end. I did lots and lots of brakes so trust me I ran into a lot of this! As a side note when I had a chance to salvage banjo bolts from factory set ups I saved them all! A trip to the local pick n pull is a good source for these bolts to have in your stock pile. I wish I had that convince up in Alaska. Remeber these days if you are a mechanic your standard tools see no to very little action it is all metric and so goes the way of the off shore crap that is shoved down our throat as replacement parts!

[Bmartin]

Thanks for the info.  Did you ever come across leaking bleeder screws?  If so, what was the best way to deal with them.  Right now, I think I have all the leaks fixes, except for possbily a right rear bleeder screw.  It seems to seep just a tad.  I've heard the best way to seal up new brake lines is to tighten, then loosen, then tighten, and repeat that about 3 times.  This supposedly seats the flares.  Have you come across any other tricks for this?

[Plymouthy Adams]

the bleeder is a undersized bottom cut center drilled bolt with a cross drill for the fluid to escape when cracked off seat....the taper fits into a matched hole in the cylinder and the thread section is actually just a clamping force for the taper to seal the hole...the thread are not designed to prevent leakage at all..just to exert the clamping force..if the cylinder surface is not smooth and even, they do not seal well..I am also not aware if there is a seat reamer for the bleeders as I do not recall ever seeing one..close inspection should show if you have pitting around the hole in the cylinder..or for that matter a pitted bleeder taper

[Jerry Roberts]

Bump .  I used information in this old thread to solve my problem . I too put on a disk brake kit from Charlie and had one leaking hose to caliper fitting . I annealed three copper washers and used two of them between the hose banjo fitting and the rebuilt caliper , and one under the banjo bolt head . ( so one extra washer ) . I also tightened the banjo bolt much tighter than I thought would be necessary . I also used just a little , thick , anti-seize compound on the surface of the used caliper where the copper washer must seal . And yes I know that no sealer should be used here but desperate situations require desperate measures . 

[Plymouthy Adams]

while the information is useful to an end user,  the reference to the brake kit by Charlie is misleading.....the parts that gave you the problem were supplied by sources other than and not within the quality control of his brake concept...I do agree, the thin and yet harder copper washers supplied today is giving many folks a fit...anyone doing a random brake job could get stuck with such a part..

[Jerry Roberts]

Yes , you are right of course . This problem with sealing has nothing that reflects on Charlie or his supplied parts . Only on the parts supplied by others . NAPA in this case . 

[JD luxury liner]

I believe a got my calipers from Autozone.They are still remanufactured . However I went to my local brake shop & had custom made hoses ,only because I could not find hoses not made in china. they were a lot more money . I got lucky on the banjo fitting although it felt like I really torqued them down. Also a Rust hope conversion. Thanks Charlie!!